Crate length_aware_paginator

Length aware paginator enables you to paginate Diesel queries and have information about the length of data being paginated. It will give you total number of items, and last page that you can navigate to and still get some kind of data.

You will only have to provide page and per_page parameters.

use diesel::pg::PgConnection;
use diesel::Connection;
use diesel::QueryDsl;
use length_aware_paginator::{LoadPaginated, Response};
use serde::{Deserialize, Serialize};

/// Get the database connection
/// *panics* if no DATABASE_URL is defined in the env or if the db is unreachable
fn get_connection() -> PgConnection {
    let database_url =
        dotenv::var("DATABASE_URL").expect("You have to provide DATABASE_URL to run tests");

    PgConnection::establish(&database_url)
        .unwrap_or_else(|_| panic!("Error connecting to {}", &database_url))
}

// schema.rs : autogenerated by diesel after running migration
table! {
    users (id) {
        id -> Int4,
        email -> Varchar,
        first_name -> Varchar,
        last_name -> Varchar,
        password -> Varchar,
    }
}

// user.rs : your model for the table represented in schema.rs
#[derive(Queryable, Deserialize, Serialize)]
pub struct User {
    id: i32,
    email: String,
    first_name: String,
    last_name: String,
    password: String,
}

#[test]
fn test_orm_query_pagination() {
    let connection = get_connection();

    // Use `length_aware_paginator::LoadPaginated` trait to enable
    // using the `load_paginated` method on your query.
    // Your query will return `length_aware_paginator::Response<T>` struct
    let response: Response<User> = schema::users::table
        .into_boxed()
        .load_paginated(connection, page, per_page)
        .unwrap();

    assert_eq!(response.page, 1);
    assert_eq!(response.per_page, 10);
    assert_eq!(response.total, 15);
    assert_eq!(response.last_page, 2);
    assert_eq!(response.data.len(), 10);
}

Limitations

Unfortunatelly this is still not implemented to work with sql_query() due to its own limitations. Maybe in the future I'll update this package to enable this.

Structs

Response

Traits

LoadPaginated
Paginate