The Top Yii Framework Interview Questions for Aspiring Developers

Yii Framework has become one of the most popular PHP frameworks for building high-performance web applications Its elegant architecture, security features, and excellent documentation make it a go-to choice for many developers

As Yii continues to gain traction, you can expect interviewers to test your knowledge of this framework if you’re applying for PHP developer roles. Mastering Yii can give you a valuable edge over other candidates.

In this comprehensive guide we provide the top Yii interview questions that assess your understanding of the framework’s key concepts. Whether you’re prepping for an upcoming interview or looking to expand your skills these questions will help prepare you for Yii-related discussions.

Let’s get started!

Yii Framework Basics

These foundational questions check your understanding of what Yii is, why it’s used, and how it compares to other frameworks:

Q1. What is the Yii Framework and what are its main features?

Yii is an open source, object-oriented MVC framework for developing web applications in PHP. Its key features include:

• High performance and fast loading
• Security tools like input validation, SQL injection prevention etc.
• In-built CRUD functionalities using ActiveRecord
• Code scaffolding with Gii tool
• Excellent documentation and tutorials
• Easy to extend and customize
• Supports RESTful APIs
• Integrated testing tools
• Database migration support

Q2. How does Yii 2 compare to Yii 1.1? What are the major differences?

The key differences between Yii 1.1 and 2 are:

• Yii 2 uses namespaces while 1.1 doesn’t
• Yii 2 requires PHP 5.4+ while 1.1 runs on PHP 5.1+
• Yii 2 uses Composer for dependency management while 1.1 uses extensions
• Yii 2 has better support for RESTful APIs
• Yii 2 has in-built support for unit testing
• The directory structure is reorganized in Yii 2
• Performance enhancements like lazy loading in Yii 2
• The DB query builder in Yii 2 supports JOINs which 1.1 doesn’t

Q3. How is Yii’s MVC architecture different from other PHP frameworks like Laravel?

Some key differences in Yii’s MVC implementation:

• Yii has objects called Behaviors that extend model functionality
• Yii controllers can have attached filters for pre-action logic
• Yii uses a front controller pattern with just a single entry script
• The components in Yii are created as object classes
• Routing is configuration-based rather than convention-based like Laravel

Debugging and Error Handling

These questions test your skills in identifying and fixing issues in Yii:

Q4. How are errors and exceptions handled in Yii?

Yii has an ErrorHandler component that handles both errors and exceptions centrally. When an error occurs it triggers an event that this component catches.

• PHP errors are converted into ErrorException objects
• Exceptions are categorized into system vs application exceptions
• System exceptions only display a generic error message

The full error details are logged for later debugging. Custom error actions can also be defined to handle different error scenarios.

Q5. Your Yii application is throwing a “Page not found” error. What are some ways you could debug this?

Some ways to debug a “Page not found” error:

• Check the logs for the Not Found exception details
• Enable route logging to see if the request is hitting any matches
• Temporarily modify error handler config to display full stack trace
• Use debug toolbar or debugger extension to analyze request details
• Manually review URL rules and controller action names
• Enable database logging to check for any query errors

Security

These questions evaluate your understanding of security best practices in Yii:

Q6. How does Yii protect applications from common web vulnerabilities?

Yii has robust security tools to prevent vulnerabilities:

• SQL Injection: Prepared statements, bound parameters

• XSS: Encoding output data contexts, validation filters

• CSRF: Stateless CSRF tokens, CORS validation

• Session hijacking: Encrypted cookie-based sessions

• Unauthorized access: RBAC, rule-based auth managers

Q7. What steps would you take to add user authentication to a Yii application?

Steps to add authentication:

1. Create User model extending IdentityInterface
2. Implement methods like findIdentity(), getId() etc.
3. Configure auth manager component in config
4. Create LoginController with actions like login, logout
5. Generate login form view and handle authentication logic
6. Use AccessControl filter to limit access

Database and ActiveRecord

These questions test your proficiency in integrating database CRUD operations:

Q8. Explain what ActiveRecord is in Yii and how it works.

ActiveRecord implements the active record design pattern. It represents data as model objects tied to database rows.

Key features:

• Declarative definition of model attributes
• Automatically generated CRUD methods
• ActiveQuery builder methods like find(), all()
• Relational query methods like hasOne()

You can use models directly to manipulate associated data.

Q9. How can you optimize ActiveRecord performance in Yii?

Some ways to optimize ActiveRecord:

• Enable query caching to reuse similar queries
• Set profiling filters to identify slow queries
• Use eager loading and joins to reduce queries
• Leverage pagination and batch processing
• Enable schema caching in meta-data
• Add database indexes on commonly queried columns

Customization

These questions evaluate your skills in adapting Yii to meet project needs:

Q10. How can you extend the functionality of a core Yii class?

To extend core Yii classes:

1. Create a new class inheriting from the core Yii class
2. Override methods of the parent class as needed
3. Add any new methods you need
4. Configure Yii to use your extended class

For example:

class MyClass extends YiiBaseClass {  //override someMethod()    //add new method}//in config'components' => [  'myComponent' => ['class' => 'MyClass']]

Q11. How would you create and use a custom validator in Yii for form input?

Steps:

1. Create validator class extending Validator
2. Implement validateAttribute()
3. Add logic to check attribute value
4. Return validation error or null if valid
5. In model rules(), use validator classname

For example:

class MyValidator extends Validator {  public function validateAttribute($model, $attribute) {    if (!validCondition) {      $this->addError($model, $attribute, 'Error msg');     }   }}// In model: public function rules() {  return [    ['attribute', MyValidator::className()]  ];}

Caching and Performance

These questions test your knowledge of Yii caching and performance optimization:

Q12. What caching options are available in Yii? How would you implement page caching?

Yii supports:

• Fragment caching: Cache output fragments
• Page caching: Cache entire page output
• Data caching: Cache custom data

To implement page caching:

1. Configure ‘cache’ component
2. In controller, add PageCache filter
3. Set variations for dynamic params
4. Configure cache key based on request

This will automatically cache page output.

Q13. You need to improve performance for dynamic pages that are slow to generate. What are some strategies you could use?

Some strategies:

• Enable HTTP caching with proper headers
• Implement fragment