Laravel Cursor Paginator

Easily have cursor based pagination in your Eloquent models and query builders, read this article to understand the benefits of cursor pagination and the problems it attempts to solve.

There's another cursor-pagination package but unfortunately it doesn't support retrieving previous pages or multi-column ordering, that's why I decided to create this one.

Features

• Automatically paginates based on columns ordering.
• Supports multi-column ordering which makes it easy to have a deterministic row sequence.
• Detects if the model has date casts.
• Mutiple cursor directions:
  • before: returns the items before the cursor.
  • before_i: returns the items before the cursor (including the item at the cursor).
  • after: returns the items after the cursor.
  • after_i: returns the items after the cursor (including the item at the cursor).

Installation

First install the package via composer:

composer require amrnn/laravel-cursor-paginator

You can optionally publish the config file:

php artisan vendor:publish --provider="Amrnn\CursorPaginator\PaginatorServiceProvider"

Register service provider

The package automatically registers itself, but if you need to you can add the service provider manually.

// config/app.php

'providers' => [
    // ...
    Amrnn\CursorPaginator\PaginatorServiceProvider::class,
];

Usage

This package provides a myCursorPaginate() method that you can invoke on your Eloquent models or query builders:

Route::get('/posts', function() {
    return Post::select('id')->orderBy('id', 'desc')->myCursorPaginate(5);
})

which will return something like this:

{
    /**
    * the result items
    */
    "data": [{"id": 10},{"id": 9},{"id": 8},{"id": 7},{"id": 6}],

    /**
    * number of items per page
    */
    "per_page": 5,

    /**
    * total items in result set for your query
    */
    "total": 10,

    /**
    * the following boundary item if you continue to paginate in this direction
    */
    "next_item": { "id": 5 },

    /**
    * navigation urls, you can change the cursor names in the url query string by
    * editing the (directions) array in config file.
    */
    "first_page_url": "http://localhost:8000/posts?after_i=10",
    "last_page_url": "http://localhost:8000/posts?before_i=1",
    "next_page_url": "http://localhost:8000/posts?after=6",
    "prev_page_url": "http://localhost:8000/posts?before=10",

    /*
    * these provide the cursor data structures.
    * they are given in case you want to construct the url manually,
    * but usually you will  just use the urls shown above.
    */
    "current_page": {...},
    "first_page": {...},
    "last_page": {...},
    "next_page": {...},
    "previous_page": {...},

    /*
    * determine if there are more next/previous items
    */
    "has_next": true,
    "has_previous": false,

}

Options

You can pass an optional first argument to paginateCursor() to specify the number of items per page (if left empty a default value from config file is used):

// will return 10 items per page
Post::orderBy('id')->myCursorPaginate(10);

The package should automatically determine date casts by inspecting your model. However, if you're invoking the pagination on a plain query builder then you may need to pass a second argument which tells it about the date casts:

// no need to specify date casts here
Post::orderBy('created_at')->myCursorPaginate(10);

// must tell a plain query builder about the dates
DB::table('posts')
    ->orderBy('created_at')
    ->myCursorPaginate(10, ['dates' => ['created_at']]);

Multiple Columns

You can order by multiple columns and pagination should work as expected:

Post::orderBy('created_at')->orderBy('id')->myCursorPaginate();

Post::orderBy('created_at', 'desc')->orderBy('id', 'desc'')->myCursorPaginate();

It's not recommended to mix directions (asc, desc) when ordering by multiple columns. Doing that would make using table indexes hard for your database.

Caveats

All the columns that you're ordering by must also appear in your select statement, for example the following won't work:

Post::select('id')->orderBy('created_at')->myCursorPaginate();

You have to do any of the following instead:

Post::select('id', 'created_at')->orderBy('created_at')->myCursorPaginate();

// or

Post::orderBy('created_at')->myCursorPaginate()

Config

return [
    /**
     *
     * Cursor direction names
     *
     * these appear in the url query string, change their mappings if you need to.
     * for example if you change:
     *
     * 'before' => 'b'
     *
     * then your urls might look like:
     * http://localhost:8000/b=10 instead of http://localhost:8000/before=10
     */
    'directions' => [
        'before' => 'before',
        'before_i' => 'before_i',
        'after' => 'after',
        'after_i' => 'after_i',
    ],

    /**
     * Whether to encode url query.
     *
     * If set to true then your urls might look like:
     * http://localhost:8000/cursor=eyJhZnRlciI6M30 instead of http://localhost:8000/after=3
     */
    'encode_cursor' => false,

    /**
     * Cursor url query name to use when `encode_cursor` set to is `true`.
     *
     * for example if you change:
     * 'encoded_cursor_name' => 'page-id'
     *
     * then your urls might look like:
     * http://localhost:8000/page-id=eyJhZnRlciI6M30 instead of http://localhost:8000/cursor=eyJhZnRlciI6M30
     */
    'encoded_cursor_name' => 'cursor',

    /**
     * Default number of items per page.
     *
     * This can be overridden by passing a first argument to the `myCursorPaginate()` method.
     */
    'per_page' => 10,
];

License

This project is licensed under the MIT License - see the LICENSE.md file for details.