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http: better handling of 0-length Request.Body

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As rsc suggested after change 58a6bdac3d12 was committed, we
now read the first byte of Request.Body when the
Request.ContentLength is 0 to disambiguate between a truly
zero-length body and a body of unknown length where the user
didn't set the ContentLength field.

This was also causing the reverse proxy problem where incoming
requests (which always have a body, of private type http.body,
even for 0-lengthed requests) were being relayed to the http
Transport for fetching, which was serializing the request as a
chunked request (since ContentLength was 0 and Body was
non-nil)

Fixes #1999

R=golang-dev, kevlar
CC=golang-dev
https://golang.org/cl/4628063
This commit is contained in:
Brad Fitzpatrick 2011-06-24 16:46:14 -07:00
parent e16b74075f
commit 5d4eea6a2f
4 changed files with 114 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/pkg/http/request.go
View File

@ -511,13 +511,6 @@ func NewRequest(method, url string, body io.Reader) (*Request, os.Error) {
req.ContentLength = int64(v.Len())
case *bytes.Buffer:
req.ContentLength = int64(v.Len())
default:
req.ContentLength = -1 // chunked
}
if req.ContentLength == 0 {
// To prevent chunking and disambiguate this
// from the default ContentLength zero value.
req.TransferEncoding = []string{"identity"}
}
}

119
src/pkg/http/requestwrite_test.go
View File

@ -6,6 +6,7 @@ package http
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
@ -15,7 +16,7 @@ import (
type reqWriteTest struct {
Req Request
Body []byte
Body interface{} // optional []byte or func() io.ReadCloser to populate Req.Body
Raw string
RawProxy string
}
@ -98,13 +99,13 @@ var reqWriteTests = []reqWriteTest{
"Host: www.google.com\r\n" +
"User-Agent: Go http package\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
"6\r\nabcdef\r\n0\r\n\r\n",
chunk("abcdef") + chunk(""),
"GET http://www.google.com/search HTTP/1.1\r\n" +
"Host: www.google.com\r\n" +
"User-Agent: Go http package\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
"6\r\nabcdef\r\n0\r\n\r\n",
chunk("abcdef") + chunk(""),
},
// HTTP/1.1 POST => chunked coding; body; empty trailer
{
@ -129,14 +130,14 @@ var reqWriteTests = []reqWriteTest{
"User-Agent: Go http package\r\n" +
"Connection: close\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
"6\r\nabcdef\r\n0\r\n\r\n",
chunk("abcdef") + chunk(""),
"POST http://www.google.com/search HTTP/1.1\r\n" +
"Host: www.google.com\r\n" +
"User-Agent: Go http package\r\n" +
"Connection: close\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
"6\r\nabcdef\r\n0\r\n\r\n",
chunk("abcdef") + chunk(""),
},
// HTTP/1.1 POST with Content-Length, no chunking
@ -224,13 +225,72 @@ var reqWriteTests = []reqWriteTest{
"User-Agent: Go http package\r\n" +
"\r\n",
},
// Request with a 0 ContentLength and a 0 byte body.
{
Request{
Method: "POST",
RawURL: "/",
Host: "example.com",
ProtoMajor: 1,
ProtoMinor: 1,
ContentLength: 0, // as if unset by user
},
func() io.ReadCloser { return ioutil.NopCloser(io.LimitReader(strings.NewReader("xx"), 0)) },
"POST / HTTP/1.1\r\n" +
"Host: example.com\r\n" +
"User-Agent: Go http package\r\n" +
"\r\n",
"POST / HTTP/1.1\r\n" +
"Host: example.com\r\n" +
"User-Agent: Go http package\r\n" +
"\r\n",
},
// Request with a 0 ContentLength and a 1 byte body.
{
Request{
Method: "POST",
RawURL: "/",
Host: "example.com",
ProtoMajor: 1,
ProtoMinor: 1,
ContentLength: 0, // as if unset by user
},
func() io.ReadCloser { return ioutil.NopCloser(io.LimitReader(strings.NewReader("xx"), 1)) },
"POST / HTTP/1.1\r\n" +
"Host: example.com\r\n" +
"User-Agent: Go http package\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
chunk("x") + chunk(""),
"POST / HTTP/1.1\r\n" +
"Host: example.com\r\n" +
"User-Agent: Go http package\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
chunk("x") + chunk(""),
},
}
func TestRequestWrite(t *testing.T) {
for i := range reqWriteTests {
tt := &reqWriteTests[i]
setBody := func() {
switch b := tt.Body.(type) {
case []byte:
tt.Req.Body = ioutil.NopCloser(bytes.NewBuffer(b))
case func() io.ReadCloser:
tt.Req.Body = b()
}
}
if tt.Body != nil {
tt.Req.Body = ioutil.NopCloser(bytes.NewBuffer(tt.Body))
setBody()
}
if tt.Req.Header == nil {
tt.Req.Header = make(Header)
@ -248,7 +308,7 @@ func TestRequestWrite(t *testing.T) {
}
if tt.Body != nil {
tt.Req.Body = ioutil.NopCloser(bytes.NewBuffer(tt.Body))
setBody()
}
var praw bytes.Buffer
err = tt.Req.WriteProxy(&praw)
@ -280,41 +340,30 @@ func (rc *closeChecker) Close() os.Error {
func TestRequestWriteClosesBody(t *testing.T) {
rc := &closeChecker{Reader: strings.NewReader("my body")}
req, _ := NewRequest("POST", "http://foo.com/", rc)
if g, e := req.ContentLength, int64(-1); g != e {
t.Errorf("got req.ContentLength %d, want %d", g, e)
if req.ContentLength != 0 {
t.Errorf("got req.ContentLength %d, want 0", req.ContentLength)
}
buf := new(bytes.Buffer)
req.Write(buf)
if !rc.closed {
t.Error("body not closed after write")
}
if g, e := buf.String(), "POST / HTTP/1.1\r\nHost: foo.com\r\nUser-Agent: Go http package\r\nTransfer-Encoding: chunked\r\n\r\n7\r\nmy body\r\n0\r\n\r\n"; g != e {
t.Errorf("write:\n got: %s\nwant: %s", g, e)
expected := "POST / HTTP/1.1\r\n" +
"Host: foo.com\r\n" +
"User-Agent: Go http package\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
// TODO: currently we don't buffer before chunking, so we get a
// single "m" chunk before the other chunks, as this was the 1-byte
// read from our MultiReader where we stiched the Body back together
// after sniffing whether the Body was 0 bytes or not.
chunk("m") +
chunk("y body") +
chunk("")
if buf.String() != expected {
t.Errorf("write:\n got: %s\nwant: %s", buf.String(), expected)
}
}
func TestZeroLengthNewRequest(t *testing.T) {
var buf bytes.Buffer
// Writing with default identity encoding
req, _ := NewRequest("PUT", "http://foo.com/", strings.NewReader(""))
if len(req.TransferEncoding) == 0 || req.TransferEncoding[0] != "identity" {
t.Fatalf("got req.TransferEncoding of %v, want %v", req.TransferEncoding, []string{"identity"})
}
if g, e := req.ContentLength, int64(0); g != e {
t.Errorf("got req.ContentLength %d, want %d", g, e)
}
req.Write(&buf)
if g, e := buf.String(), "PUT / HTTP/1.1\r\nHost: foo.com\r\nUser-Agent: Go http package\r\nContent-Length: 0\r\n\r\n"; g != e {
t.Errorf("identity write:\n got: %s\nwant: %s", g, e)
}
// Overriding identity encoding and forcing chunked.
req, _ = NewRequest("PUT", "http://foo.com/", strings.NewReader(""))
req.TransferEncoding = nil
buf.Reset()
req.Write(&buf)
if g, e := buf.String(), "PUT / HTTP/1.1\r\nHost: foo.com\r\nUser-Agent: Go http package\r\nTransfer-Encoding: chunked\r\n\r\n0\r\n\r\n"; g != e {
t.Errorf("chunked write:\n got: %s\nwant: %s", g, e)
}
func chunk(s string) string {
return fmt.Sprintf("%x\r\n%s\r\n", len(s), s)
}

3
src/pkg/http/reverseproxy_test.go
View File

@ -17,6 +17,9 @@ func TestReverseProxy(t *testing.T) {
const backendResponse = "I am the backend"
const backendStatus = 404
backend := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
if len(r.TransferEncoding) > 0 {
t.Errorf("backend got unexpected TransferEncoding: %v", r.TransferEncoding)
}
if r.Header.Get("X-Forwarded-For") == "" {
t.Errorf("didn't get X-Forwarded-For header")
}

31
src/pkg/http/transfer.go
View File

@ -5,6 +5,7 @@
package http
import (
"bytes"
"bufio"
"io"
"io/ioutil"
@ -17,7 +18,8 @@ import (
// sanitizes them without changing the user object and provides methods for
// writing the respective header, body and trailer in wire format.
type transferWriter struct {
Body io.ReadCloser
Body io.Reader
BodyCloser io.Closer
ResponseToHEAD bool
ContentLength int64
Close bool
@ -33,16 +35,37 @@ func newTransferWriter(r interface{}) (t *transferWriter, err os.Error) {
switch rr := r.(type) {
case *Request:
t.Body = rr.Body
t.BodyCloser = rr.Body
t.ContentLength = rr.ContentLength
t.Close = rr.Close
t.TransferEncoding = rr.TransferEncoding
t.Trailer = rr.Trailer
atLeastHTTP11 = rr.ProtoAtLeast(1, 1)
if t.Body != nil && t.ContentLength <= 0 && len(t.TransferEncoding) == 0 && atLeastHTTP11 {
t.TransferEncoding = []string{"chunked"}
if t.Body != nil && len(t.TransferEncoding) == 0 && atLeastHTTP11 {
if t.ContentLength == 0 {
// Test to see if it's actually zero or just unset.
var buf [1]byte
n, _ := io.ReadFull(t.Body, buf[:])
if n == 1 {
// Oh, guess there is data in this Body Reader after all.
// The ContentLength field just wasn't set.
// Stich the Body back together again, re-attaching our
// consumed byte.
t.ContentLength = -1
t.Body = io.MultiReader(bytes.NewBuffer(buf[:]), t.Body)
} else {
// Body is actually empty.
t.Body = nil
t.BodyCloser = nil
}
}
if t.ContentLength < 0 {
t.TransferEncoding = []string{"chunked"}
}
}
case *Response:
t.Body = rr.Body
t.BodyCloser = rr.Body
t.ContentLength = rr.ContentLength
t.Close = rr.Close
t.TransferEncoding = rr.TransferEncoding
@ -147,7 +170,7 @@ func (t *transferWriter) WriteBody(w io.Writer) (err os.Error) {
if err != nil {
return err
}
if err = t.Body.Close(); err != nil {
if err = t.BodyCloser.Close(); err != nil {
return err
}
}