1 files changed, 71 insertions, 0 deletions
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
new file mode 100644
index 0000000..1d697fe
--- /dev/null
+++ b/src/utils/mod.rs
@@ -0,0 +1,71 @@
+use diesel::pg::PgConnection;
+use r2d2;
+use r2d2_diesel::ConnectionManager;
+use dotenv::dotenv;
+use std::env;
+
+// An alias to the type for a pool of Diesel PostgreSql connections.
+type Pool = r2d2::Pool<ConnectionManager<PgConnection>>;
+
+/// Initializes a database pool.
+pub fn init_db_pool() -> Pool {
+    dotenv().ok();
+
+    let config = r2d2::Config::default();
+    let dburl = env::var("DATABASE_URL")
+        .expect("DATABASE_URL environment variable must be set");
+
+    let manager = ConnectionManager::<PgConnection>::new(dburl);
+    r2d2::Pool::new(config, manager).expect("db pool")
+}
+
+use std::ops::Deref;
+use rocket::http::Status;
+use rocket::request::{self, FromRequest};
+use rocket::{Request, State, Outcome};
+
+// Connection request guard type: a wrapper around an r2d2 pooled connection.
+pub struct DbConn(pub r2d2::PooledConnection<ConnectionManager<PgConnection>>);
+
+/// 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 an &SqliteConnection.
+impl Deref for DbConn {
+    type Target = PgConnection;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+macro_rules! implement_responder_for {
+    // Implement a responder for the given template type
+    //
+    // Seems I can't add the lifetime after the matcher,
+    // like this: `$template_type<'a>`
+    // So it will have to be passed in to the argument at
+    // the macro incovation instead.
+    ($template_type:ty) => (
+        impl<'a> ::rocket::response::Responder<'a> for $template_type {
+            fn respond_to(self, _: &::rocket::Request) -> Result<::rocket::Response<'static>, ::rocket::http::Status> {
+                ::rocket::Response::build()
+                    .header(::rocket::http::ContentType::HTML)
+                    .sized_body(::std::io::Cursor::new(format!("{}", &self)))
+                    .ok()
+            }
+        }
+    )
+}