Module app 

Application builder and runtime for fastapi_rust.

This module provides a fluent API for building web applications with type-safe route registration, middleware ordering, and shared state.

Design Principles

• Fluent Builder API: Chain methods to configure the application
• Type-Safe State: Shared state is type-checked at compile time
• Explicit Middleware Order: Middleware runs in registration order
• Compile-Time Validation: Invalid configurations fail at compile time

Example

use fastapi_core::app::{App, AppBuilder};
use fastapi_core::{Request, Response, RequestContext};

async fn hello(ctx: &RequestContext, req: &mut Request) -> Response {
    Response::ok().body_text("Hello, World!")
}

async fn health(ctx: &RequestContext, req: &mut Request) -> Response {
    Response::ok().body_json(&serde_json::json!({"status": "healthy"}))
}

let app = App::builder()
    .route("/", Method::Get, hello)
    .route("/health", Method::Get, health)
    .middleware(RequestIdMiddleware::new())
    .middleware(LoggingMiddleware::new())
    .build();

Structs

App

A configured web application.

AppBuilder

Builder for constructing an App.

AppConfig

Application configuration for the FastAPI Rust framework.

ExceptionHandlers

Registry for custom exception handlers.

LifespanError

Error during lifespan startup.

LifespanScope

Scope returned by a lifespan function containing state and cleanup logic.

MountedApp

A mounted sub-application with its path prefix.

RouteEntry

A registered route with its handler.

StartupHookError

Error returned when a startup hook fails.

StateContainer

Type-safe application state container.

Enums

ConfigError

Configuration loading errors.

StartupHook

A startup hook that runs before the server starts accepting connections.

StartupOutcome

Outcome of running all startup hooks.

Traits

HasState

Marker trait indicating that type T is present in state registry S.

RequiresState

Trait for types that require specific state to be registered.

StateRegistry

Marker trait for the type-level state registry.

Type Aliases

BoxExceptionHandler

A boxed exception handler function.

BoxHandler

A boxed handler function.

BoxLifespanFn

Boxed lifespan function type.

BoxPanicHandler

A boxed panic handler function.