bui-backend - Brower User Interfaces (BUIs) with Tokio

This is a work in progress. The API will likely evolve somewhat. The docs need work.

This library, bui-backend, enables an application to serve a Browser User Interface (BUI). The browser becomes your GUI. The API is based on futures and reactively pushes state to the browser. Assets can be served from the filesystem or bundled in the executable. The server provides an "escape hatch" to allow server-client communication outside of bui-backend. The demo includes a Rust web assembly (wasm), plain Javascript frontend and an Elm frontend. Together, this lets you ship an application written in Rust as a single file with a browser-based UI.

The operating principle is that the server runs an HTTP server (based on hyper) to which the browser connects. The initial page tells the browser to open a connection to a Server Sent Events endpoint and the server can subsequently push updates to the browser. Additionally, the server listens for POST callbacks on another endpoint. All data is encoded as JSON.

Features

• Uses raii-change-tracker to ensure that server state changes are reactively sent to all connected frontends.
• To keep things simple, server state is shared with all connected clients.
• Session keys (per browser) and connection keys (per tab) are maintained and allow taking control of communication using pre-established event stream. (This is an "escape hatch" to break out of the bui-backend abstractions as required by some use cases.)
• Demo frontends written in Rust web assembly (wasm), Javascript and Elm. (Use bui-demo with frontend_rust_wasm, frontend_js, or frontend_elm feature.)
• Written in async style using futures-rs.
• Uses Serde JSON.
• Compile-time choice between bundling served files into executable (with bundle_files feature) or reading files from disk (serve_files).

Potential improvements

• Add example with user login.
• Implement more sophisticated state-sharing allowing partial views and minimal updates.
• When ReadableStream is more widely supported, use it (instead of Server Sent Events).
• Your idea here.

Security warning

Due to its nature, the program listens and responds to client connections from the network. If you expose your program to untrusted network connections, ensure that code within any callback handlers you write is safe when handling malicious input.

Other crates in this repository

• codegen - Buildtime codegen support for bui-backend.
• bui-demo - Example program with Javascript and Elm frontends.

License

Licensed under either of

• Apache License, Version 2.0, (./LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (./LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Code of conduct

Anyone who interacts with bui-backend in any space including but not limited to this GitHub repository is expected to follow our code of conduct.