1 files changed, 94 insertions, 17 deletions
diff --git a/src/pkg/net/http/client.go b/src/pkg/net/http/client.go
index 22f2e865c..a5a3abe61 100644
--- a/src/pkg/net/http/client.go
+++ b/src/pkg/net/http/client.go
@@ -14,9 +14,12 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
 	"net/url"
 	"strings"
+	"sync"
+	"time"
 )
 
 // A Client is an HTTP client. Its zero value (DefaultClient) is a
@@ -52,6 +55,20 @@ type Client struct {
 	// If Jar is nil, cookies are not sent in requests and ignored
 	// in responses.
 	Jar CookieJar
+
+	// Timeout specifies a time limit for requests made by this
+	// Client. The timeout includes connection time, any
+	// redirects, and reading the response body. The timer remains
+	// running after Get, Head, Post, or Do return and will
+	// interrupt reading of the Response.Body.
+	//
+	// A Timeout of zero means no timeout.
+	//
+	// The Client's Transport must support the CancelRequest
+	// method or Client will return errors when attempting to make
+	// a request with Get, Head, Post, or Do. Client's default
+	// Transport (DefaultTransport) supports CancelRequest.
+	Timeout time.Duration
 }
 
 // DefaultClient is the default Client and is used by Get, Head, and Post.
@@ -74,8 +91,9 @@ type RoundTripper interface {
 	// authentication, or cookies.
 	//
 	// RoundTrip should not modify the request, except for
-	// consuming and closing the Body. The request's URL and
-	// Header fields are guaranteed to be initialized.
+	// consuming and closing the Body, including on errors. The
+	// request's URL and Header fields are guaranteed to be
+	// initialized.
 	RoundTrip(*Request) (*Response, error)
 }
 
@@ -97,7 +115,7 @@ func (c *Client) send(req *Request) (*Response, error) {
 			req.AddCookie(cookie)
 		}
 	}
-	resp, err := send(req, c.Transport)
+	resp, err := send(req, c.transport())
 	if err != nil {
 		return nil, err
 	}
@@ -123,6 +141,9 @@ func (c *Client) send(req *Request) (*Response, error) {
 // (typically Transport) may not be able to re-use a persistent TCP
 // connection to the server for a subsequent "keep-alive" request.
 //
+// The request Body, if non-nil, will be closed by the underlying
+// Transport, even on errors.
+//
 // Generally Get, Post, or PostForm will be used instead of Do.
 func (c *Client) Do(req *Request) (resp *Response, err error) {
 	if req.Method == "GET" || req.Method == "HEAD" {
@@ -134,22 +155,28 @@ func (c *Client) Do(req *Request) (resp *Response, err error) {
 	return c.send(req)
 }
 
+func (c *Client) transport() RoundTripper {
+	if c.Transport != nil {
+		return c.Transport
+	}
+	return DefaultTransport
+}
+
 // send issues an HTTP request.
 // Caller should close resp.Body when done reading from it.
 func send(req *Request, t RoundTripper) (resp *Response, err error) {
 	if t == nil {
-		t = DefaultTransport
-		if t == nil {
-			err = errors.New("http: no Client.Transport or DefaultTransport")
-			return
-		}
+		req.closeBody()
+		return nil, errors.New("http: no Client.Transport or DefaultTransport")
 	}
 
 	if req.URL == nil {
+		req.closeBody()
 		return nil, errors.New("http: nil Request.URL")
 	}
 
 	if req.RequestURI != "" {
+		req.closeBody()
 		return nil, errors.New("http: Request.RequestURI can't be set in client requests.")
 	}
 
@@ -257,21 +284,40 @@ func (c *Client) doFollowingRedirects(ireq *Request, shouldRedirect func(int) bo
 	var via []*Request
 
 	if ireq.URL == nil {
+		ireq.closeBody()
 		return nil, errors.New("http: nil Request.URL")
 	}
 
+	var reqmu sync.Mutex // guards req
 	req := ireq
+
+	var timer *time.Timer
+	if c.Timeout > 0 {
+		type canceler interface {
+			CancelRequest(*Request)
+		}
+		tr, ok := c.transport().(canceler)
+		if !ok {
+			return nil, fmt.Errorf("net/http: Client Transport of type %T doesn't support CancelRequest; Timeout not supported", c.transport())
+		}
+		timer = time.AfterFunc(c.Timeout, func() {
+			reqmu.Lock()
+			defer reqmu.Unlock()
+			tr.CancelRequest(req)
+		})
+	}
+
 	urlStr := "" // next relative or absolute URL to fetch (after first request)
 	redirectFailed := false
 	for redirect := 0; ; redirect++ {
 		if redirect != 0 {
-			req = new(Request)
-			req.Method = ireq.Method
+			nreq := new(Request)
+			nreq.Method = ireq.Method
 			if ireq.Method == "POST" || ireq.Method == "PUT" {
-				req.Method = "GET"
+				nreq.Method = "GET"
 			}
-			req.Header = make(Header)
-			req.URL, err = base.Parse(urlStr)
+			nreq.Header = make(Header)
+			nreq.URL, err = base.Parse(urlStr)
 			if err != nil {
 				break
 			}
@@ -279,15 +325,18 @@ func (c *Client) doFollowingRedirects(ireq *Request, shouldRedirect func(int) bo
 				// Add the Referer header.
 				lastReq := via[len(via)-1]
 				if lastReq.URL.Scheme != "https" {
-					req.Header.Set("Referer", lastReq.URL.String())
+					nreq.Header.Set("Referer", lastReq.URL.String())
 				}
 
-				err = redirectChecker(req, via)
+				err = redirectChecker(nreq, via)
 				if err != nil {
 					redirectFailed = true
 					break
 				}
 			}
+			reqmu.Lock()
+			req = nreq
+			reqmu.Unlock()
 		}
 
 		urlStr = req.URL.String()
@@ -296,6 +345,12 @@ func (c *Client) doFollowingRedirects(ireq *Request, shouldRedirect func(int) bo
 		}
 
 		if shouldRedirect(resp.StatusCode) {
+			// Read the body if small so underlying TCP connection will be re-used.
+			// No need to check for errors: if it fails, Transport won't reuse it anyway.
+			const maxBodySlurpSize = 2 << 10
+			if resp.ContentLength == -1 || resp.ContentLength <= maxBodySlurpSize {
+				io.CopyN(ioutil.Discard, resp.Body, maxBodySlurpSize)
+			}
 			resp.Body.Close()
 			if urlStr = resp.Header.Get("Location"); urlStr == "" {
 				err = errors.New(fmt.Sprintf("%d response missing Location header", resp.StatusCode))
@@ -305,7 +360,10 @@ func (c *Client) doFollowingRedirects(ireq *Request, shouldRedirect func(int) bo
 			via = append(via, req)
 			continue
 		}
-		return
+		if timer != nil {
+			resp.Body = &cancelTimerBody{timer, resp.Body}
+		}
+		return resp, nil
 	}
 
 	method := ireq.Method
@@ -349,7 +407,7 @@ func Post(url string, bodyType string, body io.Reader) (resp *Response, err erro
 // Caller should close resp.Body when done reading from it.
 //
 // If the provided body is also an io.Closer, it is closed after the
-// body is successfully written to the server.
+// request.
 func (c *Client) Post(url string, bodyType string, body io.Reader) (resp *Response, err error) {
 	req, err := NewRequest("POST", url, body)
 	if err != nil {
@@ -408,3 +466,22 @@ func (c *Client) Head(url string) (resp *Response, err error) {
 	}
 	return c.doFollowingRedirects(req, shouldRedirectGet)
 }
+
+type cancelTimerBody struct {
+	t  *time.Timer
+	rc io.ReadCloser
+}
+
+func (b *cancelTimerBody) Read(p []byte) (n int, err error) {
+	n, err = b.rc.Read(p)
+	if err == io.EOF {
+		b.t.Stop()
+	}
+	return
+}
+
+func (b *cancelTimerBody) Close() error {
+	err := b.rc.Close()
+	b.t.Stop()
+	return err
+}