RESTful API: Essential Question & Answers
Tags: restapi, rest, interview, webdev
Published: 2024-04-23 17:50:42

Hello there! 👋

Today, we’re going to explore a fascinating topic in the world of web development - REST APIs. Whether you’re a seasoned developer or just starting out, understanding REST APIs is crucial in today’s interconnected digital world. 

So, let’s get started!

### Q1: What is a REST API? 
A REST (**Representational State Transfer**) API (**Application Programming Interface**) is a set of rules and conventions for building and interacting with web services. It uses HTTP methods like **GET, POST, PUT, PATCH, DELETE** to operate on data.

### Q2: What is a URI in REST? 
A URI (Uniform Resource Identifier) is a string of characters that identifies a name or a resource on the Internet. In REST, we use URI to identify the resource on which the operation is to be performed.

### Q3: What are the HTTP methods used in REST? 
The main HTTP methods used in REST are:
- **GET**: Retrieves data.
- **POST**: Sends data to be processed to a specified resource.
- **PUT**: Updates a current resource with new data.
- **PATCH**: Partially updates a current resource with new data.
- **DELETE**: Removes a specified resource.

### Q4: What does it mean when an API is RESTful? 
When an API is RESTful, it adheres to the principles of REST. It is stateless, meaning each request from a client to a server must contain all the information needed to understand and process the request. 

For example, if you’re building a RESTful API for a library, each request to check out a book would need to include all necessary information, such as the user’s ID and the book’s ID.

### Q5: What is a Resource in REST? 
In REST, a resource is an object with a type, associated data, relationships to other resources, and a set of methods that operate on it. 

For example, in a blogging platform, a post could be a resource. It has data (the content of the post), relationships (the author of the post, comments on the post), and methods that operate on it (create a new post, update the post, delete the post).

### Q6: What is the difference between SOAP and REST? 
SOAP (Simple Object Access Protocol) and REST are both web service communication protocols. 

SOAP is a protocol whereas REST is an architectural style. SOAP uses service interfaces to expose its functionality to client applications while REST uses Uniform Service locators to access to the components on the hardware device. 

For example, in a weather application, a SOAP approach would have specific methods like `GetTemperature()`, `GetHumidity()`, etc. In contrast, a REST approach would have a single endpoint like `/weather` and use different HTTP methods to get temperature, humidity, etc.

### Q7. What's the difference between PUT and PATCH?
The difference between PUT and PATCH in the context of HTTP methods used in REST APIs:

**PUT:** This method is used to update an existing resource and it’s idempotent. That means making the same PUT request multiple times will always result in the same outcome. It requires the client to send an entire representation of a resource to update it. 

For example, if you’re updating a user’s profile with a new email and address, you’d need to include both the new email and address in the PUT request, even if only one field has changed.

**PATCH:** This method is used to partially update a resource. Unlike PUT, PATCH is not idempotent, which means making the same PATCH request multiple times may result in different outcomes. With PATCH, you only need to send the fields that you want to update. 

For example, if you’re updating a user’s profile and you only want to update the email, you’d only need to include the new email in the PATCH request.

### Q8.What is an API endpoint?
An API endpoint is a specific URL or URI (Uniform Resource Identifier) that an API interacts with. For example, in a blogging API, `/posts` might be the endpoint to retrieve all blog posts.

### Q9: What is the purpose of HTTP status codes in RESTful APIs? 
HTTP status codes are used to indicate the success or failure of a request. For example, `200` means the request was successful, `404` means the requested resource was not found, and `500` indicates a server error.

### Q10: What is CORS? 
CORS (Cross-Origin Resource Sharing) is a mechanism that allows many resources (e.g., fonts, JavaScript, etc.) on a web page to be **requested from another domain outside the domain** from which the resource originated.

### Q11: What is authentication and authorization in the context of RESTful APIs? 
Authentication verifies **who you are**, and authorization determines **what you can do**. 

In RESTful APIs, authentication might involve providing a username and password to confirm your identity. Once authenticated, authorization rules determine what resources or operations the authenticated user can access.

### Q12: What are common authentication methods used in RESTful APIs? 
Common methods include **Basic Auth** (username and password), **API keys**, **OAuth** (delegated authorization), and **JWT** (JSON Web Tokens) for information exchange.

### Q13: How do you handle errors in RESTful APIs? 
Errors in RESTful APIs are typically handled by returning appropriate **HTTP status codes** along with meaningful **error messages** in the response body.

### Q14: What are the advantages of using RESTful API over other architectural styles? 
RESTful APIs are **stateless, scalable, can use standard HTTP methods, can be easily cached**, and are often **easier** for developers to understand and use.

### Q15: How do you document RESTful API? 
Documentation can be done manually, but there are also tools like **Swagger** or **Postman** that can generate interactive documentation for your API.

### Q16: What are tools or frameworks commonly used for building RESTful APIs? 
There are many tools and frameworks to help build RESTful APIs. Some popular ones include **Express.js** for Node.js, **Django and Flask** for Python, and **Spring** for Java.

And that’s a wrap on our journey through the world of REST APIs! I hope you found this Q&A session helpful and easy to understand.