micropython/ports/webassembly
elibdev b2ad7e238b webassembly: Make mp_js_do_str asynchronous.
This fixes a bug where `gc.collect()` would crash due to
emscripten_scan_stack being called synchronously within mp_js_do_str.  The
fix is to make mp_js_do_str asynchronous.

Fixes #10692.

Signed-off-by: Eli Bierman <eli@elib.dev>
2023-06-27 15:26:42 +10:00
..
Makefile webassembly/modutime: Use extmod version of time module. 2023-04-27 15:11:52 +10:00
README.md webassembly: Make mp_js_do_str asynchronous. 2023-06-27 15:26:42 +10:00
library.h javascript: Rename this port to 'webassembly'. 2022-08-22 12:03:39 +01:00
library.js webassembly/library: Extract and send data to print as UInt8Array. 2022-12-13 17:16:37 +11:00
main.c webassembly: Add support for VFS and enable VFS_POSIX. 2022-11-01 13:53:06 +11:00
mpconfigport.h webassembly/modutime: Use extmod version of time module. 2023-04-27 15:11:52 +10:00
mphalport.c javascript: Rename this port to 'webassembly'. 2022-08-22 12:03:39 +01:00
mphalport.h webassembly: Add support for VFS and enable VFS_POSIX. 2022-11-01 13:53:06 +11:00
node_run.sh javascript: Rename this port to 'webassembly'. 2022-08-22 12:03:39 +01:00
qstrdefsport.h javascript: Rename this port to 'webassembly'. 2022-08-22 12:03:39 +01:00
wrapper.js webassembly: Make mp_js_do_str asynchronous. 2023-06-27 15:26:42 +10:00

README.md

MicroPython WebAssembly

MicroPython for WebAssembly.

Dependencies

Building webassembly port bears the same requirements as the standard MicroPython ports with the addition of Emscripten (and uglify-js for the minified file).

The output includes micropython.js (a JavaScript wrapper for the MicroPython runtime) and firmware.wasm (actual MicroPython compiled to WASM).

Build instructions

In order to build micropython.js, run:

$ make

To generate the minified file micropython.min.js, run:

$ make min

Running with Node.js

Access the repl with:

$ node build/micropython.js

Stack size may be modified using:

$ node build/micropython.js -X stack=64K

Where stack size may be represented in Bytes, KiB or MiB.

MicroPython scripts may be executed using:

$ node build/micropython.js hello.py

Alternatively micropython.js may by accessed by other javascript programs in node using the require command and the general API outlined below. For example:

var mp_js = require('./build/micropython.js');

mp_js_init(64 * 1024);
await mp_js_do_str("print('hello world')\n");

Running with HTML

The prerequisite for browser operation of micropython.js is to listen to the micropython-print event, which is passed data when MicroPython code prints something to stdout. The following code demonstrates basic functionality:

<!doctype html>
<html>
  <head>
    <script src="build/micropython.js"></script>
  </head>
  <body>
    <pre id="micropython-stdout"></pre>
    <script>
      document.addEventListener("micropython-print", function(e) {
        let output = document.getElementById("micropython-stdout");
        output.innerText += new TextDecoder().decode(e.detail);
      }, false);

      var mp_js_startup = Module["onRuntimeInitialized"];
      Module["onRuntimeInitialized"] = async function() {
        mp_js_startup();
        mp_js_init(64 * 1024);
        await mp_js_do_str("print('hello world')");
      };
    </script>
  </body>
</html>

MicroPython code execution will suspend the browser so be sure to atomize usage within this environment. Unfortunately interrupts have not been implemented for the browser.

Testing

Run the test suite using:

$ make test

API

The following functions have been exposed to javascript.

mp_js_init(stack_size)

Initialize MicroPython with the given stack size in bytes. This must be called before attempting to interact with MicroPython.

await mp_js_do_str(code)

Execute the input code. code must be a string.

mp_js_init_repl()

Initialize MicroPython repl. Must be called before entering characters into the repl.

mp_js_process_char(char)

Input character into MicroPython repl. char must be of type number. This will execute MicroPython code when necessary.