http: add NewRequest helper

NewRequest will save a lot of boilerplate code.

This also updates some docs on Request.Write and
adds some tests.

R=rsc, petar-m, r
CC=golang-dev
https://golang.org/cl/4406047

src/pkg/http/request.go

@@ -199,10 +199,14 @@ const defaultUserAgent = "Go http package"
 //	UserAgent (defaults to defaultUserAgent)
 //	Referer
 //	Header
+//	Cookie
+//	ContentLength
+//	TransferEncoding
 //	Body
 //
-// If Body is present, Write forces "Transfer-Encoding: chunked" as a header
-// and then closes Body when finished sending it.
+// If Body is present but Content-Length is <= 0, Write adds
+// "Transfer-Encoding: chunked" to the header. Body is closed after
+// it is sent.
 func (req *Request) Write(w io.Writer) os.Error {
 	return req.write(w, false)
 }
@@ -420,6 +424,29 @@ func (cr *chunkedReader) Read(b []uint8) (n int, err os.Error) {
 	return n, cr.err
 }
 
+// NewRequest returns a new Request given a method, URL, and optional body.
+func NewRequest(method, url string, body io.Reader) (*Request, os.Error) {
+	u, err := ParseURL(url)
+	if err != nil {
+		return nil, err
+	}
+	rc, ok := body.(io.ReadCloser)
+	if !ok && body != nil {
+		rc = ioutil.NopCloser(body)
+	}
+	req := &Request{
+		Method:     method,
+		URL:        u,
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     make(Header),
+		Body:       rc,
+		Host:       u.Host,
+	}
+	return req, nil
+}
+
 // ReadRequest reads and parses a request from b.
 func ReadRequest(b *bufio.Reader) (req *Request, err os.Error) {
 

src/pkg/http/requestwrite_test.go

@@ -6,7 +6,10 @@ package http
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
+	"os"
+	"strings"
 	"testing"
 )
 
@@ -133,6 +136,41 @@ var reqWriteTests = []reqWriteTest{
 			"Transfer-Encoding: chunked\r\n\r\n" +
 			"6\r\nabcdef\r\n0\r\n\r\n",
 	},
+
+	// HTTP/1.1 POST with Content-Length, no chunking
+	{
+		Request{
+			Method: "POST",
+			URL: &URL{
+				Scheme: "http",
+				Host:   "www.google.com",
+				Path:   "/search",
+			},
+			ProtoMajor:    1,
+			ProtoMinor:    1,
+			Header:        Header{},
+			Close:         true,
+			ContentLength: 6,
+		},
+
+		[]byte("abcdef"),
+
+		"POST /search HTTP/1.1\r\n" +
+			"Host: www.google.com\r\n" +
+			"User-Agent: Go http package\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 6\r\n" +
+			"\r\n" +
+			"abcdef",
+
+		"POST http://www.google.com/search HTTP/1.1\r\n" +
+			"User-Agent: Go http package\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 6\r\n" +
+			"\r\n" +
+			"abcdef",
+	},
+
 	// default to HTTP/1.1
 	{
 		Request{
@@ -189,3 +227,26 @@ func TestRequestWrite(t *testing.T) {
 		}
 	}
 }
+
+type closeChecker struct {
+	io.Reader
+	closed bool
+}
+
+func (rc *closeChecker) Close() os.Error {
+	rc.closed = true
+	return nil
+}
+
+// TestRequestWriteClosesBody tests that Request.Write does close its request.Body.
+// It also indirectly tests NewRequest and that it doesn't wrap an existing Closer
+// inside a NopCloser.
+func TestRequestWriteClosesBody(t *testing.T) {
+	rc := &closeChecker{Reader: strings.NewReader("my body")}
+	req, _ := NewRequest("GET", "http://foo.com/", rc)
+	buf := new(bytes.Buffer)
+	req.Write(buf)
+	if !rc.closed {
+		t.Error("body not closed after write")
+	}
+}