Remove TravisCI badge (#503)

* Add documentation for using mux to serve a SPA

* r -> router to prevent shadowing

* Expand SPA acronym

* BrowserRouter link

* Add more comments to explain how the spaHandler.ServeHTTP method works

.circleci/config.yml

@@ -0,0 +1,87 @@
+version: 2.0
+
+jobs:
+  # Base test configuration for Go library tests Each distinct version should
+  # inherit this base, and override (at least) the container image used.
+  "test": &test
+    docker:
+      - image: circleci/golang:latest
+    working_directory: /go/src/github.com/gorilla/mux
+    steps: &steps
+      # Our build steps: we checkout the repo, fetch our deps, lint, and finally
+      # run "go test" on the package.
+      - checkout
+      # Logs the version in our build logs, for posterity
+      - run: go version
+      - run:
+          name: "Fetch dependencies"
+          command: >
+            go get -t -v ./...
+      # Only run gofmt, vet & lint against the latest Go version
+      - run:
+          name: "Run golint"
+          command: >
+            if [ "${LATEST}" = true ] && [ -z "${SKIP_GOLINT}" ]; then
+              go get -u golang.org/x/lint/golint
+              golint ./...
+            fi
+      - run:
+          name: "Run gofmt"
+          command: >
+            if [[ "${LATEST}" = true ]]; then
+              diff -u <(echo -n) <(gofmt -d -e .)
+            fi
+      - run:
+          name: "Run go vet"
+          command:  >
+            if [[ "${LATEST}" = true ]]; then
+              go vet -v ./...
+            fi
+      - run: go test -v -race ./...
+
+  "latest":
+    <<: *test
+    environment:
+      LATEST: true
+
+  "1.12":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.12
+
+  "1.11":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.11
+
+  "1.10":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.10
+
+  "1.9":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.9
+
+  "1.8":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.8
+
+  "1.7":
+    <<: *test
+    docker:
+      - image: circleci/golang:1.7
+
+workflows:
+  version: 2
+  build:
+    jobs:
+      - "latest"
+      - "1.12"
+      - "1.11"
+      - "1.10"
+      - "1.9"
+      - "1.8"
+      - "1.7"

.github/release-drafter.yml

@@ -0,0 +1,8 @@
+# Config for https://github.com/apps/release-drafter
+template: |
+  
+  <summary of changes here>
+  
+  ## CHANGELOG
+
+  $CHANGES

.github/stale.yml

@@ -0,0 +1,12 @@
+daysUntilStale: 75
+daysUntilClose: 14
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - proposal
+  - needs review
+  - build system
+staleLabel: stale
+markComment: >
+  This issue has been automatically marked as stale because it hasn't seen
+  a recent update. It'll be automatically closed in a few days.
+closeComment: false

.travis.yml

@@ -1,22 +0,0 @@
-language: go
-sudo: false
-
-matrix:
-  include:
-    - go: 1.5
-    - go: 1.6
-    - go: 1.7
-    - go: 1.8
-    - go: 1.9
-    - go: tip
-  allow_failures:
-    - go: tip
-
-install:
-  - # Skip
-
-script:
-  - go get -t -v ./...
-  - diff -u <(echo -n) <(gofmt -d .)
-  - go tool vet .
-  - go test -v -race ./...

AUTHORS

@@ -0,0 +1,8 @@
+# This is the official list of gorilla/mux authors for copyright purposes.
+#
+# Please keep the list sorted.
+
+Google LLC (https://opensource.google.com/)
+Kamil Kisielk <kamil@kamilkisiel.net>
+Matt Silverlock <matt@eatsleeprepeat.net>
+Rodrigo Moraes (https://github.com/moraes)

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2012 Rodrigo Moraes. All rights reserved.
+Copyright (c) 2012-2018 The Gorilla Authors. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are

README.md

@@ -1,12 +1,12 @@
-gorilla/mux
-===
+# gorilla/mux
+
 [![GoDoc](https://godoc.org/github.com/gorilla/mux?status.svg)](https://godoc.org/github.com/gorilla/mux)
-[![Build Status](https://travis-ci.org/gorilla/mux.svg?branch=master)](https://travis-ci.org/gorilla/mux)
+[![CircleCI](https://circleci.com/gh/gorilla/mux.svg?style=svg)](https://circleci.com/gh/gorilla/mux)
 [![Sourcegraph](https://sourcegraph.com/github.com/gorilla/mux/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/mux?badge)
 
 ![Gorilla Logo](http://www.gorillatoolkit.org/static/images/gorilla-icon-64.png)
 
-http://www.gorillatoolkit.org/pkg/mux
+https://www.gorillatoolkit.org/pkg/mux
 
 Package `gorilla/mux` implements a request router and dispatcher for matching incoming requests to
 their respective handler.
@@ -25,8 +25,13 @@ The name mux stands for "HTTP request multiplexer". Like the standard `http.Serv
 * [Examples](#examples)
 * [Matching Routes](#matching-routes)
 * [Static Files](#static-files)
+* [Serving Single Page Applications](#serving-single-page-applications) (e.g. React, Vue, Ember.js, etc.)
 * [Registered URLs](#registered-urls)
 * [Walking Routes](#walking-routes)
+* [Graceful Shutdown](#graceful-shutdown)
+* [Middleware](#middleware)
+* [Handling CORS Requests](#handling-cors-requests)
+* [Testing Handlers](#testing-handlers)
 * [Full Example](#full-example)
 
 ---
@@ -45,11 +50,11 @@ Let's start registering a couple of URL paths and handlers:
 
 ```go
 func main() {
-	r := mux.NewRouter()
-	r.HandleFunc("/", HomeHandler)
-	r.HandleFunc("/products", ProductsHandler)
-	r.HandleFunc("/articles", ArticlesHandler)
-	http.Handle("/", r)
+    r := mux.NewRouter()
+    r.HandleFunc("/", HomeHandler)
+    r.HandleFunc("/products", ProductsHandler)
+    r.HandleFunc("/articles", ArticlesHandler)
+    http.Handle("/", r)
 }
 ```
 
@@ -68,9 +73,9 @@ The names are used to create a map of route variables which can be retrieved cal
 
 ```go
 func ArticlesCategoryHandler(w http.ResponseWriter, r *http.Request) {
-	vars := mux.Vars(r)
-	w.WriteHeader(http.StatusOK)
-	fmt.Fprintf(w, "Category: %v\n", vars["category"])
+    vars := mux.Vars(r)
+    w.WriteHeader(http.StatusOK)
+    fmt.Fprintf(w, "Category: %v\n", vars["category"])
 }
 ```
 
@@ -85,7 +90,7 @@ r := mux.NewRouter()
 // Only matches if domain is "www.example.com".
 r.Host("www.example.com")
 // Matches a dynamic subdomain.
-r.Host("{subdomain:[a-z]+}.domain.com")
+r.Host("{subdomain:[a-z]+}.example.com")
 ```
 
 There are several other matchers that can be added. To match path prefixes:
@@ -122,7 +127,7 @@ r.Queries("key", "value")
 
 ```go
 r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool {
-	return r.ProtoMajor == 0
+    return r.ProtoMajor == 0
 })
 ```
 
@@ -176,85 +181,115 @@ s.HandleFunc("/{key}/", ProductHandler)
 // "/products/{key}/details"
 s.HandleFunc("/{key}/details", ProductDetailsHandler)
 ```
-### Listing Routes
 
-Routes on a mux can be listed using the Router.Walk method—useful for generating documentation:
-
-```go
-package main
-
-import (
-    "fmt"
-    "net/http"
-    "strings"
-
-    "github.com/gorilla/mux"
-)
-
-func handler(w http.ResponseWriter, r *http.Request) {
-    return
-}
-
-func main() {
-    r := mux.NewRouter()
-    r.HandleFunc("/", handler)
-    r.HandleFunc("/products", handler).Methods("POST")
-    r.HandleFunc("/articles", handler).Methods("GET")
-    r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT")
-    r.HandleFunc("/authors", handler).Queries("surname", "{surname}")
-    r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
-        t, err := route.GetPathTemplate()
-        if err != nil {
-            return err
-        }
-        qt, err := route.GetQueriesTemplates()
-        if err != nil {
-            return err
-        }
-        // p will contain regular expression is compatible with regular expression in Perl, Python, and other languages.
-        // for instance the regular expression for path '/articles/{id}' will be '^/articles/(?P<v0>[^/]+)$'
-        p, err := route.GetPathRegexp()
-        if err != nil {
-            return err
-        }
-        // qr will contain a list of regular expressions with the same semantics as GetPathRegexp,
-        // just applied to the Queries pairs instead, e.g., 'Queries("surname", "{surname}") will return
-        // {"^surname=(?P<v0>.*)$}. Where each combined query pair will have an entry in the list.
-        qr, err := route.GetQueriesRegexp()
-        if err != nil {
-            return err
-        }
-        m, err := route.GetMethods()
-        if err != nil {
-            return err
-        }
-        fmt.Println(strings.Join(m, ","), strings.Join(qt, ","), strings.Join(qr, ","), t, p)
-        return nil
-    })
-    http.Handle("/", r)
-}
-```
 
 ### Static Files
 
 Note that the path provided to `PathPrefix()` represents a "wildcard": calling
 `PathPrefix("/static/").Handler(...)` means that the handler will be passed any
-request that matches "/static/*". This makes it easy to serve static files with mux:
+request that matches "/static/\*". This makes it easy to serve static files with mux:
 
 ```go
 func main() {
-	var dir string
+    var dir string
 
-	flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir")
-	flag.Parse()
-	r := mux.NewRouter()
+    flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir")
+    flag.Parse()
+    r := mux.NewRouter()
 
-	// This will serve files under http://localhost:8000/static/<filename>
-	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir))))
+    // This will serve files under http://localhost:8000/static/<filename>
+    r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir))))
+
+    srv := &http.Server{
+        Handler:      r,
+        Addr:         "127.0.0.1:8000",
+        // Good practice: enforce timeouts for servers you create!
+        WriteTimeout: 15 * time.Second,
+        ReadTimeout:  15 * time.Second,
+    }
+
+    log.Fatal(srv.ListenAndServe())
+}
+```
+
+### Serving Single Page Applications
+
+Most of the time it makes sense to serve your SPA on a separate web server from your API,
+but sometimes it's desirable to serve them both from one place. It's possible to write a simple
+handler for serving your SPA (for use with React Router's [BrowserRouter](https://reacttraining.com/react-router/web/api/BrowserRouter) for example), and leverage
+mux's powerful routing for your API endpoints.
+
+```go
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/gorilla/mux"
+)
+
+// spaHandler implements the http.Handler interface, so we can use it
+// to respond to HTTP requests. The path to the static directory and
+// path to the index file within that static directory are used to
+// serve the SPA in the given static directory.
+type spaHandler struct {
+	staticPath string
+	indexPath  string
+}
+
+// ServeHTTP inspects the URL path to locate a file within the static dir
+// on the SPA handler. If a file is found, it will be served. If not, the
+// file located at the index path on the SPA handler will be served. This
+// is suitable behavior for serving an SPA (single page application).
+func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+    // get the absolute path to prevent directory traversal
+	path, err := filepath.Abs(r.URL.Path)
+	if err != nil {
+        // if we failed to get the absolute path respond with a 400 bad request
+        // and stop
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+    // prepend the path with the path to the static directory
+	path = filepath.Join(h.staticPath, path)
+
+    // check whether a file exists at the given path
+	_, err = os.Stat(path)
+	if os.IsNotExist(err) {
+		// file does not exist, serve index.html
+		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
+		return
+	} else if err != nil {
+        // if we got an error (that wasn't that the file doesn't exist) stating the
+        // file, return a 500 internal server error and stop
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+    // otherwise, use http.FileServer to serve the static dir
+	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
+}
+
+func main() {
+	router := mux.NewRouter()
+
+	router.HandleFunc("/api/health", func(w http.ResponseWriter, r *http.Request) {
+		// an example API handler
+		json.NewEncoder(w).Encode(map[string]bool{"ok": true})
+	})
+
+	spa := spaHandler{staticPath: "build", indexPath: "index.html"}
+	router.PathPrefix("/").Handler(spa)
 
 	srv := &http.Server{
-		Handler:      r,
-		Addr:         "127.0.0.1:8000",
+		Handler: router,
+		Addr:    "127.0.0.1:8000",
 		// Good practice: enforce timeouts for servers you create!
 		WriteTimeout: 15 * time.Second,
 		ReadTimeout:  15 * time.Second,
@@ -292,13 +327,13 @@ This also works for host and query value variables:
 
 ```go
 r := mux.NewRouter()
-r.Host("{subdomain}.domain.com").
+r.Host("{subdomain}.example.com").
   Path("/articles/{category}/{id:[0-9]+}").
   Queries("filter", "{filter}").
   HandlerFunc(ArticleHandler).
   Name("article")
 
-// url.String() will be "http://news.domain.com/articles/technology/42?filter=gorilla"
+// url.String() will be "http://news.example.com/articles/technology/42?filter=gorilla"
 url, err := r.Get("article").URL("subdomain", "news",
                                  "category", "technology",
                                  "id", "42",
@@ -318,7 +353,7 @@ r.HeadersRegexp("Content-Type", "application/(text|json)")
 There's also a way to build only the URL host or path for a route: use the methods `URLHost()` or `URLPath()` instead. For the previous route, we would do:
 
 ```go
-// "http://news.domain.com/"
+// "http://news.example.com/"
 host, err := r.Get("article").URLHost("subdomain", "news")
 
 // "/articles/technology/42"
@@ -329,12 +364,12 @@ And if you use subrouters, host and path defined separately can be built as well
 
 ```go
 r := mux.NewRouter()
-s := r.Host("{subdomain}.domain.com").Subrouter()
+s := r.Host("{subdomain}.example.com").Subrouter()
 s.Path("/articles/{category}/{id:[0-9]+}").
   HandlerFunc(ArticleHandler).
   Name("article")
 
-// "http://news.domain.com/articles/technology/42"
+// "http://news.example.com/articles/technology/42"
 url, err := r.Get("article").URL("subdomain", "news",
                                  "category", "technology",
                                  "id", "42")
@@ -345,42 +380,397 @@ url, err := r.Get("article").URL("subdomain", "news",
 The `Walk` function on `mux.Router` can be used to visit all of the routes that are registered on a router. For example,
 the following prints all of the registered routes:
 
+```go
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/gorilla/mux"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	return
+}
+
+func main() {
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+	r.HandleFunc("/products", handler).Methods("POST")
+	r.HandleFunc("/articles", handler).Methods("GET")
+	r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT")
+	r.HandleFunc("/authors", handler).Queries("surname", "{surname}")
+	err := r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
+		pathTemplate, err := route.GetPathTemplate()
+		if err == nil {
+			fmt.Println("ROUTE:", pathTemplate)
+		}
+		pathRegexp, err := route.GetPathRegexp()
+		if err == nil {
+			fmt.Println("Path regexp:", pathRegexp)
+		}
+		queriesTemplates, err := route.GetQueriesTemplates()
+		if err == nil {
+			fmt.Println("Queries templates:", strings.Join(queriesTemplates, ","))
+		}
+		queriesRegexps, err := route.GetQueriesRegexp()
+		if err == nil {
+			fmt.Println("Queries regexps:", strings.Join(queriesRegexps, ","))
+		}
+		methods, err := route.GetMethods()
+		if err == nil {
+			fmt.Println("Methods:", strings.Join(methods, ","))
+		}
+		fmt.Println()
+		return nil
+	})
+
+	if err != nil {
+		fmt.Println(err)
+	}
+
+	http.Handle("/", r)
+}
+```
+
+### Graceful Shutdown
+
+Go 1.8 introduced the ability to [gracefully shutdown](https://golang.org/doc/go1.8#http_shutdown) a `*http.Server`. Here's how to do that alongside `mux`:
+
+```go
+package main
+
+import (
+    "context"
+    "flag"
+    "log"
+    "net/http"
+    "os"
+    "os/signal"
+    "time"
+
+    "github.com/gorilla/mux"
+)
+
+func main() {
+    var wait time.Duration
+    flag.DurationVar(&wait, "graceful-timeout", time.Second * 15, "the duration for which the server gracefully wait for existing connections to finish - e.g. 15s or 1m")
+    flag.Parse()
+
+    r := mux.NewRouter()
+    // Add your routes as needed
+
+    srv := &http.Server{
+        Addr:         "0.0.0.0:8080",
+        // Good practice to set timeouts to avoid Slowloris attacks.
+        WriteTimeout: time.Second * 15,
+        ReadTimeout:  time.Second * 15,
+        IdleTimeout:  time.Second * 60,
+        Handler: r, // Pass our instance of gorilla/mux in.
+    }
+
+    // Run our server in a goroutine so that it doesn't block.
+    go func() {
+        if err := srv.ListenAndServe(); err != nil {
+            log.Println(err)
+        }
+    }()
+
+    c := make(chan os.Signal, 1)
+    // We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C)
+    // SIGKILL, SIGQUIT or SIGTERM (Ctrl+/) will not be caught.
+    signal.Notify(c, os.Interrupt)
+
+    // Block until we receive our signal.
+    <-c
+
+    // Create a deadline to wait for.
+    ctx, cancel := context.WithTimeout(context.Background(), wait)
+    defer cancel()
+    // Doesn't block if no connections, but will otherwise wait
+    // until the timeout deadline.
+    srv.Shutdown(ctx)
+    // Optionally, you could run srv.Shutdown in a goroutine and block on
+    // <-ctx.Done() if your application should wait for other services
+    // to finalize based on context cancellation.
+    log.Println("shutting down")
+    os.Exit(0)
+}
+```
+
+### Middleware
+
+Mux supports the addition of middlewares to a [Router](https://godoc.org/github.com/gorilla/mux#Router), which are executed in the order they are added if a match is found, including its subrouters.
+Middlewares are (typically) small pieces of code which take one request, do something with it, and pass it down to another middleware or the final handler. Some common use cases for middleware are request logging, header manipulation, or `ResponseWriter` hijacking.
+
+Mux middlewares are defined using the de facto standard type:
+
+```go
+type MiddlewareFunc func(http.Handler) http.Handler
+```
+
+Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed to it, and then calls the handler passed as parameter to the MiddlewareFunc. This takes advantage of closures being able access variables from the context where they are created, while retaining the signature enforced by the receivers.
+
+A very basic middleware which logs the URI of the request being handled could be written as:
+
+```go
+func loggingMiddleware(next http.Handler) http.Handler {
+    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+        // Do stuff here
+        log.Println(r.RequestURI)
+        // Call the next handler, which can be another middleware in the chain, or the final handler.
+        next.ServeHTTP(w, r)
+    })
+}
+```
+
+Middlewares can be added to a router using `Router.Use()`:
+
 ```go
 r := mux.NewRouter()
 r.HandleFunc("/", handler)
-r.HandleFunc("/products", handler).Methods("POST")
-r.HandleFunc("/articles", handler).Methods("GET")
-r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT")
-r.HandleFunc("/authors", handler).Queries("surname", "{surname}")
-r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
-    t, err := route.GetPathTemplate()
-    if err != nil {
-        return err
+r.Use(loggingMiddleware)
+```
+
+A more complex authentication middleware, which maps session token to users, could be written as:
+
+```go
+// Define our struct
+type authenticationMiddleware struct {
+	tokenUsers map[string]string
+}
+
+// Initialize it somewhere
+func (amw *authenticationMiddleware) Populate() {
+	amw.tokenUsers["00000000"] = "user0"
+	amw.tokenUsers["aaaaaaaa"] = "userA"
+	amw.tokenUsers["05f717e5"] = "randomUser"
+	amw.tokenUsers["deadbeef"] = "user0"
+}
+
+// Middleware function, which will be called for each request
+func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler {
+    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+        token := r.Header.Get("X-Session-Token")
+
+        if user, found := amw.tokenUsers[token]; found {
+        	// We found the token in our map
+        	log.Printf("Authenticated user %s\n", user)
+        	// Pass down the request to the next middleware (or final handler)
+        	next.ServeHTTP(w, r)
+        } else {
+        	// Write an error and stop the handler chain
+        	http.Error(w, "Forbidden", http.StatusForbidden)
+        }
+    })
+}
+```
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/", handler)
+
+amw := authenticationMiddleware{}
+amw.Populate()
+
+r.Use(amw.Middleware)
+```
+
+Note: The handler chain will be stopped if your middleware doesn't call `next.ServeHTTP()` with the corresponding parameters. This can be used to abort a request if the middleware writer wants to. Middlewares _should_ write to `ResponseWriter` if they _are_ going to terminate the request, and they _should not_ write to `ResponseWriter` if they _are not_ going to terminate it.
+
+### Handling CORS Requests
+
+[CORSMethodMiddleware](https://godoc.org/github.com/gorilla/mux#CORSMethodMiddleware) intends to make it easier to strictly set the `Access-Control-Allow-Methods` response header.
+
+* You will still need to use your own CORS handler to set the other CORS headers such as `Access-Control-Allow-Origin`
+* The middleware will set the `Access-Control-Allow-Methods` header to all the method matchers (e.g. `r.Methods(http.MethodGet, http.MethodPut, http.MethodOptions)` -> `Access-Control-Allow-Methods: GET,PUT,OPTIONS`) on a route
+* If you do not specify any methods, then:
+> _Important_: there must be an `OPTIONS` method matcher for the middleware to set the headers.
+
+Here is an example of using `CORSMethodMiddleware` along with a custom `OPTIONS` handler to set all the required CORS headers:
+
+```go
+package main
+
+import (
+	"net/http"
+	"github.com/gorilla/mux"
+)
+
+func main() {
+    r := mux.NewRouter()
+
+    // IMPORTANT: you must specify an OPTIONS method matcher for the middleware to set CORS headers
+    r.HandleFunc("/foo", fooHandler).Methods(http.MethodGet, http.MethodPut, http.MethodPatch, http.MethodOptions)
+    r.Use(mux.CORSMethodMiddleware(r))
+    
+    http.ListenAndServe(":8080", r)
+}
+
+func fooHandler(w http.ResponseWriter, r *http.Request) {
+    w.Header().Set("Access-Control-Allow-Origin", "*")
+    if r.Method == http.MethodOptions {
+        return
     }
-    qt, err := route.GetQueriesTemplates()
+
+    w.Write([]byte("foo"))
+}
+```
+
+And an request to `/foo` using something like:
+
+```bash
+curl localhost:8080/foo -v
+```
+
+Would look like:
+
+```bash
+*   Trying ::1...
+* TCP_NODELAY set
+* Connected to localhost (::1) port 8080 (#0)
+> GET /foo HTTP/1.1
+> Host: localhost:8080
+> User-Agent: curl/7.59.0
+> Accept: */*
+> 
+< HTTP/1.1 200 OK
+< Access-Control-Allow-Methods: GET,PUT,PATCH,OPTIONS
+< Access-Control-Allow-Origin: *
+< Date: Fri, 28 Jun 2019 20:13:30 GMT
+< Content-Length: 3
+< Content-Type: text/plain; charset=utf-8
+< 
+* Connection #0 to host localhost left intact
+foo
+```
+
+### Testing Handlers
+
+Testing handlers in a Go web application is straightforward, and _mux_ doesn't complicate this any further. Given two files: `endpoints.go` and `endpoints_test.go`, here's how we'd test an application using _mux_.
+
+First, our simple HTTP handler:
+
+```go
+// endpoints.go
+package main
+
+func HealthCheckHandler(w http.ResponseWriter, r *http.Request) {
+    // A very simple health check.
+    w.Header().Set("Content-Type", "application/json")
+    w.WriteHeader(http.StatusOK)
+
+    // In the future we could report back on the status of our DB, or our cache
+    // (e.g. Redis) by performing a simple PING, and include them in the response.
+    io.WriteString(w, `{"alive": true}`)
+}
+
+func main() {
+    r := mux.NewRouter()
+    r.HandleFunc("/health", HealthCheckHandler)
+
+    log.Fatal(http.ListenAndServe("localhost:8080", r))
+}
+```
+
+Our test code:
+
+```go
+// endpoints_test.go
+package main
+
+import (
+    "net/http"
+    "net/http/httptest"
+    "testing"
+)
+
+func TestHealthCheckHandler(t *testing.T) {
+    // Create a request to pass to our handler. We don't have any query parameters for now, so we'll
+    // pass 'nil' as the third parameter.
+    req, err := http.NewRequest("GET", "/health", nil)
     if err != nil {
-        return err
+        t.Fatal(err)
     }
-    // p will contain a regular expression that is compatible with regular expressions in Perl, Python, and other languages.
-    // For example, the regular expression for path '/articles/{id}' will be '^/articles/(?P<v0>[^/]+)$'.
-    p, err := route.GetPathRegexp()
-    if err != nil {
-        return err
+
+    // We create a ResponseRecorder (which satisfies http.ResponseWriter) to record the response.
+    rr := httptest.NewRecorder()
+    handler := http.HandlerFunc(HealthCheckHandler)
+
+    // Our handlers satisfy http.Handler, so we can call their ServeHTTP method
+    // directly and pass in our Request and ResponseRecorder.
+    handler.ServeHTTP(rr, req)
+
+    // Check the status code is what we expect.
+    if status := rr.Code; status != http.StatusOK {
+        t.Errorf("handler returned wrong status code: got %v want %v",
+            status, http.StatusOK)
     }
-    // qr will contain a list of regular expressions with the same semantics as GetPathRegexp,
-    // just applied to the Queries pairs instead, e.g., 'Queries("surname", "{surname}") will return
-    // {"^surname=(?P<v0>.*)$}. Where each combined query pair will have an entry in the list.
-    qr, err := route.GetQueriesRegexp()
-    if err != nil {
-        return err
+
+    // Check the response body is what we expect.
+    expected := `{"alive": true}`
+    if rr.Body.String() != expected {
+        t.Errorf("handler returned unexpected body: got %v want %v",
+            rr.Body.String(), expected)
     }
-    m, err := route.GetMethods()
-    if err != nil {
-        return err
+}
+```
+
+In the case that our routes have [variables](#examples), we can pass those in the request. We could write
+[table-driven tests](https://dave.cheney.net/2013/06/09/writing-table-driven-tests-in-go) to test multiple
+possible route variables as needed.
+
+```go
+// endpoints.go
+func main() {
+    r := mux.NewRouter()
+    // A route with a route variable:
+    r.HandleFunc("/metrics/{type}", MetricsHandler)
+
+    log.Fatal(http.ListenAndServe("localhost:8080", r))
+}
+```
+
+Our test file, with a table-driven test of `routeVariables`:
+
+```go
+// endpoints_test.go
+func TestMetricsHandler(t *testing.T) {
+    tt := []struct{
+        routeVariable string
+        shouldPass bool
+    }{
+        {"goroutines", true},
+        {"heap", true},
+        {"counters", true},
+        {"queries", true},
+        {"adhadaeqm3k", false},
     }
-    fmt.Println(strings.Join(m, ","), strings.Join(qt, ","), strings.Join(qr, ","), t, p)
-    return nil
-})
+
+    for _, tc := range tt {
+        path := fmt.Sprintf("/metrics/%s", tc.routeVariable)
+        req, err := http.NewRequest("GET", path, nil)
+        if err != nil {
+            t.Fatal(err)
+        }
+
+        rr := httptest.NewRecorder()
+	
+	// Need to create a router that we can pass the request through so that the vars will be added to the context
+	router := mux.NewRouter()
+        router.HandleFunc("/metrics/{type}", MetricsHandler)
+        router.ServeHTTP(rr, req)
+
+        // In this case, our MetricsHandler returns a non-200 response
+        // for a route variable it doesn't know about.
+        if rr.Code == http.StatusOK && !tc.shouldPass {
+            t.Errorf("handler should have failed on routeVariable %s: got %v want %v",
+                tc.routeVariable, rr.Code, http.StatusOK)
+        }
+    }
+}
 ```
 
 ## Full Example
@@ -391,22 +781,22 @@ Here's a complete, runnable example of a small `mux` based server:
 package main
 
 import (
-	"net/http"
-	"log"
-	"github.com/gorilla/mux"
+    "net/http"
+    "log"
+    "github.com/gorilla/mux"
 )
 
 func YourHandler(w http.ResponseWriter, r *http.Request) {
-	w.Write([]byte("Gorilla!\n"))
+    w.Write([]byte("Gorilla!\n"))
 }
 
 func main() {
-	r := mux.NewRouter()
-	// Routes consist of a path and a handler function.
-	r.HandleFunc("/", YourHandler)
+    r := mux.NewRouter()
+    // Routes consist of a path and a handler function.
+    r.HandleFunc("/", YourHandler)
 
-	// Bind to a port and pass our router in
-	log.Fatal(http.ListenAndServe(":8000", r))
+    // Bind to a port and pass our router in
+    log.Fatal(http.ListenAndServe(":8000", r))
 }
 ```
 

context.go

@@ -1,5 +1,3 @@
-// +build go1.7
-
 package mux
 
 import (
@@ -18,7 +16,3 @@ func contextSet(r *http.Request, key, val interface{}) *http.Request {
 
 	return r.WithContext(context.WithValue(r.Context(), key, val))
 }
-
-func contextClear(r *http.Request) {
-	return
-}

context_gorilla.go

@@ -1,26 +0,0 @@
-// +build !go1.7
-
-package mux
-
-import (
-	"net/http"
-
-	"github.com/gorilla/context"
-)
-
-func contextGet(r *http.Request, key interface{}) interface{} {
-	return context.Get(r, key)
-}
-
-func contextSet(r *http.Request, key, val interface{}) *http.Request {
-	if val == nil {
-		return r
-	}
-
-	context.Set(r, key, val)
-	return r
-}
-
-func contextClear(r *http.Request) {
-	context.Clear(r)
-}

context_gorilla_test.go

@@ -1,40 +0,0 @@
-// +build !go1.7
-
-package mux
-
-import (
-	"net/http"
-	"testing"
-
-	"github.com/gorilla/context"
-)
-
-// Tests that the context is cleared or not cleared properly depending on
-// the configuration of the router
-func TestKeepContext(t *testing.T) {
-	func1 := func(w http.ResponseWriter, r *http.Request) {}
-
-	r := NewRouter()
-	r.HandleFunc("/", func1).Name("func1")
-
-	req, _ := http.NewRequest("GET", "http://localhost/", nil)
-	context.Set(req, "t", 1)
-
-	res := new(http.ResponseWriter)
-	r.ServeHTTP(*res, req)
-
-	if _, ok := context.GetOk(req, "t"); ok {
-		t.Error("Context should have been cleared at end of request")
-	}
-
-	r.KeepContext = true
-
-	req, _ = http.NewRequest("GET", "http://localhost/", nil)
-	context.Set(req, "t", 1)
-
-	r.ServeHTTP(*res, req)
-	if _, ok := context.GetOk(req, "t"); !ok {
-		t.Error("Context should NOT have been cleared at end of request")
-	}
-
-}

context_test.go

@@ -1,5 +1,3 @@
-// +build go1.7
-
 package mux
 
 import (

doc.go

@@ -238,5 +238,69 @@ as well:
 	url, err := r.Get("article").URL("subdomain", "news",
 	                                 "category", "technology",
 	                                 "id", "42")
+
+Mux supports the addition of middlewares to a Router, which are executed in the order they are added if a match is found, including its subrouters. Middlewares are (typically) small pieces of code which take one request, do something with it, and pass it down to another middleware or the final handler. Some common use cases for middleware are request logging, header manipulation, or ResponseWriter hijacking.
+
+	type MiddlewareFunc func(http.Handler) http.Handler
+
+Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed to it, and then calls the handler passed as parameter to the MiddlewareFunc (closures can access variables from the context where they are created).
+
+A very basic middleware which logs the URI of the request being handled could be written as:
+
+	func simpleMw(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			// Do stuff here
+			log.Println(r.RequestURI)
+			// Call the next handler, which can be another middleware in the chain, or the final handler.
+			next.ServeHTTP(w, r)
+		})
+	}
+
+Middlewares can be added to a router using `Router.Use()`:
+
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+	r.Use(simpleMw)
+
+A more complex authentication middleware, which maps session token to users, could be written as:
+
+	// Define our struct
+	type authenticationMiddleware struct {
+		tokenUsers map[string]string
+	}
+
+	// Initialize it somewhere
+	func (amw *authenticationMiddleware) Populate() {
+		amw.tokenUsers["00000000"] = "user0"
+		amw.tokenUsers["aaaaaaaa"] = "userA"
+		amw.tokenUsers["05f717e5"] = "randomUser"
+		amw.tokenUsers["deadbeef"] = "user0"
+	}
+
+	// Middleware function, which will be called for each request
+	func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			token := r.Header.Get("X-Session-Token")
+
+			if user, found := amw.tokenUsers[token]; found {
+				// We found the token in our map
+				log.Printf("Authenticated user %s\n", user)
+				next.ServeHTTP(w, r)
+			} else {
+				http.Error(w, "Forbidden", http.StatusForbidden)
+			}
+		})
+	}
+
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+
+	amw := authenticationMiddleware{tokenUsers: make(map[string]string)}
+	amw.Populate()
+
+	r.Use(amw.Middleware)
+
+Note: The handler chain will be stopped if your middleware doesn't call `next.ServeHTTP()` with the corresponding parameters. This can be used to abort a request if the middleware writer wants to.
+
 */
 package mux

example_authentication_middleware_test.go

@@ -0,0 +1,46 @@
+package mux_test
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+// Define our struct
+type authenticationMiddleware struct {
+	tokenUsers map[string]string
+}
+
+// Initialize it somewhere
+func (amw *authenticationMiddleware) Populate() {
+	amw.tokenUsers["00000000"] = "user0"
+	amw.tokenUsers["aaaaaaaa"] = "userA"
+	amw.tokenUsers["05f717e5"] = "randomUser"
+	amw.tokenUsers["deadbeef"] = "user0"
+}
+
+// Middleware function, which will be called for each request
+func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		token := r.Header.Get("X-Session-Token")
+
+		if user, found := amw.tokenUsers[token]; found {
+			// We found the token in our map
+			log.Printf("Authenticated user %s\n", user)
+			next.ServeHTTP(w, r)
+		} else {
+			http.Error(w, "Forbidden", http.StatusForbidden)
+		}
+	})
+}
+
+func Example_authenticationMiddleware() {
+	r := mux.NewRouter()
+	r.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		// Do something here
+	})
+	amw := authenticationMiddleware{make(map[string]string)}
+	amw.Populate()
+	r.Use(amw.Middleware)
+}

example_cors_method_middleware_test.go

@@ -0,0 +1,37 @@
+package mux_test
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+
+	"github.com/gorilla/mux"
+)
+
+func ExampleCORSMethodMiddleware() {
+	r := mux.NewRouter()
+
+	r.HandleFunc("/foo", func(w http.ResponseWriter, r *http.Request) {
+		// Handle the request
+	}).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+	r.HandleFunc("/foo", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "http://example.com")
+		w.Header().Set("Access-Control-Max-Age", "86400")
+	}).Methods(http.MethodOptions)
+
+	r.Use(mux.CORSMethodMiddleware(r))
+
+	rw := httptest.NewRecorder()
+	req, _ := http.NewRequest("OPTIONS", "/foo", nil)                 // needs to be OPTIONS
+	req.Header.Set("Access-Control-Request-Method", "POST")           // needs to be non-empty
+	req.Header.Set("Access-Control-Request-Headers", "Authorization") // needs to be non-empty
+	req.Header.Set("Origin", "http://example.com")                    // needs to be non-empty
+
+	r.ServeHTTP(rw, req)
+
+	fmt.Println(rw.Header().Get("Access-Control-Allow-Methods"))
+	fmt.Println(rw.Header().Get("Access-Control-Allow-Origin"))
+	// Output:
+	// GET,PUT,PATCH,OPTIONS
+	// http://example.com
+}

example_route_test.go

@@ -0,0 +1,51 @@
+package mux_test
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+// This example demonstrates setting a regular expression matcher for
+// the header value. A plain word will match any value that contains a
+// matching substring as if the pattern was wrapped with `.*`.
+func ExampleRoute_HeadersRegexp() {
+	r := mux.NewRouter()
+	route := r.NewRoute().HeadersRegexp("Accept", "html")
+
+	req1, _ := http.NewRequest("GET", "example.com", nil)
+	req1.Header.Add("Accept", "text/plain")
+	req1.Header.Add("Accept", "text/html")
+
+	req2, _ := http.NewRequest("GET", "example.com", nil)
+	req2.Header.Set("Accept", "application/xhtml+xml")
+
+	matchInfo := &mux.RouteMatch{}
+	fmt.Printf("Match: %v %q\n", route.Match(req1, matchInfo), req1.Header["Accept"])
+	fmt.Printf("Match: %v %q\n", route.Match(req2, matchInfo), req2.Header["Accept"])
+	// Output:
+	// Match: true ["text/plain" "text/html"]
+	// Match: true ["application/xhtml+xml"]
+}
+
+// This example demonstrates setting a strict regular expression matcher
+// for the header value. Using the start and end of string anchors, the
+// value must be an exact match.
+func ExampleRoute_HeadersRegexp_exactMatch() {
+	r := mux.NewRouter()
+	route := r.NewRoute().HeadersRegexp("Origin", "^https://example.co$")
+
+	yes, _ := http.NewRequest("GET", "example.co", nil)
+	yes.Header.Set("Origin", "https://example.co")
+
+	no, _ := http.NewRequest("GET", "example.co.uk", nil)
+	no.Header.Set("Origin", "https://example.co.uk")
+
+	matchInfo := &mux.RouteMatch{}
+	fmt.Printf("Match: %v %q\n", route.Match(yes, matchInfo), yes.Header["Origin"])
+	fmt.Printf("Match: %v %q\n", route.Match(no, matchInfo), no.Header["Origin"])
+	// Output:
+	// Match: true ["https://example.co"]
+	// Match: false ["https://example.co.uk"]
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/gorilla/mux
+
+go 1.12

middleware.go

@@ -0,0 +1,79 @@
+package mux
+
+import (
+	"net/http"
+	"strings"
+)
+
+// MiddlewareFunc is a function which receives an http.Handler and returns another http.Handler.
+// Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed
+// to it, and then calls the handler passed as parameter to the MiddlewareFunc.
+type MiddlewareFunc func(http.Handler) http.Handler
+
+// middleware interface is anything which implements a MiddlewareFunc named Middleware.
+type middleware interface {
+	Middleware(handler http.Handler) http.Handler
+}
+
+// Middleware allows MiddlewareFunc to implement the middleware interface.
+func (mw MiddlewareFunc) Middleware(handler http.Handler) http.Handler {
+	return mw(handler)
+}
+
+// Use appends a MiddlewareFunc to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
+func (r *Router) Use(mwf ...MiddlewareFunc) {
+	for _, fn := range mwf {
+		r.middlewares = append(r.middlewares, fn)
+	}
+}
+
+// useInterface appends a middleware to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
+func (r *Router) useInterface(mw middleware) {
+	r.middlewares = append(r.middlewares, mw)
+}
+
+// CORSMethodMiddleware automatically sets the Access-Control-Allow-Methods response header
+// on requests for routes that have an OPTIONS method matcher to all the method matchers on
+// the route. Routes that do not explicitly handle OPTIONS requests will not be processed
+// by the middleware. See examples for usage.
+func CORSMethodMiddleware(r *Router) MiddlewareFunc {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			allMethods, err := getAllMethodsForRoute(r, req)
+			if err == nil {
+				for _, v := range allMethods {
+					if v == http.MethodOptions {
+						w.Header().Set("Access-Control-Allow-Methods", strings.Join(allMethods, ","))
+					}
+				}
+			}
+
+			next.ServeHTTP(w, req)
+		})
+	}
+}
+
+// getAllMethodsForRoute returns all the methods from method matchers matching a given
+// request.
+func getAllMethodsForRoute(r *Router, req *http.Request) ([]string, error) {
+	var allMethods []string
+
+	err := r.Walk(func(route *Route, _ *Router, _ []*Route) error {
+		for _, m := range route.matchers {
+			if _, ok := m.(*routeRegexp); ok {
+				if m.Match(req, &RouteMatch{}) {
+					methods, err := route.GetMethods()
+					if err != nil {
+						return err
+					}
+
+					allMethods = append(allMethods, methods...)
+				}
+				break
+			}
+		}
+		return nil
+	})
+
+	return allMethods, err
+}

middleware_test.go

@@ -0,0 +1,545 @@
+package mux
+
+import (
+	"bytes"
+	"net/http"
+	"testing"
+)
+
+type testMiddleware struct {
+	timesCalled uint
+}
+
+func (tm *testMiddleware) Middleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		tm.timesCalled++
+		h.ServeHTTP(w, r)
+	})
+}
+
+func dummyHandler(w http.ResponseWriter, r *http.Request) {}
+
+func TestMiddlewareAdd(t *testing.T) {
+	router := NewRouter()
+	router.HandleFunc("/", dummyHandler).Methods("GET")
+
+	mw := &testMiddleware{}
+
+	router.useInterface(mw)
+	if len(router.middlewares) != 1 || router.middlewares[0] != mw {
+		t.Fatal("Middleware interface was not added correctly")
+	}
+
+	router.Use(mw.Middleware)
+	if len(router.middlewares) != 2 {
+		t.Fatal("Middleware method was not added correctly")
+	}
+
+	banalMw := func(handler http.Handler) http.Handler {
+		return handler
+	}
+	router.Use(banalMw)
+	if len(router.middlewares) != 3 {
+		t.Fatal("Middleware function was not added correctly")
+	}
+}
+
+func TestMiddleware(t *testing.T) {
+	router := NewRouter()
+	router.HandleFunc("/", dummyHandler).Methods("GET")
+
+	mw := &testMiddleware{}
+	router.useInterface(mw)
+
+	rw := NewRecorder()
+	req := newRequest("GET", "/")
+
+	t.Run("regular middleware call", func(t *testing.T) {
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 1 {
+			t.Fatalf("Expected %d calls, but got only %d", 1, mw.timesCalled)
+		}
+	})
+
+	t.Run("not called for 404", func(t *testing.T) {
+		req = newRequest("GET", "/not/found")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 1 {
+			t.Fatalf("Expected %d calls, but got only %d", 1, mw.timesCalled)
+		}
+	})
+
+	t.Run("not called for method mismatch", func(t *testing.T) {
+		req = newRequest("POST", "/")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 1 {
+			t.Fatalf("Expected %d calls, but got only %d", 1, mw.timesCalled)
+		}
+	})
+
+	t.Run("regular call using function middleware", func(t *testing.T) {
+		router.Use(mw.Middleware)
+		req = newRequest("GET", "/")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 3 {
+			t.Fatalf("Expected %d calls, but got only %d", 3, mw.timesCalled)
+		}
+	})
+}
+
+func TestMiddlewareSubrouter(t *testing.T) {
+	router := NewRouter()
+	router.HandleFunc("/", dummyHandler).Methods("GET")
+
+	subrouter := router.PathPrefix("/sub").Subrouter()
+	subrouter.HandleFunc("/x", dummyHandler).Methods("GET")
+
+	mw := &testMiddleware{}
+	subrouter.useInterface(mw)
+
+	rw := NewRecorder()
+	req := newRequest("GET", "/")
+
+	t.Run("not called for route outside subrouter", func(t *testing.T) {
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 0 {
+			t.Fatalf("Expected %d calls, but got only %d", 0, mw.timesCalled)
+		}
+	})
+
+	t.Run("not called for subrouter root 404", func(t *testing.T) {
+		req = newRequest("GET", "/sub/")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 0 {
+			t.Fatalf("Expected %d calls, but got only %d", 0, mw.timesCalled)
+		}
+	})
+
+	t.Run("called once for route inside subrouter", func(t *testing.T) {
+		req = newRequest("GET", "/sub/x")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 1 {
+			t.Fatalf("Expected %d calls, but got only %d", 1, mw.timesCalled)
+		}
+	})
+
+	t.Run("not called for 404 inside subrouter", func(t *testing.T) {
+		req = newRequest("GET", "/sub/not/found")
+		router.ServeHTTP(rw, req)
+		if mw.timesCalled != 1 {
+			t.Fatalf("Expected %d calls, but got only %d", 1, mw.timesCalled)
+		}
+	})
+
+	t.Run("middleware added to router", func(t *testing.T) {
+		router.useInterface(mw)
+
+		t.Run("called once for route outside subrouter", func(t *testing.T) {
+			req = newRequest("GET", "/")
+			router.ServeHTTP(rw, req)
+			if mw.timesCalled != 2 {
+				t.Fatalf("Expected %d calls, but got only %d", 2, mw.timesCalled)
+			}
+		})
+
+		t.Run("called twice for route inside subrouter", func(t *testing.T) {
+			req = newRequest("GET", "/sub/x")
+			router.ServeHTTP(rw, req)
+			if mw.timesCalled != 4 {
+				t.Fatalf("Expected %d calls, but got only %d", 4, mw.timesCalled)
+			}
+		})
+	})
+}
+
+func TestMiddlewareExecution(t *testing.T) {
+	mwStr := []byte("Middleware\n")
+	handlerStr := []byte("Logic\n")
+
+	router := NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	})
+
+	t.Run("responds normally without middleware", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/")
+
+		router.ServeHTTP(rw, req)
+
+		if !bytes.Equal(rw.Body.Bytes(), handlerStr) {
+			t.Fatal("Handler response is not what it should be")
+		}
+	})
+
+	t.Run("responds with handler and middleware response", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/")
+
+		router.Use(func(h http.Handler) http.Handler {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.Write(mwStr)
+				h.ServeHTTP(w, r)
+			})
+		})
+
+		router.ServeHTTP(rw, req)
+		if !bytes.Equal(rw.Body.Bytes(), append(mwStr, handlerStr...)) {
+			t.Fatal("Middleware + handler response is not what it should be")
+		}
+	})
+}
+
+func TestMiddlewareNotFound(t *testing.T) {
+	mwStr := []byte("Middleware\n")
+	handlerStr := []byte("Logic\n")
+
+	router := NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	})
+	router.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write(mwStr)
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	// Test not found call with default handler
+	t.Run("not called", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/notfound")
+
+		router.ServeHTTP(rw, req)
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a 404")
+		}
+	})
+
+	t.Run("not called with custom not found handler", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/notfound")
+
+		router.NotFoundHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			rw.Write([]byte("Custom 404 handler"))
+		})
+		router.ServeHTTP(rw, req)
+
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a custom 404")
+		}
+	})
+}
+
+func TestMiddlewareMethodMismatch(t *testing.T) {
+	mwStr := []byte("Middleware\n")
+	handlerStr := []byte("Logic\n")
+
+	router := NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	}).Methods("GET")
+
+	router.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write(mwStr)
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	t.Run("not called", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("POST", "/")
+
+		router.ServeHTTP(rw, req)
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a method mismatch")
+		}
+	})
+
+	t.Run("not called with custom method not allowed handler", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("POST", "/")
+
+		router.MethodNotAllowedHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			rw.Write([]byte("Method not allowed"))
+		})
+		router.ServeHTTP(rw, req)
+
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a method mismatch")
+		}
+	})
+}
+
+func TestMiddlewareNotFoundSubrouter(t *testing.T) {
+	mwStr := []byte("Middleware\n")
+	handlerStr := []byte("Logic\n")
+
+	router := NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	})
+
+	subrouter := router.PathPrefix("/sub/").Subrouter()
+	subrouter.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	})
+
+	router.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write(mwStr)
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	t.Run("not called", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/sub/notfound")
+
+		router.ServeHTTP(rw, req)
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a 404")
+		}
+	})
+
+	t.Run("not called with custom not found handler", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/sub/notfound")
+
+		subrouter.NotFoundHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			rw.Write([]byte("Custom 404 handler"))
+		})
+		router.ServeHTTP(rw, req)
+
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a custom 404")
+		}
+	})
+}
+
+func TestMiddlewareMethodMismatchSubrouter(t *testing.T) {
+	mwStr := []byte("Middleware\n")
+	handlerStr := []byte("Logic\n")
+
+	router := NewRouter()
+	router.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	})
+
+	subrouter := router.PathPrefix("/sub/").Subrouter()
+	subrouter.HandleFunc("/", func(w http.ResponseWriter, e *http.Request) {
+		w.Write(handlerStr)
+	}).Methods("GET")
+
+	router.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write(mwStr)
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	t.Run("not called", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("POST", "/sub/")
+
+		router.ServeHTTP(rw, req)
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a method mismatch")
+		}
+	})
+
+	t.Run("not called with custom method not allowed handler", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("POST", "/sub/")
+
+		router.MethodNotAllowedHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			rw.Write([]byte("Method not allowed"))
+		})
+		router.ServeHTTP(rw, req)
+
+		if bytes.Contains(rw.Body.Bytes(), mwStr) {
+			t.Fatal("Middleware was called for a method mismatch")
+		}
+	})
+}
+
+func TestCORSMethodMiddleware(t *testing.T) {
+	testCases := []struct {
+		name                                    string
+		registerRoutes                          func(r *Router)
+		requestHeader                           http.Header
+		requestMethod                           string
+		requestPath                             string
+		expectedAccessControlAllowMethodsHeader string
+		expectedResponse                        string
+	}{
+		{
+			name: "does not set without OPTIONS matcher",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("a")).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+			},
+			requestMethod:                           "GET",
+			requestPath:                             "/foo",
+			expectedAccessControlAllowMethodsHeader: "",
+			expectedResponse:                        "a",
+		},
+		{
+			name: "sets on non OPTIONS",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("a")).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+				r.HandleFunc("/foo", stringHandler("b")).Methods(http.MethodOptions)
+			},
+			requestMethod:                           "GET",
+			requestPath:                             "/foo",
+			expectedAccessControlAllowMethodsHeader: "GET,PUT,PATCH,OPTIONS",
+			expectedResponse:                        "a",
+		},
+		{
+			name: "sets without preflight headers",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("a")).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+				r.HandleFunc("/foo", stringHandler("b")).Methods(http.MethodOptions)
+			},
+			requestMethod:                           "OPTIONS",
+			requestPath:                             "/foo",
+			expectedAccessControlAllowMethodsHeader: "GET,PUT,PATCH,OPTIONS",
+			expectedResponse:                        "b",
+		},
+		{
+			name: "does not set on error",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("a"))
+			},
+			requestMethod:                           "OPTIONS",
+			requestPath:                             "/foo",
+			expectedAccessControlAllowMethodsHeader: "",
+			expectedResponse:                        "a",
+		},
+		{
+			name: "sets header on valid preflight",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("a")).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+				r.HandleFunc("/foo", stringHandler("b")).Methods(http.MethodOptions)
+			},
+			requestMethod: "OPTIONS",
+			requestPath:   "/foo",
+			requestHeader: http.Header{
+				"Access-Control-Request-Method":  []string{"GET"},
+				"Access-Control-Request-Headers": []string{"Authorization"},
+				"Origin":                         []string{"http://example.com"},
+			},
+			expectedAccessControlAllowMethodsHeader: "GET,PUT,PATCH,OPTIONS",
+			expectedResponse:                        "b",
+		},
+		{
+			name: "does not set methods from unmatching routes",
+			registerRoutes: func(r *Router) {
+				r.HandleFunc("/foo", stringHandler("c")).Methods(http.MethodDelete)
+				r.HandleFunc("/foo/bar", stringHandler("a")).Methods(http.MethodGet, http.MethodPut, http.MethodPatch)
+				r.HandleFunc("/foo/bar", stringHandler("b")).Methods(http.MethodOptions)
+			},
+			requestMethod: "OPTIONS",
+			requestPath:   "/foo/bar",
+			requestHeader: http.Header{
+				"Access-Control-Request-Method":  []string{"GET"},
+				"Access-Control-Request-Headers": []string{"Authorization"},
+				"Origin":                         []string{"http://example.com"},
+			},
+			expectedAccessControlAllowMethodsHeader: "GET,PUT,PATCH,OPTIONS",
+			expectedResponse:                        "b",
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+			router := NewRouter()
+
+			tt.registerRoutes(router)
+
+			router.Use(CORSMethodMiddleware(router))
+
+			rw := NewRecorder()
+			req := newRequest(tt.requestMethod, tt.requestPath)
+			req.Header = tt.requestHeader
+
+			router.ServeHTTP(rw, req)
+
+			actualMethodsHeader := rw.Header().Get("Access-Control-Allow-Methods")
+			if actualMethodsHeader != tt.expectedAccessControlAllowMethodsHeader {
+				t.Fatalf("Expected Access-Control-Allow-Methods to equal %s but got %s", tt.expectedAccessControlAllowMethodsHeader, actualMethodsHeader)
+			}
+
+			actualResponse := rw.Body.String()
+			if actualResponse != tt.expectedResponse {
+				t.Fatalf("Expected response to equal %s but got %s", tt.expectedResponse, actualResponse)
+			}
+		})
+	}
+}
+
+func TestMiddlewareOnMultiSubrouter(t *testing.T) {
+	first := "first"
+	second := "second"
+	notFound := "404 not found"
+
+	router := NewRouter()
+	firstSubRouter := router.PathPrefix("/").Subrouter()
+	secondSubRouter := router.PathPrefix("/").Subrouter()
+
+	router.NotFoundHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		rw.Write([]byte(notFound))
+	})
+
+	firstSubRouter.HandleFunc("/first", func(w http.ResponseWriter, r *http.Request) {
+
+	})
+
+	secondSubRouter.HandleFunc("/second", func(w http.ResponseWriter, r *http.Request) {
+
+	})
+
+	firstSubRouter.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write([]byte(first))
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	secondSubRouter.Use(func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Write([]byte(second))
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	t.Run("/first uses first middleware", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/first")
+
+		router.ServeHTTP(rw, req)
+		if rw.Body.String() != first {
+			t.Fatalf("Middleware did not run: expected %s middleware to write a response (got %s)", first, rw.Body.String())
+		}
+	})
+
+	t.Run("/second uses second middleware", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/second")
+
+		router.ServeHTTP(rw, req)
+		if rw.Body.String() != second {
+			t.Fatalf("Middleware did not run: expected %s middleware to write a response (got %s)", second, rw.Body.String())
+		}
+	})
+
+	t.Run("uses not found handler", func(t *testing.T) {
+		rw := NewRecorder()
+		req := newRequest("GET", "/second/not-exist")
+
+		router.ServeHTTP(rw, req)
+		if rw.Body.String() != notFound {
+			t.Fatalf("Notfound handler did not run: expected %s for not-exist, (got %s)", notFound, rw.Body.String())
+		}
+	})
+}

mux.go

@@ -13,13 +13,16 @@ import (
 )
 
 var (
+	// ErrMethodMismatch is returned when the method in the request does not match
+	// the method defined against the route.
 	ErrMethodMismatch = errors.New("method is not allowed")
-	ErrNotFound       = errors.New("no matching route was found")
+	// ErrNotFound is returned when no route match is found.
+	ErrNotFound = errors.New("no matching route was found")
 )
 
 // NewRouter returns a new router instance.
 func NewRouter() *Router {
-	return &Router{namedRoutes: make(map[string]*Route), KeepContext: false}
+	return &Router{namedRoutes: make(map[string]*Route)}
 }
 
 // Router registers routes to be matched and dispatches a handler.
@@ -47,22 +50,76 @@ type Router struct {
 	// Configurable Handler to be used when the request method does not match the route.
 	MethodNotAllowedHandler http.Handler
 
-	// Parent route, if this is a subrouter.
-	parent parentRoute
 	// Routes to be matched, in order.
 	routes []*Route
+
 	// Routes by name for URL building.
 	namedRoutes map[string]*Route
-	// See Router.StrictSlash(). This defines the flag for new routes.
-	strictSlash bool
-	// See Router.SkipClean(). This defines the flag for new routes.
-	skipClean bool
+
 	// If true, do not clear the request context after handling the request.
-	// This has no effect when go1.7+ is used, since the context is stored
+	//
+	// Deprecated: No effect when go1.7+ is used, since the context is stored
 	// on the request itself.
 	KeepContext bool
-	// see Router.UseEncodedPath(). This defines a flag for all routes.
+
+	// Slice of middlewares to be called after a match is found
+	middlewares []middleware
+
+	// configuration shared with `Route`
+	routeConf
+}
+
+// common route configuration shared between `Router` and `Route`
+type routeConf struct {
+	// If true, "/path/foo%2Fbar/to" will match the path "/path/{var}/to"
 	useEncodedPath bool
+
+	// If true, when the path pattern is "/path/", accessing "/path" will
+	// redirect to the former and vice versa.
+	strictSlash bool
+
+	// If true, when the path pattern is "/path//to", accessing "/path//to"
+	// will not redirect
+	skipClean bool
+
+	// Manager for the variables from host and path.
+	regexp routeRegexpGroup
+
+	// List of matchers.
+	matchers []matcher
+
+	// The scheme used when building URLs.
+	buildScheme string
+
+	buildVarsFunc BuildVarsFunc
+}
+
+// returns an effective deep copy of `routeConf`
+func copyRouteConf(r routeConf) routeConf {
+	c := r
+
+	if r.regexp.path != nil {
+		c.regexp.path = copyRouteRegexp(r.regexp.path)
+	}
+
+	if r.regexp.host != nil {
+		c.regexp.host = copyRouteRegexp(r.regexp.host)
+	}
+
+	c.regexp.queries = make([]*routeRegexp, 0, len(r.regexp.queries))
+	for _, q := range r.regexp.queries {
+		c.regexp.queries = append(c.regexp.queries, copyRouteRegexp(q))
+	}
+
+	c.matchers = make([]matcher, len(r.matchers))
+	copy(c.matchers, r.matchers)
+
+	return c
+}
+
+func copyRouteRegexp(r *routeRegexp) *routeRegexp {
+	c := *r
+	return &c
 }
 
 // Match attempts to match the given request against the router's registered routes.
@@ -79,6 +136,12 @@ type Router struct {
 func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
 	for _, route := range r.routes {
 		if route.Match(req, match) {
+			// Build middleware chain if no error was found
+			if match.MatchErr == nil {
+				for i := len(r.middlewares) - 1; i >= 0; i-- {
+					match.Handler = r.middlewares[i].Middleware(match.Handler)
+				}
+			}
 			return true
 		}
 	}
@@ -87,9 +150,9 @@ func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
 		if r.MethodNotAllowedHandler != nil {
 			match.Handler = r.MethodNotAllowedHandler
 			return true
-		} else {
-			return false
 		}
+
+		return false
 	}
 
 	// Closest match for a router (includes sub-routers)
@@ -144,33 +207,35 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		handler = http.NotFoundHandler()
 	}
 
-	if !r.KeepContext {
-		defer contextClear(req)
-	}
 	handler.ServeHTTP(w, req)
 }
 
 // Get returns a route registered with the given name.
 func (r *Router) Get(name string) *Route {
-	return r.getNamedRoutes()[name]
+	return r.namedRoutes[name]
 }
 
 // GetRoute returns a route registered with the given name. This method
 // was renamed to Get() and remains here for backwards compatibility.
 func (r *Router) GetRoute(name string) *Route {
-	return r.getNamedRoutes()[name]
+	return r.namedRoutes[name]
 }
 
 // StrictSlash defines the trailing slash behavior for new routes. The initial
 // value is false.
 //
-// When true, if the route path is "/path/", accessing "/path" will redirect
+// When true, if the route path is "/path/", accessing "/path" will perform a redirect
 // to the former and vice versa. In other words, your application will always
 // see the path as specified in the route.
 //
 // When false, if the route path is "/path", accessing "/path/" will not match
 // this route and vice versa.
 //
+// The re-direct is a HTTP 301 (Moved Permanently). Note that when this is set for
+// routes with a non-idempotent method (e.g. POST, PUT), the subsequent re-directed
+// request will be made as a GET by most clients. Use middleware or client settings
+// to modify this behaviour as needed.
+//
 // Special case: when a route sets a path prefix using the PathPrefix() method,
 // strict slash is ignored for that route because the redirect behavior can't
 // be determined from a prefix alone. However, any subrouters created from that
@@ -196,10 +261,6 @@ func (r *Router) SkipClean(value bool) *Router {
 // UseEncodedPath tells the router to match the encoded original path
 // to the routes.
 // For eg. "/path/foo%2Fbar/to" will match the path "/path/{var}/to".
-// This behavior has the drawback of needing to match routes against
-// r.RequestURI instead of r.URL.Path. Any modifications (such as http.StripPrefix)
-// to r.URL.Path will not affect routing when this flag is on and thus may
-// induce unintended behavior.
 //
 // If not called, the router will match the unencoded path to the routes.
 // For eg. "/path/foo%2Fbar/to" will match the path "/path/foo/bar/to"
@@ -208,55 +269,24 @@ func (r *Router) UseEncodedPath() *Router {
 	return r
 }
 
-// ----------------------------------------------------------------------------
-// parentRoute
-// ----------------------------------------------------------------------------
-
-func (r *Router) getBuildScheme() string {
-	if r.parent != nil {
-		return r.parent.getBuildScheme()
-	}
-	return ""
-}
-
-// getNamedRoutes returns the map where named routes are registered.
-func (r *Router) getNamedRoutes() map[string]*Route {
-	if r.namedRoutes == nil {
-		if r.parent != nil {
-			r.namedRoutes = r.parent.getNamedRoutes()
-		} else {
-			r.namedRoutes = make(map[string]*Route)
-		}
-	}
-	return r.namedRoutes
-}
-
-// getRegexpGroup returns regexp definitions from the parent route, if any.
-func (r *Router) getRegexpGroup() *routeRegexpGroup {
-	if r.parent != nil {
-		return r.parent.getRegexpGroup()
-	}
-	return nil
-}
-
-func (r *Router) buildVars(m map[string]string) map[string]string {
-	if r.parent != nil {
-		m = r.parent.buildVars(m)
-	}
-	return m
-}
-
 // ----------------------------------------------------------------------------
 // Route factories
 // ----------------------------------------------------------------------------
 
 // NewRoute registers an empty route.
 func (r *Router) NewRoute() *Route {
-	route := &Route{parent: r, strictSlash: r.strictSlash, skipClean: r.skipClean, useEncodedPath: r.useEncodedPath}
+	// initialize a route with a copy of the parent router's configuration
+	route := &Route{routeConf: copyRouteConf(r.routeConf), namedRoutes: r.namedRoutes}
 	r.routes = append(r.routes, route)
 	return route
 }
 
+// Name registers a new route with a name.
+// See Route.Name().
+func (r *Router) Name(name string) *Route {
+	return r.NewRoute().Name(name)
+}
+
 // Handle registers a new route with a matcher for the URL path.
 // See Route.Path() and Route.Handler().
 func (r *Router) Handle(path string, handler http.Handler) *Route {

old_test.go

@@ -681,7 +681,7 @@ func TestNewRegexp(t *testing.T) {
 	}
 
 	for pattern, paths := range tests {
-		p, _ = newRouteRegexp(pattern, false, false, false, false, false)
+		p, _ = newRouteRegexp(pattern, regexpTypePath, routeRegexpOptions{})
 		for path, result := range paths {
 			matches = p.regexp.FindStringSubmatch(path)
 			if result == nil {

regexp.go

@@ -14,6 +14,20 @@ import (
 	"strings"
 )
 
+type routeRegexpOptions struct {
+	strictSlash    bool
+	useEncodedPath bool
+}
+
+type regexpType int
+
+const (
+	regexpTypePath   regexpType = 0
+	regexpTypeHost   regexpType = 1
+	regexpTypePrefix regexpType = 2
+	regexpTypeQuery  regexpType = 3
+)
+
 // newRouteRegexp parses a route template and returns a routeRegexp,
 // used to match a host, a path or a query string.
 //
@@ -24,7 +38,7 @@ import (
 // Previously we accepted only Python-like identifiers for variable
 // names ([a-zA-Z_][a-zA-Z0-9_]*), but currently the only restriction is that
 // name and pattern can't be empty, and names can't contain a colon.
-func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash, useEncodedPath bool) (*routeRegexp, error) {
+func newRouteRegexp(tpl string, typ regexpType, options routeRegexpOptions) (*routeRegexp, error) {
 	// Check if it is well-formed.
 	idxs, errBraces := braceIndices(tpl)
 	if errBraces != nil {
@@ -34,19 +48,18 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash,
 	template := tpl
 	// Now let's parse it.
 	defaultPattern := "[^/]+"
-	if matchQuery {
+	if typ == regexpTypeQuery {
 		defaultPattern = ".*"
-	} else if matchHost {
+	} else if typ == regexpTypeHost {
 		defaultPattern = "[^.]+"
-		matchPrefix = false
 	}
 	// Only match strict slash if not matching
-	if matchPrefix || matchHost || matchQuery {
-		strictSlash = false
+	if typ != regexpTypePath {
+		options.strictSlash = false
 	}
 	// Set a flag for strictSlash.
 	endSlash := false
-	if strictSlash && strings.HasSuffix(tpl, "/") {
+	if options.strictSlash && strings.HasSuffix(tpl, "/") {
 		tpl = tpl[:len(tpl)-1]
 		endSlash = true
 	}
@@ -88,18 +101,25 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash,
 	// Add the remaining.
 	raw := tpl[end:]
 	pattern.WriteString(regexp.QuoteMeta(raw))
-	if strictSlash {
+	if options.strictSlash {
 		pattern.WriteString("[/]?")
 	}
-	if matchQuery {
+	if typ == regexpTypeQuery {
 		// Add the default pattern if the query value is empty
 		if queryVal := strings.SplitN(template, "=", 2)[1]; queryVal == "" {
 			pattern.WriteString(defaultPattern)
 		}
 	}
-	if !matchPrefix {
+	if typ != regexpTypePrefix {
 		pattern.WriteByte('$')
 	}
+
+	var wildcardHostPort bool
+	if typ == regexpTypeHost {
+		if !strings.Contains(pattern.String(), ":") {
+			wildcardHostPort = true
+		}
+	}
 	reverse.WriteString(raw)
 	if endSlash {
 		reverse.WriteByte('/')
@@ -118,15 +138,14 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash,
 
 	// Done!
 	return &routeRegexp{
-		template:       template,
-		matchHost:      matchHost,
-		matchQuery:     matchQuery,
-		strictSlash:    strictSlash,
-		useEncodedPath: useEncodedPath,
-		regexp:         reg,
-		reverse:        reverse.String(),
-		varsN:          varsN,
-		varsR:          varsR,
+		template:         template,
+		regexpType:       typ,
+		options:          options,
+		regexp:           reg,
+		reverse:          reverse.String(),
+		varsN:            varsN,
+		varsR:            varsR,
+		wildcardHostPort: wildcardHostPort,
 	}, nil
 }
 
@@ -135,15 +154,10 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash,
 type routeRegexp struct {
 	// The unmodified template.
 	template string
-	// True for host match, false for path or query string match.
-	matchHost bool
-	// True for query string match, false for path and host match.
-	matchQuery bool
-	// The strictSlash value defined on the route, but disabled if PathPrefix was used.
-	strictSlash bool
-	// Determines whether to use encoded req.URL.EnscapedPath() or unencoded
-	// req.URL.Path for path matching
-	useEncodedPath bool
+	// The type of match
+	regexpType regexpType
+	// Options for matching
+	options routeRegexpOptions
 	// Expanded regexp.
 	regexp *regexp.Regexp
 	// Reverse template.
@@ -152,22 +166,31 @@ type routeRegexp struct {
 	varsN []string
 	// Variable regexps (validators).
 	varsR []*regexp.Regexp
+	// Wildcard host-port (no strict port match in hostname)
+	wildcardHostPort bool
 }
 
 // Match matches the regexp against the URL host or path.
 func (r *routeRegexp) Match(req *http.Request, match *RouteMatch) bool {
-	if !r.matchHost {
-		if r.matchQuery {
+	if r.regexpType == regexpTypeHost {
+		host := getHost(req)
+		if r.wildcardHostPort {
+			// Don't be strict on the port match
+			if i := strings.Index(host, ":"); i != -1 {
+				host = host[:i]
+			}
+		}
+		return r.regexp.MatchString(host)
+	} else {
+		if r.regexpType == regexpTypeQuery {
 			return r.matchQueryString(req)
 		}
 		path := req.URL.Path
-		if r.useEncodedPath {
+		if r.options.useEncodedPath {
 			path = req.URL.EscapedPath()
 		}
 		return r.regexp.MatchString(path)
 	}
-
-	return r.regexp.MatchString(getHost(req))
 }
 
 // url builds a URL part using the given values.
@@ -178,7 +201,7 @@ func (r *routeRegexp) url(values map[string]string) (string, error) {
 		if !ok {
 			return "", fmt.Errorf("mux: missing route variable %q", v)
 		}
-		if r.matchQuery {
+		if r.regexpType == regexpTypeQuery {
 			value = url.QueryEscape(value)
 		}
 		urlValues[k] = value
@@ -203,7 +226,7 @@ func (r *routeRegexp) url(values map[string]string) (string, error) {
 // For a URL with foo=bar&baz=ding, we return only the relevant key
 // value pair for the routeRegexp.
 func (r *routeRegexp) getURLQuery(req *http.Request) string {
-	if !r.matchQuery {
+	if r.regexpType != regexpTypeQuery {
 		return ""
 	}
 	templateKey := strings.SplitN(r.template, "=", 2)[0]
@@ -261,7 +284,7 @@ type routeRegexpGroup struct {
 }
 
 // setMatch extracts the variables from the URL once a route matches.
-func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route) {
+func (v routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route) {
 	// Store host variables.
 	if v.host != nil {
 		host := getHost(req)
@@ -280,7 +303,7 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 		if len(matches) > 0 {
 			extractVars(path, matches, v.path.varsN, m.Vars)
 			// Check if we should redirect.
-			if v.path.strictSlash {
+			if v.path.options.strictSlash {
 				p1 := strings.HasSuffix(path, "/")
 				p2 := strings.HasSuffix(v.path.template, "/")
 				if p1 != p2 {
@@ -290,7 +313,7 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 					} else {
 						u.Path += "/"
 					}
-					m.Handler = http.RedirectHandler(u.String(), 301)
+					m.Handler = http.RedirectHandler(u.String(), http.StatusMovedPermanently)
 				}
 			}
 		}
@@ -306,17 +329,13 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 }
 
 // getHost tries its best to return the request host.
+// According to section 14.23 of RFC 2616 the Host header
+// can include the port number if the default value of 80 is not used.
 func getHost(r *http.Request) string {
 	if r.URL.IsAbs() {
 		return r.URL.Host
 	}
-	host := r.Host
-	// Slice off any port information.
-	if i := strings.Index(host, ":"); i != -1 {
-		host = host[:i]
-	}
-	return host
-
+	return r.Host
 }
 
 func extractVars(input string, matches []int, names []string, output map[string]string) {

route.go

@@ -15,24 +15,8 @@ import (
 
 // Route stores information to match a request and build URLs.
 type Route struct {
-	// Parent where the route was registered (a Router).
-	parent parentRoute
 	// Request handler for the route.
 	handler http.Handler
-	// List of matchers.
-	matchers []matcher
-	// Manager for the variables from host and path.
-	regexp *routeRegexpGroup
-	// If true, when the path pattern is "/path/", accessing "/path" will
-	// redirect to the former and vice versa.
-	strictSlash bool
-	// If true, when the path pattern is "/path//to", accessing "/path//to"
-	// will not redirect
-	skipClean bool
-	// If true, "/path/foo%2Fbar/to" will match the path "/path/{var}/to"
-	useEncodedPath bool
-	// The scheme used when building URLs.
-	buildScheme string
 	// If true, this route never matches: it is only used to build URLs.
 	buildOnly bool
 	// The name used to build URLs.
@@ -40,9 +24,15 @@ type Route struct {
 	// Error resulted from building a route.
 	err error
 
-	buildVarsFunc BuildVarsFunc
+	// "global" reference to all named routes
+	namedRoutes map[string]*Route
+
+	// config possibly passed in from `Router`
+	routeConf
 }
 
+// SkipClean reports whether path cleaning is enabled for this route via
+// Router.SkipClean.
 func (r *Route) SkipClean() bool {
 	return r.skipClean
 }
@@ -62,6 +52,18 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 				matchErr = ErrMethodMismatch
 				continue
 			}
+
+			// Ignore ErrNotFound errors. These errors arise from match call
+			// to Subrouters.
+			//
+			// This prevents subsequent matching subrouters from failing to
+			// run middleware. If not ignored, the middleware would see a
+			// non-nil MatchErr and be skipped, even when there was a
+			// matching route.
+			if match.MatchErr == ErrNotFound {
+				match.MatchErr = nil
+			}
+
 			matchErr = nil
 			return false
 		}
@@ -75,6 +77,8 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 	if match.MatchErr == ErrMethodMismatch {
 		// We found a route which matches request method, clear MatchErr
 		match.MatchErr = nil
+		// Then override the mis-matched handler
+		match.Handler = r.handler
 	}
 
 	// Yay, we have a match. Let's collect some info about it.
@@ -89,9 +93,7 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 	}
 
 	// Set variables.
-	if r.regexp != nil {
-		r.regexp.setMatch(req, match, r)
-	}
+	r.regexp.setMatch(req, match, r)
 	return true
 }
 
@@ -133,7 +135,7 @@ func (r *Route) GetHandler() http.Handler {
 // Name -----------------------------------------------------------------------
 
 // Name sets the name for the route, used to build URLs.
-// If the name was registered already it will be overwritten.
+// It is an error to call Name more than once on a route.
 func (r *Route) Name(name string) *Route {
 	if r.name != "" {
 		r.err = fmt.Errorf("mux: route already has name %q, can't set %q",
@@ -141,7 +143,7 @@ func (r *Route) Name(name string) *Route {
 	}
 	if r.err == nil {
 		r.name = name
-		r.getNamedRoutes()[name] = r
+		r.namedRoutes[name] = r
 	}
 	return r
 }
@@ -169,12 +171,11 @@ func (r *Route) addMatcher(m matcher) *Route {
 }
 
 // addRegexpMatcher adds a host or path matcher and builder to a route.
-func (r *Route) addRegexpMatcher(tpl string, matchHost, matchPrefix, matchQuery bool) error {
+func (r *Route) addRegexpMatcher(tpl string, typ regexpType) error {
 	if r.err != nil {
 		return r.err
 	}
-	r.regexp = r.getRegexpGroup()
-	if !matchHost && !matchQuery {
+	if typ == regexpTypePath || typ == regexpTypePrefix {
 		if len(tpl) > 0 && tpl[0] != '/' {
 			return fmt.Errorf("mux: path must start with a slash, got %q", tpl)
 		}
@@ -182,7 +183,10 @@ func (r *Route) addRegexpMatcher(tpl string, matchHost, matchPrefix, matchQuery
 			tpl = strings.TrimRight(r.regexp.path.template, "/") + tpl
 		}
 	}
-	rr, err := newRouteRegexp(tpl, matchHost, matchPrefix, matchQuery, r.strictSlash, r.useEncodedPath)
+	rr, err := newRouteRegexp(tpl, typ, routeRegexpOptions{
+		strictSlash:    r.strictSlash,
+		useEncodedPath: r.useEncodedPath,
+	})
 	if err != nil {
 		return err
 	}
@@ -191,7 +195,7 @@ func (r *Route) addRegexpMatcher(tpl string, matchHost, matchPrefix, matchQuery
 			return err
 		}
 	}
-	if matchHost {
+	if typ == regexpTypeHost {
 		if r.regexp.path != nil {
 			if err = uniqueVars(rr.varsN, r.regexp.path.varsN); err != nil {
 				return err
@@ -204,7 +208,7 @@ func (r *Route) addRegexpMatcher(tpl string, matchHost, matchPrefix, matchQuery
 				return err
 			}
 		}
-		if matchQuery {
+		if typ == regexpTypeQuery {
 			r.regexp.queries = append(r.regexp.queries, rr)
 		} else {
 			r.regexp.path = rr
@@ -256,7 +260,8 @@ func (m headerRegexMatcher) Match(r *http.Request, match *RouteMatch) bool {
 //               "X-Requested-With", "XMLHttpRequest")
 //
 // The above route will only match if both the request header matches both regular expressions.
-// It the value is an empty string, it will match any value if the key is set.
+// If the value is an empty string, it will match any value if the key is set.
+// Use the start and end of string anchors (^ and $) to match an exact value.
 func (r *Route) HeadersRegexp(pairs ...string) *Route {
 	if r.err == nil {
 		var headers map[string]*regexp.Regexp
@@ -286,7 +291,7 @@ func (r *Route) HeadersRegexp(pairs ...string) *Route {
 // Variable names must be unique in a given route. They can be retrieved
 // calling mux.Vars(request).
 func (r *Route) Host(tpl string) *Route {
-	r.err = r.addRegexpMatcher(tpl, true, false, false)
+	r.err = r.addRegexpMatcher(tpl, regexpTypeHost)
 	return r
 }
 
@@ -346,7 +351,7 @@ func (r *Route) Methods(methods ...string) *Route {
 // Variable names must be unique in a given route. They can be retrieved
 // calling mux.Vars(request).
 func (r *Route) Path(tpl string) *Route {
-	r.err = r.addRegexpMatcher(tpl, false, false, false)
+	r.err = r.addRegexpMatcher(tpl, regexpTypePath)
 	return r
 }
 
@@ -362,7 +367,7 @@ func (r *Route) Path(tpl string) *Route {
 // Also note that the setting of Router.StrictSlash() has no effect on routes
 // with a PathPrefix matcher.
 func (r *Route) PathPrefix(tpl string) *Route {
-	r.err = r.addRegexpMatcher(tpl, false, true, false)
+	r.err = r.addRegexpMatcher(tpl, regexpTypePrefix)
 	return r
 }
 
@@ -378,7 +383,7 @@ func (r *Route) PathPrefix(tpl string) *Route {
 // The above route will only match if the URL contains the defined queries
 // values, e.g.: ?foo=bar&id=42.
 //
-// It the value is an empty string, it will match any value if the key is set.
+// If the value is an empty string, it will match any value if the key is set.
 //
 // Variables can define an optional regexp pattern to be matched:
 //
@@ -393,7 +398,7 @@ func (r *Route) Queries(pairs ...string) *Route {
 		return nil
 	}
 	for i := 0; i < length; i += 2 {
-		if r.err = r.addRegexpMatcher(pairs[i]+"="+pairs[i+1], false, false, true); r.err != nil {
+		if r.err = r.addRegexpMatcher(pairs[i]+"="+pairs[i+1], regexpTypeQuery); r.err != nil {
 			return r
 		}
 	}
@@ -416,7 +421,7 @@ func (r *Route) Schemes(schemes ...string) *Route {
 	for k, v := range schemes {
 		schemes[k] = strings.ToLower(v)
 	}
-	if r.buildScheme == "" && len(schemes) > 0 {
+	if len(schemes) > 0 {
 		r.buildScheme = schemes[0]
 	}
 	return r.addMatcher(schemeMatcher(schemes))
@@ -431,7 +436,15 @@ type BuildVarsFunc func(map[string]string) map[string]string
 // BuildVarsFunc adds a custom function to be used to modify build variables
 // before a route's URL is built.
 func (r *Route) BuildVarsFunc(f BuildVarsFunc) *Route {
-	r.buildVarsFunc = f
+	if r.buildVarsFunc != nil {
+		// compose the old and new functions
+		old := r.buildVarsFunc
+		r.buildVarsFunc = func(m map[string]string) map[string]string {
+			return f(old(m))
+		}
+	} else {
+		r.buildVarsFunc = f
+	}
 	return r
 }
 
@@ -450,7 +463,8 @@ func (r *Route) BuildVarsFunc(f BuildVarsFunc) *Route {
 // Here, the routes registered in the subrouter won't be tested if the host
 // doesn't match.
 func (r *Route) Subrouter() *Router {
-	router := &Router{parent: r, strictSlash: r.strictSlash}
+	// initialize a subrouter with a copy of the parent route's configuration
+	router := &Router{routeConf: copyRouteConf(r.routeConf), namedRoutes: r.namedRoutes}
 	r.addMatcher(router)
 	return router
 }
@@ -494,9 +508,6 @@ func (r *Route) URL(pairs ...string) (*url.URL, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
-	if r.regexp == nil {
-		return nil, errors.New("mux: route doesn't have a host or path")
-	}
 	values, err := r.prepareVars(pairs...)
 	if err != nil {
 		return nil, err
@@ -508,8 +519,8 @@ func (r *Route) URL(pairs ...string) (*url.URL, error) {
 			return nil, err
 		}
 		scheme = "http"
-		if s := r.getBuildScheme(); s != "" {
-			scheme = s
+		if r.buildScheme != "" {
+			scheme = r.buildScheme
 		}
 	}
 	if r.regexp.path != nil {
@@ -539,7 +550,7 @@ func (r *Route) URLHost(pairs ...string) (*url.URL, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
-	if r.regexp == nil || r.regexp.host == nil {
+	if r.regexp.host == nil {
 		return nil, errors.New("mux: route doesn't have a host")
 	}
 	values, err := r.prepareVars(pairs...)
@@ -554,8 +565,8 @@ func (r *Route) URLHost(pairs ...string) (*url.URL, error) {
 		Scheme: "http",
 		Host:   host,
 	}
-	if s := r.getBuildScheme(); s != "" {
-		u.Scheme = s
+	if r.buildScheme != "" {
+		u.Scheme = r.buildScheme
 	}
 	return u, nil
 }
@@ -567,7 +578,7 @@ func (r *Route) URLPath(pairs ...string) (*url.URL, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
-	if r.regexp == nil || r.regexp.path == nil {
+	if r.regexp.path == nil {
 		return nil, errors.New("mux: route doesn't have a path")
 	}
 	values, err := r.prepareVars(pairs...)
@@ -592,7 +603,7 @@ func (r *Route) GetPathTemplate() (string, error) {
 	if r.err != nil {
 		return "", r.err
 	}
-	if r.regexp == nil || r.regexp.path == nil {
+	if r.regexp.path == nil {
 		return "", errors.New("mux: route doesn't have a path")
 	}
 	return r.regexp.path.template, nil
@@ -606,7 +617,7 @@ func (r *Route) GetPathRegexp() (string, error) {
 	if r.err != nil {
 		return "", r.err
 	}
-	if r.regexp == nil || r.regexp.path == nil {
+	if r.regexp.path == nil {
 		return "", errors.New("mux: route does not have a path")
 	}
 	return r.regexp.path.regexp.String(), nil
@@ -616,12 +627,12 @@ func (r *Route) GetPathRegexp() (string, error) {
 // route queries.
 // This is useful for building simple REST API documentation and for instrumentation
 // against third-party services.
-// An empty list will be returned if the route does not have queries.
+// An error will be returned if the route does not have queries.
 func (r *Route) GetQueriesRegexp() ([]string, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
-	if r.regexp == nil || r.regexp.queries == nil {
+	if r.regexp.queries == nil {
 		return nil, errors.New("mux: route doesn't have queries")
 	}
 	var queries []string
@@ -635,12 +646,12 @@ func (r *Route) GetQueriesRegexp() ([]string, error) {
 // query matching.
 // This is useful for building simple REST API documentation and for instrumentation
 // against third-party services.
-// An empty list will be returned if the route does not define queries.
+// An error will be returned if the route does not define queries.
 func (r *Route) GetQueriesTemplates() ([]string, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
-	if r.regexp == nil || r.regexp.queries == nil {
+	if r.regexp.queries == nil {
 		return nil, errors.New("mux: route doesn't have queries")
 	}
 	var queries []string
@@ -653,7 +664,7 @@ func (r *Route) GetQueriesTemplates() ([]string, error) {
 // GetMethods returns the methods the route matches against
 // This is useful for building simple REST API documentation and for instrumentation
 // against third-party services.
-// An empty list will be returned if route does not have methods.
+// An error will be returned if route does not have methods.
 func (r *Route) GetMethods() ([]string, error) {
 	if r.err != nil {
 		return nil, r.err
@@ -663,7 +674,7 @@ func (r *Route) GetMethods() ([]string, error) {
 			return []string(methods), nil
 		}
 	}
-	return nil, nil
+	return nil, errors.New("mux: route doesn't have methods")
 }
 
 // GetHostTemplate returns the template used to build the
@@ -675,7 +686,7 @@ func (r *Route) GetHostTemplate() (string, error) {
 	if r.err != nil {
 		return "", r.err
 	}
-	if r.regexp == nil || r.regexp.host == nil {
+	if r.regexp.host == nil {
 		return "", errors.New("mux: route doesn't have a host")
 	}
 	return r.regexp.host.template, nil
@@ -692,64 +703,8 @@ func (r *Route) prepareVars(pairs ...string) (map[string]string, error) {
 }
 
 func (r *Route) buildVars(m map[string]string) map[string]string {
-	if r.parent != nil {
-		m = r.parent.buildVars(m)
-	}
 	if r.buildVarsFunc != nil {
 		m = r.buildVarsFunc(m)
 	}
 	return m
 }
-
-// ----------------------------------------------------------------------------
-// parentRoute
-// ----------------------------------------------------------------------------
-
-// parentRoute allows routes to know about parent host and path definitions.
-type parentRoute interface {
-	getBuildScheme() string
-	getNamedRoutes() map[string]*Route
-	getRegexpGroup() *routeRegexpGroup
-	buildVars(map[string]string) map[string]string
-}
-
-func (r *Route) getBuildScheme() string {
-	if r.buildScheme != "" {
-		return r.buildScheme
-	}
-	if r.parent != nil {
-		return r.parent.getBuildScheme()
-	}
-	return ""
-}
-
-// getNamedRoutes returns the map where named routes are registered.
-func (r *Route) getNamedRoutes() map[string]*Route {
-	if r.parent == nil {
-		// During tests router is not always set.
-		r.parent = NewRouter()
-	}
-	return r.parent.getNamedRoutes()
-}
-
-// getRegexpGroup returns regexp definitions from this route.
-func (r *Route) getRegexpGroup() *routeRegexpGroup {
-	if r.regexp == nil {
-		if r.parent == nil {
-			// During tests router is not always set.
-			r.parent = NewRouter()
-		}
-		regexp := r.parent.getRegexpGroup()
-		if regexp == nil {
-			r.regexp = new(routeRegexpGroup)
-		} else {
-			// Copy.
-			r.regexp = &routeRegexpGroup{
-				host:    regexp.host,
-				path:    regexp.path,
-				queries: regexp.queries,
-			}
-		}
-	}
-	return r.regexp
-}

test_helpers.go

@@ -0,0 +1,19 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mux
+
+import "net/http"
+
+// SetURLVars sets the URL variables for the given request, to be accessed via
+// mux.Vars for testing route behaviour. Arguments are not modified, a shallow
+// copy is returned.
+//
+// This API should only be used for testing purposes; it provides a way to
+// inject variables into the request context. Alternatively, URL variables
+// can be set by making a route that captures the required variables,
+// starting a server and sending the request to that server.
+func SetURLVars(r *http.Request, val map[string]string) *http.Request {
+	return setVars(r, val)
+}