/http/client.go
http://github.com/petar/GoHTTP · Go · 295 lines · 147 code · 28 blank · 120 comment · 38 complexity · 3c80cbd24656d69bf86582d2113076b3 MD5 · raw file
- // Copyright 2009 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- // Primitive HTTP client. See RFC 2616.
- package http
- import (
- "encoding/base64"
- "fmt"
- "io"
- "os"
- "strings"
- "url"
- )
- // A Client is an HTTP client. Its zero value (DefaultClient) is a usable client
- // that uses DefaultTransport.
- //
- // The Client's Transport typically has internal state (cached
- // TCP connections), so Clients should be reused instead of created as
- // needed. Clients are safe for concurrent use by multiple goroutines.
- //
- // Client is not yet very configurable.
- type Client struct {
- Transport RoundTripper // if nil, DefaultTransport is used
- // If CheckRedirect is not nil, the client calls it before
- // following an HTTP redirect. The arguments req and via
- // are the upcoming request and the requests made already,
- // oldest first. If CheckRedirect returns an error, the client
- // returns that error instead of issue the Request req.
- //
- // If CheckRedirect is nil, the Client uses its default policy,
- // which is to stop after 10 consecutive requests.
- CheckRedirect func(req *Request, via []*Request) os.Error
- }
- // DefaultClient is the default Client and is used by Get, Head, and Post.
- var DefaultClient = &Client{}
- // RoundTripper is an interface representing the ability to execute a
- // single HTTP transaction, obtaining the Response for a given Request.
- //
- // A RoundTripper must be safe for concurrent use by multiple
- // goroutines.
- type RoundTripper interface {
- // RoundTrip executes a single HTTP transaction, returning
- // the Response for the request req. RoundTrip should not
- // attempt to interpret the response. In particular,
- // RoundTrip must return err == nil if it obtained a response,
- // regardless of the response's HTTP status code. A non-nil
- // err should be reserved for failure to obtain a response.
- // Similarly, RoundTrip should not attempt to handle
- // higher-level protocol details such as redirects,
- // authentication, or cookies.
- //
- // RoundTrip may modify the request. The request Headers field is
- // guaranteed to be initialized.
- RoundTrip(req *Request) (resp *Response, err os.Error)
- }
- // Given a string of the form "host", "host:port", or "[ipv6::address]:port",
- // return true if the string includes a port.
- func hasPort(s string) bool { return strings.LastIndex(s, ":") > strings.LastIndex(s, "]") }
- // Used in Send to implement io.ReadCloser by bundling together the
- // bufio.Reader through which we read the response, and the underlying
- // network connection.
- type readClose struct {
- io.Reader
- io.Closer
- }
- // Do sends an HTTP request and returns an HTTP response, following
- // policy (e.g. redirects, cookies, auth) as configured on the client.
- //
- // A non-nil response always contains a non-nil resp.Body.
- //
- // Callers should close resp.Body when done reading from it. If
- // resp.Body is not closed, the Client's underlying RoundTripper
- // (typically Transport) may not be able to re-use a persistent TCP
- // connection to the server for a subsequent "keep-alive" request.
- //
- // Generally Get, Post, or PostForm will be used instead of Do.
- func (c *Client) Do(req *Request) (resp *Response, err os.Error) {
- if req.Method == "GET" || req.Method == "HEAD" {
- return c.doFollowingRedirects(req)
- }
- return send(req, c.Transport)
- }
- // send issues an HTTP request. Caller should close resp.Body when done reading from it.
- func send(req *Request, t RoundTripper) (resp *Response, err os.Error) {
- if t == nil {
- t = DefaultTransport
- if t == nil {
- err = os.NewError("no http.Client.Transport or http.DefaultTransport")
- return
- }
- }
- // Most the callers of send (Get, Post, et al) don't need
- // Headers, leaving it uninitialized. We guarantee to the
- // Transport that this has been initialized, though.
- if req.Header == nil {
- req.Header = make(Header)
- }
- info := req.URL.RawUserinfo
- if len(info) > 0 {
- if req.Header == nil {
- req.Header = make(Header)
- }
- req.Header.Set("Authorization", "Basic "+base64.URLEncoding.EncodeToString([]byte(info)))
- }
- return t.RoundTrip(req)
- }
- // True if the specified HTTP status code is one for which the Get utility should
- // automatically redirect.
- func shouldRedirect(statusCode int) bool {
- switch statusCode {
- case StatusMovedPermanently, StatusFound, StatusSeeOther, StatusTemporaryRedirect:
- return true
- }
- return false
- }
- // Get issues a GET to the specified URL. If the response is one of the following
- // redirect codes, Get follows the redirect, up to a maximum of 10 redirects:
- //
- // 301 (Moved Permanently)
- // 302 (Found)
- // 303 (See Other)
- // 307 (Temporary Redirect)
- //
- // Caller should close r.Body when done reading from it.
- //
- // Get is a convenience wrapper around DefaultClient.Get.
- func Get(url string) (r *Response, err os.Error) {
- return DefaultClient.Get(url)
- }
- // Get issues a GET to the specified URL. If the response is one of the
- // following redirect codes, Get follows the redirect after calling the
- // Client's CheckRedirect function.
- //
- // 301 (Moved Permanently)
- // 302 (Found)
- // 303 (See Other)
- // 307 (Temporary Redirect)
- //
- // Caller should close r.Body when done reading from it.
- func (c *Client) Get(url string) (r *Response, err os.Error) {
- req, err := NewRequest("GET", url, nil)
- if err != nil {
- return nil, err
- }
- return c.doFollowingRedirects(req)
- }
- func (c *Client) doFollowingRedirects(ireq *Request) (r *Response, err os.Error) {
- // TODO: if/when we add cookie support, the redirected request shouldn't
- // necessarily supply the same cookies as the original.
- var base *url.URL
- redirectChecker := c.CheckRedirect
- if redirectChecker == nil {
- redirectChecker = defaultCheckRedirect
- }
- var via []*Request
- req := ireq
- urlStr := "" // next relative or absolute URL to fetch (after first request)
- for redirect := 0; ; redirect++ {
- if redirect != 0 {
- req = new(Request)
- req.Method = ireq.Method
- req.Header = make(Header)
- req.URL, err = base.Parse(urlStr)
- if err != nil {
- break
- }
- if len(via) > 0 {
- // Add the Referer header.
- lastReq := via[len(via)-1]
- if lastReq.URL.Scheme != "https" {
- req.Header.Set("Referer", lastReq.URL.String())
- }
- err = redirectChecker(req, via)
- if err != nil {
- break
- }
- }
- }
- urlStr = req.URL.String()
- if r, err = send(req, c.Transport); err != nil {
- break
- }
- if shouldRedirect(r.StatusCode) {
- r.Body.Close()
- if urlStr = r.Header.Get("Location"); urlStr == "" {
- err = os.NewError(fmt.Sprintf("%d response missing Location header", r.StatusCode))
- break
- }
- base = req.URL
- via = append(via, req)
- continue
- }
- return
- }
- method := ireq.Method
- err = &url.Error{method[0:1] + strings.ToLower(method[1:]), urlStr, err}
- return
- }
- func defaultCheckRedirect(req *Request, via []*Request) os.Error {
- if len(via) >= 10 {
- return os.NewError("stopped after 10 redirects")
- }
- return nil
- }
- // Post issues a POST to the specified URL.
- //
- // Caller should close r.Body when done reading from it.
- //
- // Post is a wrapper around DefaultClient.Post
- func Post(url string, bodyType string, body io.Reader) (r *Response, err os.Error) {
- return DefaultClient.Post(url, bodyType, body)
- }
- // Post issues a POST to the specified URL.
- //
- // Caller should close r.Body when done reading from it.
- func (c *Client) Post(url string, bodyType string, body io.Reader) (r *Response, err os.Error) {
- req, err := NewRequest("POST", url, body)
- if err != nil {
- return nil, err
- }
- req.Header.Set("Content-Type", bodyType)
- return send(req, c.Transport)
- }
- // PostForm issues a POST to the specified URL,
- // with data's keys and values urlencoded as the request body.
- //
- // Caller should close r.Body when done reading from it.
- //
- // PostForm is a wrapper around DefaultClient.PostForm
- func PostForm(url string, data url.Values) (r *Response, err os.Error) {
- return DefaultClient.PostForm(url, data)
- }
- // PostForm issues a POST to the specified URL,
- // with data's keys and values urlencoded as the request body.
- //
- // Caller should close r.Body when done reading from it.
- func (c *Client) PostForm(url string, data url.Values) (r *Response, err os.Error) {
- return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
- }
- // Head issues a HEAD to the specified URL. If the response is one of the
- // following redirect codes, Head follows the redirect after calling the
- // Client's CheckRedirect function.
- //
- // 301 (Moved Permanently)
- // 302 (Found)
- // 303 (See Other)
- // 307 (Temporary Redirect)
- //
- // Head is a wrapper around DefaultClient.Head
- func Head(url string) (r *Response, err os.Error) {
- return DefaultClient.Head(url)
- }
- // Head issues a HEAD to the specified URL. If the response is one of the
- // following redirect codes, Head follows the redirect after calling the
- // Client's CheckRedirect function.
- //
- // 301 (Moved Permanently)
- // 302 (Found)
- // 303 (See Other)
- // 307 (Temporary Redirect)
- func (c *Client) Head(url string) (r *Response, err os.Error) {
- req, err := NewRequest("HEAD", url, nil)
- if err != nil {
- return nil, err
- }
- return c.doFollowingRedirects(req)
- }