REST Interview Questions & Answers- Part 8

Answer:

Client-side Cache vs. Server-side Cache:

• Client-side caching operates within the user’s web browser, retaining cached data on the client’s side.
• Server-side caching occurs within an intermediate cache layer positioned between the API and the database, typically on the server.

Answer:

Implementing webhooks in RESTful web services necessitates providing a mechanism for clients to register a designated URL to receive webhook notifications. When an event of interest occurs on the server, it dispatches an HTTP POST request to the registered URL, transmitting relevant data in the request body. Subsequently, the client can process this data and initiate appropriate actions in response to the event.

Answer:

Swagger is a suite of open-source tools designed to assist developers in the design, development, and documentation of RESTful web services. In contrast, OpenAPI constitutes a specification for constructing APIs, previously recognized as Swagger. The OpenAPI specification defines a standardized format for describing RESTful APIs, which can be utilized by tools like Swagger for documentation and other purposes.

Answer:

Implementing input parameter validation in a RESTful API can be achieved by utilizing validation libraries such as Joi or Validator.js. These libraries enable developers to define specific validation rules for each input parameter, ensuring that the data provided by clients adheres to these rules. This validation process helps maintain data integrity and security within the API.

Answer:

Implementing pagination in a REST API entails the following steps:

1. Incorporate query parameters to enable clients to specify the page size and page number, typically using “page” and “page_size” query parameters.
2. Develop server-side logic to calculate the offset and limit based on the provided page size and page number, using the formulas:

– offset = (page – 1) * page_size

– limit = page_size

3. Execute the relevant database query using the calculated offset and limit values to retrieve the appropriate results for the current page.
4. Include the paginated results in the API response, along with details such as the total number of results, page size, and current page number. Additionally, provide links to navigate to previous and next pages if applicable.

Answer:

RESTful web services employ various techniques for enabling searching, including:

• Query parameters: Utilize query parameters to filter and sort the data returned by the API, allowing clients to specify search criteria.
• Full-text search: Employ full-text search engines like Elasticsearch to enable users to search for specific text within the data.
• Custom search endpoints: Create custom endpoints that permit users to conduct searches using custom criteria tailored to their specific requirements.
• Faceted search: Implement faceted search to enable users to refine search results based on specific attributes or facets associated with the data.

Answer:

To implement search functionality in RESTful web services:

1. Utilize query parameters to pass search criteria to the server, allowing clients to specify filters, sorting options, and pagination.
2. Design server-side logic to process the query parameters and formulate a database query based on the specified search criteria.
3. Execute the database query to retrieve matching results from the data source.
4. Present the search results as part of the API response, ensuring that clients can easily access the data they have queried for.

Answer:

Monolithic architecture is a software design pattern where all components of an application are tightly integrated and deployed as a single unit, while microservice architecture involves loosely coupled and independently deployable services, each providing specific functionality.

Answer:

To migrate a monolithic application to a microservices architecture, you can start by identifying distinct and independent functionalities within the monolith. Gradually refactor and break these functionalities into smaller, independent services. This requires redesigning the architecture for distributed systems and service communication. The migration can be gradual to minimize disruption, with parts of the application moving to microservices over time.

Answer:

Testing strategies for a RESTful API include:

1. Unit Testing: Testing individual functions or components.
2. Integration Testing: Ensuring that components and services interact correctly.
3. Functional Testing: Validating API behavior against expected outcomes.
4. Performance Testing: Evaluating response time and throughput.
5. Security Testing: Identifying and fixing vulnerabilities.
6. End-to-End Testing: Testing the API in a complete system environment.

Answer:

To ensure backward compatibility in RESTful web services:

• Version the API using URLs or media types.
• Employ feature flags, deprecation warnings, and API gateways.
• Maintain support for older versions while introducing new features.
• Document versioning and provide migration guides for clients.

Answer:

API documentation in a RESTful web service serves to provide developers with comprehensive information about the API, including resource details, parameters, and responses. It assists developers in effectively using the API, reducing integration time, and improving the quality of client code.

Answer:

Best practices for securing a RESTful API include:

• Using HTTPS for data encryption.
• Implementing strong authentication and encouraging 2FA.
• Employing proper access controls.
• Validating input data to prevent malicious input.
• Sanitizing data from users or third-party sources.
• Logging and monitoring API calls for anomalies and suspicious activity.

Answer:

To validate output parameters in a RESTful API:

1. Define expected output formats in API documentation.
2. Use JSON Schema or validation libraries to check response data.
3. Ensure that returned data is not empty or null.
4. Employ appropriate HTTP response codes for errors.
5. Provide clear error messages in the response body to aid client understanding.

Answer:

No, it’s not common to send a payload (request body) in the GET and DELETE methods. These methods typically do not have request bodies. Data for these methods is typically sent via query parameters (GET) or request URLs (DELETE).

Answer:

Postman is a widely used tool for designing, testing, documenting, and publishing APIs. It simplifies various aspects of API development and lifecycle management, making it easier to work with APIs during development and testing.

Answer:

Major security issues faced by web services include:

• Data Encryption: Ensuring data confidentiality with encryption.
• Authentication: Properly authenticating users to prevent unauthorized access.
• Authorization: Implementing access controls to limit user actions.
• Input Validation: Validating user input to prevent vulnerabilities like SQL injection.
• Data Sanitization: Ensuring data from users or external sources is safe.
• Logging and Monitoring: Detecting and responding to security threats in real-time.

Answer:

The “Options” HTTP method is used to retrieve information about the various HTTP operations supported by a resource or endpoint. It helps clients determine which operations are available, aiding in decision-making. Additionally, it’s used in Cross-Origin Resource Sharing (CORS) for specifying which origins are permitted to access a resource.