flesh out http server.

convert to uppercase names.

R=r
DELTA=613  (460 added, 61 deleted, 92 changed)
OCL=24139
CL=24145

5 files changed, 545 insertions, 147 deletions

diff --git a/src/lib/http/conn.go b/src/lib/http/conn.go
deleted file mode 100644
index 909863ef5..000000000
--- a/src/lib/http/conn.go
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright 2009 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package http
-
-import (
-	"io";
-	"bufio";
-	"http";
-	"os"
-)
-
-// Active HTTP connection (server side).
-type Conn struct {
-	rwc io.ReadWriteClose;
-	br *bufio.BufRead;
-	bw *bufio.BufWrite;
-	close bool;
-	chunking bool;
-}
-
-// Create new connection from rwc.
-func NewConn(rwc io.ReadWriteClose) (c *Conn, err *os.Error) {
-	c = new(Conn);
-	c.rwc = rwc;
-	if c.br, err = bufio.NewBufRead(rwc); err != nil {
-		return nil, err
-	}
-	if c.bw, err = bufio.NewBufWrite(rwc); err != nil {
-		return nil, err
-	}
-	return c, nil
-}
-
-// Read next request from connection.
-func (c *Conn) ReadRequest() (req *Request, err *os.Error) {
-	if req, err = ReadRequest(c.br); err != nil {
-		return nil, err
-	}
-
-	// TODO: Proper handling of (lack of) Connection: close,
-	// and chunked transfer encoding on output.
-	c.close = true;
-	return req, nil
-}
-
-// Close the connection.
-func (c *Conn) Close() {
-	c.bw.Flush();
-	c.rwc.Close();
-}
-
diff --git a/src/lib/http/request.go b/src/lib/http/request.go
index ba1a7a694..5d1fd67d7 100644
--- a/src/lib/http/request.go
+++ b/src/lib/http/request.go
@@ -9,14 +9,15 @@ package http
 import (
 	"bufio";
 	"http";
+	"io";
 	"os";
 	"strings"
 )
 
 const (
-	_MaxLineLength = 1024;	// assumed < bufio.DefaultBufSize
-	_MaxValueLength = 1024;
-	_MaxHeaderLines = 1024;
+	maxLineLength = 1024;	// assumed < bufio.DefaultBufSize
+	maxValueLength = 1024;
+	maxHeaderLines = 1024;
 )
 
 var (
@@ -30,30 +31,36 @@ var (
 
 // HTTP Request
 type Request struct {
-	method string;		// GET, PUT,etc.
-	rawurl string;
-	url *URL;		// URI after GET, PUT etc.
-	proto string;	// "HTTP/1.0"
-	pmajor int;	// 1
-	pminor int;	// 0
-
-	header map[string] string;
-
-	close bool;
-	host string;
-	referer string;
-	useragent string;
+	Method string;		// GET, PUT,etc.
+	RawUrl string;
+	Url *URL;		// URI after GET, PUT etc.
+	Proto string;	// "HTTP/1.0"
+	ProtoMajor int;	// 1
+	ProtoMinor int;	// 0
+
+	Header map[string] string;
+
+	Close bool;
+	Host string;
+	Referer string;	// referer [sic]
+	UserAgent string;
 }
 
+func (r *Request) ProtoAtLeast(major, minor int) bool {
+	return r.ProtoMajor > major ||
+		r.ProtoMajor == major && r.ProtoMinor >= minor
+}
+
+
 // Read a line of bytes (up to \n) from b.
-// Give up if the line exceeds _MaxLineLength.
+// Give up if the line exceeds maxLineLength.
 // The returned bytes are a pointer into storage in
 // the bufio, so they are only valid until the next bufio read.
 func readLineBytes(b *bufio.BufRead) (p []byte, err *os.Error) {
 	if p, err = b.ReadLineSlice('\n'); err != nil {
 		return nil, err
 	}
-	if len(p) >= _MaxLineLength {
+	if len(p) >= maxLineLength {
 		return nil, LineTooLong
 	}
 
@@ -132,7 +139,7 @@ func readKeyValue(b *bufio.BufRead) (key, value string, err *os.Error) {
 				}
 				value += " " + string(line);
 
-				if len(value) >= _MaxValueLength {
+				if len(value) >= maxValueLength {
 					return "", "", ValueTooLong
 				}
 			}
@@ -179,6 +186,37 @@ func parseHTTPVersion(vers string) (int, int, bool) {
 	return major, minor, true
 }
 
+var cmap = make(map[string]string)
+
+func CanonicalHeaderKey(s string) string {
+	if t, ok := cmap[s]; ok {
+		return t;
+	}
+
+	// canonicalize: first letter upper case
+	// and upper case after each dash.
+	// (Host, User-Agent, If-Modified-Since).
+	// HTTP headers are ASCII only, so no Unicode issues.
+	a := io.StringBytes(s);
+	upper := true;
+	for i,v := range a {
+		if upper && 'a' <= v && v <= 'z' {
+			a[i] = v + 'A' - 'a';
+		}
+		if !upper && 'A' <= v && v <= 'Z' {
+			a[i] = v + 'a' - 'A';
+		}
+		upper = false;
+		if v == '-' {
+			upper = true;
+		}
+	}
+	t := string(a);
+	cmap[s] = t;
+	return t;
+}
+
+
 // Read and parse a request from b.
 func ReadRequest(b *bufio.BufRead) (req *Request, err *os.Error) {
 	req = new(Request);
@@ -193,19 +231,19 @@ func ReadRequest(b *bufio.BufRead) (req *Request, err *os.Error) {
 	if f = strings.Split(s, " "); len(f) != 3 {
 		return nil, BadRequest
 	}
-	req.method, req.rawurl, req.proto = f[0], f[1], f[2];
+	req.Method, req.RawUrl, req.Proto = f[0], f[1], f[2];
 	var ok bool;
-	if req.pmajor, req.pminor, ok = parseHTTPVersion(req.proto); !ok {
+	if req.ProtoMajor, req.ProtoMinor, ok = parseHTTPVersion(req.Proto); !ok {
 		return nil, BadHTTPVersion
 	}
 
-	if req.url, err = ParseURL(req.rawurl); err != nil {
+	if req.Url, err = ParseURL(req.RawUrl); err != nil {
 		return nil, err
 	}
 
 	// Subsequent lines: Key: value.
 	nheader := 0;
-	req.header = make(map[string] string);
+	req.Header = make(map[string] string);
 	for {
 		var key, value string;
 		if key, value, err = readKeyValue(b); err != nil {
@@ -214,18 +252,20 @@ func ReadRequest(b *bufio.BufRead) (req *Request, err *os.Error) {
 		if key == "" {
 			break
 		}
-		if nheader++; nheader >= _MaxHeaderLines {
+		if nheader++; nheader >= maxHeaderLines {
 			return nil, HeaderTooLong
 		}
 
+		key = CanonicalHeaderKey(key);
+
 		// RFC 2616 says that if you send the same header key
 		// multiple times, it has to be semantically equivalent
 		// to concatenating the values separated by commas.
-		oldvalue, present := req.header[key];
+		oldvalue, present := req.Header[key];
 		if present {
-			req.header[key] = oldvalue+","+value
+			req.Header[key] = oldvalue+","+value
 		} else {
-			req.header[key] = value
+			req.Header[key] = value
 		}
 	}
 
@@ -236,40 +276,39 @@ func ReadRequest(b *bufio.BufRead) (req *Request, err *os.Error) {
 	//	GET http://www.google.com/index.html HTTP/1.1
 	//	Host: doesntmatter
 	// the same.  In the second case, any Host line is ignored.
-	if v, have := req.header["Host"]; have && req.url.host == "" {
-		req.host = v
+	if v, present := req.Header["Host"]; present && req.Url.Host == "" {
+		req.Host = v
 	}
 
 	// RFC2616: Should treat
 	//	Pragma: no-cache
 	// like
-	//	Cache-control: no-cache
-	if v, have := req.header["Pragma"]; have && v == "no-cache" {
-		if cc, havecc := req.header["Cache-control"]; !havecc {
-			req.header["Cache-control"] = "no-cache"
+	//	Cache-Control: no-cache
+	if v, present := req.Header["Pragma"]; present && v == "no-cache" {
+		if cc, presentcc := req.Header["Cache-Control"]; !presentcc {
+			req.Header["Cache-Control"] = "no-cache"
 		}
 	}
 
 	// Determine whether to hang up after sending the reply.
-	if req.pmajor < 1 || (req.pmajor == 1 && req.pminor < 1) {
-		req.close = true
-	} else if v, have := req.header["Connection"]; have {
+	if req.ProtoMajor < 1 || (req.ProtoMajor == 1 && req.ProtoMinor < 1) {
+		req.Close = true
+	} else if v, present := req.Header["Connection"]; present {
 		// TODO: Should split on commas, toss surrounding white space,
 		// and check each field.
 		if v == "close" {
-			req.close = true
+			req.Close = true
 		}
 	}
 
 	// Pull out useful fields as a convenience to clients.
-	if v, have := req.header["Referer"]; have {
-		req.referer = v
+	if v, present := req.Header["Referer"]; present {
+		req.Referer = v
 	}
-	if v, have := req.header["User-Agent"]; have {
-		req.useragent = v
+	if v, present := req.Header["User-Agent"]; present {
+		req.UserAgent = v
 	}
 
-
 	// TODO: Parse specific header values:
 	//	Accept
 	//	Accept-Encoding
diff --git a/src/lib/http/server.go b/src/lib/http/server.go
index 855eb98a5..970cd7e38 100644
--- a/src/lib/http/server.go
+++ b/src/lib/http/server.go
@@ -2,64 +2,448 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Trivial HTTP server
+// HTTP server.  See RFC 2616.
 
-// TODO: Routines for writing responses.
+// TODO(rsc):
+//	logging
+//	cgi support
+//	post support
 
 package http
 
 import (
+	"bufio";
+	"fmt";
+	"http";
 	"io";
-	"os";
 	"net";
-	"http";
+	"os";
 	"strconv";
 )
 
-// Serve a new connection.
-func serveConnection(fd net.Conn, raddr string, f func(*Conn, *Request)) {
-	c, err := NewConn(fd);
-	if err != nil {
+var ErrWriteAfterFlush = os.NewError("Conn.Write called after Flush")
+
+type Conn struct
+
+// Interface implemented by servers using this library.
+type Handler interface {
+	ServeHTTP(*Conn, *Request);
+}
+
+// Active HTTP connection (server side).
+type Conn struct {
+	Fd io.ReadWriteClose;
+	RemoteAddr string;
+	Req *Request;
+	Br *bufio.BufRead;
+
+	br *bufio.BufRead;
+	bw *bufio.BufWrite;
+	close bool;
+	chunking bool;
+	flushed bool;
+	header map[string] string;
+	wroteHeader bool;
+	handler Handler;
+}
+
+// HTTP response codes.
+// TODO(rsc): Maybe move these to their own file, so that
+// clients can use them too.
+
+const (
+	StatusContinue = 100;
+	StatusSwitchingProtocols = 101;
+
+	StatusOK = 200;
+	StatusCreated = 201;
+	StatusAccepted = 202;
+	StatusNonAuthoritativeInfo = 203;
+	StatusNoContent = 204;
+	StatusResetContent = 205;
+	StatusPartialContent = 206;
+
+	StatusMultipleChoices = 300;
+	StatusMovedPermanently = 301;
+	StatusFound = 302;
+	StatusSeeOther = 303;
+	StatusNotModified = 304;
+	StatusUseProxy = 305;
+	StatusTemporaryRedirect = 307;
+
+	StatusBadRequest = 400;
+	StatusUnauthorized = 401;
+	StatusPaymentRequired = 402;
+	StatusForbidden = 403;
+	StatusNotFound = 404;
+	StatusMethodNotAllowed = 405;
+	StatusNotAcceptable = 406;
+	StatusProxyAuthRequired = 407;
+	StatusRequestTimeout = 408;
+	StatusConflict = 409;
+	StatusGone = 410;
+	StatusLengthRequired = 411;
+	StatusPreconditionFailed = 412;
+	StatusRequestEntityTooLarge = 413;
+	StatusRequestURITooLong = 414;
+	StatusUnsupportedMediaType = 415;
+	StatusRequestedRangeNotSatisfiable = 416;
+	StatusExpectationFailed = 417;
+
+	StatusInternalServerError = 500;
+	StatusNotImplemented = 501;
+	StatusBadGateway = 502;
+	StatusServiceUnavailable = 503;
+	StatusGatewayTimeout = 504;
+	StatusHTTPVersionNotSupported = 505;
+)
+
+var statusText = map[int]string {
+	StatusContinue:			"Continue",
+	StatusSwitchingProtocols:	"Switching Protocols",
+
+	StatusOK:			"OK",
+	StatusCreated:			"Created",
+	StatusAccepted:			"Accepted",
+	StatusNonAuthoritativeInfo:	"Non-Authoritative Information",
+	StatusNoContent:		"No Content",
+	StatusResetContent:		"Reset Content",
+	StatusPartialContent:		"Partial Content",
+
+	StatusMultipleChoices:		"Multiple Choices",
+	StatusMovedPermanently:		"Moved Permanently",
+	StatusFound:			"Found",
+	StatusSeeOther:			"See Other",
+	StatusNotModified:		"Not Modified",
+	StatusUseProxy:			"Use Proxy",
+	StatusTemporaryRedirect:	"Temporary Redirect",
+
+	StatusBadRequest:		"Bad Request",
+	StatusUnauthorized:		"Unauthorized",
+	StatusPaymentRequired:		"Payment Required",
+	StatusForbidden:		"Forbidden",
+	StatusNotFound:			"Not Found",
+	StatusMethodNotAllowed:		"Method Not Allowed",
+	StatusNotAcceptable:		"Not Acceptable",
+	StatusProxyAuthRequired:	"Proxy Authentication Required",
+	StatusRequestTimeout:		"Request Timeout",
+	StatusConflict:			"Conflict",
+	StatusGone:			"Gone",
+	StatusLengthRequired:		"Length Required",
+	StatusPreconditionFailed:	"Precondition Failed",
+	StatusRequestEntityTooLarge:	"Request Entity Too Large",
+	StatusRequestURITooLong:	"Request URI Too Long",
+	StatusUnsupportedMediaType:	"Unsupported Media Type",
+	StatusRequestedRangeNotSatisfiable:	"Requested Range Not Satisfiable",
+	StatusExpectationFailed:	"Expectation Failed",
+
+	StatusInternalServerError:	"Internal Server Error",
+	StatusNotImplemented:		"Not Implemented",
+	StatusBadGateway:		"Bad Gateway",
+	StatusServiceUnavailable:	"Service Unavailable",
+	StatusGatewayTimeout:		"Gateway Timeout",
+	StatusHTTPVersionNotSupported:	"HTTP Version Not Supported",
+}
+
+// Create new connection from rwc.
+func newConn(rwc io.ReadWriteClose, raddr string, handler Handler) (c *Conn, err *os.Error) {
+	c = new(Conn);
+	c.Fd = rwc;
+	c.RemoteAddr = raddr;
+	c.handler = handler;
+	if c.br, err = bufio.NewBufRead(rwc.(io.Read)); err != nil {
+		return nil, err
+	}
+c.Br = c.br;
+	if c.bw, err = bufio.NewBufWrite(rwc); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func (c *Conn) SetHeader(hdr, val string)
+
+// Read next request from connection.
+func (c *Conn) readRequest() (req *Request, err *os.Error) {
+	if req, err = ReadRequest(c.br); err != nil {
+		return nil, err
+	}
+
+	// Reset per-request connection state.
+	c.header = make(map[string] string);
+	c.wroteHeader = false;
+	c.flushed = false;
+	c.Req = req;
+
+	// Default output is HTML encoded in UTF-8.
+	c.SetHeader("Content-Type", "text/html; charset=utf-8");
+
+	if req.ProtoAtLeast(1, 1) {
+		// HTTP/1.1 or greater: use chunked transfer encoding
+		// to avoid closing the connection at EOF.
+		c.chunking = true;
+		c.SetHeader("Transfer-Encoding", "chunked");
+	} else {
+		// HTTP version < 1.1: cannot do chunked transfer
+		// encoding, so signal EOF by closing connection.
+		// Could avoid closing the connection if there is
+		// a Content-Length: header in the response,
+		// but everyone who expects persistent connections
+		// does HTTP/1.1 now.
+		c.close = true;
+		c.chunking = false;
+	}
+
+	return req, nil
+}
+
+func (c *Conn) SetHeader(hdr, val string) {
+	c.header[CanonicalHeaderKey(hdr)] = val;
+}
+
+// Write header.
+func (c *Conn) WriteHeader(code int) {
+	if c.wroteHeader {
+		// TODO(rsc): log
+		return
+	}
+	c.wroteHeader = true;
+	if !c.Req.ProtoAtLeast(1, 0) {
+		return
+	}
+	proto := "HTTP/1.0";
+	if c.Req.ProtoAtLeast(1, 1) {
+		proto = "HTTP/1.1";
+	}
+	codestring := strconv.Itoa(code);
+	text, ok := statusText[code];
+	if !ok {
+		text = "status code " + codestring;
+	}
+	io.WriteString(c.bw, proto + " " + codestring + " " + text + "\r\n");
+	for k,v := range c.header {
+		io.WriteString(c.bw, k + ": " + v + "\r\n");
+	}
+	io.WriteString(c.bw, "\r\n");
+}
+
+// TODO(rsc): BUG in 6g: must return "nn int" not "n int"
+// so that the implicit struct assignment in
+// return c.bw.Write(data) works.  oops
+func (c *Conn) Write(data []byte) (nn int, err *os.Error) {
+	if c.flushed {
+		return 0, ErrWriteAfterFlush
+	}
+	if !c.wroteHeader {
+		c.WriteHeader(StatusOK);
+	}
+	if len(data) == 0 {
+		return 0, nil
+	}
+
+	// TODO(rsc): if chunking happened after the buffering,
+	// then there would be fewer chunk headers
+	if c.chunking {
+		fmt.Fprintf(c.bw, "%x\r\n", len(data));	// TODO(rsc): use strconv not fmt
+	}
+	return c.bw.Write(data);
+}
+
+func (c *Conn) Flush() {
+	if c.flushed {
 		return
 	}
+	if !c.wroteHeader {
+		c.WriteHeader(StatusOK);
+	}
+	if c.chunking {
+		io.WriteString(c.bw, "0\r\n");
+		// trailer key/value pairs, followed by blank line
+		io.WriteString(c.bw, "\r\n");
+	}
+	c.bw.Flush();
+	c.flushed = true;
+}
+
+// Close the connection.
+func (c *Conn) Close() {
+	if c.bw != nil {
+		c.bw.Flush();
+		c.bw = nil;
+	}
+	if c.Fd != nil {
+		c.Fd.Close();
+		c.Fd = nil;
+	}
+}
+
+// Serve a new connection.
+func (c *Conn) serve() {
 	for {
-		req, err := c.ReadRequest();
+		req, err := c.readRequest();
 		if err != nil {
 			break
 		}
-		f(c, req);
+		// HTTP cannot have multiple simultaneous active requests.
+		// Until the server replies to this request, it can't read another,
+		// so we might as well run the handler in this thread.
+		c.handler.ServeHTTP(c, req);
+		if c.Fd == nil {
+			// Handler took over the connection.
+			return;
+		}
+		if !c.flushed {
+			c.Flush();
+		}
 		if c.close {
-			break
+			break;
 		}
 	}
 	c.Close();
 }
 
-// Web server: already listening on l, call f for each request.
-func Serve(l net.Listener, f func(*Conn, *Request)) *os.Error {
-	// TODO: Make this unnecessary
-	s, e := os.Getenv("GOMAXPROCS");
-	if n, ok := strconv.Atoi(s); n < 3 {
-		print("Warning: $GOMAXPROCS needs to be at least 3.\n");
+// Adapter: can use RequestFunction(f) as Handler
+type handlerFunc struct {
+	f func(*Conn, *Request)
+}
+func (h handlerFunc) ServeHTTP(c *Conn, req *Request) {
+	h.f(c, req)
+}
+func HandlerFunc(f func(*Conn, *Request)) Handler {
+	return handlerFunc{f}
+}
+
+/* simpler version of above, not accepted by 6g:
+
+type HandlerFunc func(*Conn, *Request)
+func (f HandlerFunc) ServeHTTP(c *Conn, req *Request) {
+	f(c, req);
+}
+*/
+
+// Helper handlers
+
+// 404 not found
+func notFound(c *Conn, req *Request) {
+	c.SetHeader("Content-Type", "text/plain; charset=utf-8");
+	c.WriteHeader(StatusNotFound);
+	io.WriteString(c, "404 page not found\n");
+}
+
+var NotFoundHandler = HandlerFunc(notFound)
+
+// Redirect to a fixed URL
+type redirectHandler struct {
+	to string;
+}
+func (h *redirectHandler) ServeHTTP(c *Conn, req *Request) {
+	c.SetHeader("Location", h.to);
+	c.WriteHeader(StatusMovedPermanently);
+}
+
+func RedirectHandler(to string) Handler {
+	return &redirectHandler{to};
+}
+
+// Path-based HTTP request multiplexer.
+// Patterns name fixed paths, like "/favicon.ico",
+// or subtrees, like "/images/".
+// For now, patterns must begin with /.
+// Eventually, might want to allow host name
+// at beginning of pattern, so that you could register
+//	/codesearch
+//	codesearch.google.com/
+// but not take over /.
+
+type ServeMux struct {
+	m map[string] Handler
+}
+
+func NewServeMux() *ServeMux {
+	return &ServeMux{make(map[string] Handler)};
+}
+
+var DefaultServeMux = NewServeMux();
+
+// Does path match pattern?
+func pathMatch(pattern, path string) bool {
+	if len(pattern) == 0 {
+		// should not happen
+		return false
+	}
+	n := len(pattern);
+	if pattern[n-1] != '/' {
+		return pattern == path
 	}
+	return len(path) >= n && path[0:n] == pattern;
+}
+
+func (mux *ServeMux) ServeHTTP(c *Conn, req *Request) {
+	// Most-specific (longest) pattern wins.
+	var h Handler;
+	var n = 0;
+	for k, v := range mux.m {
+		if !pathMatch(k, req.Url.Path) {
+			continue;
+		}
+		if h == nil || len(k) > n {
+			n = len(k);
+			h = v;
+		}
+	}
+	if h == nil {
+		h = NotFoundHandler;
+	}
+	h.ServeHTTP(c, req);
+}
 
+func (mux *ServeMux) Handle(pattern string, handler Handler) {
+	if pattern == "" || pattern[0] != '/' {
+		panicln("http: invalid pattern", pattern);
+	}
+
+	mux.m[pattern] = handler;
+
+	// Helpful behavior:
+	// If pattern is /tree/, insert redirect for /tree.
+	n := len(pattern);
+	if n > 0 && pattern[n-1] == '/' {
+		mux.m[pattern[0:n-1]] = RedirectHandler(pattern);
+	}
+}
+
+func Handle(pattern string, h Handler) {
+	DefaultServeMux.Handle(pattern, h);
+}
+
+
+// Web server: listening on l, call handler.ServeHTTP for each request.
+func Serve(l net.Listener, handler Handler) *os.Error {
+	if handler == nil {
+		handler = DefaultServeMux;
+	}
 	for {
 		rw, raddr, e := l.Accept();
 		if e != nil {
 			return e
 		}
-		go serveConnection(rw, raddr, f)
+		c, err := newConn(rw, raddr, handler);
+		if err != nil {
+			continue;
+		}
+		go c.serve();
 	}
 	panic("not reached")
 }
 
 // Web server: listen on address, call f for each request.
-func ListenAndServe(addr string, f func(*Conn, *Request)) *os.Error {
+func ListenAndServe(addr string, handler Handler) *os.Error {
 	l, e := net.Listen("tcp", addr);
 	if e != nil {
 		return e
 	}
-	e = Serve(l, f);
+	e = Serve(l, handler);
 	l.Close();
 	return e
 }
+
diff --git a/src/lib/http/triv.go b/src/lib/http/triv.go
index a7eb35aa2..136100135 100644
--- a/src/lib/http/triv.go
+++ b/src/lib/http/triv.go
@@ -5,24 +5,52 @@
 package main
 
 import (
-	"io";
 	"bufio";
-	"os";
+	"flag";
+	"fmt";
+	"http";
+	"io";
 	"net";
-	"http"
+	"os";
 )
 
-func Echo(conn *http.Conn, req *http.Request) {
-	fd := conn.bw;
-	conn.close = true;
-	io.WriteString(fd, "HTTP/1.1 200 OK\r\n"
-		"Content-Type: text/plain\r\n"
-		"\r\n");
-	io.WriteString(fd, req.method+" "+req.rawurl+" "+req.proto+"\r\n")
+
+// hello world, the web server
+func HelloServer(c *http.Conn, req *http.Request) {
+	io.WriteString(c, "hello, world!\n");
+}
+
+// simple counter server
+type Counter struct {
+	n int;
+}
+
+func (ctr *Counter) ServeHTTP(c *http.Conn, req *http.Request) {
+	fmt.Fprintf(c, "counter = %d\n", ctr.n);
+	ctr.n++;
+}
+
+// simple file server
+var webroot = flag.String("root", "/home/rsc", "web root directory")
+func FileServer(c *http.Conn, req *http.Request) {
+	c.SetHeader("content-type", "text/plain; charset=utf-8");
+	path := *webroot + req.Url.Path;	// TODO: insecure: use os.CleanName
+	fd, err := os.Open(path, os.O_RDONLY, 0);
+	if err != nil {
+		c.WriteHeader(http.StatusNotFound);
+		fmt.Fprintf(c, "open %s: %v\n", path, err);
+		return;
+	}
+	n, err1 := io.Copy(fd, c);
+	fmt.Fprintf(c, "[%d bytes]\n", n);
 }
 
 func main() {
-	err := http.ListenAndServe("0.0.0.0:12345", &Echo);
+	flag.Parse();
+	http.Handle("/counter", new(Counter));
+	http.Handle("/go/", http.HandlerFunc(FileServer));
+	http.Handle("/go/hello", http.HandlerFunc(HelloServer));
+	err := http.ListenAndServe(":12345", nil);
 	if err != nil {
 		panic("ListenAndServe: ", err.String())
 	}
diff --git a/src/lib/http/url.go b/src/lib/http/url.go
index 9c1a94e2b..f0a94d68b 100644
--- a/src/lib/http/url.go
+++ b/src/lib/http/url.go
@@ -77,15 +77,15 @@ func URLUnescape(s string) (string, *os.Error) {
 }
 
 type URL struct {
-	raw string;
-	scheme string;
-	rawpath string;
-	authority string;
-	userinfo string;
-	host string;
-	path string;
-	query string;
-	fragment string;
+	Raw string;
+	Scheme string;
+	RawPath string;
+	Authority string;
+	Userinfo string;
+	Host string;
+	Path string;
+	Query string;
+	Fragment string;
 }
 
 // Maybe rawurl is of the form scheme:path.
@@ -132,39 +132,39 @@ func ParseURL(rawurl string) (url *URL, err *os.Error) {
 		return nil, BadURL
 	}
 	url = new(URL);
-	url.raw = rawurl;
+	url.Raw = rawurl;
 
 	// split off possible leading "http:", "mailto:", etc.
 	var path string;
-	if url.scheme, path, err = getscheme(rawurl); err != nil {
+	if url.Scheme, path, err = getscheme(rawurl); err != nil {
 		return nil, err
 	}
-	url.rawpath = path;
+	url.RawPath = path;
 
 	// RFC 2396: a relative URI (no scheme) has a ?query,
 	// but absolute URIs only have query if path begins with /
-	if url.scheme == "" || len(path) > 0 && path[0] == '/' {
-		path, url.query = split(path, '?', true);
-		if url.query, err = URLUnescape(url.query); err != nil {
+	if url.Scheme == "" || len(path) > 0 && path[0] == '/' {
+		path, url.Query = split(path, '?', true);
+		if url.Query, err = URLUnescape(url.Query); err != nil {
 			return nil, err
 		}
 	}
 
 	// Maybe path is //authority/path
 	if len(path) > 2 && path[0:2] == "//" {
-		url.authority, path = split(path[2:len(path)], '/', false);
+		url.Authority, path = split(path[2:len(path)], '/', false);
 	}
 
 	// If there's no @, split's default is wrong.  Check explicitly.
-	if strings.Index(url.authority, "@") < 0 {
-		url.host = url.authority;
+	if strings.Index(url.Authority, "@") < 0 {
+		url.Host = url.Authority;
 	} else {
-		url.userinfo, url.host = split(url.authority, '@', true);
+		url.Userinfo, url.Host = split(url.Authority, '@', true);
 	}
 
 	// What's left is the path.
 	// TODO: Canonicalize (remove . and ..)?
-	if url.path, err = URLUnescape(path); err != nil {
+	if url.Path, err = URLUnescape(path); err != nil {
 		return nil, err
 	}
 
@@ -178,7 +178,7 @@ func ParseURLReference(rawurlref string) (url *URL, err *os.Error) {
 	if url, err = ParseURL(rawurl); err != nil {
 		return nil, err
 	}
-	if url.fragment, err = URLUnescape(frag); err != nil {
+	if url.Fragment, err = URLUnescape(frag); err != nil {
 		return nil, err
 	}
 	return url, nil