PAGE HUNTER

Page Hunter library is a Rust-based pagination tool that provides a way to manage and navigate through pages of data. It offers a set of resources that encapsulates all the necessary pagination information such as the current page, total pages, previous page, next page and the items on the current page.

The library also includes validation methods to ensure the integrity of the pagination data. It's designed to be flexible and easy to integrate into any Rust project that requires pagination functionality and standard data validation.

To use page-hunter from GitHub repository with specific version, set the dependency in Cargo.toml file as follows:

[dependencies]
page-hunter = { git = "https://github.com/JMTamayo/page-hunter.git", version = "0.2.0", features = ["serde"] }

You can depend on it via cargo by adding the following dependency to your Cargo.toml file:

[dependencies]
page-hunter = { version = "0.2.0", features = ["utoipa", "pg-sqlx"] }

CRATE FEATURES

• serde: Add Serialize and Deserialize support for Page and Book based on serde. This feature is useful for implementing pagination models as a request or response body in REST APIs, among other implementations.
• utoipa: Add ToSchema support for Page and Book based on utoipa. This feature is useful for generating OpenAPI schemas for pagination models. This feature depends on the serde feature and therefore you only need to implement utoipa to get both.
• pg-sqlx: Add support for pagination with SQLx for PostgreSQL database.
• mysql-sqlx: Add support for pagination with SQLx for MySQL database.

BASIC OPERATION

The page-hunter library provides two main models to manage pagination:

• Page: Represents a page of records with the current page, total pages, previous page, next page, and the items on the current page.
• Book: Represents a book of pages with a collection of Page instances.

The library also provides a set of functions to paginate records into a Page model and bind records into a Book model. The following examples show how to use the page-hunter library:

Paginate records:

If you need to paginate records and get a specific Page:

    use page_hunter::*;

    let records: Vec<u32> = vec![1, 2, 3, 4, 5];
    let page: usize = 0;
    let size: usize = 2;

    let pagination_result: PaginationResult<Page<u32>> =
        paginate_records(&records, page, size);

To create a new instance of a Page from known parameters:

    use page_hunter::*;

    let items: Vec<u32> = vec![1, 2];
    let page: usize = 0;
    let size: usize = 2;
    let total_elements: usize = 5;

    let page_model_result: PaginationResult<Page<u32>> = Page::new(
        &items,
        page,
        size,
        total_elements,
    );

On feature serde enabled, you can serialize and deserialize a Page as follows:

    use page_hunter::*;

    let items: Vec<u32> = vec![1, 2];
    let page: usize = 0;
    let size: usize = 2;
    let total_elements: usize = 5;

    let page_model: PaginationResult<Page<u32>> = Page::new(
        &items,
        page,
        size,
        total_elements,
    ).unwrap_or_else(|error| {
        panic!("Error creating page model: {:?}", error);
    });

    let serialized_page: String = serde_json::to_string(&page_model).unwrap_or_else(|error| {
        panic!("Error serializing page model: {:?}", error);
    });

    let deserialized_page: Page<u32> = serde_json::from_str(&serialized_page).unwrap_or_else(|error| {
        panic!("Error deserializing page model: {:?}", error);
    });

When you create a new Page instance from the constructor or deserialization, the following rules are validated for the fields on the page:

• pages must be equal to total divided by size rounded up. When size is 0, pages must be 1.
• page must be less than or equal to pages - 1.
• if page is less than pages - 1, items length must be equal to size.
• if page is equal to pages - 1, total must be equal to (pages - 1) * size + items length.
• previous_page must be equal to page - 1 if page is greater than 0, otherwise it must be None.
• next_page must be equal to page + 1 if page is less than pages - 1, otherwise it must be None.

If any of these rules are violated, a PaginationError will be returned.

Bind records:

If you need to bind records into a Book model:

    use page_hunter::*;

    let records: Vec<u32> = vec![1, 2, 3, 4, 5];
    let size: usize = 2;

    let book_result: PaginationResult<Book<u32>> =
        bind_records(&records, size);

To create a new Book instance from known parameters:

    use page_hunter::*;

    let sheets: Vec<Page<u32>> = vec![
        Page::new(&vec![1, 2], 0, 2, 5).unwrap(),
        Page::new(&vec![3, 4], 1, 2, 5).unwrap(),
    ];

    let book: Book<u32> = Book::new(&sheets);

On feature serde enabled, you can serialize and deserialize a Book as follows:

    use page_hunter::*;

    let sheets: Vec<Page<u32>> = vec![
        Page::new(&vec![1, 2], 0, 2, 5).unwrap(),
        Page::new(&vec![3, 4], 1, 2, 5).unwrap(),
    ];

    let book: Book<u32> = Book::new(&sheets);

    let serialized_book: String = serde_json::to_string(&book).unwrap_or_else(|error| {
        panic!("Error serializing book model: {:?}", error);
    });

    let deserialized_book: Book<u32> = serde_json::from_str(&serialized_book).unwrap_or_else(|error| {
        panic!("Error deserializing book model: {:?}", error);
    });

Generate OpenAPI schemas:

On feature utoipa enabled, you can generate OpenAPI schemas for Page and Book models as follows:

   use page_hunter::*;
   use utoipa::ToSchema;
   use serde::{Deserialize, Serialize};

   #[derive(Clone, ToSchema)]
   pub struct Person {
       id: u16,
       name: String,
       last_name: String,
       still_alive: bool,
   }

   pub type PeoplePage = Page<Person>;
   pub type PeopleBook = Book<Person>;

   #[derive(OpenApi)]
   #[openapi(
       components(schemas(PeoplePage, PeopleBook))
   )]
   pub struct ApiDoc;

Take a look at the examples folder where you can find practical uses in REST API implementations with some web frameworks.

Paginate records from a PostgreSQL database with SQLx:

To paginate records from a PostgreSQL database:

    use page_hunter::*;
    use sqlx::postgres::{PgPool, Postgres};
    use sqlx::{FromRow, QueryBuilder};
    use uuid::Uuid;

    #[tokio::main]
    async fn main() {
        #[derive(Clone, Debug, FromRow)]
        pub struct Country {
            id: Uuid,
            name: String,
        }

        let pool: PgPool = PgPool::connect(
            "postgres://username:password@localhost/db"
        ).await.unwrap_or_else(|error| {
           panic!("Error connecting to database: {:?}", error);
       });

        let query: QueryBuilder<Postgres> = QueryBuilder::new(
            "SELECT * FROM db.geo.countries"
        );

        let page: Page<Country> =
            query.paginate(&pool, 0, 10).await.unwrap_or_else(|error| {
                panic!("Error paginating records: {:?}", error);
            });
    }

To paginate records from a MySQL database:

    use page_hunter::*;
    use sqlx::mysql::{MySqlPool, MySql};
    use sqlx::{FromRow, QueryBuilder};
    use uuid::Uuid;

    #[tokio::main]
    async fn main() {
        #[derive(Clone, Debug, FromRow)]
        pub struct Country {
            id: Uuid,
            name: String,
        }

        let pool: MySqlPool = MySqlPool::connect(
            "mysql://username:password@localhost/db"
        ).await.unwrap_or_else(|error| {
            panic!("Error connecting to database: {:?}", error);
        });

        let query: QueryBuilder<MySql> = QueryBuilder::new(
            "SELECT * FROM countries"
        );

        let page: Page<Country> =
            query.paginate(&pool, 0, 10).await.unwrap_or_else(|error| {
               panic!("Error paginating records: {:?}", error);
            });
    }

DEVELOPMENT

To test page-hunter, follow these recommendations:

Set env variables:

Create local.env file at workspace folder to store the required environment variables

    DB_HOST=localhost
    DB_USER=test
    DB_PASSWORD=docker
    DB_NAME=test
    PG_DB_PORT=5432
    MYSQL_DB_PORT=3306

Setup databases:

Run databases as Docker containers using the following commands:

Postgres SQL:

    make pg-db-docker 

MySQL:

    make mysql-db-docker

Run database migrations:

• Install sqlx-cli:

    make install-sqlx-cli

Postgres SQL

• Run migrations:

    make run-postgres-migrations

• Revert migrations:

    make revert-postgres-migrations

MySQL

• Run migrations:

    make run-mysql-migrations

• Revert migrations:

    make revert-mysql-migrations

To test:

    make test

To test using tarpaulin:

• Install cargo-tarpaulin:

    make install-tarpaulin

• Run tests:

    make test-tarpaulin

To test using llvm-cov:

• Install llvm-cov:

    make install-llvm-cov

• Run tests:

    make test-llvm-cov

CONTRIBUTIONS

The Page Hunter project is open source and therefore any interested software developer can contribute to its improvement. To contribute, take a look at the following recommendations:

• Bug Reports: If you find a bug, please create an issue detailing the problem, the steps to reproduce it, and the expected behavior.
• Feature Requests: If you have an idea for a new feature or an enhancement to an existing one, please create an issue describing your idea.
• Pull Requests: If you've fixed a bug or implemented a new feature, we'd love to see your work! Please submit a pull request. Make sure your code follows the existing style and all tests pass.