Trait AppState 

pub trait AppState:
    Clone
    + Send
    + Sync
    + 'static {
    // Required methods
    fn version(&self) -> &str;
    fn db(&self) -> &PgPool;
    fn cookie_key(&self) -> &CookieKey;
}

A trait representing the application state that must be implemented by users of the cja framework.

This trait provides access to core components like the database pool and cookie encryption key. The AppState is cloned for each request, so it should be cheap to clone (usually by wrapping expensive resources in Arc).

Example

use cja::app_state::AppState;
use cja::server::cookies::CookieKey;
use sqlx::PgPool;

#[derive(Clone)]
struct MyAppState {
    db: PgPool,
    cookie_key: CookieKey,
}

impl AppState for MyAppState {
    fn version(&self) -> &str {
        "1.0.0"
    }
     
    fn db(&self) -> &PgPool {
        &self.db
    }
     
    fn cookie_key(&self) -> &CookieKey {
        &self.cookie_key
    }
}

Using with Axum

use cja::app_state::AppState;
use cja::server::cookies::CookieKey;
use sqlx::postgres::PgPoolOptions;
use axum::{Router, routing::get, extract::State};

#[derive(Clone)]
struct MyAppState {
    db: sqlx::PgPool,
    cookie_key: CookieKey,
}

impl AppState for MyAppState {
    fn version(&self) -> &str { "1.0.0" }
    fn db(&self) -> &sqlx::PgPool { &self.db }
    fn cookie_key(&self) -> &CookieKey { &self.cookie_key }
}

async fn handler(State(state): State<MyAppState>) -> String {
    format!("App version: {}", state.version())
}

 async fn example() -> Result<(), Box<dyn std::error::Error>> {
 use sqlx::postgres::PgPoolOptions;
let db = PgPoolOptions::new()
     .connect(&std::env::var("DATABASE_URL").unwrap_or_else(|_| "postgres://test".to_string()))
     .await
     .map_err(|_| "Database connection failed")?;
     
let state = MyAppState {
    db,
    cookie_key: CookieKey::from_env_or_generate()?,
};

let app: Router = Router::new()
    .route("/", get(handler))
    .with_state(state);

// Run the server

Required Methods

fn version(&self) -> &str

Returns the version string for the application. This is useful for health checks and debugging.

fn db(&self) -> &PgPool

Returns a reference to the database connection pool. The pool is typically shared across all requests.

fn cookie_key(&self) -> &CookieKey

Returns the cookie encryption key used for secure cookies. This key should be consistent across application restarts to maintain session continuity.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors