Example #1
0
// 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
	}

	// Request cancelation changed in Go 1.5, see cancelreq.go and cancelreq_go14.go.
	cancel := canceler(client, req)

	type responseAndError struct {
		resp *http.Response
		err  error
	}
	result := make(chan responseAndError, 1)

	go func() {
		resp, err := client.Do(req)
		testHookDoReturned()
		result <- responseAndError{resp, err}
	}()

	var resp *http.Response

	select {
	case <-ctx.Done():
		testHookContextDoneBeforeHeaders()
		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():
			cancel()
		case <-c:
			// The response's Body is closed.
		}
	}()
	resp.Body = &notifyingReader{resp.Body, c}

	return resp, nil
}