The goal of the project is to be able to run WebAssembly binaries from PHP directly. So much fun coming!
Quoting the WebAssembly site:
WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable target for compilation of high-level languages like C/C++/Rust, enabling deployment on the web for client and server applications.
About speed:
WebAssembly aims to execute at native speed by taking advantage of common hardware capabilities available on a wide range of platforms.
About safety:
WebAssembly describes a memory-safe, sandboxed execution environment […].
This extension has some goals in minds. Let's list some of them:
Taking the example of an image manipulation library, like face
detection, one can use an existing Rust or C++ library, then compile
it to a WebAssembly binary, and use it directly in PHP through the
php-ext-wasm extension.
Writing a C extension for PHP with the Zend API is no longer necessary.
Because WebAssembly is a portable target, i.e. binaries are platform agnostics, once a library has been compiled to a WebAssembly binary, it is immediately distributable on all platforms where PHP runs. There is no compilation steps required. And to be clear, compiling a library to a WebAssembly binary does not required any PHP headers.
To push the logic further, a library compiled as a WebAssembly binary can be packaged with Composer (the PHP dependency manager), along with some PHP code to ease the manipulation of the compiled library.
Distributing a new version of a WebAssembly binary simply reduces to
distributing a new file. Composer can also add constraints over the
available extensions with their
versions (see
ext-name). All packaging scenarios are handled.
Since version 0.2.0, php-ext-wasm uses the wasmer
library. It is 28x times faster than the
previous library (wasmi, see
#5 for more
information).
It is still possible to improve the performance. We are working on it right now. After some more work, we want to publish a benchmark.
WebAssembly brings safety guarantees, notably due to its memory model and its sandboxed execution environment. If Rust is used as the source of a WebAssembly binary, then more safety is brought in the game. In any case, without real numbers or studies, we imagine that it is safer to use a WebAssembly binary extension rather than writing C code.
A WebAssembly binary has no access to the PHP environment (so no access to its memory or functions). It is executed in a sandbox. A WebAssembly binary is totally blind regarding the host/the system where it runs: Whether it runs in a Web browser, a server, or a PHP process, this is the same.
There is a toy program in examples/simple.rs, written in Rust
(or any other language that compiles to Wasm):
#[no_mangle]
pub extern fn sum(x: i32, y: i32) -> i32 {
x + y
}This program compiles to Wasm, with just compile-wasm examples/simple. We end up with a examples/simple.wasm binary file.
Then, we can execute it in PHP (!) with the examples/simple.php file:
$instance = new Wasm\Instance(__DIR__ . '/simple.wasm');
var_dump(
$instance->sum(5, 37) // 42!
);And then, finally, enjoy by running:
$ php -d extension=wasm examples/simple.php
int(42)This repository contains basically two things:
- The
php-ext-wasmextension, and - The
Wasmlibrary.
The php-ext-wasm extension provides a raw API around
WebAssembly. The Wasm library is a layer on top of php-ext-wasm to
provide more safety and a more user-friendly API.
See the API documentations with examples.
To compile the entire project, run the following commands:
$ just rust
$ just php
$ php -d extension=wasm examples/simple.php(Yes, you need just).
Once the extension is compiled and installed (just run just rust && just php), run the following commands:
$ composer install
$ composer testThe entire project is under the BSD-3-Clause license. Please read the
LICENSE file.