Arwa: A(nother) Rusty Web-API

The Arwa project aims to expose modern web-APIs as Rust APIs, allowing you to interact with browser functionality such as the DOM, the browser console, the fetch API, and many more. Arwa builds on top of web-sys. web-sys by itself also exposes the browser's web-APIs; it achieves this by automatically generating rust bindings from the WebIDL specifications of the web-APIs. However, APIs designed for Javascript do not always map neatly to Rust idioms. Arwa is an attempt at providing a better developer experience, by tailoring more opinionated decisions on how to best expose web-functionality in Rust on a case by case basis. A core guiding concept in the design of this mapping is the following "hierarchy of consistency":

1. Arwa first and foremost tries to be internally consistent (even when the web-standards themselves not always quite manage to be).
2. Secondly, Arwa tries to be consistent with the Rust ecosystem, in particular with std, the Rust standard library. As a simple example, Arwa uses len - not length - for the size of a collection.
3. Lastly, Arwa tries to be consistent with the Javascript web-APIs.

This hierarchy means that Arwa may not always closely follow the idioms of the Javascript APIs, though hopefully those versed in interacting with the browser through Javascript will hopefully quickly find it familiar.

As Arwa builds on top of web-sys, most Arwa types can be converted to a corresponding web-sys type through a From / Into conversion (which is almost always zero-cost). This means that if Arwa does not (yet) implement a certain web API, but web_sys does, you will still be able to interact with this API by "lowering" into web_sys types and using "raw" web_sys. It also means that you can use other crates that build on top of web_sys and interoperate with Arwa.

Project Status

Arwa is still very young and thus the API is in still in flux. Arwa currently has (mostly) complete APIs for the following set of web APIs (as distinguished by MDN):

• CSSOM
• Console API
• DOM
• Fetch API
• File API
• Fullscreen API
• Geolocation API
• HTML DOM (including HTML Media Elements and Custom Elements)
• HTML Drag And Drop API
• History API
• Page Visibility API
• Performance API
• Pointer Events
• Pointer Lock API
• Resource Timing API
• Selection API
• Service Worker API (without postMessage, see below)
• UI Events
• URL API (currently only parsed from strings, no builder API yet)
• Vibration API
• Web Crypto API (but not "subtle" crypto; random number generation only)
• Web Storage API
• Web Workers API (without postMessage, see below)

Note on postMessage: how messages are to be composed is currently an unsolved question. The current general plan is to mimic Serde -like serialization, but that is in itself a substantial project. For the time being it is recommended you lower to web_sys types and post plain JsValue objects.

License

MIT