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// 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"
"flag"
"io/ioutil"
"log"
"net/http"
"os"
"os/exec"
"path/filepath"
"regexp"
"runtime"
"strconv"
"text/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)
)
func main() {
flag.Parse()
// source of unique numbers
go func() {
for i := 0; ; i++ {
uniq <- i
}
}()
http.HandleFunc("/", FrontPage)
http.HandleFunc("/compile", Compile)
log.Fatal(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(w, data)
}
// Compile is an HTTP handler that reads Go source code from the request,
// runs the program (returning any errors),
// and sends the program's output as the HTTP response.
func Compile(w http.ResponseWriter, req *http.Request) {
out, err := compile(req)
if err != nil {
error_(w, out, err)
return
}
// write the output of x as the http response
if *htmlOutput {
w.Write(out)
} else {
output.Execute(w, out)
}
}
var (
commentRe = regexp.MustCompile(`(?m)^#.*\n`)
tmpdir string
)
func init() {
// find real temporary directory (for rewriting filename in output)
var err error
tmpdir, err = filepath.EvalSymlinks(os.TempDir())
if err != nil {
log.Fatal(err)
}
}
func compile(req *http.Request) (out []byte, err error) {
// x is the base name for .go, .6, executable files
x := filepath.Join(tmpdir, "compile"+strconv.Itoa(<-uniq))
src := x + ".go"
bin := x
if runtime.GOOS == "windows" {
bin += ".exe"
}
// rewrite filename in error output
defer func() {
if err != nil {
// drop messages from the go tool like '# _/compile0'
out = commentRe.ReplaceAll(out, nil)
}
out = bytes.Replace(out, []byte(src+":"), []byte("main.go:"), -1)
}()
// write body to x.go
body := new(bytes.Buffer)
if _, err = body.ReadFrom(req.Body); err != nil {
return
}
defer os.Remove(src)
if err = ioutil.WriteFile(src, body.Bytes(), 0666); err != nil {
return
}
// build x.go, creating x
dir, file := filepath.Split(src)
out, err = run(dir, "go", "build", "-o", bin, file)
defer os.Remove(bin)
if err != nil {
return
}
// run x
return run("", bin)
}
// 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 error) {
w.WriteHeader(404)
if out != nil {
output.Execute(w, out)
} else {
output.Execute(w, err.Error())
}
}
// run executes the specified command and returns its output and an error.
func run(dir string, args ...string) ([]byte, error) {
var buf bytes.Buffer
cmd := exec.Command(args[0], args[1:]...)
cmd.Dir = dir
cmd.Stdout = &buf
cmd.Stderr = cmd.Stdout
err := cmd.Run()
return buf.Bytes(), err
}
var frontPage = template.Must(template.New("frontPage").Parse(frontPageText)) // HTML template
var output = template.Must(template.New("output").Parse(outputText)) // HTML template
var outputText = `<pre>{{printf "%s" . |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 preventDefault(e) {
if (e.preventDefault) {
e.preventDefault();
} else {
e.cancelBubble = true;
}
}
function keyHandler(event) {
var e = window.event || event;
if (e.keyCode == 9) { // tab
insertTabs(1);
preventDefault(e);
return false;
}
if (e.keyCode == 13) { // enter
if (e.shiftKey) { // +shift
compile(e.target);
preventDefault(e);
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(event);" onkeyup="autocompile();">{{printf "%s" . |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")
}
`)
|
