blob: 14e98418310f1bd8431ff1b22aed929b8382ecd3 [file] [log] [blame] [edit]
// Copyright 2013 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.
// Package playground registers HTTP handlers at "/compile" and "/share" that
// proxy requests to the golang.org playground service.
// This package may be used unaltered on App Engine Standard with Go 1.11+ runtime.
package playground // import "golang.org/x/tools/playground"
import (
"bytes"
"context"
"fmt"
"io"
"log"
"net/http"
"os"
"strings"
"time"
"golang.org/x/tools/godoc/golangorgenv"
)
const baseURL = "https://play.golang.org"
func init() {
http.HandleFunc("/compile", bounce)
http.HandleFunc("/share", bounce)
}
func bounce(w http.ResponseWriter, r *http.Request) {
b := new(bytes.Buffer)
if err := passThru(b, r); os.IsPermission(err) {
http.Error(w, "403 Forbidden", http.StatusForbidden)
log.Println(err)
return
} else if err != nil {
http.Error(w, "500 Internal Server Error", http.StatusInternalServerError)
log.Println(err)
return
}
io.Copy(w, b)
}
func passThru(w io.Writer, req *http.Request) error {
if req.URL.Path == "/share" && googleCN(req) {
return os.ErrPermission
}
defer req.Body.Close()
url := baseURL + req.URL.Path
ctx, cancel := context.WithTimeout(req.Context(), 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)
}
defer r.Body.Close()
if _, err := io.Copy(w, r.Body); err != nil {
return fmt.Errorf("copying response Body: %v", err)
}
return nil
}
func post(ctx context.Context, url, contentType string, body io.Reader) (*http.Response, error) {
req, err := http.NewRequest(http.MethodPost, url, body)
if err != nil {
return nil, fmt.Errorf("http.NewRequest: %v", err)
}
req.Header.Set("Content-Type", contentType)
return http.DefaultClient.Do(req.WithContext(ctx))
}
// googleCN reports whether request r is considered
// to be served from golang.google.cn.
func googleCN(r *http.Request) bool {
if r.FormValue("googlecn") != "" {
return true
}
if strings.HasSuffix(r.Host, ".cn") {
return true
}
if !golangorgenv.CheckCountry() {
return false
}
switch r.Header.Get("X-Appengine-Country") {
case "", "ZZ", "CN":
return true
}
return false
}