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// Copyright 2016 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 gensupport
import (
"context"
"encoding/json"
"errors"
"net/http"
"time"
)
// SendRequest sends a single HTTP request using the given client.
// If ctx is non-nil, it calls all hooks, then sends the request with
// req.WithContext, then calls any functions returned by the hooks in
// reverse order.
func SendRequest(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
// Disallow Accept-Encoding because it interferes with the automatic gzip handling
// done by the default http.Transport. See https://github.com/google/google-api-go-client/issues/219.
if _, ok := req.Header["Accept-Encoding"]; ok {
return nil, errors.New("google api: custom Accept-Encoding headers not allowed")
}
if ctx == nil {
return client.Do(req)
}
return send(ctx, client, req)
}
func send(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
if client == nil {
client = http.DefaultClient
}
resp, err := client.Do(req.WithContext(ctx))
// If we got an error, and the context has been canceled,
// the context's error is probably more useful.
if err != nil {
select {
case <-ctx.Done():
err = ctx.Err()
default:
}
}
return resp, err
}
// SendRequestWithRetry sends a single HTTP request using the given client,
// with retries if a retryable error is returned.
// If ctx is non-nil, it calls all hooks, then sends the request with
// req.WithContext, then calls any functions returned by the hooks in
// reverse order.
func SendRequestWithRetry(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
// Disallow Accept-Encoding because it interferes with the automatic gzip handling
// done by the default http.Transport. See https://github.com/google/google-api-go-client/issues/219.
if _, ok := req.Header["Accept-Encoding"]; ok {
return nil, errors.New("google api: custom Accept-Encoding headers not allowed")
}
if ctx == nil {
return client.Do(req)
}
return sendAndRetry(ctx, client, req)
}
func sendAndRetry(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
if client == nil {
client = http.DefaultClient
}
var resp *http.Response
var err error
// Loop to retry the request, up to the context deadline.
var pause time.Duration
bo := backoff()
for {
select {
case <-ctx.Done():
// If we got an error, and the context has been canceled,
// the context's error is probably more useful.
if err == nil {
err = ctx.Err()
}
return resp, err
case <-time.After(pause):
}
resp, err = client.Do(req.WithContext(ctx))
var status int
if resp != nil {
status = resp.StatusCode
}
// Check if we can retry the request. A retry can only be done if the error
// is retryable and the request body can be re-created using GetBody (this
// will not be possible if the body was unbuffered).
if req.GetBody == nil || !shouldRetry(status, err) {
break
}
var errBody error
req.Body, errBody = req.GetBody()
if errBody != nil {
break
}
pause = bo.Pause()
if resp != nil && resp.Body != nil {
resp.Body.Close()
}
}
return resp, err
}
// DecodeResponse decodes the body of res into target. If there is no body,
// target is unchanged.
func DecodeResponse(target interface{}, res *http.Response) error {
if res.StatusCode == http.StatusNoContent {
return nil
}
return json.NewDecoder(res.Body).Decode(target)
}
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