bump gorilla/mux v1.7.3

full diff: https://github.com/gorilla/mux/compare/ed099d42384823742bba0bf9a72b53b55c9e2e38...00bdffe0f3c77e27d2cf6f5c70232a2d3e4d9c15

changes included:

- gorilla/mux#477 Improve CORS Method Middleware
    - implements gorilla/mux#477 Make CORSMethodMiddleware actually make sense
- gorilla/mux#489 Fix nil panic in authentication middleware example

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor.conf

@@ -4,7 +4,7 @@ github.com/Microsoft/go-winio                       6c72808b55902eae4c5943626030
 github.com/docker/libtrust                          9cbd2a1374f46905c68a4eb3694a130610adc62a
 github.com/golang/gddo                              72a348e765d293ed6d1ded7b699591f14d6cd921
 github.com/google/uuid                              0cd6bf5da1e1c83f8b45653022c74f71af0538a4 # v1.1.1
-github.com/gorilla/mux                              ed099d42384823742bba0bf9a72b53b55c9e2e38 # v1.7.2
+github.com/gorilla/mux                              00bdffe0f3c77e27d2cf6f5c70232a2d3e4d9c15 # v1.7.3
 github.com/Microsoft/opengcs                        a10967154e143a36014584a6f664344e3bb0aa64
 
 github.com/creack/pty                               3a6a957789163cacdfe0e291617a1c8e80612c11 # v1.1.9

vendor/github.com/gorilla/mux/README.md

@@ -2,6 +2,7 @@
 
 [![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)
@@ -29,6 +30,7 @@ The name mux stands for "HTTP request multiplexer". Like the standard `http.Serv
 * [Walking Routes](#walking-routes)
 * [Graceful Shutdown](#graceful-shutdown)
 * [Middleware](#middleware)
+* [Handling CORS Requests](#handling-cors-requests)
 * [Testing Handlers](#testing-handlers)
 * [Full Example](#full-example)
 
@@ -491,6 +493,73 @@ 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
+    }
+
+    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_.

vendor/github.com/gorilla/mux/doc.go

@@ -295,7 +295,7 @@ A more complex authentication middleware, which maps session token to users, cou
 	r := mux.NewRouter()
 	r.HandleFunc("/", handler)
 
-	amw := authenticationMiddleware{}
+	amw := authenticationMiddleware{tokenUsers: make(map[string]string)}
 	amw.Populate()
 
 	r.Use(amw.Middleware)

vendor/github.com/gorilla/mux/middleware.go

@@ -32,37 +32,19 @@ func (r *Router) useInterface(mw middleware) {
 	r.middlewares = append(r.middlewares, mw)
 }
 
-// CORSMethodMiddleware sets the Access-Control-Allow-Methods response header
-// on a request, by matching routes based only on paths. It also handles
-// OPTIONS requests, by settings Access-Control-Allow-Methods, and then
-// returning without calling the next http handler.
+// 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) {
-			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
-			})
-
+			allMethods, err := getAllMethodsForRoute(r, req)
 			if err == nil {
-				w.Header().Set("Access-Control-Allow-Methods", strings.Join(append(allMethods, "OPTIONS"), ","))
-
-				if req.Method == "OPTIONS" {
-					return
+				for _, v := range allMethods {
+					if v == http.MethodOptions {
+						w.Header().Set("Access-Control-Allow-Methods", strings.Join(allMethods, ","))
+					}
 				}
 			}
 
@@ -70,3 +52,28 @@ func CORSMethodMiddleware(r *Router) MiddlewareFunc {
 		})
 	}
 }
+
+// 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
+}