README

Automatic rating aggregation for Laravel Eloquent models with reviews.

This package aggregates the ratings' average and count of a model, which is reviewed, and updates the model on the occurance of the specified events, e.g.: after saving or deleting a review. So, it facilitates the access to these values and eliminates the problem of n+1 queries when retrieving a list of the models with their aggregate-rating values and also the need for subqueries when sorting the models based on their rating.

Setup

First, modify the database table of the model that is reviewed and add two new columns, one to store the ratings' average and another one for the ratings' count, forexample:

	$table->float('rating_average')->nullable();
	$table->unsignedInteger('rating_count')->default(0);

Obviously, there has to be a rating column on the reviews table.

Then, there're two traits. One is intended to be used in the model that is reviewed. It contains an abstract method that has to be implemented to return the relationship to the review model.

use AggregateRating\HasAggregateRating;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasMany

Class Item extends Model
{
	use HasAggregateRating;

	public function aggregateRatingReviews(): HasMany
	{
		return $this->reviews();
	}

	// ...
}

The other is to be used in the review model. It contains an abstract method to return the relationship to the model that is reviewed.

use AggregateRating\HasIndividualRating;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

Class Review extends Model
{
	use HasIndividualRating;

	public function aggregateRatingItem(): BelongsTo
	{
		return $this->item();
	}

	// ...
}

Triggering Events

The aggregateRatingEvents(), which is on the HasIndividualRating trait, returns the events on the review model that trigger the process of the aggregation and updating the related model. This method's default definition is as the following:

	/**
     * Return the model events that require updating the aggregate rating.
     *
     * @return array
     */
	protected static function aggregateRatingEvents()
	{ 
		return [
			'saved', 'deleted',
		];
	}

But you can overwrite it to spicify your custom events:

	/**
     * Return the model events that require updating the aggregate rating.
     *
     * @return array
     */
	protected static function aggregateRatingEvents()
	{ 
		return [
			'approved', 'suspended', 'rejected', 'deleted',
		];
	}

Customizing The Column Names

If you want to choose other names for your columns, set the following constants on your models to the corresponding values.

use AggregateRating\HasAggregateRating;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasMany

Class Item extends Model
{
	use HasAggregateRating;

	const RATING_AVERAGE = 'rating_average';
	const RATING_COUNT = 'rating_count';

	public function aggregateRatingReviews(): HasMany
	{
		return $this->reviews();
	}

	// ...
}

use AggregateRating\HasIndividualRating;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

Class Review extends Model
{
	use HasIndividualRating;

	const RATING = 'rating';

	public function aggregateRatingItem(): BelongsTo
	{
		return $this->item();
	}

	// ...
}