Make HTTP middleware easier to use

server/router/example_test.go

+// Copyright 2016 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package router_test
+
+import (
+        "fmt"
+        "log"
+        "math/rand"
+        "net/http"
+        "time"
+
+        "golang.org/x/net/context"
+
+        "github.com/luci/luci-go/server/router"
+)
+
+var durations []time.Duration
+
+func Logger(c *router.Context, next router.Handler) {
+        log.Println(c.Request.URL.String())
+        next(c)
+}
+
+func Monitor(c *router.Context, next router.Handler) {
+        start := time.Now()
+        next(c)
+        durations = append(durations, time.Since(start))
+}
+
+func AuthCheck(c *router.Context, next router.Handler) {
+        var authenticated bool
+        if !authenticated {
+                c.WriteHeader(http.StatusUnauthorized)
+                return
+        }
+        next(c)
+}
+
+func GenerateRandom(c *router.Context, next router.Handler) {
+        secret := rand.Int()
+        c.Context = context.WithValue(c.Context, "secret", secret)
+        next(c)
+}
+
+func Root(c *router.Context) {
+        c.WriteHeader(http.StatusOK)
+}
+
+func Hello(c *router.Context) {
+        name := c.Params[0].Value
+        fmt.Fprintf(c, "Hello, %s", name)
+}
+
+func Random(c *router.Context) {
+        s := c.Value("secret").(int)
+        fmt.Fprintf(c, "secret: %d", s)
+}
+
+// Example_createServer demonstrates creating an HTTP server using the imported
+// router package.
+func Example_createServer() {
+        r := router.New()
+        r.Use(router.MiddlewareChain{Logger, Monitor})
+        r.GET("/", nil, Root)
+        r.GET("/hello/:name", nil, Hello)
+
+        auth := r.Subrouter("authenticated")
+        auth.Use(router.MiddlewareChain{AuthCheck})
+        auth.GET("/random", router.MiddlewareChain{GenerateRandom}, Random)
+
+        http.Handle("/", r)
+        log.Fatal(http.ListenAndServe(":8080", nil))

[iannucci, 2016/06/16 00:54:24]

I think you need

  // Output:
  // something
  // something else

For this to actually run as an example test. (go silently ignores it otherwise
:()

[nishanths, 2016/06/16 03:43:27]

Cool, done. :) 
If you have time, please check to make sure it's along the lines of what you
expected.

+}