From 7e6536fb2494f93ddfaa74bbfb5add8f843cb380 Mon Sep 17 00:00:00 2001
From: Will McCutchen <will@mccutch.org>
Date: Thu, 1 Dec 2016 15:21:03 -0800
Subject: [PATCH] Add /gzip handler

---
 httpbin/handlers.go      | 23 ++++++++++++++++++++
 httpbin/handlers_test.go | 47 ++++++++++++++++++++++++++++++++++++++++
 httpbin/httpbin.go       |  8 +++++++
 3 files changed, 78 insertions(+)

diff --git a/httpbin/handlers.go b/httpbin/handlers.go
index 6963faa..bf2e889 100644
--- a/httpbin/handlers.go
+++ b/httpbin/handlers.go
@@ -1,6 +1,8 @@
 package httpbin
 
 import (
+	"bytes"
+	"compress/gzip"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -67,6 +69,27 @@ func (h *HTTPBin) RequestWithBody(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, body, http.StatusOK)
 }
 
+// Gzip returns a gzipped response
+func (h *HTTPBin) Gzip(w http.ResponseWriter, r *http.Request) {
+	resp := &gzipResponse{
+		Headers: r.Header,
+		Origin:  getOrigin(r),
+		Gzipped: true,
+	}
+	body, _ := json.Marshal(resp)
+
+	buf := &bytes.Buffer{}
+	gzw := gzip.NewWriter(buf)
+	gzw.Write(body)
+	gzw.Close()
+
+	gzBody := buf.Bytes()
+
+	w.Header().Set("Content-Encoding", "gzip")
+	w.Header().Set("Content-Length", fmt.Sprintf("%d", len(gzBody)))
+	writeJSON(w, gzBody, http.StatusOK)
+}
+
 // IP echoes the IP address of the incoming request
 func (h *HTTPBin) IP(w http.ResponseWriter, r *http.Request) {
 	body, _ := json.Marshal(&ipResponse{
diff --git a/httpbin/handlers_test.go b/httpbin/handlers_test.go
index fca583b..b48f492 100644
--- a/httpbin/handlers_test.go
+++ b/httpbin/handlers_test.go
@@ -2,13 +2,16 @@ package httpbin
 
 import (
 	"bytes"
+	"compress/gzip"
 	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"mime/multipart"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -1075,3 +1078,47 @@ func TestDigestAuth(t *testing.T) {
 		})
 	}
 }
+
+func TestGzip(t *testing.T) {
+	r, _ := http.NewRequest("GET", "/gzip", nil)
+	w := httptest.NewRecorder()
+	handler.ServeHTTP(w, r)
+
+	assertContentType(t, w, "application/json; encoding=utf-8")
+	assertHeader(t, w, "Content-Encoding", "gzip")
+	assertStatusCode(t, w, http.StatusOK)
+
+	zippedContentLengthStr := w.HeaderMap.Get("Content-Length")
+	if zippedContentLengthStr == "" {
+		t.Fatalf("missing Content-Length header in response")
+	}
+
+	zippedContentLength, err := strconv.Atoi(zippedContentLengthStr)
+	if err != nil {
+		t.Fatalf("error converting Content-Lengh %v to integer: %s", zippedContentLengthStr, err)
+	}
+
+	gzipReader, err := gzip.NewReader(w.Body)
+	if err != nil {
+		t.Fatalf("error creating gzip reader: %s", err)
+	}
+
+	unzippedBody, err := ioutil.ReadAll(gzipReader)
+	if err != nil {
+		t.Fatalf("error reading gzipped body: %s", err)
+	}
+
+	var resp *gzipResponse
+	err = json.Unmarshal(unzippedBody, &resp)
+	if err != nil {
+		t.Fatalf("error unmarshalling response: %s", err)
+	}
+
+	if resp.Gzipped != true {
+		t.Fatalf("expected resp.Gzipped == true")
+	}
+
+	if len(unzippedBody) >= zippedContentLength {
+		t.Fatalf("expected compressed body")
+	}
+}
diff --git a/httpbin/httpbin.go b/httpbin/httpbin.go
index 52b819b..d08b57e 100644
--- a/httpbin/httpbin.go
+++ b/httpbin/httpbin.go
@@ -46,6 +46,12 @@ type authResponse struct {
 	User       string `json:"user"`
 }
 
+type gzipResponse struct {
+	Headers http.Header `json:"headers"`
+	Origin  string      `json:"origin"`
+	Gzipped bool        `json:"gzipped"`
+}
+
 // Options are used to configure HTTPBin
 type Options struct {
 	MaxMemory int64
@@ -88,6 +94,8 @@ func (h *HTTPBin) Handler() http.Handler {
 	mux.HandleFunc("/hidden-basic-auth/", h.HiddenBasicAuth)
 	mux.HandleFunc("/digest-auth/", h.DigestAuth)
 
+	mux.HandleFunc("/gzip", h.Gzip)
+
 	// Make sure our ServeMux doesn't "helpfully" redirect these invalid
 	// endpoints by adding a trailing slash. See the ServeMux docs for more
 	// info: https://golang.org/pkg/net/http/#ServeMux
-- 
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