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// 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.
// Package ctxhttp provides helper functions for performing context-aware HTTP requests.
package ctxhttp // import "golang.org/x/net/context/ctxhttp"
import (
"io"
"net/http"
"net/url"
"strings"
"golang.org/x/net/context"
)
func nop() {}
var (
testHookContextDoneBeforeHeaders = nop
testHookDoReturned = nop
testHookDidBodyClose = nop
)
// Do sends an HTTP request with the provided http.Client and returns an HTTP response.
// If the client is nil, http.DefaultClient is used.
// If the context is canceled or times out, ctx.Err() will be returned.
func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
if client == nil {
client = http.DefaultClient
}
// TODO(djd): Respect any existing value of req.Cancel.
cancel := make(chan struct{})
req.Cancel = cancel
type responseAndError struct {
resp *http.Response
err error
}
result := make(chan responseAndError, 1)
// Make local copies of test hooks closed over by goroutines below.
// Prevents data races in tests.
testHookDoReturned := testHookDoReturned
testHookDidBodyClose := testHookDidBodyClose
go func() {
resp, err := client.Do(req)
testHookDoReturned()
result <- responseAndError{resp, err}
}()
var resp *http.Response
select {
case <-ctx.Done():
testHookContextDoneBeforeHeaders()
close(cancel)
// Clean up after the goroutine calling client.Do:
go func() {
if r := <-result; r.resp != nil {
testHookDidBodyClose()
r.resp.Body.Close()
}
}()
return nil, ctx.Err()
case r := <-result:
var err error
resp, err = r.resp, r.err
if err != nil {
return resp, err
}
}
c := make(chan struct{})
go func() {
select {
case <-ctx.Done():
close(cancel)
case <-c:
// The response's Body is closed.
}
}()
resp.Body = ¬ifyingReader{resp.Body, c}
return resp, nil
}
// Get issues a GET request via the Do function.
func Get(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
return Do(ctx, client, req)
}
// Head issues a HEAD request via the Do function.
func Head(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
req, err := http.NewRequest("HEAD", url, nil)
if err != nil {
return nil, err
}
return Do(ctx, client, req)
}
// Post issues a POST request via the Do function.
func Post(ctx context.Context, client *http.Client, url string, bodyType string, body io.Reader) (*http.Response, error) {
req, err := http.NewRequest("POST", url, body)
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", bodyType)
return Do(ctx, client, req)
}
// PostForm issues a POST request via the Do function.
func PostForm(ctx context.Context, client *http.Client, url string, data url.Values) (*http.Response, error) {
return Post(ctx, client, url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
}
// notifyingReader is an io.ReadCloser that closes the notify channel after
// Close is called or a Read fails on the underlying ReadCloser.
type notifyingReader struct {
io.ReadCloser
notify chan<- struct{}
}
func (r *notifyingReader) Read(p []byte) (int, error) {
n, err := r.ReadCloser.Read(p)
if err != nil && r.notify != nil {
close(r.notify)
r.notify = nil
}
return n, err
}
func (r *notifyingReader) Close() error {
err := r.ReadCloser.Close()
if r.notify != nil {
close(r.notify)
r.notify = nil
}
return err
}
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