PHP Developer – Interview Questions, Answer, Industry Salary

Some popular PHP frameworks include Laravel, Symfony, and CodeIgniter. Laravel is known for its elegant syntax, extensive feature set, and developer-friendly approach. It offers features like routing, authentication, caching, and database abstraction out-of-the-box, enabling rapid application development. Symfony is a mature and highly flexible framework that follows best practices and offers a modular architecture. It provides a broad set of reusable components and comprehensive documentation. CodeIgniter is a lightweight and beginner-friendly framework that focuses on simplicity and performance. It offers a small footprint, quick setup, and easy integration with databases and third-party libraries.

In PHP development, I have worked with databases such as MySQL, PostgreSQL, and MongoDB. MySQL is a widely used relational database management system that offers strong data integrity, scalability, and performance. In PHP, I utilized the MySQLi extension or PDO (PHP Data Objects) to establish database connections, execute queries, and fetch results. PostgreSQL is another powerful open-source relational database that offers advanced features such as JSON support and full-text search. I used similar PHP extensions to interact with PostgreSQL. MongoDB is a NoSQL document-oriented database. To interact with MongoDB, I used the MongoDB extension or an Object-Document Mapping (ODM) library like Doctrine MongoDB ODM.

In PHP, I use built-in functions and validation libraries to handle form validation and data sanitization. For example, I utilize the filter_input() function to retrieve and validate user input from forms based on predefined filters like email, URL, or integer. I also employ functions like htmlspecialchars() or mysqli_real_escape_string() to sanitize user input and prevent XSS (cross-site scripting) or SQL injection attacks. Additionally, I validate form data using custom PHP code and display appropriate error messages to users when validation fails.

Dependency injection is a design pattern that promotes loose coupling and modular code. In PHP, dependency injection involves injecting dependencies into a class instead of creating or managing them internally. This allows for more flexible and maintainable code, as dependencies can be easily substituted or mocked during testing. Dependency injection containers, like Symfony’s DependencyInjection component, are often used to manage and resolve dependencies automatically. The benefits of dependency injection include improved code reusability, testability, and maintainability.

Yes, I have experience using testing frameworks like PHPUnit and Behat in PHP development. PHPUnit is a widely-used testing framework for unit testing in PHP. It provides a rich set of assertion methods and allows for the creation of test cases to validate the functionality of individual units of code. Behat, on the other hand, is a behavior-driven development (BDD) framework that enables testing from a user’s perspective. It allows for the definition of behavior scenarios in a human-readable format and the execution of automated tests based on those scenarios.

Authentication and authorization can be implemented in PHP applications using techniques such as sessions and access control lists (ACLs). For authentication, I utilize functions like password_hash() and password_verify() to securely store and verify user passwords. Sessions are used to maintain user authentication state across requests. Authorization is typically managed through role-based access control (RBAC) or permissions systems. I implement user roles, define permissions, and check user authorization before allowing access to certain parts of the application.

Caching is a technique used to store computed or retrieved data in a cache to improve performance and reduce the load on the application or database. In PHP, caching can be implemented using various approaches. For example, I utilize caching mechanisms like Memcached or Redis to store frequently accessed data in memory. This reduces the need to fetch data from the database on every request, resulting in faster response times. Additionally, I implement opcode caching with tools like APCu or OPcache to cache compiled PHP code, further enhancing performance.

In PHP, I handle file uploads by utilizing the $_FILES superglobal variable and appropriate functions like move_uploaded_file(). When a file is uploaded through a form, PHP populates the $_FILES array with information about the uploaded file, such as its name, type, size, and temporary location. I validate the uploaded file’s properties, perform any necessary security checks, and move the file to a permanent location using the move_uploaded_file() function. I also handle any additional processing required for the uploaded file, such as resizing images or storing metadata in a database.

Ensuring the security of PHP applications involves implementing best practices such as input validation, output encoding, secure coding techniques, and proper handling of sensitive data. I validate and sanitize user input to prevent common vulnerabilities like SQL injection and cross-site scripting (XSS) attacks. I utilize prepared statements or parameterized queries to prevent SQL injection. To mitigate XSS attacks, I employ output encoding functions like htmlspecialchars() when displaying user-generated content. I also follow security guidelines, such as using secure communication protocols (HTTPS), enforcing strong password policies, and implementing proper authentication and access control mechanisms to protect sensitive data.