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Comment by throw_m239339 | Hacker News Reader

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throw_m239339·

That article doesn't explain what the WASM code does in Drupal.

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I understood that Drupal/php is compiled to WASM and then run on a WASM runtime.

So no WASM inside Drupal, but Drupal run as, and in WASM.

Exactly. The Drupal code is unmodified and runs on top of the PHP interpreter compiled to Wasm [0]. The Drupal PHP code is not compiled to Wasm.

- [0] https://github.com/vmware-labs/webassembly-language-runtimes

Is that possible, though? To compile PHP to WASM seems possible¹, but not sure if Drupal can be compiled: drupal does (did? back when I did Drupal it certainly did. I certainly did) some really funky metaprogramming and eval() stuff. Like keeping PHP in the database.

¹https://github.com/wapm-packages/php

I think you missed this paragraph:

The Apache HTTP server and the Drupal packages remain unchanged. However, instead of loading the libphp.so extension module, it incorporates mod_wasm.so. In addition, instead of relying on the traditional PHP interpreter, it utilizes a PHP build in the WebAssembly binary format.

So instead of trusting libphp.so, you have to trust mod_wasm.so that is running a php interpreter internally. Is this a win? Genuine question.

The biggest gain comes from mod_wasm using a Wasm runtime to run the PHP interpreter in a sandboxed environment. And mod_wasm can be used the same with Python or Ruby, or anything that builds for WebAssembly.

- No errors (even fatal) from the Wasm module will bring down Apache HTTPD. - mod_wasm's code base is small enough to inspect thoroughly and test thoroughly to ensure it is secure - Indeed you will now have to trust the embedded Wasm runtime (wasmtime as of today). As a naïve analogy, this is the equivalent of trusting a virtual CPU(Wasm)+OS(WASI), which gets tested in thousands of other scenarios than the ones used in mod_wasm and issues get fixed and corrected asap.

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