147 lines
3.6 KiB
Go
147 lines
3.6 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package ctxhttp provides helper functions for performing context-aware HTTP requests.
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package ctxhttp // import "golang.org/x/net/context/ctxhttp"
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import (
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"io"
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"net/http"
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"net/url"
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"strings"
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"golang.org/x/net/context"
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)
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func nop() {}
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var (
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testHookContextDoneBeforeHeaders = nop
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testHookDoReturned = nop
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testHookDidBodyClose = nop
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)
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// Do sends an HTTP request with the provided http.Client and returns an HTTP response.
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// If the client is nil, http.DefaultClient is used.
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// If the context is canceled or times out, ctx.Err() will be returned.
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func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
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if client == nil {
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client = http.DefaultClient
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}
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// TODO(djd): Respect any existing value of req.Cancel.
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cancel := make(chan struct{})
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req.Cancel = cancel
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type responseAndError struct {
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resp *http.Response
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err error
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}
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result := make(chan responseAndError, 1)
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// Make local copies of test hooks closed over by goroutines below.
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// Prevents data races in tests.
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testHookDoReturned := testHookDoReturned
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testHookDidBodyClose := testHookDidBodyClose
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go func() {
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resp, err := client.Do(req)
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testHookDoReturned()
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result <- responseAndError{resp, err}
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}()
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var resp *http.Response
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select {
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case <-ctx.Done():
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testHookContextDoneBeforeHeaders()
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close(cancel)
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// Clean up after the goroutine calling client.Do:
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go func() {
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if r := <-result; r.resp != nil {
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testHookDidBodyClose()
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r.resp.Body.Close()
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}
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}()
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return nil, ctx.Err()
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case r := <-result:
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var err error
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resp, err = r.resp, r.err
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if err != nil {
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return resp, err
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}
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}
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c := make(chan struct{})
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go func() {
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select {
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case <-ctx.Done():
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close(cancel)
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case <-c:
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// The response's Body is closed.
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}
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}()
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resp.Body = ¬ifyingReader{resp.Body, c}
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return resp, nil
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}
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// Get issues a GET request via the Do function.
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func Get(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
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req, err := http.NewRequest("GET", url, nil)
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if err != nil {
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return nil, err
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}
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return Do(ctx, client, req)
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}
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// Head issues a HEAD request via the Do function.
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func Head(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
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req, err := http.NewRequest("HEAD", url, nil)
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if err != nil {
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return nil, err
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}
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return Do(ctx, client, req)
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}
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// Post issues a POST request via the Do function.
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func Post(ctx context.Context, client *http.Client, url string, bodyType string, body io.Reader) (*http.Response, error) {
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req, err := http.NewRequest("POST", url, body)
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if err != nil {
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return nil, err
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}
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req.Header.Set("Content-Type", bodyType)
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return Do(ctx, client, req)
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}
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// PostForm issues a POST request via the Do function.
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func PostForm(ctx context.Context, client *http.Client, url string, data url.Values) (*http.Response, error) {
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return Post(ctx, client, url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
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}
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// notifyingReader is an io.ReadCloser that closes the notify channel after
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// Close is called or a Read fails on the underlying ReadCloser.
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type notifyingReader struct {
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io.ReadCloser
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notify chan<- struct{}
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}
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func (r *notifyingReader) Read(p []byte) (int, error) {
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n, err := r.ReadCloser.Read(p)
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if err != nil && r.notify != nil {
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close(r.notify)
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r.notify = nil
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}
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return n, err
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}
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func (r *notifyingReader) Close() error {
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err := r.ReadCloser.Close()
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if r.notify != nil {
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close(r.notify)
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r.notify = nil
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}
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return err
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}
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