2 minutes November 27, 2024

How to Create Filters in Laravel?

Filters are the basics in Laravel that are used for query refinement and efficient data handling. Relationships, query builders, and even pagination experience difficulties during development. This article elaborates on common problems and their solutions while creating filters in Laravel.

Common Issues When Creating Filters in Laravel

1. Incorrect Relationships

Defining relationships with incorrect keys can lead to issues where the queries fail or get the wrong results. For instance:

Using ‘bath_id‘ instead of ‘id‘ in the ProductCategory and ProductType models will cause broken relations.

// Incorrect relationship in ProductCategory model 
public function products() 
{ 
     return $this->hasMany(Product::class, 'bath_id'); // 'bath_id' does not exist
}

// Incorrect relationship in ProductCategory model

public function products()

{

return $this->hasMany(Product::class, 'bath_id'); // 'bath_id' does not exist

}

2. Typos in Foreign Key Names

A simple typo: the model ProductImages now has a column for ‘propuct_id‘ instead of ‘product_id‘, disrupts the model relationships.

// In the ProductImages model
public function product() {
    return $this->belongsTo(Product::class, 'propuct_id'); // Typo in 'product_id'
}

// In the ProductImages model

public function product() {

return $this->belongsTo(Product::class, 'propuct_id'); // Typo in 'product_id'

}

3. Misuse of Query Builder in Filters

In a custom filter class, using $this->query instead of $this->builder prevents query modification.

public function title($name) {
    return $this->query->where('name', 'like', $name . '%'); // Wrong property: should be $this->builder
}

public function title($name) {

return $this->query->where('name', 'like', $name . '%'); // Wrong property: should be $this->builder

}

4. Incorrect Pagination Syntax

Passing unnecessary arguments like ‘page‘ to the paginate method results in unexpected pagination behavior.

Solutions to Filter Issues

1. Fix Relationships

Ensure foreign keys are correctly defined:

// In ProductCategory model
public function products() {
    return $this->hasMany(Product::class, 'category_id', 'id'); 
    // 'category_id' is the foreign key in the 'products' table, and 'id' is the primary key in this model.
}

// In ProductImages model
public function product() {
    return $this->belongsTo(Product::class, 'product_id'); // Fix the typo in foreign key
}

// In ProductCategory model

public function products() {

return $this->hasMany(Product::class, 'category_id', 'id');

// 'category_id' is the foreign key in the 'products' table, and 'id' is the primary key in this model.

}

// In ProductImages model

public function product() {

return $this->belongsTo(Product::class, 'product_id'); // Fix the typo in foreign key

}

2. Correct Filter Syntax

Replace $this->query with $this->builder in filter methods:

// Custom filter class (e.g., ProductFilter.php)
public function title($name) {
return $this->builder->where(‘name’, ‘like’, $name . ‘%’);
}

3. Use Proper Pagination

Eliminate redundant parameters in the paginate method:

// Fetch products with filters and pagination
$products = Product::filter($filter)
    ->with(['category', 'type', 'images']) // Eager loading relationships
    ->orderBy('name', 'asc')              // Sort by product name
    ->paginate(40);                       // Limit to 40 results per page

// Fetch products with filters and pagination

$products = Product::filter($filter)

->with(['category', 'type', 'images']) // Eager loading relationships

->orderBy('name', 'asc') // Sort by product name

->paginate(40); // Limit to 40 results per page

4. Validate Relationships

Test relationships and filter queries independently to identify errors. Use Laravel Tinker or PHPUnit for debugging.

Example: Debugging with Laravel Tinker

php artisan tinker
>>> Product::with('category')->filter($filter)->toSql();

1 2	php artisan tinker >>> Product::with('category')->filter($filter)->toSql();

Example: Testing with PHPUnit

public function testProductFilterByCategory() {
    $filter = ['category' => 'Electronics'];
    $products = Product::filter($filter)->get();
    
    $this->assertCount(10, $products); // Validate the expected number of results
}

public function testProductFilterByCategory() {

$filter = ['category' => 'Electronics'];

$products = Product::filter($filter)->get();

$this->assertCount(10, $products); // Validate the expected number of results

}

Pro Tips for Better Filters

Stick to Conventions

Avoid making mistakes by following Laravel’s field and relation naming conventions.

Utilize Query Scopes

Wrap the repetitive query logic within the model scopes.

// In Product model
public function scopeFilterByCategory($query, $categoryId) {
    return $query->where('category_id', $categoryId);
}

// Usage
$products = Product::filterByCategory(1)->get();

// In Product model

public function scopeFilterByCategory($query, $categoryId) {

return $query->where('category_id', $categoryId);

}

// Usage

$products = Product::filterByCategory(1)->get();

Implement Chainable Filter Classes

Use custom filter classes to organize and manage filter logic.

// app/Filters/ProductFilter.php
namespace App\Filters;

use Illuminate\Database\Eloquent\Builder;

class ProductFilter {
    protected $builder;

    public function apply(Builder $builder, $filters) {
        $this->builder = $builder;

        foreach ($filters as $filter => $value) {
            if (method_exists($this, $filter)) {
                $this->$filter($value);
            }
        }

        return $this->builder;
    }

    public function category($categoryId) {
        return $this->builder->where('category_id', $categoryId);
    }

    public function priceRange($min, $max) {
        return $this->builder->whereBetween('price', [$min, $max]);
    }
}

// app/Filters/ProductFilter.php

namespace App\Filters;

use Illuminate\Database\Eloquent\Builder;

class ProductFilter {

protected $builder;

public function apply(Builder $builder, $filters) {

$this->builder = $builder;

foreach ($filters as $filter => $value) {

if (method_exists($this, $filter)) {

$this->$filter($value);

}

return $this->builder;

}

public function category($categoryId) {

return $this->builder->where('category_id', $categoryId);

}

public function priceRange($min, $max) {

return $this->builder->whereBetween('price', [$min, $max]);

}

Code Example: Applying the Filter

// In Controller
$filters = [
    'category' => 1,
    'priceRange' => [100, 500]
];

$products = Product::filter(new ProductFilter, $filters)->get();

// In Controller

$filters = [

'category' => 1,

'priceRange' => [100, 500]

];

$products = Product::filter(new ProductFilter, $filters)->get();

Debug with Laravel Debugbar

To identify problems with queries and performance, use Debugbar.

Automate Tests:
Automate the tests of your filters to ensure consistency.

Conclusion

Creating filters in Laravel is straightforward when best practices are followed, but challenges like incorrect relationships or typos can complicate the process. The solutions and tips shared can help you implement effective filters in your Laravel projects.

For advanced assistance, consider hiring Laravel developers.

Recent help desk articles

Greetings! I'm Aneesh Sreedharan, CEO of 2Hats Logic Solutions. At 2Hats Logic Solutions, we are dedicated to providing technical expertise and resolving your concerns in the world of technology. Our blog page serves as a resource where we share insights and experiences, offering valuable perspectives on your queries.

Aneesh Sreedharan

Founder & CEO, 2Hats Logic Solutions

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