Add some ORM/Diesel helper macros

src/helpers.rs

@@ -0,0 +1,75 @@
+//! Some ORM helpers
+//!
+//! The macros, types and traits in this module are used to create a simple GraphQL API on top of
+//! models that are in the database.
+
+#![allow(unused_macros)]
+
+macro_rules! all {
+    ($model_name:ident, $conn:expr) => {{
+        use diesel::associations::HasTable;
+
+        let table = $crate::models::$model_name::table();
+        table.load(&$conn)
+    }};
+}
+
+macro_rules! retrieve {
+    ($model_name:ident, $primary_key:expr, $conn:expr) => {{
+        use diesel::associations::HasTable;
+
+        let table = $crate::models::$model_name::table();
+        table.find($primary_key).first(&$conn)
+    }};
+}
+
+macro_rules! create {
+    ($model_name:ident, $object:expr, $conn:expr) => {{
+        use diesel::associations::HasTable;
+        use diesel::{ExpressionMethods, QueryDsl, RunQueryDsl, Table};
+
+        let table = $crate::models::$model_name::table();
+        let primary_key = table.primary_key();
+        $conn.transaction::<$model_name, diesel::result::Error, _>(|| {
+            diesel::insert_into(table).values($object).execute(&$conn)?;
+            table.order(primary_key.desc()).first(&$conn)
+        })
+    }};
+}
+
+macro_rules! update {
+    ($model_name:ident, $primary_key:expr, $object:expr, $conn:expr) => {{
+        use diesel::associations::HasTable;
+
+        let table = $crate::models::$model_name::table();
+        $conn.transaction::<_, diesel::result::Error, _>(|| {
+            diesel::update(table.find($primary_key))
+                .set($object)
+                .execute(&$conn)?;
+            table.find($primary_key).first(&$conn)
+        })
+    }};
+}
+
+macro_rules! destroy {
+    ($model_name:ident, $primary_key:expr, $conn:expr) => {{
+        use diesel::associations::HasTable;
+
+        let table = $crate::models::$model_name::table();
+        let result: Result<$model_name, _> = get!($model_name, $primary_key, $conn);
+        match result {
+            Ok(_) => diesel::delete(table.find($primary_key)).execute(&$conn),
+            Err(e) => Err(e),
+        }
+    }};
+}
+
+macro_rules! destroy_all {
+    ($model_name:ident, $conn:expr) => {{
+        use diesel::associations::HasTable;
+        use diesel::RunQueryDsl;
+
+        let table = $crate::models::$model_name::table();
+        diesel::delete(table).execute(&$conn)
+    }};
+}

src/main.rs

@@ -11,6 +11,9 @@ use rocket::{catchers, routes, Rocket};
 use rocket_contrib::database;
 use rocket_contrib::serve::StaticFiles;
 
+#[macro_use]
+pub mod helpers;
+
 pub mod catchers;
 pub mod handlers;