Source: transport.go in package golang.org/x/oauth2


package oauth2

import (
	"errors"
	"log"
	"net/http"
	"sync"
)

Transport is an http.RoundTripper that makes OAuth 2.0 HTTP requests, wrapping a base RoundTripper and adding an Authorization header with a token from the supplied Sources. Transport is a low-level mechanism. Most code will use the higher-level Config.Client method instead.

Source supplies the token to add to outgoing requests' Authorization headers.

	Source TokenSource

Base is the base RoundTripper used to make HTTP requests. If nil, http.DefaultTransport is used.

	Base http.RoundTripper
}

RoundTrip authorizes and authenticates the request with an access token from Transport's Source.

func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
	reqBodyClosed := false
	if req.Body != nil {
		defer func() {
			if !reqBodyClosed {
				req.Body.Close()
			}
		}()
	}

	if t.Source == nil {
		return nil, errors.New("oauth2: Transport's Source is nil")
	}
	token, err := t.Source.Token()
	if err != nil {
		return nil, err
	}

	req2 := cloneRequest(req) // per RoundTripper contract
	token.SetAuthHeader(req2)

req.Body is assumed to be closed by the base RoundTripper.

	reqBodyClosed = true
	return t.base().RoundTrip(req2)
}

var cancelOnce sync.Once

CancelRequest does nothing. It used to be a legacy cancellation mechanism but now only it only logs on first use to warn that it's deprecated. Deprecated: use contexts for cancellation instead.

func (t *Transport) CancelRequest(req *http.Request) {
	cancelOnce.Do(func() {
		log.Printf("deprecated: golang.org/x/oauth2: Transport.CancelRequest no longer does anything; use contexts")
	})
}

func (t *Transport) base() http.RoundTripper {
	if t.Base != nil {
		return t.Base
	}
	return http.DefaultTransport
}

cloneRequest returns a clone of the provided *http.Request. The clone is a shallow copy of the struct and its Header map.

shallow copy of the struct

	r2 := new(http.Request)

deep copy of the Header

	r2.Header = make(http.Header, len(r.Header))
	for k, s := range r.Header {
		r2.Header[k] = append([]string(nil), s...)
	}
	return r2