net/http: add Request.RequestURI field

The new url.URL's parsing can be too canonicalizing for
certain applications. By keeping the original request URI
around, we give applications a gross escape hatch while
keeping the URL package clean and simple for normal uses.

(From a discussion with Gary Burd, Gustavo Niemeyer,
and Russ Cox.)

Fixes #2782

R=golang-dev, rsc, dsymonds
CC=golang-dev
https://golang.org/cl/5580044

src/pkg/net/http/client.go

@@ -116,6 +116,10 @@ func send(req *Request, t RoundTripper) (resp *Response, err error) {
 		return nil, errors.New("http: nil Request.URL")
 	}
 
+	if req.RequestURI != "" {
+		return nil, errors.New("http: Request.RequestURI can't be set in client requests.")
+	}
+
 	// 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.

src/pkg/net/http/client_test.go

@@ -428,3 +428,15 @@ func TestClientInsecureTransport(t *testing.T) {
 		}
 	}
 }
+
+func TestClientErrorWithRequestURI(t *testing.T) {
+	req, _ := NewRequest("GET", "http://localhost:1234/", nil)
+	req.RequestURI = "/this/field/is/illegal/and/should/error/"
+	_, err := DefaultClient.Do(req)
+	if err == nil {
+		t.Fatalf("expected an error")
+	}
+	if !strings.Contains(err.Error(), "RequestURI") {
+		t.Errorf("wanted error mentioning RequestURI; got error: %v", err)
+	}
+}

src/pkg/net/http/readrequest_test.go

@@ -64,6 +64,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 7,
 			Host:          "www.techcrunch.com",
+			RequestURI:    "http://www.techcrunch.com/",
 		},
 
 		"abcdef\n",
@@ -89,6 +90,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 0,
 			Host:          "foo.com",
+			RequestURI:    "/",
 		},
 
 		noBody,
@@ -114,6 +116,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 0,
 			Host:          "test",
+			RequestURI:    "//user@host/is/actually/a/path/",
 		},
 
 		noBody,
@@ -163,6 +166,7 @@ var reqTests = []reqTest{
 			Header:           Header{},
 			ContentLength:    -1,
 			Host:             "foo.com",
+			RequestURI:       "/",
 		},
 
 		"foobar",
@@ -188,6 +192,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 0,
 			Host:          "www.google.com:443",
+			RequestURI:    "www.google.com:443",
 		},
 
 		noBody,
@@ -211,6 +216,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 0,
 			Host:          "127.0.0.1:6060",
+			RequestURI:    "127.0.0.1:6060",
 		},
 
 		noBody,
@@ -234,6 +240,7 @@ var reqTests = []reqTest{
 			Close:         false,
 			ContentLength: 0,
 			Host:          "",
+			RequestURI:    "/_goRPC_",
 		},
 
 		noBody,

src/pkg/net/http/request.go

@@ -153,6 +153,12 @@ type Request struct {
 	// This field is ignored by the HTTP client.
 	RemoteAddr string
 
+	// RequestURI is the unmodified Request-URI of the
+	// Request-Line (RFC 2616, Section 5.1) as sent by the client
+	// to a server. Usually the URL field should be used instead.
+	// It is an error to set this field in an HTTP client request.
+	RequestURI string
+
 	// TLS allows HTTP servers and other software to record
 	// information about the TLS connection on which the request
 	// was received. This field is not filled in by ReadRequest.
@@ -459,8 +465,8 @@ func ReadRequest(b *bufio.Reader) (req *Request, err error) {
 	if f = strings.SplitN(s, " ", 3); len(f) < 3 {
 		return nil, &badStringError{"malformed HTTP request", s}
 	}
-	var rawurl string
+	req.Method, req.RequestURI, req.Proto = f[0], f[1], f[2]
-	req.Method, rawurl, req.Proto = f[0], f[1], f[2]
+	rawurl := req.RequestURI
 	var ok bool
 	if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok {
 		return nil, &badStringError{"malformed HTTP version", req.Proto}