Macro define_router

macro_rules! define_router {
    (event = $event_type:ty, module = $module:ident, state = $state_type:ty) => { ... };
    (event = $event_type:ty, state = $state_type:ty) => { ... };
}

Defines a router module with the necessary type aliases for your Lambda application.

This macro creates a module containing type aliases for the router components, making them easily accessible throughout your application. It’s typically used at the beginning of your Lambda function to set up the routing infrastructure.

Type Aliases

The macro creates the following type aliases:

• Event - The Lambda HTTP event type (e.g., ApiGatewayV2httpRequest)
• Router - The router instance type for your application
• RouterBuilder - The builder type for constructing routers
• RouteContext - The context type passed to route handlers

Arguments

• event - The Lambda HTTP event type (required). Supported types:
  • ApiGatewayV2httpRequest - API Gateway HTTP API v2
  • ApiGatewayProxyRequest - API Gateway REST API v1
  • AlbTargetGroupRequest - Application Load Balancer
  • ApiGatewayWebsocketProxyRequest - API Gateway WebSocket
• module - The module name (optional, defaults to an internal name)
• state - The state type for the router

Examples

Basic usage with default module name:

use lambda_lw_http_router::define_router;
use aws_lambda_events::apigw::ApiGatewayV2httpRequest;
use serde_json::{json, Value};
use lambda_runtime::Error;

// Define your application state
#[derive(Clone)]
struct AppState {
    // your state fields here
}

define_router!(event = ApiGatewayV2httpRequest, state = AppState);

// This creates a module with the following types:
// Router - Router<AppState, ApiGatewayV2httpRequest>
// RouterBuilder - RouterBuilder<AppState, ApiGatewayV2httpRequest>
// RouteContext - RouteContext<AppState, ApiGatewayV2httpRequest>

Custom module name for better readability or multiple routers:

use lambda_lw_http_router::define_router;
use aws_lambda_events::apigw::ApiGatewayV2httpRequest;
use aws_lambda_events::alb::AlbTargetGroupRequest;
use serde_json::{json, Value};
use lambda_runtime::Error;

// Define your application state
#[derive(Clone)]
struct AppState {
    // your state fields here
}

// Define an API Gateway router
define_router!(event = ApiGatewayV2httpRequest, module = api_router, state = AppState);

// Define an ALB router in the same application
define_router!(event = AlbTargetGroupRequest, module = alb_router, state = AppState);

// Now you can use specific types for each router:
// api_router::Router
// api_router::RouterBuilder
// api_router::RouteContext
//
// alb_router::Router
// alb_router::RouterBuilder
// alb_router::RouteContext

Usage with Route Handlers

The module name defined here should match the module parameter in your route handlers:

use lambda_lw_http_router::{define_router, route};
use aws_lambda_events::apigw::ApiGatewayV2httpRequest;
use serde_json::{json, Value};
use lambda_runtime::Error;

// Define your application state
#[derive(Clone)]
struct AppState {
    // your state fields here
}

define_router!(event = ApiGatewayV2httpRequest, module = api_router, state = AppState);

#[route(path = "/hello", module = "api_router")]
async fn handle_hello(ctx: api_router::RouteContext) -> Result<Value, Error> {
    let name = ctx.params.get("name").map(|s| s.as_str()).unwrap_or("World");
    Ok(json!({ "message": format!("Hello, {}!", name) }))
}