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// 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 (
"bufio"
"bytes"
"crypto/tls"
"encoding/base64"
"fmt"
"io"
"net"
"os"
"strconv"
"strings"
)
// 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
}
// Send issues an HTTP request. Caller should close resp.Body when done reading it.
//
// TODO: support persistent connections (multiple requests on a single connection).
// send() method is nonpublic because, when we refactor the code for persistent
// connections, it may no longer make sense to have a method with this signature.
func send(req *Request) (resp *Response, err os.Error) {
if req.URL.Scheme != "http" && req.URL.Scheme != "https" {
return nil, &badStringError{"unsupported protocol scheme", req.URL.Scheme}
}
addr := req.URL.Host
if !hasPort(addr) {
addr += ":" + req.URL.Scheme
}
info := req.URL.RawUserinfo
if len(info) > 0 {
enc := base64.URLEncoding
encoded := make([]byte, enc.EncodedLen(len(info)))
enc.Encode(encoded, []byte(info))
if req.Header == nil {
req.Header = make(map[string]string)
}
req.Header["Authorization"] = "Basic " + string(encoded)
}
var conn io.ReadWriteCloser
if req.URL.Scheme == "http" {
conn, err = net.Dial("tcp", "", addr)
if err != nil {
return nil, err
}
} else { // https
conn, err = tls.Dial("tcp", "", addr, nil)
if err != nil {
return nil, err
}
h := req.URL.Host
if hasPort(h) {
h = h[0:strings.LastIndex(h, ":")]
}
if err := conn.(*tls.Conn).VerifyHostname(h); err != nil {
return nil, err
}
}
err = req.Write(conn)
if err != nil {
conn.Close()
return nil, err
}
reader := bufio.NewReader(conn)
resp, err = ReadResponse(reader, req.Method)
if err != nil {
conn.Close()
return nil, err
}
resp.Body = readClose{resp.Body, conn}
return
}
// 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, it follows the redirect, up to a maximum of 10 redirects:
//
// 301 (Moved Permanently)
// 302 (Found)
// 303 (See Other)
// 307 (Temporary Redirect)
//
// finalURL is the URL from which the response was fetched -- identical to the
// input URL unless redirects were followed.
//
// Caller should close r.Body when done reading it.
func Get(url string) (r *Response, finalURL string, err os.Error) {
// TODO: if/when we add cookie support, the redirected request shouldn't
// necessarily supply the same cookies as the original.
// TODO: set referrer header on redirects.
for redirect := 0; ; redirect++ {
if redirect >= 10 {
err = os.ErrorString("stopped after 10 redirects")
break
}
var req Request
if req.URL, err = ParseURL(url); err != nil {
break
}
url = req.URL.String()
if r, err = send(&req); err != nil {
break
}
if shouldRedirect(r.StatusCode) {
r.Body.Close()
if url = r.GetHeader("Location"); url == "" {
err = os.ErrorString(fmt.Sprintf("%d response missing Location header", r.StatusCode))
break
}
continue
}
finalURL = url
return
}
err = &URLError{"Get", url, err}
return
}
// Post issues a POST to the specified URL.
//
// Caller should close r.Body when done reading it.
func Post(url string, bodyType string, body io.Reader) (r *Response, err os.Error) {
var req Request
req.Method = "POST"
req.ProtoMajor = 1
req.ProtoMinor = 1
req.Close = true
req.Body = nopCloser{body}
req.Header = map[string]string{
"Content-Type": bodyType,
}
req.TransferEncoding = []string{"chunked"}
req.URL, err = ParseURL(url)
if err != nil {
return nil, err
}
return send(&req)
}
// 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 it.
func PostForm(url string, data map[string]string) (r *Response, err os.Error) {
var req Request
req.Method = "POST"
req.ProtoMajor = 1
req.ProtoMinor = 1
req.Close = true
body := urlencode(data)
req.Body = nopCloser{body}
req.Header = map[string]string{
"Content-Type": "application/x-www-form-urlencoded",
"Content-Length": strconv.Itoa(body.Len()),
}
req.ContentLength = int64(body.Len())
req.URL, err = ParseURL(url)
if err != nil {
return nil, err
}
return send(&req)
}
// TODO: remove this function when PostForm takes a multimap.
func urlencode(data map[string]string) (b *bytes.Buffer) {
m := make(map[string][]string, len(data))
for k, v := range data {
m[k] = []string{v}
}
return bytes.NewBuffer([]byte(EncodeQuery(m)))
}
// Head issues a HEAD to the specified URL.
func Head(url string) (r *Response, err os.Error) {
var req Request
req.Method = "HEAD"
if req.URL, err = ParseURL(url); err != nil {
return
}
url = req.URL.String()
if r, err = send(&req); err != nil {
return
}
return
}
type nopCloser struct {
io.Reader
}
func (nopCloser) Close() os.Error { return nil }