WebAssembly comes to Apache web server

VMware Labs has unveiled an extension module for Apache’s popular web server that runs WebAssembly binaries, opening new possibilities for languages and projects to run securely in Apache.

The mod_wasm extension module allows the Apache HTTP Server to reply to HTTP requests with applications compiled to WebAssembly. Internally, mod_wasm uses the Wasmtime secure runtime to configure and run Wasm modules.

When an Apache HTTP Server is run with mod_wasm enabled, the Wasm module is preloaded into memory as part of a process to speed up request handling by not loading the Wasm module from scratch every time a request is received.

Unveiled on GitHub earlier this month, mod-wasm is composed of two libraries:

• mod_wasm.so, which provides an interface between the Apache C API and Rust library to manage the Wasm runtime. This library is responsible for Apache configuration options and the bindings to connect the Rust library with Apache.
• libwasm._runtime.so, which receives HTTP requests from Apache, configuring and running the Wasm module. It also parses the response and returns control to mod_wasm.so.

WebAssembly, or Wasm, is a binary instruction format and stack-based virtual machine that provides high performance for web applications. It was designed as a portable compilation target for programming languages including C, C++, and Rust.