07_adding_a_database_to_persist_data.md

Adding a Database to Persist Data

To persist data we need to set up our Database. In this app, we will use PostgreSQL as our database and Sea-ORM to manage database migrations. We'll now update our.env file with the database connection string. My.env file looks like this after adding the connection string,

HOST = 127.0.0.1
PORT = 8080

# just added
DATABASE_URL = postgres://user:password@localhost/database-name

With that let's update our config.rs file with the database setup. Add the following to the existing file,

use std::env;
use std::env::VarError;
use lazy_static::lazy_static;

lazy_static! {
    // previous declarations omitted
    pub static ref DATABASE_URL: String = set_db();
}

fn set_db() -> String {
    get_env("DATABASE_URL").unwrap()
}

pub fn get_db() -> String {
    (*DATABASE_URL).clone()
}

Before we can add the database connection to our main, we need to create a struct that has a member of type . First, let's install sea-orm with the features we need,

cargo add sea-orm -F sea-orm/sqlx-postgres,sea-orm/runtime-tokio-rustls,sea-orm/macros

Now, we'll define a AppState struct with our database connection as its member in src/utils/app_state.rs,

use sea_orm::DatabaseConnection;

pub struct AppState {
    pub db: DatabaseConnection,
}

In main.rs we add the database connection from AppState as an application state (https://actix.rs/docs/application/#state). Add the databasee connection as an app_data() to the application instance like this, .app_data(web::Data::new(AppState { db: db.clone() })). Our main.rs should now look like this,

use sea_orm::{Database, DatabaseConnection};
use migration::{Migrator, MigratorTrait};
use utils::config::{get_address, get_db};
use utils::app_state::AppState;

// database setup
async fn setup_db() -> DatabaseConnection {
    let db_url = get_db();
    Database::connect(db_url).await.unwrap()
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    // database setup
    let db = setup_db().await;
    Migrator::up(&db, None).await.unwrap();

    HttpServer::new(move || {
        App::new()
            // database setup
            .app_data(web::Data::new(AppState { db: db.clone() }))
            .wrap(Logger::default())
            .configure(home::urls::routes)
    })
        .bind((host, port))?
        .run()
        .await
}

Our database setup is complete. We should be able to save any data in our database if we want to. To do that, let's create some models, and we will use Sea-ORM instead of typing raw SQL to query the database.