120 lines
2.6 KiB
Go
120 lines
2.6 KiB
Go
package client
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import (
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"io"
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"net/http"
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"sync"
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)
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// Transport is an http.RoundTripper that makes registry HTTP requests,
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// wrapping a base RoundTripper and adding an Authorization header
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// from an Auth source
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type Transport struct {
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AuthSource Authorizer
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ExtraHeader http.Header
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Base http.RoundTripper
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mu sync.Mutex // guards modReq
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modReq map[*http.Request]*http.Request // original -> modified
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}
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// RoundTrip authorizes and authenticates the request with an
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// access token. If no token exists or token is expired,
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// tries to refresh/fetch a new token.
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func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
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req2 := t.cloneRequest(req)
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if t.AuthSource != nil {
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if err := t.AuthSource.Authorize(req2); err != nil {
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return nil, err
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}
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}
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t.setModReq(req, req2)
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res, err := t.base().RoundTrip(req2)
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if err != nil {
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t.setModReq(req, nil)
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return nil, err
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}
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res.Body = &onEOFReader{
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rc: res.Body,
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fn: func() { t.setModReq(req, nil) },
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}
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return res, nil
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}
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// CancelRequest cancels an in-flight request by closing its connection.
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func (t *Transport) CancelRequest(req *http.Request) {
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type canceler interface {
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CancelRequest(*http.Request)
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}
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if cr, ok := t.base().(canceler); ok {
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t.mu.Lock()
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modReq := t.modReq[req]
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delete(t.modReq, req)
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t.mu.Unlock()
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cr.CancelRequest(modReq)
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}
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}
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func (t *Transport) base() http.RoundTripper {
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if t.Base != nil {
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return t.Base
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}
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return http.DefaultTransport
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}
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func (t *Transport) setModReq(orig, mod *http.Request) {
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t.mu.Lock()
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defer t.mu.Unlock()
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if t.modReq == nil {
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t.modReq = make(map[*http.Request]*http.Request)
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}
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if mod == nil {
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delete(t.modReq, orig)
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} else {
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t.modReq[orig] = mod
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}
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}
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// cloneRequest returns a clone of the provided *http.Request.
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// The clone is a shallow copy of the struct and its Header map.
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func (t *Transport) cloneRequest(r *http.Request) *http.Request {
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// shallow copy of the struct
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r2 := new(http.Request)
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*r2 = *r
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// deep copy of the Header
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r2.Header = make(http.Header, len(r.Header))
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for k, s := range r.Header {
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r2.Header[k] = append([]string(nil), s...)
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}
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for k, s := range t.ExtraHeader {
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r2.Header[k] = append(r2.Header[k], s...)
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}
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return r2
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}
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type onEOFReader struct {
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rc io.ReadCloser
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fn func()
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}
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func (r *onEOFReader) Read(p []byte) (n int, err error) {
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n, err = r.rc.Read(p)
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if err == io.EOF {
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r.runFunc()
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}
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return
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}
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func (r *onEOFReader) Close() error {
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err := r.rc.Close()
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r.runFunc()
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return err
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}
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func (r *onEOFReader) runFunc() {
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if fn := r.fn; fn != nil {
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fn()
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r.fn = nil
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}
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}
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