1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // HTTP client. See RFC 7230 through 7235.
7 // This is the high-level Client interface.
8 // The low-level implementation is in transport.go.
20 "net/http/internal/ascii"
30 // A Client is an HTTP client. Its zero value (DefaultClient) is a
31 // usable client that uses DefaultTransport.
33 // The Client's Transport typically has internal state (cached TCP
34 // connections), so Clients should be reused instead of created as
35 // needed. Clients are safe for concurrent use by multiple goroutines.
37 // A Client is higher-level than a RoundTripper (such as Transport)
38 // and additionally handles HTTP details such as cookies and
41 // When following redirects, the Client will forward all headers set on the
42 // initial Request except:
44 // • when forwarding sensitive headers like "Authorization",
45 // "WWW-Authenticate", and "Cookie" to untrusted targets.
46 // These headers will be ignored when following a redirect to a domain
47 // that is not a subdomain match or exact match of the initial domain.
48 // For example, a redirect from "foo.com" to either "foo.com" or "sub.foo.com"
49 // will forward the sensitive headers, but a redirect to "bar.com" will not.
51 // • when forwarding the "Cookie" header with a non-nil cookie Jar.
52 // Since each redirect may mutate the state of the cookie jar,
53 // a redirect may possibly alter a cookie set in the initial request.
54 // When forwarding the "Cookie" header, any mutated cookies will be omitted,
55 // with the expectation that the Jar will insert those mutated cookies
56 // with the updated values (assuming the origin matches).
57 // If Jar is nil, the initial cookies are forwarded without change.
59 // Transport specifies the mechanism by which individual
60 // HTTP requests are made.
61 // If nil, DefaultTransport is used.
62 Transport RoundTripper
64 // CheckRedirect specifies the policy for handling redirects.
65 // If CheckRedirect is not nil, the client calls it before
66 // following an HTTP redirect. The arguments req and via are
67 // the upcoming request and the requests made already, oldest
68 // first. If CheckRedirect returns an error, the Client's Get
69 // method returns both the previous Response (with its Body
70 // closed) and CheckRedirect's error (wrapped in a url.Error)
71 // instead of issuing the Request req.
72 // As a special case, if CheckRedirect returns ErrUseLastResponse,
73 // then the most recent response is returned with its body
74 // unclosed, along with a nil error.
76 // If CheckRedirect is nil, the Client uses its default policy,
77 // which is to stop after 10 consecutive requests.
78 CheckRedirect func(req *Request, via []*Request) error
80 // Jar specifies the cookie jar.
82 // The Jar is used to insert relevant cookies into every
83 // outbound Request and is updated with the cookie values
84 // of every inbound Response. The Jar is consulted for every
85 // redirect that the Client follows.
87 // If Jar is nil, cookies are only sent if they are explicitly
88 // set on the Request.
91 // Timeout specifies a time limit for requests made by this
92 // Client. The timeout includes connection time, any
93 // redirects, and reading the response body. The timer remains
94 // running after Get, Head, Post, or Do return and will
95 // interrupt reading of the Response.Body.
97 // A Timeout of zero means no timeout.
99 // The Client cancels requests to the underlying Transport
100 // as if the Request's Context ended.
102 // For compatibility, the Client will also use the deprecated
103 // CancelRequest method on Transport if found. New
104 // RoundTripper implementations should use the Request's Context
105 // for cancellation instead of implementing CancelRequest.
106 Timeout time.Duration
109 // DefaultClient is the default Client and is used by Get, Head, and Post.
110 var DefaultClient = &Client{}
112 // RoundTripper is an interface representing the ability to execute a
113 // single HTTP transaction, obtaining the Response for a given Request.
115 // A RoundTripper must be safe for concurrent use by multiple
117 type RoundTripper interface {
118 // RoundTrip executes a single HTTP transaction, returning
119 // a Response for the provided Request.
121 // RoundTrip should not attempt to interpret the response. In
122 // particular, RoundTrip must return err == nil if it obtained
123 // a response, regardless of the response's HTTP status code.
124 // A non-nil err should be reserved for failure to obtain a
125 // response. Similarly, RoundTrip should not attempt to
126 // handle higher-level protocol details such as redirects,
127 // authentication, or cookies.
129 // RoundTrip should not modify the request, except for
130 // consuming and closing the Request's Body. RoundTrip may
131 // read fields of the request in a separate goroutine. Callers
132 // should not mutate or reuse the request until the Response's
133 // Body has been closed.
135 // RoundTrip must always close the body, including on errors,
136 // but depending on the implementation may do so in a separate
137 // goroutine even after RoundTrip returns. This means that
138 // callers wanting to reuse the body for subsequent requests
139 // must arrange to wait for the Close call before doing so.
141 // The Request's URL and Header fields must be initialized.
142 RoundTrip(*Request) (*Response, error)
145 // refererForURL returns a referer without any authentication info or
146 // an empty string if lastReq scheme is https and newReq scheme is http.
147 // If the referer was explicitly set, then it will continue to be used.
148 func refererForURL(lastReq, newReq *url.URL, explicitRef string) string {
149 // https://tools.ietf.org/html/rfc7231#section-5.5.2
150 // "Clients SHOULD NOT include a Referer header field in a
151 // (non-secure) HTTP request if the referring page was
152 // transferred with a secure protocol."
153 if lastReq.Scheme == "https" && newReq.Scheme == "http" {
156 if explicitRef != "" {
160 referer := lastReq.String()
161 if lastReq.User != nil {
162 // This is not very efficient, but is the best we can
164 // - introducing a new method on URL
165 // - creating a race condition
166 // - copying the URL struct manually, which would cause
167 // maintenance problems down the line
168 auth := lastReq.User.String() + "@"
169 referer = strings.Replace(referer, auth, "", 1)
174 // didTimeout is non-nil only if err != nil.
175 func (c *Client) send(req *Request, deadline time.Time) (resp *Response, didTimeout func() bool, err error) {
177 for _, cookie := range c.Jar.Cookies(req.URL) {
178 req.AddCookie(cookie)
181 resp, didTimeout, err = send(req, c.transport(), deadline)
183 return nil, didTimeout, err
186 if rc := resp.Cookies(); len(rc) > 0 {
187 c.Jar.SetCookies(req.URL, rc)
190 return resp, nil, nil
193 func (c *Client) deadline() time.Time {
195 return time.Now().Add(c.Timeout)
200 func (c *Client) transport() RoundTripper {
201 if c.Transport != nil {
204 return DefaultTransport
207 // send issues an HTTP request.
208 // Caller should close resp.Body when done reading from it.
209 func send(ireq *Request, rt RoundTripper, deadline time.Time) (resp *Response, didTimeout func() bool, err error) {
210 req := ireq // req is either the original request, or a modified fork
214 return nil, alwaysFalse, errors.New("http: no Client.Transport or DefaultTransport")
219 return nil, alwaysFalse, errors.New("http: nil Request.URL")
222 if req.RequestURI != "" {
224 return nil, alwaysFalse, errors.New("http: Request.RequestURI can't be set in client requests")
227 // forkReq forks req into a shallow clone of ireq the first
232 *req = *ireq // shallow clone
236 // Most the callers of send (Get, Post, et al) don't need
237 // Headers, leaving it uninitialized. We guarantee to the
238 // Transport that this has been initialized, though.
239 if req.Header == nil {
241 req.Header = make(Header)
244 if u := req.URL.User; u != nil && req.Header.Get("Authorization") == "" {
245 username := u.Username()
246 password, _ := u.Password()
248 req.Header = cloneOrMakeHeader(ireq.Header)
249 req.Header.Set("Authorization", "Basic "+basicAuth(username, password))
252 if !deadline.IsZero() {
255 stopTimer, didTimeout := setRequestCancel(req, rt, deadline)
257 resp, err = rt.RoundTrip(req)
261 log.Printf("RoundTripper returned a response & error; ignoring response")
263 if tlsErr, ok := err.(tls.RecordHeaderError); ok {
264 // If we get a bad TLS record header, check to see if the
265 // response looks like HTTP and give a more helpful error.
266 // See golang.org/issue/11111.
267 if string(tlsErr.RecordHeader[:]) == "HTTP/" {
268 err = errors.New("http: server gave HTTP response to HTTPS client")
271 return nil, didTimeout, err
274 return nil, didTimeout, fmt.Errorf("http: RoundTripper implementation (%T) returned a nil *Response with a nil error", rt)
276 if resp.Body == nil {
277 // The documentation on the Body field says “The http Client and Transport
278 // guarantee that Body is always non-nil, even on responses without a body
279 // or responses with a zero-length body.” Unfortunately, we didn't document
280 // that same constraint for arbitrary RoundTripper implementations, and
281 // RoundTripper implementations in the wild (mostly in tests) assume that
282 // they can use a nil Body to mean an empty one (similar to Request.Body).
283 // (See https://golang.org/issue/38095.)
285 // If the ContentLength allows the Body to be empty, fill in an empty one
286 // here to ensure that it is non-nil.
287 if resp.ContentLength > 0 && req.Method != "HEAD" {
288 return nil, didTimeout, fmt.Errorf("http: RoundTripper implementation (%T) returned a *Response with content length %d but a nil Body", rt, resp.ContentLength)
290 resp.Body = io.NopCloser(strings.NewReader(""))
292 if !deadline.IsZero() {
293 resp.Body = &cancelTimerBody{
296 reqDidTimeout: didTimeout,
299 return resp, nil, nil
302 // timeBeforeContextDeadline reports whether the non-zero Time t is
303 // before ctx's deadline, if any. If ctx does not have a deadline, it
304 // always reports true (the deadline is considered infinite).
305 func timeBeforeContextDeadline(t time.Time, ctx context.Context) bool {
306 d, ok := ctx.Deadline()
313 // knownRoundTripperImpl reports whether rt is a RoundTripper that's
314 // maintained by the Go team and known to implement the latest
315 // optional semantics (notably contexts). The Request is used
316 // to check whether this particular request is using an alternate protocol,
317 // in which case we need to check the RoundTripper for that protocol.
318 func knownRoundTripperImpl(rt RoundTripper, req *Request) bool {
319 switch t := rt.(type) {
321 if altRT := t.alternateRoundTripper(req); altRT != nil {
322 return knownRoundTripperImpl(altRT, req)
325 case *http2Transport, http2noDialH2RoundTripper:
328 // There's a very minor chance of a false positive with this.
329 // Instead of detecting our golang.org/x/net/http2.Transport,
330 // it might detect a Transport type in a different http2
331 // package. But I know of none, and the only problem would be
332 // some temporarily leaked goroutines if the transport didn't
333 // support contexts. So this is a good enough heuristic:
334 if reflect.TypeOf(rt).String() == "*http2.Transport" {
340 // setRequestCancel sets req.Cancel and adds a deadline context to req
341 // if deadline is non-zero. The RoundTripper's type is used to
342 // determine whether the legacy CancelRequest behavior should be used.
344 // As background, there are three ways to cancel a request:
345 // First was Transport.CancelRequest. (deprecated)
346 // Second was Request.Cancel.
347 // Third was Request.Context.
348 // This function populates the second and third, and uses the first if it really needs to.
349 func setRequestCancel(req *Request, rt RoundTripper, deadline time.Time) (stopTimer func(), didTimeout func() bool) {
350 if deadline.IsZero() {
351 return nop, alwaysFalse
353 knownTransport := knownRoundTripperImpl(rt, req)
354 oldCtx := req.Context()
356 if req.Cancel == nil && knownTransport {
357 // If they already had a Request.Context that's
358 // expiring sooner, do nothing:
359 if !timeBeforeContextDeadline(deadline, oldCtx) {
360 return nop, alwaysFalse
364 req.ctx, cancelCtx = context.WithDeadline(oldCtx, deadline)
365 return cancelCtx, func() bool { return time.Now().After(deadline) }
367 initialReqCancel := req.Cancel // the user's original Request.Cancel, if any
370 if timeBeforeContextDeadline(deadline, oldCtx) {
371 req.ctx, cancelCtx = context.WithDeadline(oldCtx, deadline)
374 cancel := make(chan struct{})
378 // The second way in the func comment above:
380 // The first way, used only for RoundTripper
381 // implementations written before Go 1.5 or Go 1.6.
382 type canceler interface{ CancelRequest(*Request) }
383 if v, ok := rt.(canceler); ok {
388 stopTimerCh := make(chan struct{})
393 if cancelCtx != nil {
399 timer := time.NewTimer(time.Until(deadline))
400 var timedOut atomic.Bool
404 case <-initialReqCancel:
415 return stopTimer, timedOut.Load
418 // See 2 (end of page 4) https://www.ietf.org/rfc/rfc2617.txt
419 // "To receive authorization, the client sends the userid and password,
420 // separated by a single colon (":") character, within a base64
421 // encoded string in the credentials."
422 // It is not meant to be urlencoded.
423 func basicAuth(username, password string) string {
424 auth := username + ":" + password
425 return base64.StdEncoding.EncodeToString([]byte(auth))
428 // Get issues a GET to the specified URL. If the response is one of
429 // the following redirect codes, Get follows the redirect, up to a
430 // maximum of 10 redirects:
432 // 301 (Moved Permanently)
435 // 307 (Temporary Redirect)
436 // 308 (Permanent Redirect)
438 // An error is returned if there were too many redirects or if there
439 // was an HTTP protocol error. A non-2xx response doesn't cause an
440 // error. Any returned error will be of type *url.Error. The url.Error
441 // value's Timeout method will report true if the request timed out.
443 // When err is nil, resp always contains a non-nil resp.Body.
444 // Caller should close resp.Body when done reading from it.
446 // Get is a wrapper around DefaultClient.Get.
448 // To make a request with custom headers, use NewRequest and
451 // To make a request with a specified context.Context, use NewRequestWithContext
452 // and DefaultClient.Do.
453 func Get(url string) (resp *Response, err error) {
454 return DefaultClient.Get(url)
457 // Get issues a GET to the specified URL. If the response is one of the
458 // following redirect codes, Get follows the redirect after calling the
459 // Client's CheckRedirect function:
461 // 301 (Moved Permanently)
464 // 307 (Temporary Redirect)
465 // 308 (Permanent Redirect)
467 // An error is returned if the Client's CheckRedirect function fails
468 // or if there was an HTTP protocol error. A non-2xx response doesn't
469 // cause an error. Any returned error will be of type *url.Error. The
470 // url.Error value's Timeout method will report true if the request
473 // When err is nil, resp always contains a non-nil resp.Body.
474 // Caller should close resp.Body when done reading from it.
476 // To make a request with custom headers, use NewRequest and Client.Do.
478 // To make a request with a specified context.Context, use NewRequestWithContext
480 func (c *Client) Get(url string) (resp *Response, err error) {
481 req, err := NewRequest("GET", url, nil)
488 func alwaysFalse() bool { return false }
490 // ErrUseLastResponse can be returned by Client.CheckRedirect hooks to
491 // control how redirects are processed. If returned, the next request
492 // is not sent and the most recent response is returned with its body
494 var ErrUseLastResponse = errors.New("net/http: use last response")
496 // checkRedirect calls either the user's configured CheckRedirect
497 // function, or the default.
498 func (c *Client) checkRedirect(req *Request, via []*Request) error {
499 fn := c.CheckRedirect
501 fn = defaultCheckRedirect
506 // redirectBehavior describes what should happen when the
507 // client encounters a 3xx status code from the server.
508 func redirectBehavior(reqMethod string, resp *Response, ireq *Request) (redirectMethod string, shouldRedirect, includeBody bool) {
509 switch resp.StatusCode {
511 redirectMethod = reqMethod
512 shouldRedirect = true
515 // RFC 2616 allowed automatic redirection only with GET and
516 // HEAD requests. RFC 7231 lifts this restriction, but we still
517 // restrict other methods to GET to maintain compatibility.
519 if reqMethod != "GET" && reqMethod != "HEAD" {
520 redirectMethod = "GET"
523 redirectMethod = reqMethod
524 shouldRedirect = true
527 if ireq.GetBody == nil && ireq.outgoingLength() != 0 {
528 // We had a request body, and 307/308 require
529 // re-sending it, but GetBody is not defined. So just
530 // return this response to the user instead of an
531 // error, like we did in Go 1.7 and earlier.
532 shouldRedirect = false
535 return redirectMethod, shouldRedirect, includeBody
538 // urlErrorOp returns the (*url.Error).Op value to use for the
539 // provided (*Request).Method value.
540 func urlErrorOp(method string) string {
544 if lowerMethod, ok := ascii.ToLower(method); ok {
545 return method[:1] + lowerMethod[1:]
550 // Do sends an HTTP request and returns an HTTP response, following
551 // policy (such as redirects, cookies, auth) as configured on the
554 // An error is returned if caused by client policy (such as
555 // CheckRedirect), or failure to speak HTTP (such as a network
556 // connectivity problem). A non-2xx status code doesn't cause an
559 // If the returned error is nil, the Response will contain a non-nil
560 // Body which the user is expected to close. If the Body is not both
561 // read to EOF and closed, the Client's underlying RoundTripper
562 // (typically Transport) may not be able to re-use a persistent TCP
563 // connection to the server for a subsequent "keep-alive" request.
565 // The request Body, if non-nil, will be closed by the underlying
566 // Transport, even on errors.
568 // On error, any Response can be ignored. A non-nil Response with a
569 // non-nil error only occurs when CheckRedirect fails, and even then
570 // the returned Response.Body is already closed.
572 // Generally Get, Post, or PostForm will be used instead of Do.
574 // If the server replies with a redirect, the Client first uses the
575 // CheckRedirect function to determine whether the redirect should be
576 // followed. If permitted, a 301, 302, or 303 redirect causes
577 // subsequent requests to use HTTP method GET
578 // (or HEAD if the original request was HEAD), with no body.
579 // A 307 or 308 redirect preserves the original HTTP method and body,
580 // provided that the Request.GetBody function is defined.
581 // The NewRequest function automatically sets GetBody for common
582 // standard library body types.
584 // Any returned error will be of type *url.Error. The url.Error
585 // value's Timeout method will report true if the request timed out.
586 func (c *Client) Do(req *Request) (*Response, error) {
590 var testHookClientDoResult func(retres *Response, reterr error)
592 func (c *Client) do(req *Request) (retres *Response, reterr error) {
593 if testHookClientDoResult != nil {
594 defer func() { testHookClientDoResult(retres, reterr) }()
598 return nil, &url.Error{
599 Op: urlErrorOp(req.Method),
600 Err: errors.New("http: nil Request.URL"),
605 deadline = c.deadline()
608 copyHeaders = c.makeHeadersCopier(req)
609 reqBodyClosed = false // have we closed the current req.Body?
611 // Redirect behavior:
612 redirectMethod string
615 uerr := func(err error) error {
616 // the body may have been closed already by c.send()
621 if resp != nil && resp.Request != nil {
622 urlStr = stripPassword(resp.Request.URL)
624 urlStr = stripPassword(req.URL)
627 Op: urlErrorOp(reqs[0].Method),
633 // For all but the first request, create the next
634 // request hop and replace req.
636 loc := resp.Header.Get("Location")
638 // While most 3xx responses include a Location, it is not
639 // required and 3xx responses without a Location have been
640 // observed in the wild. See issues #17773 and #49281.
643 u, err := req.URL.Parse(loc)
646 return nil, uerr(fmt.Errorf("failed to parse Location header %q: %v", loc, err))
649 if req.Host != "" && req.Host != req.URL.Host {
650 // If the caller specified a custom Host header and the
651 // redirect location is relative, preserve the Host header
652 // through the redirect. See issue #22233.
653 if u, _ := url.Parse(loc); u != nil && !u.IsAbs() {
659 Method: redirectMethod,
662 Header: make(Header),
667 if includeBody && ireq.GetBody != nil {
668 req.Body, err = ireq.GetBody()
671 return nil, uerr(err)
673 req.ContentLength = ireq.ContentLength
676 // Copy original headers before setting the Referer,
677 // in case the user set Referer on their first request.
678 // If they really want to override, they can do it in
679 // their CheckRedirect func.
682 // Add the Referer header from the most recent
683 // request URL to the new one, if it's not https->http:
684 if ref := refererForURL(reqs[len(reqs)-1].URL, req.URL, req.Header.Get("Referer")); ref != "" {
685 req.Header.Set("Referer", ref)
687 err = c.checkRedirect(req, reqs)
689 // Sentinel error to let users select the
690 // previous response, without closing its
691 // body. See Issue 10069.
692 if err == ErrUseLastResponse {
696 // Close the previous response's body. But
697 // read at least some of the body so if it's
698 // small the underlying TCP connection will be
699 // re-used. No need to check for errors: if it
700 // fails, the Transport won't reuse it anyway.
701 const maxBodySlurpSize = 2 << 10
702 if resp.ContentLength == -1 || resp.ContentLength <= maxBodySlurpSize {
703 io.CopyN(io.Discard, resp.Body, maxBodySlurpSize)
708 // Special case for Go 1 compatibility: return both the response
709 // and an error if the CheckRedirect function failed.
710 // See https://golang.org/issue/3795
711 // The resp.Body has already been closed.
713 ue.(*url.Error).URL = loc
718 reqs = append(reqs, req)
720 var didTimeout func() bool
721 if resp, didTimeout, err = c.send(req, deadline); err != nil {
722 // c.send() always closes req.Body
724 if !deadline.IsZero() && didTimeout() {
726 err: err.Error() + " (Client.Timeout exceeded while awaiting headers)",
730 return nil, uerr(err)
733 var shouldRedirect bool
734 redirectMethod, shouldRedirect, includeBody = redirectBehavior(req.Method, resp, reqs[0])
743 // makeHeadersCopier makes a function that copies headers from the
744 // initial Request, ireq. For every redirect, this function must be called
745 // so that it can copy headers into the upcoming Request.
746 func (c *Client) makeHeadersCopier(ireq *Request) func(*Request) {
747 // The headers to copy are from the very initial request.
748 // We use a closured callback to keep a reference to these original headers.
750 ireqhdr = cloneOrMakeHeader(ireq.Header)
751 icookies map[string][]*Cookie
753 if c.Jar != nil && ireq.Header.Get("Cookie") != "" {
754 icookies = make(map[string][]*Cookie)
755 for _, c := range ireq.Cookies() {
756 icookies[c.Name] = append(icookies[c.Name], c)
760 preq := ireq // The previous request
761 return func(req *Request) {
762 // If Jar is present and there was some initial cookies provided
763 // via the request header, then we may need to alter the initial
764 // cookies as we follow redirects since each redirect may end up
765 // modifying a pre-existing cookie.
767 // Since cookies already set in the request header do not contain
768 // information about the original domain and path, the logic below
769 // assumes any new set cookies override the original cookie
770 // regardless of domain or path.
772 // See https://golang.org/issue/17494
773 if c.Jar != nil && icookies != nil {
775 resp := req.Response // The response that caused the upcoming redirect
776 for _, c := range resp.Cookies() {
777 if _, ok := icookies[c.Name]; ok {
778 delete(icookies, c.Name)
783 ireqhdr.Del("Cookie")
785 for _, cs := range icookies {
786 for _, c := range cs {
787 ss = append(ss, c.Name+"="+c.Value)
790 sort.Strings(ss) // Ensure deterministic headers
791 ireqhdr.Set("Cookie", strings.Join(ss, "; "))
795 // Copy the initial request's Header values
796 // (at least the safe ones).
797 for k, vv := range ireqhdr {
798 if shouldCopyHeaderOnRedirect(k, preq.URL, req.URL) {
803 preq = req // Update previous Request with the current request
807 func defaultCheckRedirect(req *Request, via []*Request) error {
809 return errors.New("stopped after 10 redirects")
814 // Post issues a POST to the specified URL.
816 // Caller should close resp.Body when done reading from it.
818 // If the provided body is an io.Closer, it is closed after the
821 // Post is a wrapper around DefaultClient.Post.
823 // To set custom headers, use NewRequest and DefaultClient.Do.
825 // See the Client.Do method documentation for details on how redirects
828 // To make a request with a specified context.Context, use NewRequestWithContext
829 // and DefaultClient.Do.
830 func Post(url, contentType string, body io.Reader) (resp *Response, err error) {
831 return DefaultClient.Post(url, contentType, body)
834 // Post issues a POST to the specified URL.
836 // Caller should close resp.Body when done reading from it.
838 // If the provided body is an io.Closer, it is closed after the
841 // To set custom headers, use NewRequest and Client.Do.
843 // To make a request with a specified context.Context, use NewRequestWithContext
846 // See the Client.Do method documentation for details on how redirects
848 func (c *Client) Post(url, contentType string, body io.Reader) (resp *Response, err error) {
849 req, err := NewRequest("POST", url, body)
853 req.Header.Set("Content-Type", contentType)
857 // PostForm issues a POST to the specified URL, with data's keys and
858 // values URL-encoded as the request body.
860 // The Content-Type header is set to application/x-www-form-urlencoded.
861 // To set other headers, use NewRequest and DefaultClient.Do.
863 // When err is nil, resp always contains a non-nil resp.Body.
864 // Caller should close resp.Body when done reading from it.
866 // PostForm is a wrapper around DefaultClient.PostForm.
868 // See the Client.Do method documentation for details on how redirects
871 // To make a request with a specified context.Context, use NewRequestWithContext
872 // and DefaultClient.Do.
873 func PostForm(url string, data url.Values) (resp *Response, err error) {
874 return DefaultClient.PostForm(url, data)
877 // PostForm issues a POST to the specified URL,
878 // with data's keys and values URL-encoded as the request body.
880 // The Content-Type header is set to application/x-www-form-urlencoded.
881 // To set other headers, use NewRequest and Client.Do.
883 // When err is nil, resp always contains a non-nil resp.Body.
884 // Caller should close resp.Body when done reading from it.
886 // See the Client.Do method documentation for details on how redirects
889 // To make a request with a specified context.Context, use NewRequestWithContext
891 func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error) {
892 return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
895 // Head issues a HEAD to the specified URL. If the response is one of
896 // the following redirect codes, Head follows the redirect, up to a
897 // maximum of 10 redirects:
899 // 301 (Moved Permanently)
902 // 307 (Temporary Redirect)
903 // 308 (Permanent Redirect)
905 // Head is a wrapper around DefaultClient.Head.
907 // To make a request with a specified context.Context, use NewRequestWithContext
908 // and DefaultClient.Do.
909 func Head(url string) (resp *Response, err error) {
910 return DefaultClient.Head(url)
913 // Head issues a HEAD to the specified URL. If the response is one of the
914 // following redirect codes, Head follows the redirect after calling the
915 // Client's CheckRedirect function:
917 // 301 (Moved Permanently)
920 // 307 (Temporary Redirect)
921 // 308 (Permanent Redirect)
923 // To make a request with a specified context.Context, use NewRequestWithContext
925 func (c *Client) Head(url string) (resp *Response, err error) {
926 req, err := NewRequest("HEAD", url, nil)
933 // CloseIdleConnections closes any connections on its Transport which
934 // were previously connected from previous requests but are now
935 // sitting idle in a "keep-alive" state. It does not interrupt any
936 // connections currently in use.
938 // If the Client's Transport does not have a CloseIdleConnections method
939 // then this method does nothing.
940 func (c *Client) CloseIdleConnections() {
941 type closeIdler interface {
942 CloseIdleConnections()
944 if tr, ok := c.transport().(closeIdler); ok {
945 tr.CloseIdleConnections()
949 // cancelTimerBody is an io.ReadCloser that wraps rc with two features:
950 // 1. On Read error or close, the stop func is called.
951 // 2. On Read failure, if reqDidTimeout is true, the error is wrapped and
952 // marked as net.Error that hit its timeout.
953 type cancelTimerBody struct {
954 stop func() // stops the time.Timer waiting to cancel the request
956 reqDidTimeout func() bool
959 func (b *cancelTimerBody) Read(p []byte) (n int, err error) {
960 n, err = b.rc.Read(p)
967 if b.reqDidTimeout() {
969 err: err.Error() + " (Client.Timeout or context cancellation while reading body)",
976 func (b *cancelTimerBody) Close() error {
982 func shouldCopyHeaderOnRedirect(headerKey string, initial, dest *url.URL) bool {
983 switch CanonicalHeaderKey(headerKey) {
984 case "Authorization", "Www-Authenticate", "Cookie", "Cookie2":
985 // Permit sending auth/cookie headers from "foo.com"
988 // Note that we don't send all cookies to subdomains
989 // automatically. This function is only used for
990 // Cookies set explicitly on the initial outgoing
991 // client request. Cookies automatically added via the
992 // CookieJar mechanism continue to follow each
993 // cookie's scope as set by Set-Cookie. But for
994 // outgoing requests with the Cookie header set
995 // directly, we don't know their scope, so we assume
996 // it's for *.domain.com.
998 ihost := idnaASCIIFromURL(initial)
999 dhost := idnaASCIIFromURL(dest)
1000 return isDomainOrSubdomain(dhost, ihost)
1002 // All other headers are copied:
1006 // isDomainOrSubdomain reports whether sub is a subdomain (or exact
1007 // match) of the parent domain.
1009 // Both domains must already be in canonical form.
1010 func isDomainOrSubdomain(sub, parent string) bool {
1014 // If sub is "foo.example.com" and parent is "example.com",
1015 // that means sub must end in "."+parent.
1016 // Do it without allocating.
1017 if !strings.HasSuffix(sub, parent) {
1020 return sub[len(sub)-len(parent)-1] == '.'
1023 func stripPassword(u *url.URL) string {
1024 _, passSet := u.User.Password()
1026 return strings.Replace(u.String(), u.User.String()+"@", u.User.Username()+":***@", 1)