Add connection to database

src/database.rs

@@ -0,0 +1,51 @@
+use cfg_if::cfg_if;
+
+cfg_if! {
+if #[cfg(feature = "ssr")] {
+
+use lazy_static::lazy_static;
+use std::env;
+use diesel::{
+    pg::PgConnection,
+    r2d2::ConnectionManager,
+    r2d2::PooledConnection,
+    r2d2::Pool,
+};
+
+// See https://leward.eu/notes-on-diesel-a-rust-orm/
+
+// Define some types to make it easier to work with Diesel
+type PgPool = Pool<ConnectionManager<PgConnection>>;
+pub type PgPooledConn = PooledConnection<ConnectionManager<PgConnection>>;
+
+// Keep a global instance of the pool
+lazy_static! {
+    static ref DB_POOL: PgPool = init_db_pool();
+}
+
+/// Initialize the database pool
+///
+/// Will panic if the DATABASE_URL environment variable is not set, or if there is an error creating the pool.
+///
+/// # Returns
+/// A database pool object, which can be used to get pooled connections
+fn init_db_pool() -> PgPool {
+    let database_url = env::var("DATABASE_URL").expect("DATABASE_URL must be set");
+    let manager = ConnectionManager::<PgConnection>::new(database_url);
+    PgPool::builder()
+        .build(manager)
+        .expect("Failed to create pool.")
+}
+
+/// Get a pooled connection to the database
+///
+/// Will panic if there is an error getting a connection from the pool.
+///
+/// # Returns
+/// A pooled connection to the database
+pub fn get_db_conn() -> PgPooledConn {
+    DB_POOL.get().expect("Failed to get a database connection from the pool.")
+}
+
+}
+}

src/lib.rs

@@ -2,6 +2,7 @@ pub mod app;
 pub mod songdata;
 pub mod playstatus;
 pub mod playbar;
+pub mod database;
 use cfg_if::cfg_if;
 
 cfg_if! {