misc/goplay/goplay.go - go - Git at Google

 // Copyright 2010 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 main

 import (
 	"bytes"
 	"exec"
 	"flag"
 	"http"
 	"io"
 	"io/ioutil"
 	"log"
 	"os"
 	"runtime"
 	"strconv"
 	"template"
 )

 var (
 	httpListen = flag.String("http", "127.0.0.1:3999", "host:port to listen on")
 	htmlOutput = flag.Bool("html", false, "render program output as HTML")
 )

 var (
 	// a source of numbers, for naming temporary files
 	uniq = make(chan int)
 	// the architecture-identifying character of the tool chain, 5, 6, or 8
 	archChar string
 )

 func main() {
 	flag.Parse()

 	// set archChar
 	switch runtime.GOARCH {
 	case "arm":
 		archChar = "5"
 	case "amd64":
 		archChar = "6"
 	case "386":
 		archChar = "8"
 	default:
 		log.Exitln("unrecognized GOARCH:", runtime.GOARCH)
 	}

 	// source of unique numbers
 	go func() {
 		for i := 0; ; i++ {
 			uniq <- i
 		}
 	}()

 	http.HandleFunc("/", FrontPage)
 	http.HandleFunc("/compile", Compile)
 	log.Exit(http.ListenAndServe(*httpListen, nil))
 }

 // FrontPage is an HTTP handler that renders the goplay interface.
 // If a filename is supplied in the path component of the URI,
 // its contents will be put in the interface's text area.
 // Otherwise, the default "hello, world" program is displayed.
 func FrontPage(w http.ResponseWriter, req *http.Request) {
 	data, err := ioutil.ReadFile(req.URL.Path[1:])
 	if err != nil {
 		data = helloWorld
 	}
 	frontPage.Execute(data, w)
 }

 // Compile is an HTTP handler that reads Go source code from the request,
 // compiles and links the code (returning any errors), runs the program,
 // and sends the program's output as the HTTP response.
 func Compile(w http.ResponseWriter, req *http.Request) {
 	// x is the base name for .go, .6, executable files
 	x := os.TempDir() + "/compile" + strconv.Itoa(<-uniq)
 	src := x + ".go"
 	obj := x + "." + archChar
 	bin := x
 	if runtime.GOOS == "windows" {
 		bin += ".exe"
 	}

 	// write request Body to x.go
 	f, err := os.Open(src, os.O_CREAT|os.O_WRONLY|os.O_TRUNC, 0666)
 	if err != nil {
 		error(w, nil, err)
 		return
 	}
 	defer os.Remove(src)
 	defer f.Close()
 	_, err = io.Copy(f, req.Body)
 	if err != nil {
 		error(w, nil, err)
 		return
 	}
 	f.Close()

 	// build x.go, creating x.6
 	out, err := run(archChar+"g", "-o", obj, src)
 	defer os.Remove(obj)
 	if err != nil {
 		error(w, out, err)
 		return
 	}

 	// link x.6, creating x (the program binary)
 	out, err = run(archChar+"l", "-o", bin, obj)
 	defer os.Remove(bin)
 	if err != nil {
 		error(w, out, err)
 		return
 	}

 	// run x
 	out, err = run(bin)
 	if err != nil {
 		error(w, out, err)
 	}

 	// write the output of x as the http response
 	if *htmlOutput {
 		w.Write(out)
 	} else {
 		output.Execute(out, w)
 	}
 }

 // error writes compile, link, or runtime errors to the HTTP connection.
 // The JavaScript interface uses the 404 status code to identify the error.
 func error(w http.ResponseWriter, out []byte, err os.Error) {
 	w.WriteHeader(404)
 	if out != nil {
 		output.Execute(out, w)
 	} else {
 		output.Execute(err.String(), w)
 	}
 }

 // run executes the specified command and returns its output and an error.
 func run(cmd ...string) ([]byte, os.Error) {
 	// find the specified binary
 	bin, err := exec.LookPath(cmd[0])
 	if err != nil {
 		// report binary as well as the error
 		return nil, os.NewError(cmd[0] + ": " + err.String())
 	}

 	// run the binary and read its combined stdout and stderr into a buffer
 	p, err := exec.Run(bin, cmd, os.Environ(), "", exec.DevNull, exec.Pipe, exec.MergeWithStdout)
 	if err != nil {
 		return nil, err
 	}
 	var buf bytes.Buffer
 	io.Copy(&buf, p.Stdout)
 	w, err := p.Wait(0)
 	p.Close()
 	if err != nil {
 		return nil, err
 	}

 	// set the error return value if the program had a non-zero exit status
 	if !w.Exited() || w.ExitStatus() != 0 {
 		err = os.ErrorString("running " + cmd[0] + ": " + w.String())
 	}

 	return buf.Bytes(), err
 }

 var frontPage, output *template.Template // HTML templates

 func init() {
 	frontPage = template.New(nil)
 	frontPage.SetDelims("«", "»")
 	if err := frontPage.Parse(frontPageText); err != nil {
 		panic(err)
 	}
 	output = template.MustParse(outputText, nil)
 }

 var outputText = `<pre>{@|html}</pre>`

 var frontPageText = `<!doctype html>
 <html>
 <head>
 <style>
 pre, textarea {
 	font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace;
 	font-size: 100%;
 }
 .hints {
 	font-size: 0.8em;
 	text-align: right;
 }
 #edit, #output, #errors { width: 100%; text-align: left; }
 #edit { height: 500px; }
 #output { color: #00c; }
 #errors { color: #c00; }
 </style>
 <script>

 function insertTabs(n) {
 	// find the selection start and end
 	var cont  = document.getElementById("edit");
 	var start = cont.selectionStart;
 	var end   = cont.selectionEnd;
 	// split the textarea content into two, and insert n tabs
 	var v = cont.value;
 	var u = v.substr(0, start);
 	for (var i=0; i<n; i++) {
 		u += "\t";
 	}
 	u += v.substr(end);
 	// set revised content
 	cont.value = u;
 	// reset caret position after inserted tabs
 	cont.selectionStart = start+n;
 	cont.selectionEnd = start+n;
 }

 function autoindent(el) {
 	var curpos = el.selectionStart;
 	var tabs = 0;
 	while (curpos > 0) {
 		curpos--;
 		if (el.value[curpos] == "\t") {
 			tabs++;
 		} else if (tabs > 0 || el.value[curpos] == "\n") {
 			break;
 		}
 	}
 	setTimeout(function() {
 		insertTabs(tabs);
 	}, 1);
 }

 function keyHandler() {
 	var e = window.event;
 	if (e.keyCode == 9) { // tab
 		insertTabs(1);
 		e.preventDefault();
 		return false;
 	}
 	if (e.keyCode == 13) { // enter
 		if (e.shiftKey) { // +shift
 			compile(e.target);
 			e.preventDefault();
 			return false;
 		} else {
 			autoindent(e.target);
 		}
 	}
 	return true;
 }

 var xmlreq;

 function autocompile() {
 	if(!document.getElementById("autocompile").checked) {
 		return;
 	}
 	compile();
 }

 function compile() {
 	var prog = document.getElementById("edit").value;
 	var req = new XMLHttpRequest();
 	xmlreq = req;
 	req.onreadystatechange = compileUpdate;
 	req.open("POST", "/compile", true);
 	req.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
 	req.send(prog);
 }

 function compileUpdate() {
 	var req = xmlreq;
 	if(!req || req.readyState != 4) {
 		return;
 	}
 	if(req.status == 200) {
 		document.getElementById("output").innerHTML = req.responseText;
 		document.getElementById("errors").innerHTML = "";
 	} else {
 		document.getElementById("errors").innerHTML = req.responseText;
 		document.getElementById("output").innerHTML = "";
 	}
 }
 </script>
 </head>
 <body>
 <table width="100%"><tr><td width="60%" valign="top">
 <textarea autofocus="true" id="edit" spellcheck="false" onkeydown="keyHandler();" onkeyup="autocompile();">«@|html»</textarea>
 <div class="hints">
 (Shift-Enter to compile and run.)&nbsp;&nbsp;&nbsp;&nbsp;
 <input type="checkbox" id="autocompile" value="checked" /> Compile and run after each keystroke
 </div>
 <td width="3%">
 <td width="27%" align="right" valign="top">
 <div id="output"></div>
 </table>
 <div id="errors"></div>
 </body>
 </html>
 `

 var helloWorld = []byte(`package main

 import "fmt"

 func main() {
 	fmt.Println("hello, world")
 }
 `)
	// Copyright 2010 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 main

	import (
	"bytes"
	"exec"
	"flag"
	"http"
	"io"
	"io/ioutil"
	"log"
	"os"
	"runtime"
	"strconv"
	"template"
	)

	var (
	httpListen = flag.String("http", "127.0.0.1:3999", "host:port to listen on")
	htmlOutput = flag.Bool("html", false, "render program output as HTML")
	)

	var (
	// a source of numbers, for naming temporary files
	uniq = make(chan int)
	// the architecture-identifying character of the tool chain, 5, 6, or 8
	archChar string
	)

	func main() {
	flag.Parse()

	// set archChar
	switch runtime.GOARCH {
	case "arm":
	archChar = "5"
	case "amd64":
	archChar = "6"
	case "386":
	archChar = "8"
	default:
	log.Exitln("unrecognized GOARCH:", runtime.GOARCH)
	}

	// source of unique numbers
	go func() {
	for i := 0; ; i++ {
	uniq <- i
	}
	}()

	http.HandleFunc("/", FrontPage)
	http.HandleFunc("/compile", Compile)
	log.Exit(http.ListenAndServe(*httpListen, nil))
	}

	// FrontPage is an HTTP handler that renders the goplay interface.
	// If a filename is supplied in the path component of the URI,
	// its contents will be put in the interface's text area.
	// Otherwise, the default "hello, world" program is displayed.
	func FrontPage(w http.ResponseWriter, req *http.Request) {
	data, err := ioutil.ReadFile(req.URL.Path[1:])
	if err != nil {
	data = helloWorld
	}
	frontPage.Execute(data, w)
	}

	// Compile is an HTTP handler that reads Go source code from the request,
	// compiles and links the code (returning any errors), runs the program,
	// and sends the program's output as the HTTP response.
	func Compile(w http.ResponseWriter, req *http.Request) {
	// x is the base name for .go, .6, executable files
	x := os.TempDir() + "/compile" + strconv.Itoa(<-uniq)
	src := x + ".go"
	obj := x + "." + archChar
	bin := x
	if runtime.GOOS == "windows" {
	bin += ".exe"
	}

	// write request Body to x.go
	f, err := os.Open(src, os.O_CREAT\|os.O_WRONLY\|os.O_TRUNC, 0666)
	if err != nil {
	error(w, nil, err)
	return
	}
	defer os.Remove(src)
	defer f.Close()
	_, err = io.Copy(f, req.Body)
	if err != nil {
	error(w, nil, err)
	return
	}
	f.Close()

	// build x.go, creating x.6
	out, err := run(archChar+"g", "-o", obj, src)
	defer os.Remove(obj)
	if err != nil {
	error(w, out, err)
	return
	}

	// link x.6, creating x (the program binary)
	out, err = run(archChar+"l", "-o", bin, obj)
	defer os.Remove(bin)
	if err != nil {
	error(w, out, err)
	return
	}

	// run x
	out, err = run(bin)
	if err != nil {
	error(w, out, err)
	}

	// write the output of x as the http response
	if *htmlOutput {
	w.Write(out)
	} else {
	output.Execute(out, w)
	}
	}

	// error writes compile, link, or runtime errors to the HTTP connection.
	// The JavaScript interface uses the 404 status code to identify the error.
	func error(w http.ResponseWriter, out []byte, err os.Error) {
	w.WriteHeader(404)
	if out != nil {
	output.Execute(out, w)
	} else {
	output.Execute(err.String(), w)
	}
	}

	// run executes the specified command and returns its output and an error.
	func run(cmd ...string) ([]byte, os.Error) {
	// find the specified binary
	bin, err := exec.LookPath(cmd[0])
	if err != nil {
	// report binary as well as the error
	return nil, os.NewError(cmd[0] + ": " + err.String())
	}

	// run the binary and read its combined stdout and stderr into a buffer
	p, err := exec.Run(bin, cmd, os.Environ(), "", exec.DevNull, exec.Pipe, exec.MergeWithStdout)
	if err != nil {
	return nil, err
	}
	var buf bytes.Buffer
	io.Copy(&buf, p.Stdout)
	w, err := p.Wait(0)
	p.Close()
	if err != nil {
	return nil, err
	}

	// set the error return value if the program had a non-zero exit status
	if !w.Exited() \|\| w.ExitStatus() != 0 {
	err = os.ErrorString("running " + cmd[0] + ": " + w.String())
	}

	return buf.Bytes(), err
	}

	var frontPage, output *template.Template // HTML templates

	func init() {
	frontPage = template.New(nil)
	frontPage.SetDelims("«", "»")
	if err := frontPage.Parse(frontPageText); err != nil {
	panic(err)
	}
	output = template.MustParse(outputText, nil)
	}

	var outputText = `<pre>{@\|html}</pre>`

	var frontPageText = `<!doctype html>
	<html>
	<head>
	<style>
	pre, textarea {
	font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace;
	font-size: 100%;
	}
	.hints {
	font-size: 0.8em;
	text-align: right;
	}
	#edit, #output, #errors { width: 100%; text-align: left; }
	#edit { height: 500px; }
	#output { color: #00c; }
	#errors { color: #c00; }
	</style>
	<script>

	function insertTabs(n) {
	// find the selection start and end
	var cont = document.getElementById("edit");
	var start = cont.selectionStart;
	var end = cont.selectionEnd;
	// split the textarea content into two, and insert n tabs
	var v = cont.value;
	var u = v.substr(0, start);
	for (var i=0; i<n; i++) {
	u += "\t";
	}
	u += v.substr(end);
	// set revised content
	cont.value = u;
	// reset caret position after inserted tabs
	cont.selectionStart = start+n;
	cont.selectionEnd = start+n;
	}

	function autoindent(el) {
	var curpos = el.selectionStart;
	var tabs = 0;
	while (curpos > 0) {
	curpos--;
	if (el.value[curpos] == "\t") {
	tabs++;
	} else if (tabs > 0 \|\| el.value[curpos] == "\n") {
	break;
	}
	}
	setTimeout(function() {
	insertTabs(tabs);
	}, 1);
	}

	function keyHandler() {
	var e = window.event;
	if (e.keyCode == 9) { // tab
	insertTabs(1);
	e.preventDefault();
	return false;
	}
	if (e.keyCode == 13) { // enter
	if (e.shiftKey) { // +shift
	compile(e.target);
	e.preventDefault();
	return false;
	} else {
	autoindent(e.target);
	}
	}
	return true;
	}

	var xmlreq;

	function autocompile() {
	if(!document.getElementById("autocompile").checked) {
	return;
	}
	compile();
	}

	function compile() {
	var prog = document.getElementById("edit").value;
	var req = new XMLHttpRequest();
	xmlreq = req;
	req.onreadystatechange = compileUpdate;
	req.open("POST", "/compile", true);
	req.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
	req.send(prog);
	}

	function compileUpdate() {
	var req = xmlreq;
	if(!req \|\| req.readyState != 4) {
	return;
	}
	if(req.status == 200) {
	document.getElementById("output").innerHTML = req.responseText;
	document.getElementById("errors").innerHTML = "";
	} else {
	document.getElementById("errors").innerHTML = req.responseText;
	document.getElementById("output").innerHTML = "";
	}
	}
	</script>
	</head>
	<body>
	<table width="100%"><tr><td width="60%" valign="top">
	<textarea autofocus="true" id="edit" spellcheck="false" onkeydown="keyHandler();" onkeyup="autocompile();">«@\|html»</textarea>
	<div class="hints">
	(Shift-Enter to compile and run.)
	<input type="checkbox" id="autocompile" value="checked" /> Compile and run after each keystroke
	</div>
	<td width="3%">
	<td width="27%" align="right" valign="top">
	<div id="output"></div>
	</table>
	<div id="errors"></div>
	</body>
	</html>
	`

	var helloWorld = []byte(`package main

	import "fmt"

	func main() {
	fmt.Println("hello, world")
	}
	`)