87 lines
2.7 KiB
Go
87 lines
2.7 KiB
Go
// Copyright 2016 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 gensupport
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import (
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"context"
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"encoding/json"
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"errors"
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"net/http"
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)
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// Hook is the type of a function that is called once before each HTTP request
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// that is sent by a generated API. It returns a function that is called after
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// the request returns.
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// Hooks are not called if the context is nil.
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type Hook func(ctx context.Context, req *http.Request) func(resp *http.Response)
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var hooks []Hook
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// RegisterHook registers a Hook to be called before each HTTP request by a
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// generated API. Hooks are called in the order they are registered. Each
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// hook can return a function; if it is non-nil, it is called after the HTTP
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// request returns. These functions are called in the reverse order.
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// RegisterHook should not be called concurrently with itself or SendRequest.
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func RegisterHook(h Hook) {
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hooks = append(hooks, h)
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}
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// SendRequest sends a single HTTP request using the given client.
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// If ctx is non-nil, it calls all hooks, then sends the request with
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// req.WithContext, then calls any functions returned by the hooks in
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// reverse order.
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func SendRequest(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
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// Disallow Accept-Encoding because it interferes with the automatic gzip handling
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// done by the default http.Transport. See https://github.com/google/google-api-go-client/issues/219.
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if _, ok := req.Header["Accept-Encoding"]; ok {
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return nil, errors.New("google api: custom Accept-Encoding headers not allowed")
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}
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if ctx == nil {
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return client.Do(req)
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}
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// Call hooks in order of registration, store returned funcs.
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post := make([]func(resp *http.Response), len(hooks))
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for i, h := range hooks {
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fn := h(ctx, req)
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post[i] = fn
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}
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// Send request.
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resp, err := send(ctx, client, req)
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// Call returned funcs in reverse order.
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for i := len(post) - 1; i >= 0; i-- {
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if fn := post[i]; fn != nil {
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fn(resp)
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}
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}
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return resp, err
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}
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func send(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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resp, err := client.Do(req.WithContext(ctx))
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// If we got an error, and the context has been canceled,
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// the context's error is probably more useful.
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if err != nil {
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select {
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case <-ctx.Done():
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err = ctx.Err()
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default:
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}
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}
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return resp, err
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}
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// DecodeResponse decodes the body of res into target. If there is no body,
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// target is unchanged.
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func DecodeResponse(target interface{}, res *http.Response) error {
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if res.StatusCode == http.StatusNoContent {
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return nil
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}
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return json.NewDecoder(res.Body).Decode(target)
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}
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