A trait for performing search on Eloquent model columns and related tables.

SearchesEloquent.php

<?php

namespace App\Filters\Concerns;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Relations\MorphTo;

trait SearchesEloquent
{
    protected $query;

    /**
     * Apply the scope to a given Eloquent query query.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  string|null $value
     * @return void
     */
    public function apply(Builder $query, $value = null) : void
    {
        $this->query = $query;

        $this->search($value);
    }

    /**
     * Perform a search from query string.
     *
     * @param  string  $text
     * @return Illuminate\Database\Eloquent\Builder
     */
    protected function search($text = null)
    {
        if (! $text || ! $this->columns) {
            return $this->query;
        }

        $this->query->where(function ($query) use ($text) {
            // Since we have a search filter, let's spin
            // through our list of searchable columns
            $this->performSearch($query, $text);
        });

        return $this->query;
    }

    /**
     * Iterate through searchable columns.
     *
     * @param  Illuminate\Database\Eloquent\Builder  $query
     * @param  string  $text
     * @return void
     */
    protected function performSearch(Builder $builder, $text)
    {
        foreach ($this->columns as $attribute => $value) {
            // If the value is an array, that means we want to search through a relationship.
            // We need to make sure that we send through the closure's query instance so we
            // can have an 'AND' query with nested queries wrapped within a parenthesis.
            is_array($value)
                ? $this->performRelationSearch($builder, $attribute, $value, $text)
                : $this->performColumnSearch($builder, $value, $text);
        }

        return $builder;
    }

    /**
     * Peform search on model columns
     *
     * @param  Illuminate\Contracts\Database\Eloquent\Builder  $builder
     * @param  string|array  $column
     * @param  string  $text
     * @return Illuminate\Contracts\Database\Eloquent\Builder
     */
    protected function performColumnSearch(Builder $builder, $column, $text)
    {
        $builder->orWhere(function ($query) use ($column, $text) {
            foreach (explode(' ', $text) as $word) {
                $query->where($column, 'like', "{$word}%");
            }
        });

        return $builder;
    }

    /**
     * Search through related tables.
     *
     * @param  Illuminate\Database\Eloquent\Builder  $builder
     * @param  string  $related
     * @param  array|string  $columns
     * @param  string  $text
     * @return Illuminate\Database\Eloquent\Builder
     */
    protected function performRelationSearch(Builder $builder, $related, $columns, $text)
    {
        $columns = is_array($columns) ? $columns : [$columns];

        $callback = function ($query) use ($columns, $text) {
            // Here, we want to make sure that we are grouping our orWhere
            // statement inside a where statement if incase the
            // relatonship is also running query scopes
            $query->where(function ($query) use ($columns, $text) {
                foreach ($columns as $attribute => $value) {
                    is_array($value)
                        ? $this->performRelationSearch($query, $attribute, $value, $text)
                        : $this->performColumnSearch($query, $value, $text);
                }
            });
        };

        return ($builder->getModel()->$related() instanceof MorphTo)
            ? $builder->orWhereHasMorph($related, '*', $callback)
            : $builder->orWhereHas($related, $callback);
    }
}