Rest API Tutorial
In this tutorial, we are going to implement rest API example. How to implement restful web services, what is rest client. We will see below topics: what is restful API, Rest API architecture, Methods and resources.
What is web service?
Web service is a piece of software available over the network/internet and uses XML messaging system. XML is used to encode all communications to a web service.
Example: A weather API service which provides the weather details.
What is Restful API ?
Rest API also known as RESTful API is an application programming interface that confirms to the constraints of REST architecture. It is used between two computer systems to exchange the information securely over the internet. Most of the applications needs to communicate with each other to internal or external systems for specific tasks there we can use REST API for communication therefore it becomes one of the major topic to learn and understand its architecture.
REST API Architecture:
Structure of a REST Service:
Rest Service Details :
Resource : What is Resource in REST API ?
Resources are basic building blocks of a RESTful service, for example in Vehicle resources can be engine, driver, doors, mileage, etc. Resources are addressable by URLs and HTTP methods are used to do operations on resources, e.g. /get mileage of a car /car/mileage.
Each and every resource have a URI (uniform resource identifier). Like /slb/topic/rest
Representation: Each resource can have different type of formats like JSON, XML, TEXT, HTML.
REST API VS SOAP API:
| REST | SOAP |
| Architectural Approach | XML Schema Based |
| XML, JSON, Html, Text, etc. | XML Only |
| w3C | WSDL |
| http | http and MQ |
HTTP Methods:
GET: Get is used to read the information. Returns requested data. e.g. /user/ – returns a list of users from application.
POST: It is used to create something. POST creates a new record in the system. e.g. /user/ it will create a new user with data present from the body of the request.
PUT or PATCH : Used to update the existing records. e.g. /user/12 and pass the data in body of the request.
GET to return single user like this GET /user/12 It will return the single user with the ID 12.
DELETE: Used to delete/remove existing records. e.g. delete /user/12. This will delete the user with ID 12.
HTTP Headers:
For any Rest API, the most important part is the header of the request and response, as they represent meta-data associated with it. Headers carry information for request and response body, Authorization, caching, cookies. It’s like carrying an extra source of information for the API. In case of issues, the first place we look for is the header for errors.
Example:
Lest see and understand some of the common headers that we often see in REST API.
Content-type: This header specifies the format of the request and response, for example JSON. XML, etc.
Accept: This header specifies the format of the data that client is willing to receive in the response.
Authorization: Used to provide authorization credentials, such as API key or token. It is depends on the type of authentication you are using.
Cache-Control: It is the cache policy defined by the server for this response, a cached response can be stored by client and can be reused.
FAQ on REST API
What Is A REST API (Representational State Transfer)?
A RESTful API (Representational State Transfer) is a type of web service which utilizes HTTP methods such as GET, POST, PUT and DELETE in order to access and modify data. RESTful APIs are stateless services which means the server doesn’t keep track of client state. This enables greater scalability and reliability for applications using RESTful APIs.
What Are the Advantages of Rest API?
One of the main advantages of using RESTful API is increased scalability and reliability of applications. RESTful APIs are also language and platform independent, making them suitable for use on any programming language or platform. Finally, RESTful APIs are easy for developers to understand – an attractive feature.
Since we understand what a RESTful API is, let’s see some of the frequently asked questions (FAQs) about it.
1. What Is the Difference between Rest API and SOAP?
Restful APIs and Simple Object Access Protocol (SOAP) are both web service architectures; however they differ significantly in several ways. RESTful APIs are designed to be lightweight, stateless, platform independent APIs using HTTP methods for access and manipulation data while SOAP has more complex features such as using XML encoded messages for communication with its strict set of rules for interactions.
2. How Can I Call REST APIs?
Calling RESTful APIs is usually fairly straightforward. Once you identify an endpoint of an API you wish to call – typically its base URL plus any parameters or resource identifiers – making a call can be done using any HTTP method (GET, POST, PUT or DELETE), depending on its requirements for authentication or authorization credentials.
3. How Can I Secure My REST API?
There are various approaches available to you for securing a RESTful API, depending on your specific needs. These could include HTTPS encryption between clients and servers or using authentication and authorization mechanisms like OAuth or JWT (JSON Web Tokens) so only authorized users have access to it.
4. How Can I Test My Rest API?
Testing RESTful APIs depends on your requirements. One option is using tools like Postman or Swagger, which enable users to interact with endpoints and verify responses, while others utilize frameworks like JUnit or TestNG for automated tests.
5. How Can I Document my Rest API?
Documenting is an integral component of developing RESTful APIs. One method involves using tools such as Swagger or OpenAPI for interactive documentation of your API; Markdown or AsciiDoc may also help produce human-readable documentation of it.
Conclusion
RESTful APIs are an efficient means of creating scalable and reliable Rest web services, making an application development platform-independent while being easy for end-users to understand and implement. We hope that our blog has provided some answers regarding RESTful APIs.
We will see the rest API example and its details in the next post.
NEXT TOPIC: REST API EXAMPLE USING SPRING BOOT
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