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Filtering By Relationships

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Eric Tucker edited this page Jan 5, 2018 · 2 revisions

There are two ways to filter by related models. Using the $relations array to define the input to be injected into the related Model's filter. If the related model doesn't have a model filter of it's own or you just want to define how to filter that relationship locally instead of adding the logic to that Model's filter then use the related() method to filter by a related model that doesn't have a ModelFilter. You can even combine the 2 and define which input fields in the $relations array you want to use that Model's filter for as well as use the related() method to define local methods on that same relation. Both methods nest the filter constraints into the same whereHas() query on that relation.

For both examples we will use the following models:

A App\User that hasMany App\Client::class:

class User extends Model
{
    use Filterable;

    public function clients()
    {
    	return $this->hasMany(Client::class);
    }
}

And each App\Client belongs to App\Industry::class:

class Client extends Model
{
    use Filterable;

    public function industry()
    {
    	return $this->belongsTo(Industry::class);
    }
    
    public function scopeHasRevenue($query)
    {
    	return $query->where('total_revenue', '>', 0);
    }
}

We want to query our users and filter them by the industry and volume potential of their clients that have done revenue in the past.

Input used to filter:

$input = [
    'industry'         => '5',
    'potential_volume' => '10000'
];

Setup

Both methods will invoke a setup query on the relationship that will be called EVERY time this relationship is queried. The setup methods signature is {$related}Setup() and is injected with an instance of that relations query builder. For this example let's say when querying users by their clients I only ever want to show agents that have clients with revenue. Without choosing wich method to put it in (because sometimes we may not have all the input and miss the scope all together if we choose the wrong one) and to avoid query duplication by placing that constraint on ALL methods for that relation we call the related setup method in the UserFilter like:

class UserFilter extends ModelFilter
{
    public function clientsSetup($query)
    {
    	return $query->hasRevenue();
    }
}

This prepend all queries with the hasRevenue() whenever the UserFilter runs any constriants on the clients() relationship. If there are no queries to the clients() relationship then this method will not be invoked.

You can learn more about scopes here

Ways To Filter Related Models

Filter Related Models With The related() Method:

The related() method is a little easier to setup and is great if you aren't going to be using the related Model's filter to ever filter that Model explicitly. The related() method takes the same parameters as the Eloquent\Builder's where() method except for the first parameter being the relationship name.

Example:

UserFilter with an industry() method that uses the ModelFilter's related() method

class UserFilter extends ModelFilter
{
	public function industry($id)
    {
    	return $this->related('clients', 'industry_id', '=', $id);
        
        // This would also be shorthand for the same query
        // return $this->related('clients', 'industry_id', $id);
    }
    
    public function potentialVolume($volume)
    {
    	return $this->related('clients', 'potential_volume', '>=', $volume);
    }
}

Or you can even pass a closure as the second argument which will inject an instance of the related model's query builder like:

    $this->related('clients', function($query) use ($id)
    {
    	return $query->where('industry_id', $id);
    });

Filter Related Models Using The $relations Array:

Add the relation in the $relations array with the name of the relation as referred to on the model as the key and an array of input keys that was passed to the filter() method.

The related model MUST have a ModelFilter associated with it. We instantiate the related model's filter and use the input values from the $relations array to call the associated methods.

This is helpful when querying multiple columns on a relation's table while avoiding multipe whereHas() calls for the same relationship. For a single column using a $this->whereHas() method in the model filter works just fine. In fact, under ther hood the model filter applies all constraints in the whereHas() method.

Example:

UserFilter with the relation defined so it's able to be queried.

class UserFilter extends ModelFilter
{
    public $relations = [
        'clients' => ['industry', 'potential_volume'],
    ];
}

ClientFilter with the industry method that's used to filter:

Note: The $relations array should identify the relation and the input key to filter by that relation. Just as the ModelFilter works, this will access the camelCased method on that relation's filter. If the above example was using the key industry_type for the input the relations array would be $relations = ['clients' => ['industry_type']] and the ClientFilter would have the method industryType().

class ClientFilter extends ModelFilter
{
    public $relations = [];

    public function industry($id)
    {
    	return $this->where('industry_id', $id);
    }
    
    public function potentialVolume($volume)
    {
    	return $this->where('potential_volume', '>=', $volume);
    }
}

Filter Related Models With Both Methods

You can even use both together and it will produce the same result and only query the related model once. An example would be:

If the following array is passed to the filter() method:

[
    'name'                      => 'er',
    'last_name'                 => ''
    'company_id'                => 2,
    'roles'                     => [1,4,7],
    'industry'                  => 5,
    'potential_volume'          => '10000'
]

In app/ModelFilters/UserFilter.php:

<?php namespace App\ModelFilters;

use EloquentFilter\ModelFilter;

class UserFilter extends ModelFilter
{
    public $relations = [
        'clients' => ['industry'],
    ];
    
    public function clientsSetup($query)
    {
    	return $query->hasRevenue();
    }

    public function name($name)
    {
    	return $this->where(function($q)
        {
        	return $q->where('first_name', 'LIKE', $name . '%')->orWhere('last_name', 'LIKE', '%' . $name.'%');
        });
    }
    
    public function potentialVolume($volume)
    {
    	return $this->related('clients', 'potential_volume', '>=', $volume);
    }

    public function lastName($lastName)
    {
    	return $this->where('last_name', 'LIKE', '%' . $lastName);
    }

    public function company($id)
    {
    	return $this->where('company_id',$id);
    }

    public function roles($ids)
    {
    	return $this->whereHas('roles', function($query) use ($ids)
        {
        	return $query->whereIn('id', $ids);
        });
    }
}
Adding Relation Values To Filter

Sometimes, based on the value of a parameter you may need to push data to a relation filter. The push() method does just this. It accepts one argument as an array of key value pairs or to arguments as a key value pair push($key, $value). Related models are filtered AFTER all local values have been executed you can use this method in any filter method. This avoids having to query a related table more than once. For Example:

public $relations = [
    'clients' => ['industry', 'status'],
];

public function statusType($type)
{
    if($type === 'all') {
        $this->push('status', 'all');
    }
}

The above example will pass 'all' to the stats() method on the clients relation of the model.

Calling the push() method in the setup() method will allow you to push values to the input for filter it's called on

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