Real API's code examples

crud-define.rs

derive_crud!(Message; NewMessage; messages);

crud-find.rs

fn try_find(
    id: Id<$struct_name>,
    connection: &PgConnection,
) -> Result<Option<$struct_name>, ::error::Error> {
    let result = $schema::table
        .filter($schema::id.eq(&id))
        .first::<$struct_name>(connection);

    match result {
        Ok(obj) => Ok(Some(obj)),
        Err(diesel::result::Error::NotFound) => Ok(None),
        Err(e) => Err(e)
            .context(format_err!(
                "Was not able to read {}",
                stringify!($struct_name)
            ))
            .context(::error::ErrorKind::DatabaseError)
            .map_err(|err| err.into()),
    }
}

crud-trait.rs

pub trait CRUD: Sized {
    type NewEntity;

    fn create(obj: &Self::NewEntity, connection: &PgConnection) -> Result<Id<Self>, Error>;
    fn create_promote(obj: Self::NewEntity, connection: &PgConnection) -> Result<Self, Error>;

    fn try_find(id: Id<Self>, connection: &PgConnection) -> Result<Option<Self>, Error>;
    fn find(id: Id<Self>, connection: &PgConnection) -> Result<Self, Error>;
    fn read(connection: &PgConnection) -> Result<Vec<Self>, Error>;

    fn update(obj: &Self, connection: &PgConnection) -> Result<usize, Error>;
    fn delete(id: &Id<Self>, connection: &PgConnection) -> Result<usize, Error>;
}

model-attempt.rs

#[derive(FromSqlRow, AsExpression, PartialEq, Eq)]
#[sql_type = "Integer"]
pub struct Id<T>(i32, PhantomData<T>);

#[derive(Queryable, AsChangeset, Debug, Clone, PartialEq, Serialize, Deserialize, TypeName)]
#[table_name=messages]
pub struct Message {
    id: Id<Message>,
    timestamp: NaiveDateTime,
    tag: String,
    blob: JsonValue
}

#[derive(Queryable, Insertable, Debug, Clone, PartialEq, Serialize, Deserialize)]
#[table_name=messages]
pub struct NewMessage {
    timestamp: NaiveDateTime,
    tag: String,
    blob: JsonValue
}

model-macro.rs

build_model!(Message; NewMessage; "messages" => {
    timestamp: NaiveDateTime,
    tag: String,
    blob: JsonValue
});

schema-relations.rs

table! {
    use diesel::sql_types::{Serial, Nullable, Integer, Varchar, Timestamp};
    events (id) {
        id -> Serial,
        source_id -> Nullable<Integer>,
        timestamp -> Timestamp,
        subject -> Varchar,
        origin -> Varchar,
        concerns -> Varchar,
        summary -> Varchar,
        url -> Nullable<Varchar>,
    }
}
joinable!(events -> messages (source_id));

schema.rs

table! {
    use diesel::sql_types::{Serial, Varchar, Timestamp, Json};
    messages (id) {
        id -> Serial,
        timestamp -> Timestamp,
        tag -> Varchar,
        blob -> Json,
    }
}