Plume/plume-models/src/db_conn.rs
2018-09-30 14:13:56 +02:00

39 lines
1.2 KiB
Rust

use diesel::{
r2d2::{ConnectionManager, Pool, PooledConnection}
};
use rocket::{Request, State, Outcome, http::Status, request::{self, FromRequest}};
use std::ops::Deref;
use Connection;
pub type DbPool = Pool<ConnectionManager<Connection>>;
// From rocket documentation
// Connection request guard type: a wrapper around an r2d2 pooled connection.
pub struct DbConn(pub PooledConnection<ConnectionManager<Connection>>);
/// 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<Self, Self::Error> {
let pool = request.guard::<State<DbPool>>()?;
match pool.get() {
Ok(conn) => Outcome::Success(DbConn(conn)),
Err(_) => Outcome::Failure((Status::ServiceUnavailable, ()))
}
}
}
// For the convenience of using an &DbConn as an &Connection.
impl Deref for DbConn {
type Target = Connection;
fn deref(&self) -> &Self::Target {
&self.0
}
}