http: add packages http/cgi and http/httptest

R=rsc, adg, jnw, bradfitzwork
CC=golang-dev
https://golang.org/cl/4247048

8 files changed, 556 insertions, 65 deletions

diff --git a/src/pkg/Makefile b/src/pkg/Makefile
index 139cee1a48..331bb68e5a 100644
--- a/src/pkg/Makefile
+++ b/src/pkg/Makefile
@@ -96,7 +96,9 @@ DIRS=\
 	hash/crc64\
 	html\
 	http\
+	http/cgi\
 	http/pprof\
+	http/httptest\
 	image\
 	image/jpeg\
 	image/png\
@@ -172,6 +174,7 @@ NOTEST=\
 	go/token\
 	hash\
 	http/pprof\
+	http/httptest\
 	image/jpeg\
 	net/dict\
 	rand\
diff --git a/src/pkg/http/cgi/Makefile b/src/pkg/http/cgi/Makefile
new file mode 100644
index 0000000000..02f6cfc9e7
--- /dev/null
+++ b/src/pkg/http/cgi/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2011 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.
+
+include ../../../Make.inc
+
+TARG=http/cgi
+GOFILES=\
+	cgi.go\
+
+include ../../../Make.pkg
diff --git a/src/pkg/http/cgi/cgi.go b/src/pkg/http/cgi/cgi.go
new file mode 100644
index 0000000000..dba59efa27
--- /dev/null
+++ b/src/pkg/http/cgi/cgi.go
@@ -0,0 +1,201 @@
+// Copyright 2011 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 cgi implements CGI (Common Gateway Interface) as specified
+// in RFC 3875.
+//
+// Note that using CGI means starting a new process to handle each
+// request, which is typically less efficient than using a
+// long-running server.  This package is intended primarily for
+// compatibility with existing systems.
+package cgi
+
+import (
+	"encoding/line"
+	"exec"
+	"fmt"
+	"http"
+	"io"
+	"log"
+	"os"
+	"path"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var trailingPort = regexp.MustCompile(`:([0-9]+)$`)
+
+// Handler runs an executable in a subprocess with a CGI environment.
+type Handler struct {
+	Path   string      // path to the CGI executable
+	Root   string      // root URI prefix of handler or empty for "/"
+	Env    []string    // extra environment variables to set, if any
+	Logger *log.Logger // optional log for errors or nil to use log.Print
+}
+
+func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	root := h.Root
+	if root == "" {
+		root = "/"
+	}
+
+	if len(req.TransferEncoding) > 0 && req.TransferEncoding[0] == "chunked" {
+		rw.WriteHeader(http.StatusBadRequest)
+		rw.Write([]byte("Chunked request bodies are not supported by CGI."))
+		return
+	}
+
+	pathInfo := req.URL.Path
+	if root != "/" && strings.HasPrefix(pathInfo, root) {
+		pathInfo = pathInfo[len(root):]
+	}
+
+	port := "80"
+	if matches := trailingPort.FindStringSubmatch(req.Host); len(matches) != 0 {
+		port = matches[1]
+	}
+
+	env := []string{
+		"SERVER_SOFTWARE=go",
+		"SERVER_NAME=" + req.Host,
+		"HTTP_HOST=" + req.Host,
+		"GATEWAY_INTERFACE=CGI/1.1",
+		"REQUEST_METHOD=" + req.Method,
+		"QUERY_STRING=" + req.URL.RawQuery,
+		"REQUEST_URI=" + req.URL.RawPath,
+		"PATH_INFO=" + pathInfo,
+		"SCRIPT_NAME=" + root,
+		"SCRIPT_FILENAME=" + h.Path,
+		"REMOTE_ADDR=" + rw.RemoteAddr(),
+		"REMOTE_HOST=" + rw.RemoteAddr(),
+		"SERVER_PORT=" + port,
+	}
+
+	for k, _ := range req.Header {
+		k = strings.Map(upperCaseAndUnderscore, k)
+		env = append(env, "HTTP_"+k+"="+req.Header.Get(k))
+	}
+
+	if req.ContentLength > 0 {
+		env = append(env, fmt.Sprintf("CONTENT_LENGTH=%d", req.ContentLength))
+	}
+	if ctype := req.Header.Get("Content-Type"); ctype != "" {
+		env = append(env, "CONTENT_TYPE="+ctype)
+	}
+
+	if h.Env != nil {
+		env = append(env, h.Env...)
+	}
+
+	// TODO: use filepath instead of path when available
+	cwd, pathBase := path.Split(h.Path)
+	if cwd == "" {
+		cwd = "."
+	}
+
+	cmd, err := exec.Run(
+		pathBase,
+		[]string{h.Path},
+		env,
+		cwd,
+		exec.Pipe,        // stdin
+		exec.Pipe,        // stdout
+		exec.PassThrough, // stderr (for now)
+	)
+	if err != nil {
+		rw.WriteHeader(http.StatusInternalServerError)
+		h.printf("CGI error: %v", err)
+		return
+	}
+	defer func() {
+		cmd.Stdin.Close()
+		cmd.Stdout.Close()
+		cmd.Wait(0) // no zombies
+	}()
+
+	if req.ContentLength != 0 {
+		go io.Copy(cmd.Stdin, req.Body)
+	}
+
+	linebody := line.NewReader(cmd.Stdout, 1024)
+	headers := make(map[string]string)
+	statusCode := http.StatusOK
+	for {
+		line, isPrefix, err := linebody.ReadLine()
+		if isPrefix {
+			rw.WriteHeader(http.StatusInternalServerError)
+			h.printf("CGI: long header line from subprocess.")
+			return
+		}
+		if err == os.EOF {
+			break
+		}
+		if err != nil {
+			rw.WriteHeader(http.StatusInternalServerError)
+			h.printf("CGI: error reading headers: %v", err)
+			return
+		}
+		if len(line) == 0 {
+			break
+		}
+		parts := strings.Split(string(line), ":", 2)
+		if len(parts) < 2 {
+			h.printf("CGI: bogus header line: %s", string(line))
+			continue
+		}
+		header, val := parts[0], parts[1]
+		header = strings.TrimSpace(header)
+		val = strings.TrimSpace(val)
+		switch {
+		case header == "Status":
+			if len(val) < 3 {
+				h.printf("CGI: bogus status (short): %q", val)
+				return
+			}
+			code, err := strconv.Atoi(val[0:3])
+			if err != nil {
+				h.printf("CGI: bogus status: %q", val)
+				h.printf("CGI: line was %q", line)
+				return
+			}
+			statusCode = code
+		default:
+			headers[header] = val
+		}
+	}
+	for h, v := range headers {
+		rw.SetHeader(h, v)
+	}
+	rw.WriteHeader(statusCode)
+
+	_, err = io.Copy(rw, linebody)
+	if err != nil {
+		h.printf("CGI: copy error: %v", err)
+	}
+}
+
+func (h *Handler) printf(format string, v ...interface{}) {
+	if h.Logger != nil {
+		h.Logger.Printf(format, v...)
+	} else {
+		log.Printf(format, v...)
+	}
+}
+
+func upperCaseAndUnderscore(rune int) int {
+	switch {
+	case rune >= 'a' && rune <= 'z':
+		return rune - ('a' - 'A')
+	case rune == '-':
+		return '_'
+	case rune == '=':
+		// Maybe not part of the CGI 'spec' but would mess up
+		// the environment in any case, as Go represents the
+		// environment as a slice of "key=value" strings.
+		return '_'
+	}
+	// TODO: other transformations in spec or practice?
+	return rune
+}
diff --git a/src/pkg/http/cgi/cgi_test.go b/src/pkg/http/cgi/cgi_test.go
new file mode 100644
index 0000000000..41ea26e3a6
--- /dev/null
+++ b/src/pkg/http/cgi/cgi_test.go
@@ -0,0 +1,200 @@
+// Copyright 2011 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.
+
+// Tests for package cgi
+
+package cgi
+
+import (
+	"bufio"
+	"fmt"
+	"http"
+	"http/httptest"
+	"os"
+	"strings"
+	"testing"
+)
+
+func newRequest(httpreq string) *http.Request {
+	buf := bufio.NewReader(strings.NewReader(httpreq))
+	req, err := http.ReadRequest(buf)
+	if err != nil {
+		panic("cgi: bogus http request in test: " + httpreq)
+	}
+	return req
+}
+
+func runCgiTest(t *testing.T, h *Handler, httpreq string, expectedMap map[string]string) *httptest.ResponseRecorder {
+	rw := httptest.NewRecorder()
+	req := newRequest(httpreq)
+	h.ServeHTTP(rw, req)
+
+	// Make a map to hold the test map that the CGI returns.
+	m := make(map[string]string)
+readlines:
+	for {
+		line, err := rw.Body.ReadString('\n')
+		switch {
+		case err == os.EOF:
+			break readlines
+		case err != nil:
+			t.Fatalf("unexpected error reading from CGI: %v", err)
+		}
+		line = strings.TrimRight(line, "\r\n")
+		split := strings.Split(line, "=", 2)
+		if len(split) != 2 {
+			t.Fatalf("Unexpected %d parts from invalid line: %q", len(split), line)
+		}
+		m[split[0]] = split[1]
+	}
+
+	for key, expected := range expectedMap {
+		if got := m[key]; got != expected {
+			t.Errorf("for key %q got %q; expected %q", key, got, expected)
+		}
+	}
+	return rw
+}
+
+func TestCGIBasicGet(t *testing.T) {
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "/test.cgi",
+	}
+	expectedMap := map[string]string{
+		"test":                  "Hello CGI",
+		"param-a":               "b",
+		"param-foo":             "bar",
+		"env-GATEWAY_INTERFACE": "CGI/1.1",
+		"env-HTTP_HOST":         "example.com",
+		"env-PATH_INFO":         "",
+		"env-QUERY_STRING":      "foo=bar&a=b",
+		"env-REMOTE_ADDR":       "1.2.3.4",
+		"env-REMOTE_HOST":       "1.2.3.4",
+		"env-REQUEST_METHOD":    "GET",
+		"env-REQUEST_URI":       "/test.cgi?foo=bar&a=b",
+		"env-SCRIPT_FILENAME":   "testdata/test.cgi",
+		"env-SCRIPT_NAME":       "/test.cgi",
+		"env-SERVER_NAME":       "example.com",
+		"env-SERVER_PORT":       "80",
+		"env-SERVER_SOFTWARE":   "go",
+	}
+	replay := runCgiTest(t, h, "GET /test.cgi?foo=bar&a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
+
+	if expected, got := "text/html", replay.Header.Get("Content-Type"); got != expected {
+		t.Errorf("got a Content-Type of %q; expected %q", got, expected)
+	}
+	if expected, got := "X-Test-Value", replay.Header.Get("X-Test-Header"); got != expected {
+		t.Errorf("got a X-Test-Header of %q; expected %q", got, expected)
+	}
+}
+
+func TestCGIBasicGetAbsPath(t *testing.T) {
+	pwd, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("getwd error: %v", err)
+	}
+	h := &Handler{
+		Path: pwd + "/testdata/test.cgi",
+		Root: "/test.cgi",
+	}
+	expectedMap := map[string]string{
+		"env-REQUEST_URI":     "/test.cgi?foo=bar&a=b",
+		"env-SCRIPT_FILENAME": pwd + "/testdata/test.cgi",
+		"env-SCRIPT_NAME":     "/test.cgi",
+	}
+	runCgiTest(t, h, "GET /test.cgi?foo=bar&a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
+}
+
+func TestPathInfo(t *testing.T) {
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "/test.cgi",
+	}
+	expectedMap := map[string]string{
+		"param-a":             "b",
+		"env-PATH_INFO":       "/extrapath",
+		"env-QUERY_STRING":    "a=b",
+		"env-REQUEST_URI":     "/test.cgi/extrapath?a=b",
+		"env-SCRIPT_FILENAME": "testdata/test.cgi",
+		"env-SCRIPT_NAME":     "/test.cgi",
+	}
+	runCgiTest(t, h, "GET /test.cgi/extrapath?a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
+}
+
+func TestPathInfoDirRoot(t *testing.T) {
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "/myscript/",
+	}
+	expectedMap := map[string]string{
+		"env-PATH_INFO":       "bar",
+		"env-QUERY_STRING":    "a=b",
+		"env-REQUEST_URI":     "/myscript/bar?a=b",
+		"env-SCRIPT_FILENAME": "testdata/test.cgi",
+		"env-SCRIPT_NAME":     "/myscript/",
+	}
+	runCgiTest(t, h, "GET /myscript/bar?a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
+}
+
+func TestPathInfoNoRoot(t *testing.T) {
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "",
+	}
+	expectedMap := map[string]string{
+		"env-PATH_INFO":       "/bar",
+		"env-QUERY_STRING":    "a=b",
+		"env-REQUEST_URI":     "/bar?a=b",
+		"env-SCRIPT_FILENAME": "testdata/test.cgi",
+		"env-SCRIPT_NAME":     "/",
+	}
+	runCgiTest(t, h, "GET /bar?a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
+}
+
+func TestCGIBasicPost(t *testing.T) {
+	postReq := `POST /test.cgi?a=b HTTP/1.0
+Host: example.com
+Content-Type: application/x-www-form-urlencoded
+Content-Length: 15
+
+postfoo=postbar`
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "/test.cgi",
+	}
+	expectedMap := map[string]string{
+		"test":               "Hello CGI",
+		"param-postfoo":      "postbar",
+		"env-REQUEST_METHOD": "POST",
+		"env-CONTENT_LENGTH": "15",
+		"env-REQUEST_URI":    "/test.cgi?a=b",
+	}
+	runCgiTest(t, h, postReq, expectedMap)
+}
+
+func chunk(s string) string {
+	return fmt.Sprintf("%x\r\n%s\r\n", len(s), s)
+}
+
+// The CGI spec doesn't allow chunked requests.
+func TestCGIPostChunked(t *testing.T) {
+	postReq := `POST /test.cgi?a=b HTTP/1.1
+Host: example.com
+Content-Type: application/x-www-form-urlencoded
+Transfer-Encoding: chunked
+
+` + chunk("postfoo") + chunk("=") + chunk("postbar") + chunk("")
+
+	h := &Handler{
+		Path: "testdata/test.cgi",
+		Root: "/test.cgi",
+	}
+	expectedMap := map[string]string{}
+	resp := runCgiTest(t, h, postReq, expectedMap)
+	if got, expected := resp.Code, http.StatusBadRequest; got != expected {
+		t.Fatalf("Expected %v response code from chunked request body; got %d",
+			expected, got)
+	}
+}
diff --git a/src/pkg/http/cgi/testdata/test.cgi b/src/pkg/http/cgi/testdata/test.cgi
new file mode 100755
index 0000000000..b931b04c55
--- /dev/null
+++ b/src/pkg/http/cgi/testdata/test.cgi
@@ -0,0 +1,34 @@
+#!/usr/bin/perl
+# Copyright 2011 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.
+#
+# Test script run as a child process under cgi_test.go
+
+use strict;
+use CGI;
+
+my $q = CGI->new;
+my $params = $q->Vars;
+
+my $NL = "\r\n";
+$NL = "\n" if 1 || $params->{mode} eq "NL";
+
+my $p = sub {
+  print "$_[0]$NL";
+};
+
+# With carriage returns
+$p->("Content-Type: text/html");
+$p->("X-Test-Header: X-Test-Value");
+$p->("");
+
+print "test=Hello CGI\n";
+
+foreach my $k (sort keys %$params) {
+  print "param-$k=$params->{$k}\n";
+}
+
+foreach my $k (sort keys %ENV) {
+  print "env-$k=$ENV{$k}\n";
+}
diff --git a/src/pkg/http/httptest/Makefile b/src/pkg/http/httptest/Makefile
new file mode 100644
index 0000000000..fa5ec1db00
--- /dev/null
+++ b/src/pkg/http/httptest/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2011 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.
+
+include ../../../Make.inc
+
+TARG=http/httptest
+GOFILES=\
+	recorder.go\
+
+include ../../../Make.pkg
diff --git a/src/pkg/http/httptest/recorder.go b/src/pkg/http/httptest/recorder.go
new file mode 100644
index 0000000000..44571ddd2b
--- /dev/null
+++ b/src/pkg/http/httptest/recorder.go
@@ -0,0 +1,88 @@
+// Copyright 2011 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.
+
+// The httptest package provides utilities for HTTP testing.
+package httptest
+
+import (
+	"bufio"
+	"bytes"
+	"http"
+	"io"
+	"os"
+)
+
+// ResponseRecorder is an implementation of http.ResponseWriter that
+// records its mutations for later inspection in tests.
+//
+// Note that Hijack is not implemented and simply panics.
+type ResponseRecorder struct {
+	Code    int           // the HTTP response code from WriteHeader
+	Header  http.Header   // if non-nil, the headers to populate
+	Body    *bytes.Buffer // if non-nil, the bytes.Buffer to append written data to
+	Flushed bool
+
+	FakeRemoteAddr string // the fake RemoteAddr to return, or "" for DefaultRemoteAddr
+	FakeUsingTLS   bool   // whether to return true from the UsingTLS method
+}
+
+// NewRecorder returns an initialized ResponseRecorder.
+func NewRecorder() *ResponseRecorder {
+	return &ResponseRecorder{
+		Header: http.Header(make(map[string][]string)),
+		Body:   new(bytes.Buffer),
+	}
+}
+
+// DefaultRemoteAddr is the default remote address to return in RemoteAddr if
+// an explicit DefaultRemoteAddr isn't set on ResponseRecorder.
+const DefaultRemoteAddr = "1.2.3.4"
+
+// RemoteAddr returns the value of rw.FakeRemoteAddr, if set, else
+// returns DefaultRemoteAddr.
+func (rw *ResponseRecorder) RemoteAddr() string {
+	if rw.FakeRemoteAddr != "" {
+		return rw.FakeRemoteAddr
+	}
+	return DefaultRemoteAddr
+}
+
+// UsingTLS returns the fake value in rw.FakeUsingTLS
+func (rw *ResponseRecorder) UsingTLS() bool {
+	return rw.FakeUsingTLS
+}
+
+// SetHeader populates rw.Header, if non-nil.
+func (rw *ResponseRecorder) SetHeader(k, v string) {
+	if rw.Header != nil {
+		if v == "" {
+			rw.Header.Del(k)
+		} else {
+			rw.Header.Set(k, v)
+		}
+	}
+}
+
+// Write always succeeds and writes to rw.Body, if not nil.
+func (rw *ResponseRecorder) Write(buf []byte) (int, os.Error) {
+	if rw.Body != nil {
+		rw.Body.Write(buf)
+	}
+	return len(buf), nil
+}
+
+// WriteHeader sets rw.Code.
+func (rw *ResponseRecorder) WriteHeader(code int) {
+	rw.Code = code
+}
+
+// Flush sets rw.Flushed to true.
+func (rw *ResponseRecorder) Flush() {
+	rw.Flushed = true
+}
+
+// Hijack is not implemented in ResponseRecorder and instead panics.
+func (rw *ResponseRecorder) Hijack() (io.ReadWriteCloser, *bufio.ReadWriter, os.Error) {
+	panic("Hijack not implemented in ResponseRecorder")
+}
diff --git a/src/pkg/http/serve_test.go b/src/pkg/http/serve_test.go
index 42fe3e5e4d..80fb829004 100644
--- a/src/pkg/http/serve_test.go
+++ b/src/pkg/http/serve_test.go
@@ -4,13 +4,14 @@
 
 // End-to-end serving tests
 
-package http
+package http_test
 
 import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"io"
+	. "http"
+	"http/httptest"
 	"io/ioutil"
 	"os"
 	"net"
@@ -205,46 +206,6 @@ func TestHostHandlers(t *testing.T) {
 	}
 }
 
-type responseWriterMethodCall struct {
-	method                 string
-	headerKey, headerValue string // if method == "SetHeader"
-	bytesWritten           []byte // if method == "Write"
-	responseCode           int    // if method == "WriteHeader"
-}
-
-type recordingResponseWriter struct {
-	log []*responseWriterMethodCall
-}
-
-func (rw *recordingResponseWriter) RemoteAddr() string {
-	return "1.2.3.4"
-}
-
-func (rw *recordingResponseWriter) UsingTLS() bool {
-	return false
-}
-
-func (rw *recordingResponseWriter) SetHeader(k, v string) {
-	rw.log = append(rw.log, &responseWriterMethodCall{method: "SetHeader", headerKey: k, headerValue: v})
-}
-
-func (rw *recordingResponseWriter) Write(buf []byte) (int, os.Error) {
-	rw.log = append(rw.log, &responseWriterMethodCall{method: "Write", bytesWritten: buf})
-	return len(buf), nil
-}
-
-func (rw *recordingResponseWriter) WriteHeader(code int) {
-	rw.log = append(rw.log, &responseWriterMethodCall{method: "WriteHeader", responseCode: code})
-}
-
-func (rw *recordingResponseWriter) Flush() {
-	rw.log = append(rw.log, &responseWriterMethodCall{method: "Flush"})
-}
-
-func (rw *recordingResponseWriter) Hijack() (io.ReadWriteCloser, *bufio.ReadWriter, os.Error) {
-	panic("Not supported")
-}
-
 // Tests for http://code.google.com/p/go/issues/detail?id=900
 func TestMuxRedirectLeadingSlashes(t *testing.T) {
 	paths := []string{"//foo.txt", "///foo.txt", "/../../foo.txt"}
@@ -254,35 +215,17 @@ func TestMuxRedirectLeadingSlashes(t *testing.T) {
 			t.Errorf("%s", err)
 		}
 		mux := NewServeMux()
-		resp := new(recordingResponseWriter)
-		resp.log = make([]*responseWriterMethodCall, 0)
+		resp := httptest.NewRecorder()
 
 		mux.ServeHTTP(resp, req)
 
-		dumpLog := func() {
-			t.Logf("For path %q:", path)
-			for _, call := range resp.log {
-				t.Logf("Got call: %s, header=%s, value=%s, buf=%q, code=%d", call.method,
-					call.headerKey, call.headerValue, call.bytesWritten, call.responseCode)
-			}
-		}
-
-		if len(resp.log) != 2 {
-			dumpLog()
-			t.Errorf("expected 2 calls to response writer; got %d", len(resp.log))
-			return
-		}
-
-		if resp.log[0].method != "SetHeader" ||
-			resp.log[0].headerKey != "Location" || resp.log[0].headerValue != "/foo.txt" {
-			dumpLog()
-			t.Errorf("Expected SetHeader of Location to /foo.txt")
+		if loc, expected := resp.Header.Get("Location"), "/foo.txt"; loc != expected {
+			t.Errorf("Expected Location header set to %q; got %q", expected, loc)
 			return
 		}
 
-		if resp.log[1].method != "WriteHeader" || resp.log[1].responseCode != StatusMovedPermanently {
-			dumpLog()
-			t.Errorf("Expected WriteHeader of StatusMovedPermanently")
+		if code, expected := resp.Code, StatusMovedPermanently; code != expected {
+			t.Errorf("Expected response code of StatusMovedPermanently; got %d", code)
 			return
 		}
 	}