| // 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{}, |
| } |
| } |