1. What is REST API?
RESTful API (Representational State Transfer) is used to set some rules that need to be followed while developing web services. The architectural style is designed to use the current protocols. It is an API (Application Programming Interface) that uses HTTP for POST, DELETE, and PUT commands.
2. What are some important characteristics of REST API?
The important characteristics of the REST API are as follows:
- It uses HTTP for POST, DELETE, and PUT commands.
- The architecture is based on the client and server model.
- The architecture supports both XML and JSON, which is very helpful for developers as the flexibility of the development is more.
- It is stateless as the server does not keep any data required to fulfill client requests. It makes the architecture scalable and visible.
- It is properly documented for the benefit of the developers.
3. What is REST architecture?
REST has the following architectural constraints for developing web services:
- Client and server based – This means that the client and server application must not be dependent on each other and can work separately.
- Statelessness – This means that the server does not keep any data required to fulfill client requests. It makes the architecture scalable and visible. Each request is treated as a new one.
- Interface uniformity – The application interface must be uniform, and the resources must be properly distributed for the users to access it easily.
- Layered architecture – The REST API lets the use of layered architecture for developing web services. It states that an application has to be layered where each layer has to be independent.
4. What is a REST web service?
Web services that are based on the REST architecture are called RESTful web services. The architecture is used to build scalable and lightweight applications. It is used to set some rules that need to be followed while developing web services. The architectural style is designed to use the current protocols. It is an API (Application Programming Interface) that uses HTTP for POST, DELETE, and PUT commands.
5. What is REST Assured?
The REST Assured is a Java library that is used by developers for creating tests for the RESTful web services. The library uses a DSL (Domain Specific Language). To access the web services, the HTTP requests can be customized as per our choice.
6. What are REST parameters?
The REST API has four types of parameters, which are:
- Request parameters – These are submitted as JSON parameters present in the request.
- Header parameters – These are present in the request header.
- Query string parameters – These are provided at the endpoint of the query.
- Path parameters – These are provided in the endpoint path.
7. Why REST is stateless?
REST is stateless as the server does not keep track of the data required to complete the client requests. It makes the architecture scalable and visible. Each request is treated as a new one. As the past interactions with the client are not stored, the application becomes simpler.
8. What are REST API endpoints?
An endpoint in REST can be considered as a URI that is used to send a request. It is an URL that is a part of the REST API, where they are present for each resource.
9. How does REST API work?
The REST API provides the set of rules through which two applications on different systems communicate with each other. It implements the HTTP protocol for POST, DELETE, PUT operations. The API ensures that the proper resource is obtained through the corresponding URL.
10. How to call REST API from Java?
The REST API can be called from Java using the following steps:
- If the API is being called from Facebook or Twitter, the javax.net.ssl.HttpsURLConnection or java.net.HttpURLConnection can be used.
- To obtain the result, the connection.getInputStream() method needs to be used.
- The InputStream that will be received needs to be converted into a string, and later parsed into the JSON or XML object.
- The Apache HTTP client can also be used.
11. How to consume REST API in C#?
The different ways to consume REST API through C#:
- Using HTTPWebRequest class – This allows complete control over the development of the request. For the responses to the requests, it provides a container to accept them.
- ServiceStack HTTP Utils – It is a very useful library that deals with third-party APIs HTTP utils.
- HTTPClient class – This class is not dependent on a particular server, and it is used to send multiple requests.
- RestSharp NuGet package – It is a very useful library that allows the developers to work both asynchronously and synchronously.
- WebClient class – This class works as a wrapper for the HTTPWebRequest class and reduces the excess writing of code for the developers.
12. How to call REST API from Android app?
The REST API can be called from an Android application using the android-async-HTTP library.
13. Can REST API be asynchronous?
Yes, REST API can be asynchronous. However, the asynchronous or synchronous behavior is dependent on the client who is making the request for the resource.
14. What are the REST API headers?
The headers available for the REST API are Accept and Content-Type, which are used for modifying the data inside the requests. They support the values:
- Content-Type: application/json, application/XML
- Accept: application/json, application/XML
15. How REST API authentication works?
The REST API authentication is based on the transfer of credentials from the client to the server. The basic authentication is based on the HTTP header. The HTTP header is used for providing the username and password that is encoded in base64.
GET / HTTP/1.1 Host: example.org Authorization: Basic Zm9vOmJhcg==
16. What is the difference between PUT and POST method in REST API?
| PUT | POST |
|---|---|
| It is used to develop or overwrite a resource. | It is used to modify or update a resource. |
| If the resource is updated or created using PUT, the state of the resource remains the same even if the call is made again. | Two similar POST calls will result in two resources having similar information. |
| The responses to the calls made are cacheable. | The responses are not cacheable. |
| It can be used when a singular resource that is a part of the resource collection needs modification. | It is used to add a child resource under a resource collection. |
17. What is REST client?
REST client applications are used to communicate with the resources related to the RESTful web servers. It is used to start communication by a request. The REST Client is a Python + wxWidgets Desktop application that can be used to easily establish communication with a RESTful web service. It supports PUT, POST, GET, DELETE. It is a Python-based application.
18. How to use advanced REST client?
The Advanced REST Client is used to develop HTTP requests and test them. The GET and POST methods are used. The steps to use the Advanced REST client are given below:
- Install the Advanced REST Client for Google Chrome.
- In the specified area, enter the URL of your choice.
- Choose the method option from PUT, POST, GET, DELETE, etc. from the drop-down beside it.
- Select the header key and content of the header.
- Provide the request for the content above.
19. What is the difference between SOAP and REST?
| SOAP | REST |
|---|---|
| It is the Simple Object Access Protocol used for messaging based on XML. | It is an architecture used for laying out the protocols for web services. |
| It supports both XML and JSON formats. | It supports JSON and XML formats. |
| It is more complex. | It is simpler and easier to use. |
20. What are the advantages of REST over SOAP?
REST has various advantages over SOAP:
- REST uses HTTP directly, which is more lightweight and efficient.
- It allows multiple data formats such as XML, JSON, and even plain text, while SOAP is more limited.
- REST is stateless, which means there is less overhead.
- It is easier to integrate with web-based applications.
Which framework is best for REST API?
The best frameworks for REST API are Spring MVC, ASP.Net, Flask, Django, JSF, Hibernate, Struts, Express.js, and many others.
What is the use of DELETE in REST API?
The DELETE is a request that is used for removing a resource.