playground: increase urlfetch timeout on GAE classic

The default timeout for urlfetch requests on App Engine Classic is
5 seconds. Sometimes the requests can take longer, so increase it to
the maximum value of 60 seconds. The playground has its own timeout for
running code so there's no need to impose a second level of protection.

Also cleans up the code to remove old appenginevm code and use the
correct imports.

Change-Id: I15da96e5ba70fb008bf821f4609f431847662223
Reviewed-on: https://go-review.googlesource.com/129395
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/playground/appengine.go b/playground/appengine.go
index 94c5d52..08c61f3 100644
--- a/playground/appengine.go
+++ b/playground/appengine.go
@@ -7,20 +7,28 @@
 package playground
 
 import (
+	"context"
+	"io"
 	"net/http"
 
-	"appengine"
-	"appengine/urlfetch"
+	"google.golang.org/appengine"
+	"google.golang.org/appengine/log"
+	"google.golang.org/appengine/urlfetch"
 )
 
 func init() {
 	onAppengine = !appengine.IsDevAppServer()
 }
 
-func client(r *http.Request) *http.Client {
-	return urlfetch.Client(appengine.NewContext(r))
+func contextFunc(r *http.Request) context.Context {
+	return appengine.NewContext(r)
+}
+
+func post(ctx context.Context, url, contentType string, body io.Reader) (*http.Response, error) {
+	return urlfetch.Client(ctx).Post(url, contentType, body)
 }
 
 func report(r *http.Request, err error) {
-	appengine.NewContext(r).Errorf("%v", err)
+	ctx := appengine.NewContext(r)
+	log.Errorf(ctx, "%v", err)
 }
diff --git a/playground/appenginevm.go b/playground/appenginevm.go
deleted file mode 100644
index aa3a212..0000000
--- a/playground/appenginevm.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright 2015 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build appenginevm
-
-package playground
-
-func init() {
-	onAppengine = true
-}
diff --git a/playground/common.go b/playground/common.go
index 81df9e0..f34a4b7 100644
--- a/playground/common.go
+++ b/playground/common.go
@@ -9,10 +9,12 @@
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 )
 
 const baseURL = "https://golang.org"
@@ -25,7 +27,7 @@
 func bounce(w http.ResponseWriter, r *http.Request) {
 	b := new(bytes.Buffer)
 	if err := passThru(b, r); err != nil {
-		http.Error(w, "Server error.", http.StatusInternalServerError)
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 		report(r, err)
 		return
 	}
@@ -38,7 +40,9 @@
 	}
 	defer req.Body.Close()
 	url := baseURL + req.URL.Path
-	r, err := client(req).Post(url, req.Header.Get("Content-type"), req.Body)
+	ctx, cancel := context.WithTimeout(contextFunc(req), 60*time.Second)
+	defer cancel()
+	r, err := post(ctx, url, req.Header.Get("Content-type"), req.Body)
 	if err != nil {
 		return fmt.Errorf("making POST request: %v", err)
 	}
@@ -49,7 +53,7 @@
 	return nil
 }
 
-var onAppengine = false // will be overridden by appengine.go and appenginevm.go
+var onAppengine = false // will be overridden by appengine.go
 
 func allowShare(r *http.Request) bool {
 	if !onAppengine {
diff --git a/playground/local.go b/playground/local.go
index b114b87..452054b 100644
--- a/playground/local.go
+++ b/playground/local.go
@@ -7,12 +7,23 @@
 package playground
 
 import (
+	"context"
+	"fmt"
+	"io"
 	"log"
 	"net/http"
 )
 
-func client(r *http.Request) *http.Client {
-	return http.DefaultClient
+func post(ctx context.Context, url, contentType string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, fmt.Errorf("http.NewRequest: %v", err)
+	}
+	return http.DefaultClient.Do(req.WithContext(ctx))
+}
+
+func contextFunc(_ *http.Request) context.Context {
+	return context.Background()
 }
 
 func report(r *http.Request, err error) {