cpython/Tools/wasm/emscripten/web_example/python.html

434 lines
17 KiB
HTML

<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="author" content="Katie Bell" />
<meta name="description" content="Simple REPL for Python WASM" />
<title>wasm-python terminal</title>
<link
rel="stylesheet"
href="https://unpkg.com/xterm@4.18.0/css/xterm.css"
crossorigin
integrity="sha384-4eEEn/eZgVHkElpKAzzPx/Kow/dTSgFk1BNe+uHdjHa+NkZJDh5Vqkq31+y7Eycd"
/>
<style>
body {
font-family: arial;
max-width: 800px;
margin: 0 auto;
}
#code {
width: 100%;
height: 180px;
}
#info {
padding-top: 20px;
}
.button-container {
display: flex;
justify-content: end;
height: 50px;
align-items: center;
gap: 10px;
}
button {
padding: 6px 18px;
}
</style>
<script
src="https://unpkg.com/xterm@4.18.0/lib/xterm.js"
crossorigin
integrity="sha384-yYdNmem1ioP5Onm7RpXutin5A8TimLheLNQ6tnMi01/ZpxXdAwIm2t4fJMx1Djs+"
/>
<script type="module">
class WorkerManager {
constructor(
workerURL,
standardIO,
readyCallBack,
finishedCallback,
) {
this.workerURL = workerURL;
this.worker = null;
this.standardIO = standardIO;
this.readyCallBack = readyCallBack;
this.finishedCallback = finishedCallback;
this.initialiseWorker();
}
async initialiseWorker() {
if (!this.worker) {
this.worker = new Worker(this.workerURL, {
type: "module",
});
this.worker.addEventListener(
"message",
this.handleMessageFromWorker,
);
}
}
async run(options) {
this.worker.postMessage({
type: "run",
args: options.args || [],
files: options.files || {},
});
}
reset() {
if (this.worker) {
this.worker.terminate();
this.worker = null;
}
this.standardIO.message("Worker process terminated.");
this.initialiseWorker();
}
handleStdinData(inputValue) {
if (this.stdinbuffer && this.stdinbufferInt) {
let startingIndex = 1;
if (this.stdinbufferInt[0] > 0) {
startingIndex = this.stdinbufferInt[0];
}
const data = new TextEncoder().encode(inputValue);
data.forEach((value, index) => {
this.stdinbufferInt[startingIndex + index] = value;
});
this.stdinbufferInt[0] =
startingIndex + data.length - 1;
Atomics.notify(this.stdinbufferInt, 0, 1);
}
}
handleMessageFromWorker = (event) => {
const type = event.data.type;
if (type === "ready") {
this.readyCallBack();
} else if (type === "stdout") {
this.standardIO.stdout(event.data.stdout);
} else if (type === "stderr") {
this.standardIO.stderr(event.data.stderr);
} else if (type === "stdin") {
// Leave it to the terminal to decide whether to chunk it into lines
// or send characters depending on the use case.
this.stdinbuffer = event.data.buffer;
this.stdinbufferInt = new Int32Array(this.stdinbuffer);
this.standardIO.stdin().then((inputValue) => {
this.handleStdinData(inputValue);
});
} else if (type === "finished") {
this.standardIO.message(
`Exited with status: ${event.data.returnCode}`,
);
this.finishedCallback();
}
};
}
class WasmTerminal {
constructor() {
this.inputBuffer = new BufferQueue();
this.input = "";
this.resolveInput = null;
this.activeInput = false;
this.inputStartCursor = null;
this.xterm = new Terminal({
scrollback: 10000,
fontSize: 14,
theme: { background: "#1a1c1f" },
cols: 100,
});
this.xterm.onKey((keyEvent) => {
// Fix for iOS Keyboard Jumping on space
if (keyEvent.key === " ") {
keyEvent.domEvent.preventDefault();
}
});
this.xterm.onData(this.handleTermData);
}
open(container) {
this.xterm.open(container);
}
handleTermData = (data) => {
const ord = data.charCodeAt(0);
data = data.replace(/\r(?!\n)/g, "\n"); // Convert lone CRs to LF
// Handle pasted data
if (data.length > 1 && data.includes("\n")) {
let alreadyWrittenChars = 0;
// If line already had data on it, merge pasted data with it
if (this.input != "") {
this.inputBuffer.addData(this.input);
alreadyWrittenChars = this.input.length;
this.input = "";
}
this.inputBuffer.addData(data);
// If input is active, write the first line
if (this.activeInput) {
let line = this.inputBuffer.nextLine();
this.writeLine(line.slice(alreadyWrittenChars));
this.resolveInput(line);
this.activeInput = false;
}
// When input isn't active, add to line buffer
} else if (!this.activeInput) {
// Skip non-printable characters
if (!(ord === 0x1b || ord == 0x7f || ord < 32)) {
this.inputBuffer.addData(data);
}
// TODO: Handle ANSI escape sequences
} else if (ord === 0x1b) {
// Handle special characters
} else if (ord < 32 || ord === 0x7f) {
switch (data) {
case "\x0c": // CTRL+L
this.clear();
break;
case "\n": // ENTER
case "\x0a": // CTRL+J
case "\x0d": // CTRL+M
this.resolveInput(
this.input + this.writeLine("\n"),
);
this.input = "";
this.activeInput = false;
break;
case "\x7F": // BACKSPACE
case "\x08": // CTRL+H
this.handleCursorErase(true);
break;
case "\x04": // CTRL+D
// Send empty input
if (this.input === "") {
this.resolveInput("");
this.activeInput = false;
}
}
} else {
this.handleCursorInsert(data);
}
};
writeLine(line) {
this.xterm.write(line.slice(0, -1));
this.xterm.write("\r\n");
return line;
}
handleCursorInsert(data) {
this.input += data;
this.xterm.write(data);
}
handleCursorErase() {
// Don't delete past the start of input
if (
this.xterm.buffer.active.cursorX <=
this.inputStartCursor
) {
return;
}
this.input = this.input.slice(0, -1);
this.xterm.write("\x1B[D");
this.xterm.write("\x1B[P");
}
prompt = async () => {
this.activeInput = true;
// Hack to allow stdout/stderr to finish before we figure out where input starts
setTimeout(() => {
this.inputStartCursor =
this.xterm.buffer.active.cursorX;
}, 1);
// If line buffer has a line ready, send it immediately
if (this.inputBuffer.hasLineReady()) {
return new Promise((resolve, reject) => {
resolve(
this.writeLine(this.inputBuffer.nextLine()),
);
this.activeInput = false;
});
// If line buffer has an incomplete line, use it for the active line
} else if (this.inputBuffer.lastLineIsIncomplete()) {
// Hack to ensure cursor input start doesn't end up after user input
setTimeout(() => {
this.handleCursorInsert(
this.inputBuffer.nextLine(),
);
}, 1);
}
return new Promise((resolve, reject) => {
this.resolveInput = (value) => {
resolve(value);
};
});
};
clear() {
this.xterm.clear();
}
print(charCode) {
let array = [charCode];
if (charCode == 10) {
array = [13, 10]; // Replace \n with \r\n
}
this.xterm.write(new Uint8Array(array));
}
}
class BufferQueue {
constructor(xterm) {
this.buffer = [];
}
isEmpty() {
return this.buffer.length == 0;
}
lastLineIsIncomplete() {
return (
!this.isEmpty() &&
!this.buffer[this.buffer.length - 1].endsWith("\n")
);
}
hasLineReady() {
return !this.isEmpty() && this.buffer[0].endsWith("\n");
}
addData(data) {
let lines = data.match(/.*(\n|$)/g);
if (this.lastLineIsIncomplete()) {
this.buffer[this.buffer.length - 1] += lines.shift();
}
for (let line of lines) {
this.buffer.push(line);
}
}
nextLine() {
return this.buffer.shift();
}
}
const runButton = document.getElementById("run");
const replButton = document.getElementById("repl");
const stopButton = document.getElementById("stop");
const clearButton = document.getElementById("clear");
const codeBox = document.getElementById("codebox");
window.onload = () => {
const terminal = new WasmTerminal();
terminal.open(document.getElementById("terminal"));
const stdio = {
stdout: (charCode) => {
terminal.print(charCode);
},
stderr: (charCode) => {
terminal.print(charCode);
},
stdin: async () => {
return await terminal.prompt();
},
message: (text) => {
terminal.writeLine(`\r\n${text}\r\n`);
},
};
const programRunning = (isRunning) => {
if (isRunning) {
replButton.setAttribute("disabled", true);
runButton.setAttribute("disabled", true);
stopButton.removeAttribute("disabled");
} else {
replButton.removeAttribute("disabled");
runButton.removeAttribute("disabled");
stopButton.setAttribute("disabled", true);
}
};
runButton.addEventListener("click", (e) => {
terminal.clear();
programRunning(true);
const code = codeBox.value;
pythonWorkerManager.run({
args: ["main.py"],
files: { "main.py": code },
});
});
replButton.addEventListener("click", (e) => {
terminal.clear();
programRunning(true);
// Need to use "-i -" to force interactive mode.
// Looks like isatty always returns false in emscripten
pythonWorkerManager.run({ args: ["-i", "-"], files: {} });
});
stopButton.addEventListener("click", (e) => {
programRunning(false);
pythonWorkerManager.reset();
});
clearButton.addEventListener("click", (e) => {
terminal.clear();
});
const readyCallback = () => {
replButton.removeAttribute("disabled");
runButton.removeAttribute("disabled");
clearButton.removeAttribute("disabled");
};
const finishedCallback = () => {
programRunning(false);
};
const pythonWorkerManager = new WorkerManager(
"./python.worker.mjs",
stdio,
readyCallback,
finishedCallback,
);
};
</script>
</head>
<body>
<h1>Simple REPL for Python WASM</h1>
<textarea id="codebox" cols="108" rows="16">
print('Welcome to WASM!')
</textarea
>
<div class="button-container">
<button id="run" disabled>Run</button>
<button id="repl" disabled>Start REPL</button>
<button id="stop" disabled>Stop</button>
<button id="clear" disabled>Clear</button>
</div>
<div id="terminal"></div>
<div id="info">
The simple REPL provides a limited Python experience in the browser.
<a
href="https://github.com/python/cpython/blob/main/Tools/wasm/README.md"
>
Tools/wasm/README.md
</a>
contains a list of known limitations and issues. Networking,
subprocesses, and threading are not available.
</div>
</body>
</html>