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REST is an acronym for "REpresentational State Transfer" and is an architectural style for distributed systems based on the HTTP protocol. It was introduced by Roy Fielding in his dissertation in 2000 and has since established itself as one of the most important approaches for the development of web applications. REST enables communication between client and server via standardised interfaces, thereby promoting the scalability, reliability and maintainability of web applications.
REST is based on the principle of resources that are represented by unique identifiers (URIs). These resources can be represented in various formats such as JSON, XML or HTML and can be manipulated using standardised HTTP methods such as GET, POST, PUT and DELETE. RESTful services are stateless, which means that the server does not store any information about the state of the client. Instead, each request contains all the information required to understand and process it. This allows for better scalability and reliability of web applications as the server is not burdened with the state of the client.
The principles of REST
REST is based on a number of principles that help to improve the interoperability, scalability and maintainability of web applications. One of the most important principles of REST is the unique identification of resources through URIs. Each resource should have a unique URI that allows the client to access and interact with it.
Another important principle of REST is the use of standardised HTTP methods such as GET, POST, PUT and DELETE to manipulate resources. These methods allow the client to perform the desired actions on the resources, resulting in consistent and predictable interaction with the server.
Another important principle of REST is the use of hypermedia as the engine of the application state (HATEOAS). This means that the server provides the client with links to other resources that are linked to the current resource. This allows the client to navigate the application state without having to be aware of specific endpoints.
The architecture of REST
The Architecture of REST is based on the concept of resources, which are represented by unique identifiers (URIs). These resources can be represented in various formats such as JSON, XML or HTML and can be manipulated using standardised HTTP methods such as GET, POST, PUT and DELETE.
Another important concept in the Architecture of REST is the stateless communication between client and server. This means that each request from the client contains all the necessary information to be understood and processed by the server. The server does not store any information about the client's state between requests, which leads to better scalability and reliability of web applications.
Another important concept in the architecture of REST is the use of hypermedia as the engine of the application state (HATEOAS). This means that the server provides the client with links to other resources that are linked to the current resource. This allows the client to navigate the application state without having to be aware of specific endpoints.
Resources and URIs
| Resource | URI |
|---|---|
| Homepage | www.beispiel.de |
| Product page | www.beispiel.de/produkte |
| Contact page | www.beispiel.de/kontakt |
Resources are the central concept in REST and are represented by unique identifiers (URIs). A resource can be anything that can be identified via the Internet, such as a document, an image or a user profile. Each resource should have a unique URI that allows the client to access and interact with it.
URIs are hierarchically structured and can contain parameters to indicate specific aspects of a resource. For example, a URI for a user profile could contain the ID of the user as a parameter to access the profile of a specific user.
HTTP methods in REST
HTTP methods play a central role in REST and are used to manipulate resources. The most important HTTP methods in REST are GET, POST, PUT and DELETE.
The GET method is used to retrieve a specific resource from the server. The client sends a GET request to the server and receives the requested resource in response.
The POST method is used to create a new resource on the server. The client sends a POST request to the server with the Data for the new resource and the server creates the resource accordingly.
The PUT method is used to update an existing resource on the server. The client sends a PUT request to the server with the updated Data for the resource and the server updates the resource accordingly.
The DELETE method is used to delete a specific resource from the server. The client sends a DELETE request to the server and the resource is deleted from the server.
Status codes in REST
Status codes play an important role in REST and are used to indicate the status of a request to the server. The most important status codes in REST are 200 (OK), 201 (Created), 404 (Not Found) and 500 (Internal Server Error).
The status code 200 (OK) is used to indicate that the request was successful and the requested resource was returned.
The status code 201 (Created) is used to indicate that a new resource has been successfully created.
The status code 404 (Not Found) is used to indicate that the requested resource was not found.
The status code 500 (Internal Server Error) is used to indicate that an internal server error has occurred. Error has occurred on the server.
Best practices for the use of REST
There are a number of best practices for using REST that can help improve the interoperability, scalability and maintainability of web applications.
A best practice is to use unique URIs for each resource. This ensures that each resource is uniquely identifiable and can be easily accessed by the client.
Another best practice is the use of standardised HTTP methods to manipulate resources. This makes it easier for the client to perform the desired actions on the resources and leads to consistent and predictable interaction with the server.
Another best practice is the use of hypermedia as the engine of the application state (HATEOAS). This allows the server to provide the client with links to other resources that are linked to the current resource, resulting in better navigability of the application state.
Overall, REST offers a powerful architecture for the development of distributed systems and web applications. By adhering to the principles and best practices of REST, developers can create highly scalable and reliable web applications that are easy to maintain and extend.
FAQs
What is Representational State Transfer (REST)?
Representational State Transfer (REST) is an architectural style for distributed systems based on the HTTP protocol. It enables communication between client and server via standardised HTTP methods.
What are the underlying principles of REST?
REST is based on several principles, including the use of standardised HTTP methods such as GET, POST, PUT and DELETE, the unique identification of resources via URIs and the use of hypermedia to represent relationships between resources.
What advantages does REST offer?
REST offers a number of advantages, including scalability, simplicity, flexibility and the ability to connect different platforms. It also enables the separation of client and server, which improves the maintainability and expandability of systems.
How is REST used in practice?
In practice, REST is often used for the development of web APIs that make it possible to access resources and data via standardised HTTP methods. It is also used in the development of microservices and cloud applications.
What role does REST play in the context of web services?
REST plays an important role in the context of web services, as it is a standardised and widely used method for communication between distributed systems. It enables the development of lightweight and interoperable interfaces for data exchange.
