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"
+        "io/ioutil"
+        "math/rand"
+        "net/http"
+        "net/http/httptest"
+
+        "golang.org/x/net/context"
+
+        "github.com/luci/luci-go/server/router"
+)
+
+func Logger(c *router.Context, next router.Handler) {
+        fmt.Println(c.Request.URL)
+        next(c)
+}
+
+func AuthCheck(c *router.Context, next router.Handler) {
+        var authenticated bool
+        if !authenticated {
+                c.Writer.WriteHeader(http.StatusUnauthorized)
+                c.Writer.Write([]byte("Authentication failed"))
+                return
+        }
+        next(c)
+}
+
+func GenerateSecret(c *router.Context, next router.Handler) {
+        c.Context = context.WithValue(c.Context, "secret", rand.Int())
+        next(c)
+}
+
+func makeRequest(client *http.Client, url string) string {
+        res, err := client.Get(url + "/")
+        if err != nil {
+                panic(err)
+        }
+        defer res.Body.Close()
+        p, err := ioutil.ReadAll(res.Body)
+        if err != nil {
+                panic(err)
+        }
+        if len(p) == 0 {
+                return fmt.Sprintf("%d", res.StatusCode)
+        }
+        return fmt.Sprintf("%d %s", res.StatusCode, p)
+}
+
+func makeRequests(url string) {
+        c := &http.Client{}
+        fmt.Println(makeRequest(c, url+"/hello"))
+        fmt.Println(makeRequest(c, url+"/hello/darknessmyoldfriend"))
+        fmt.Println(makeRequest(c, url+"/authenticated/secret"))
+}
+
+// Example_createServer demonstrates creating an HTTP server using the router
+// package.
+func Example_createServer() {
+        r := router.New()
+        r.Use(router.MiddlewareChain{Logger})
+        r.GET("/hello", nil, func(c *router.Context) {
+                fmt.Fprintf(c.Writer, "Hello")
+        })
+        r.GET("/hello/:name", nil, func(c *router.Context) {
+                fmt.Fprintf(c.Writer, "Hello %s", c.Params.ByName("name"))
+        })
+
+        auth := r.Subrouter("authenticated")
+        auth.Use(router.MiddlewareChain{AuthCheck})
+        auth.GET("/secret", router.MiddlewareChain{GenerateSecret}, func(c *router.Context) {
+                fmt.Fprintf(c.Writer, "secret: %d", c.Context.Value("secret"))
+        })
+
+        server := httptest.NewServer(r)
+        defer server.Close()
+
+        makeRequests(server.URL)
+
+        // Output:
+        // /hello
+        // 200 Hello
+        // /hello/darknessmyoldfriend
+        // 200 Hello darknessmyoldfriend
+        // /authenticated/secret
+        // 401 Authentication failed
+}