webhookrelay / whr-rs

Webhook Relay Functions rust lib

This is a helper library to transform webhook request with Webhook Relay Functions.

Functions can be executed on public endpoints and for each destination (Webhook Relay can send same request to multiple destinations) allowing to customize data per service. In general, functions modify your request properties:

Example:

extern crate whr;
use whr::{Request};

// handler is a user handler, incoming Request struct let's you get
// body, method, path, query and headers
fn handler(req: Request) {    
    let new_body = format!("{{\"text\": \"{}\"}}", req.get_body());
    let new_path = format!("{}/page/10", req.get_path());

    // we can use whr crate public functions to modify request
    whr::set_request_method("POST".to_string());
    whr::set_request_header("Content-Type".to_string(), "application/json".to_string());
    whr::set_request_body(new_body);
    whr::set_request_path(new_path);
}

// our entry point into the application, this is called by Webhook Relay with
// initial request payload
#[no_mangle]
pub extern "C" fn handleRequest(ptr: i32, len: i32) {
    whr::run(ptr, len, handler)
}

To build rust function into a compatible wasm binary, use cargo:

cargo build --target wasm32-unknown-unknown --release

Once wasm binary is built, add it to your functions using relay CLI:

relay function create path/to/hello_world.wasm

To view your functions:

relay function ls                                                                         
ID                                     NAME                 DRIVER              SIZE                AGE                 UPDATED AGO
064cf2ad-03e9-4707-b410-35be5bc125e9   hello_world          wasm                501 kB              11 hours            11 hours

To create a public endpoint that's transforming webhooks with your function before sending them to your specified destination:

relay forward --bucket lib-rs --function hello_world --type public https://some-service.example.com/webhooks

Installing toolchain

Toolchain can be installed using rustup:

rustup toolchain add nightly-2019-11-24
rustup target add wasm32-unknown-unknown --toolchain nightly-2019-11-24