WASM PHP

Project based on https://github.com/seanmorris/php-wasm which was forked from https://github.com/oraoto/pib

I fixed some inconsistencies in the Makefile and removed non-essential things. This fork:

• builds sqlite3
• builds libxml
• no javascript abstraction
• exposes FS and builds with IDBFS
• does not build https://github.com/seanmorris/vrzno which allows javascript access from PHP (TODO add this back opt-in cause it's really cool)
• does not add preloaded data, having this separatly from php-wasm builds allows for more flexibility (see preload data section)

Build

docker buildx bake

Builded files will be located in build/php-web.js and build/php-web.wasm. The module we export in this image is called createPhpModule.

Build arguments

Use this as template to build PHP with emscripten. At build these arguments are available:

LIBXML2_TAG=v2.9.10
PHP_BRANCH=PHP-8.3.0

The next args are used for emcc options -sOPTION see settings.js. In fact it's even easier for you to set them directly in the Dockerfile.

WASM_ENVIRONMENT=web
ASSERTIONS=0
OPTIMIZE=-O2
INITIAL_MEMORY=256mb
JAVASCRIPT_EXTENSION=mjs # change by js if needed
MODULARIZE=1
EXPORT_ES6=1
EXPORT_NAME=createPhpModule

Preload data

My preferred option is to use the file_packager tool to build the preloaded data in a php-web.data.js (and php-web.data file). These are preloaded into IDBFS. That can be changed changing the -lidbfs.js argument to emcc.

This will preload SOME_DIR into the /src directory inside the WASM filesystem:

mkdir -p php-wasm
docker run -v SOME_DIR:/src -v $(pwd)/php-wasm:/dist -w /dist soyuka/php-wasm:8.2.9 python3 /emsdk/upstream/emscripten/tools/file_packager.py php-web.data --use-preload-cache --lz4 --preload "/src" --js-output=php-web.data.js --no-node --exclude '*/.*' --export-name=createPhpModule
ls php-wasm/

Note that the php-web.data.js must be either used as PRE_JS argument to emcc or it needs to be included inside the php-web.js:

sed '/--pre-js/r php-wasm/php-web.data.js' php-wasm/php-web.mjs > this-has-preloaded-data-php-web.mjs

We match the export-name with the emcc EXPORT_NAME option. Use excludes to downsize the preloaded data weight.

Usage

To execute some php, call phpw_exec using ccall, for example:

const phpBinary = require('build/php-web');

return phpBinary({
    onAbort: function(reason) {
      console.error('WASM aborted: ' + reason)
    },
    print: function (...args) {
      console.log('stdout: ', args)
    },
    printErr: function (...args) {
      console.log('stderr: ', args)
    }
})
.then(({ccall, FS}) => {
  const phpVersion = ccall(
    'phpw_exec'
    , 'string'
    , ['string']
    , [`phpversion();`]
  );
})

API

phpw_exec(string code): string
phpw_run(string code): void
phpw(string filePath): void

Example calls:

const STR = 'string';
ccall("phpw", null, [STR], ["public/index.php"]);
console.log(ccall("phpw_exec", STR, [STR], ["phpversion();"]));

More about how to call exposed functions

Demo

Before running the demo, you need to build the library.

docker buildx bake

Then you need to copy the php-web.js and php-web.wasm to the demo directory.

$ cp build/php-web.* demo/public/

Then to build the preloaded data:

docker run \
  -v $(pwd)/demo/src:/src \
  -v $(pwd)/demo/public:/dist \
  -w /dist \
  soyuka/php-wasm:8.2.9 \
  python3 \
    /emsdk/upstream/emscripten/tools/file_packager.py \
    php-web.data \
      --use-preload-cache \
      --lz4 \
      --preload "/src" \
      --js-output=php-web.data.js \
      --no-node \
      --exclude '*/.*' \
      --export-name=createPhpModule

Then attach the php-web.data.js to the demo/public/php-web.mjs:

sed '/--pre-js/r demo/public/php-web.data.js' demo/public/php-web.mjs > this-has-preloaded-data-php-web.mjs ; mv this-has-preloaded-data-php-web.mjs demo/public/php-web.mjs

And finally open a web sserver in the demo directory:

$ php -S 127.0.0.1:8000 -t demo/public

TODO

• add opt-in / opt-out sqlite libxml vrzno and mb more