History

Christian Heimes 43839ba438 bpo-40280: Add --with-emscripten-target to build for browser or node (GH-30552) Co-authored-by: Ethan Smith <ethan@ethanhs.me>		2022-01-12 16:08:19 +01:00
..
README.md	bpo-40280: Add --with-emscripten-target to build for browser or node (GH-30552)	2022-01-12 16:08:19 +01:00
config.site-wasm32-emscripten	bpo-40280: Add --with-emscripten-target to build for browser or node (GH-30552)	2022-01-12 16:08:19 +01:00
wasm_assets.py	bpo-40280: Add Tools/wasm with helpers for cross building (GH-29984)	2021-12-18 15:54:02 +01:00

README.md

Python WebAssembly (WASM) build

This directory contains configuration and helpers to facilitate cross compilation of CPython to WebAssembly (WASM).

wasm32-emscripten build

Cross compiling to wasm32-emscripten platform needs the Emscripten tool chain and a build Python interpreter. All commands below are relative to a repository checkout.

Compile a build Python interpreter

mkdir -p builddir/build
pushd builddir/build
../../configure -C
make -j$(nproc)
popd

Fetch and build additional emscripten ports

embuilder build zlib

Cross compile to wasm32-emscripten

For browser:

mkdir -p builddir/emscripten
pushd builddir/emscripten

CONFIG_SITE=../../Tools/wasm/config.site-wasm32-emscripten \
  emconfigure ../../configure -C \
    --host=wasm32-unknown-emscripten \
    --build=$(../../config.guess) \
    --with-emscripten-target=browser \
    --with-build-python=$(pwd)/../build/python

emmake make -j$(nproc)

For node:

CONFIG_SITE=../../Tools/wasm/config.site-wasm32-emscripten \
  emconfigure ../../configure -C \
    --host=wasm32-unknown-emscripten \
    --build=$(../../config.guess) \
    --with-emscripten-target=node \
    --with-build-python=$(pwd)/../build/python

emmake make -j$(nproc)

Test in browser

Serve python.html with a local webserver and open the file in a browser.

emrun python.html

python3 -m http.server