First working version

src/db/mod.rs

@@ -0,0 +1,60 @@
+use std::ops::Deref;
+
+use diesel::{Connection as DieselConnection, ConnectionError};
+use diesel::sqlite::SqliteConnection;
+use r2d2;
+use r2d2_diesel::ConnectionManager;
+
+use rocket::http::Status;
+use rocket::request::{self, FromRequest};
+use rocket::{Outcome, Request, State};
+
+use CONFIG;
+
+/// An alias to the database connection used
+type Connection = SqliteConnection;
+
+/// An alias to the type for a pool of Diesel SQLite connections.
+type Pool = r2d2::Pool<ConnectionManager<Connection>>;
+
+/// Connection request guard type: a wrapper around an r2d2 pooled connection.
+pub struct DbConn(pub r2d2::PooledConnection<ConnectionManager<Connection>>);
+
+pub mod schema;
+pub mod models;
+
+/// Initializes a database pool.
+pub fn init_pool() -> Pool {
+    let manager = ConnectionManager::new(&*CONFIG.database_url);
+
+    r2d2::Pool::builder()
+        .build(manager)
+        .expect("Failed to create pool")
+}
+
+pub fn get_connection() -> Result<Connection, ConnectionError> {
+    Connection::establish(&CONFIG.database_url)
+}
+
+/// Attempts to retrieve a single connection from the managed database pool. If
+/// no pool is currently managed, fails with an `InternalServerError` status. If
+/// no connections are available, fails with a `ServiceUnavailable` status.
+impl<'a, 'r> FromRequest<'a, 'r> for DbConn {
+    type Error = ();
+
+    fn from_request(request: &'a Request<'r>) -> request::Outcome<DbConn, ()> {
+        let pool = request.guard::<State<Pool>>()?;
+        match pool.get() {
+            Ok(conn) => Outcome::Success(DbConn(conn)),
+            Err(_) => Outcome::Failure((Status::ServiceUnavailable, ()))
+        }
+    }
+}
+
+// For the convenience of using an &DbConn as a &Database.
+impl Deref for DbConn {
+    type Target = Connection;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}