Creating a PHP extension in Rust

http://jaredonline.svbtle.com/creating-a-php-extension-in-rust

by jaredonline • 11 years ago

79 11 11 years ago

jaredonline.svbtle.com

duveit• 11 years ago

Nice job!

tveita• 11 years ago

So who is deallocating the returned string in confirm_hello_from_rust_compiled? Looks like you lost a fair bit of the safety checking in the Rust to C transition, if you didn't even have to mark the whole function unsafe.

masklinn• 11 years ago

That's not how unsafe works. Marking a function as unsafe is more or less solely a decision of the developer (though foreign functions are implicitly unsafe), and an unsafe block does not taint the enclosing function or it wouldn't be possible to build safe interface from unsafe building blocks, making the whole thing serve a completely different purpose.

pornel• 11 years ago

It looks like a bug indeed.

Rust is freeing the string when the function ends, since to_ptr doesn't extended its lifetime.

C seems to be getting freed memory.

AFAIK the right way is to use mem::forget to "leak" memory when giving it to C, and later have C free it by calling a Rust function that casts it back to the original type.

jaredonline• 11 years ago

Nice catch. I'll need to do some reading to figure out the best way to actually handle the string safely.

In this small example we lost a lot of the safety, but for a larger library I'm hoping you could still keep most of the safety of Rust and just expose a smaller subsection of "unsafe" code.

decasteve• 11 years ago

I've also toyed with a similar idea. I'm not a huge fan of writing anything "significant" in PHP but it does make html templating convenient. I would rather write the bulk of my code in a language like C++ or Rust, and then pass off to PHP to do the html (or json or xml) view.

smt883• 11 years ago

I used to think PHP was good for templating, but then I learned about code-less templating engines like Jinja, and I'll never go back.

When you use a templating engine, you can change the backend entirely without messing with the template. You can also compile/optimize the display of data in the template more easily.

Some awesome person has made a Jinja2 lib that comes with Rust bindings, which looks cool (though I haven't tried it yet): https://github.com/jroweboy/jinja2-c

Mahn2• 11 years ago

When you use a templating engine, you can change the backend entirely without messing with the template. You can also compile/optimize the display of data in the template more easily.

To be fair, all that you can do with a templating engine you can do "natively" as well. You can for example have code-less templates in PHP if you are disciplined enough to keep it that way. The only thing template engines do is enforce not being able to shoot yourself in the feet, but it's not an absolute must if you know what you are doing.

Creating a PHP extension in Rust

Related Stories