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- // Copyright 2015 Google LLC
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- // Package http supports network connections to HTTP servers.
- // This package is not intended for use by end developers. Use the
- // google.golang.org/api/option package to configure API clients.
- package http
-
- import (
- "context"
- "errors"
- "net/http"
-
- "go.opencensus.io/plugin/ochttp"
- "golang.org/x/oauth2"
- "google.golang.org/api/googleapi/transport"
- "google.golang.org/api/internal"
- "google.golang.org/api/option"
- "google.golang.org/api/transport/http/internal/propagation"
- )
-
- // NewClient returns an HTTP client for use communicating with a Google cloud
- // service, configured with the given ClientOptions. It also returns the endpoint
- // for the service as specified in the options.
- func NewClient(ctx context.Context, opts ...option.ClientOption) (*http.Client, string, error) {
- settings, err := newSettings(opts)
- if err != nil {
- return nil, "", err
- }
- // TODO(cbro): consider injecting the User-Agent even if an explicit HTTP client is provided?
- if settings.HTTPClient != nil {
- return settings.HTTPClient, settings.Endpoint, nil
- }
- trans, err := newTransport(ctx, defaultBaseTransport(ctx), settings)
- if err != nil {
- return nil, "", err
- }
- return &http.Client{Transport: trans}, settings.Endpoint, nil
- }
-
- // NewTransport creates an http.RoundTripper for use communicating with a Google
- // cloud service, configured with the given ClientOptions. Its RoundTrip method delegates to base.
- func NewTransport(ctx context.Context, base http.RoundTripper, opts ...option.ClientOption) (http.RoundTripper, error) {
- settings, err := newSettings(opts)
- if err != nil {
- return nil, err
- }
- if settings.HTTPClient != nil {
- return nil, errors.New("transport/http: WithHTTPClient passed to NewTransport")
- }
- return newTransport(ctx, base, settings)
- }
-
- func newTransport(ctx context.Context, base http.RoundTripper, settings *internal.DialSettings) (http.RoundTripper, error) {
- trans := base
- trans = parameterTransport{
- base: trans,
- userAgent: settings.UserAgent,
- quotaProject: settings.QuotaProject,
- requestReason: settings.RequestReason,
- }
- trans = addOCTransport(trans)
- switch {
- case settings.NoAuth:
- // Do nothing.
- case settings.APIKey != "":
- trans = &transport.APIKey{
- Transport: trans,
- Key: settings.APIKey,
- }
- default:
- creds, err := internal.Creds(ctx, settings)
- if err != nil {
- return nil, err
- }
- trans = &oauth2.Transport{
- Base: trans,
- Source: creds.TokenSource,
- }
- }
- return trans, nil
- }
-
- func newSettings(opts []option.ClientOption) (*internal.DialSettings, error) {
- var o internal.DialSettings
- for _, opt := range opts {
- opt.Apply(&o)
- }
- if err := o.Validate(); err != nil {
- return nil, err
- }
- if o.GRPCConn != nil {
- return nil, errors.New("unsupported gRPC connection specified")
- }
- return &o, nil
- }
-
- type parameterTransport struct {
- userAgent string
- quotaProject string
- requestReason string
-
- base http.RoundTripper
- }
-
- func (t parameterTransport) RoundTrip(req *http.Request) (*http.Response, error) {
- rt := t.base
- if rt == nil {
- return nil, errors.New("transport: no Transport specified")
- }
- if t.userAgent == "" {
- return rt.RoundTrip(req)
- }
- newReq := *req
- newReq.Header = make(http.Header)
- for k, vv := range req.Header {
- newReq.Header[k] = vv
- }
- // TODO(cbro): append to existing User-Agent header?
- newReq.Header.Set("User-Agent", t.userAgent)
-
- // Attach system parameters into the header
- if t.quotaProject != "" {
- newReq.Header.Set("X-Goog-User-Project", t.quotaProject)
- }
- if t.requestReason != "" {
- newReq.Header.Set("X-Goog-Request-Reason", t.requestReason)
- }
-
- return rt.RoundTrip(&newReq)
- }
-
- // Set at init time by dial_appengine.go. If nil, we're not on App Engine.
- var appengineUrlfetchHook func(context.Context) http.RoundTripper
-
- // defaultBaseTransport returns the base HTTP transport.
- // On App Engine, this is urlfetch.Transport, otherwise it's http.DefaultTransport.
- func defaultBaseTransport(ctx context.Context) http.RoundTripper {
- if appengineUrlfetchHook != nil {
- return appengineUrlfetchHook(ctx)
- }
- return http.DefaultTransport
- }
-
- func addOCTransport(trans http.RoundTripper) http.RoundTripper {
- return &ochttp.Transport{
- Base: trans,
- Propagation: &propagation.HTTPFormat{},
- }
- }
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