http: have client set Content-Length when possible

Also some cleanup, removing redundant code. Make more
things use NewRequest. Add some tests, docs.

R=golang-dev, adg, rsc
CC=golang-dev
https://golang.org/cl/4561047

src/pkg/http/client.go

@@ -11,9 +11,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
-	"strconv"
 	"strings"
 )
 
@@ -228,23 +226,12 @@ func Post(url string, bodyType string, body io.Reader) (r *Response, err os.Erro
 //
 // 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) {
-	var req Request
+	req, err := NewRequest("POST", url, body)
-	req.Method = "POST"
-	req.ProtoMajor = 1
-	req.ProtoMinor = 1
-	req.Close = true
-	req.Body = ioutil.NopCloser(body)
-	req.Header = Header{
-		"Content-Type": {bodyType},
-	}
-	req.TransferEncoding = []string{"chunked"}
-
-	req.URL, err = ParseURL(url)
 	if err != nil {
 		return nil, err
 	}
-
+	req.Header.Set("Content-Type", bodyType)
-	return send(&req, c.Transport)
+	return send(req, c.Transport)
 }
 
 // PostForm issues a POST to the specified URL, 
@@ -262,25 +249,7 @@ func PostForm(url string, data map[string]string) (r *Response, err os.Error) {
 //
 // Caller should close r.Body when done reading from it.
 func (c *Client) PostForm(url string, data map[string]string) (r *Response, err os.Error) {
-	var req Request
+	return c.Post(url, "application/x-www-form-urlencoded", urlencode(data))
-	req.Method = "POST"
-	req.ProtoMajor = 1
-	req.ProtoMinor = 1
-	req.Close = true
-	body := urlencode(data)
-	req.Body = ioutil.NopCloser(body)
-	req.Header = Header{
-		"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, c.Transport)
 }
 
 // TODO: remove this function when PostForm takes a multimap.

src/pkg/http/client_test.go

@@ -78,6 +78,61 @@ func TestGetRequestFormat(t *testing.T) {
 	}
 }
 
+func TestPostRequestFormat(t *testing.T) {
+	tr := &recordingTransport{}
+	client := &Client{Transport: tr}
+
+	url := "http://dummy.faketld/"
+	json := `{"key":"value"}`
+	b := strings.NewReader(json)
+	client.Post(url, "application/json", b) // Note: doesn't hit network
+
+	if tr.req.Method != "POST" {
+		t.Errorf("got method %q, want %q", tr.req.Method, "POST")
+	}
+	if tr.req.URL.String() != url {
+		t.Errorf("got URL %q, want %q", tr.req.URL.String(), url)
+	}
+	if tr.req.Header == nil {
+		t.Fatalf("expected non-nil request Header")
+	}
+	if tr.req.Close {
+		t.Error("got Close true, want false")
+	}
+	if g, e := tr.req.ContentLength, int64(len(json)); g != e {
+		t.Errorf("got ContentLength %d, want %d", g, e)
+	}
+}
+
+func TestPostFormRequestFormat(t *testing.T) {
+	tr := &recordingTransport{}
+	client := &Client{Transport: tr}
+
+	url := "http://dummy.faketld/"
+	form := map[string]string{"foo": "bar"}
+	client.PostForm(url, form) // Note: doesn't hit network
+
+	if tr.req.Method != "POST" {
+		t.Errorf("got method %q, want %q", tr.req.Method, "POST")
+	}
+	if tr.req.URL.String() != url {
+		t.Errorf("got URL %q, want %q", tr.req.URL.String(), url)
+	}
+	if tr.req.Header == nil {
+		t.Fatalf("expected non-nil request Header")
+	}
+	if g, e := tr.req.Header.Get("Content-Type"), "application/x-www-form-urlencoded"; g != e {
+		t.Errorf("got Content-Type %q, want %q", g, e)
+	}
+	if tr.req.Close {
+		t.Error("got Close true, want false")
+	}
+	if g, e := tr.req.ContentLength, int64(len("foo=bar")); g != e {
+		t.Errorf("got ContentLength %d, want %d", g, e)
+	}
+
+}
+
 func TestRedirects(t *testing.T) {
 	var ts *httptest.Server
 	ts = httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {

src/pkg/http/request.go

@@ -10,6 +10,7 @@ package http
 
 import (
 	"bufio"
+	"bytes"
 	"crypto/tls"
 	"container/vector"
 	"encoding/base64"
@@ -231,7 +232,7 @@ const defaultUserAgent = "Go http package"
 //	Method (defaults to "GET")
 //	UserAgent (defaults to defaultUserAgent)
 //	Referer
-//	Header
+//	Header (only keys not already in this list)
 //	Cookie
 //	ContentLength
 //	TransferEncoding
@@ -256,6 +257,9 @@ func (req *Request) WriteProxy(w io.Writer) os.Error {
 func (req *Request) write(w io.Writer, usingProxy bool) os.Error {
 	host := req.Host
 	if host == "" {
+		if req.URL == nil {
+			return os.NewError("http: Request.Write on Request with no Host or URL set")
+		}
 		host = req.URL.Host
 	}
 
@@ -475,6 +479,17 @@ func NewRequest(method, url string, body io.Reader) (*Request, os.Error) {
 		Body:       rc,
 		Host:       u.Host,
 	}
+	if body != nil {
+		switch v := body.(type) {
+		case *strings.Reader:
+			req.ContentLength = int64(v.Len())
+		case *bytes.Buffer:
+			req.ContentLength = int64(v.Len())
+		default:
+			req.ContentLength = -1 // chunked
+		}
+	}
+
 	return req, nil
 }
 

src/pkg/http/requestwrite_test.go

@@ -175,6 +175,35 @@ var reqWriteTests = []reqWriteTest{
 			"abcdef",
 	},
 
+	// HTTP/1.1 POST with Content-Length in headers
+	{
+		Request{
+			Method: "POST",
+			RawURL: "http://example.com/",
+			Host:   "example.com",
+			Header: Header{
+				"Content-Length": []string{"10"}, // ignored
+			},
+			ContentLength: 6,
+		},
+
+		[]byte("abcdef"),
+
+		"POST http://example.com/ HTTP/1.1\r\n" +
+			"Host: example.com\r\n" +
+			"User-Agent: Go http package\r\n" +
+			"Content-Length: 6\r\n" +
+			"\r\n" +
+			"abcdef",
+
+		"POST http://example.com/ HTTP/1.1\r\n" +
+			"Host: example.com\r\n" +
+			"User-Agent: Go http package\r\n" +
+			"Content-Length: 6\r\n" +
+			"\r\n" +
+			"abcdef",
+	},
+
 	// default to HTTP/1.1
 	{
 		Request{

src/pkg/strings/reader.go

@@ -17,6 +17,12 @@ type Reader struct {
 	prevRune int // index of previous rune; or < 0
 }
 
+// Len returns the number of bytes of the unread portion of the
+// string.
+func (r *Reader) Len() int {
+	return len(r.s) - r.i
+}
+
 func (r *Reader) Read(b []byte) (n int, err os.Error) {
 	if r.i >= len(r.s) {
 		return 0, os.EOF