whatcanGOwrong

go/pkg/mod/golang.org/x/tools@v0.25.0/playground/playground.go

@@ -0,0 +1,72 @@
+// 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 an HTTP handler at "/compile" that
+// proxies 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"
+	"time"
+)
+
+const baseURL = "https://play.golang.org"
+
+func init() {
+	http.Handle("/compile", Proxy())
+}
+
+// Proxy returns a handler that can be registered on /compile to proxy requests to the Go playground.
+//
+// This package already contains a func init that does:
+//
+//	func init() {
+//		http.Handle("/compile", Proxy())
+//	}
+//
+// Proxy may be useful for servers that use HTTP muxes other than the default mux.
+func Proxy() http.Handler {
+	return http.HandlerFunc(bounce)
+}
+
+func bounce(w http.ResponseWriter, r *http.Request) {
+	b := new(bytes.Buffer)
+	if err := passThru(b, r); 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 {
+	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))
+}