#mediator

#Quick Start

#Add dependency

moon add moonrockz/mediator

#1. Define message and handler

// messages.mbt
pub struct GetUser { id : Int }

// handlers.mbt — convention: handle_<MessageName>(MessageName) -> Result[T]
pub fn handle_GetUser(req : GetUser) -> @core.Result[User] {
  @core.ok(User::{ id: req.id, name: "Alice" })
}

#2. Import core and generate dispatch

import { "moonrockz/mediator/core" }

mediator gen -d src -o src/mediator_gen.mbt

#3. Use the mediator

let mediator = @core.Mediator::new(dispatch)
let res = mediator.send(Request::GetUser(GetUser::{ id: 1 }))
match res {
  UserResult(wrap) => match wrap.value {
    @core.Result::Ok(u) => println(u.name)
    _ => ()
  }
}

#Middleware

let mw = @core.middleware(
  Some(@core.before(fn(_req, ctx) { println("before"); ctx })),
  Some(@core.after(fn(_req, _res, _ctx) { println("after") })),
  Some(@core.finally(fn(_req, _ctx, _err) { println("finally") })),
)
let mediator = @core.Mediator::new(dispatch).with_middleware([mw])

#Result type

#Examples

• examples/minimal — one request (GetUser), one handler, no middleware
• examples/with_middleware — same plus logging middleware

cd examples/minimal && moon check && moon run src/main.mbt
cd examples/with_middleware && moon check && moon run src/main.mbt

#CLI

moon install moonrockz/mediator/src/cmd/main

• mediator gen -d <dir> -o <file> — scan directory for handlers, write generated code
• mediator version — print version

#CI and release

• CI (push/PR to main): format check, moon check, moon test (wasm-gc and js).
• Release: Triggered by pushing a tag v* or via workflow_dispatch. Runs validate, publishes to mooncakes.io (requires MOONCAKES_USER_TOKEN repo secret), then creates a GitHub Release. Use conventional commits and mise run release:version to compute the next tag.