REST API
REST API (Representational State Transfer Application Programming Interface) is an architectural style for designing networked applications. It leverages the HTTP protocol to define a set of operations that can be performed on resources, making it a popular choice for web services.
History and Context
Roy Fielding introduced REST in his 2000 doctoral dissertation as part of his work on defining the HTTP/1.1 and URI specifications. REST was designed to take advantage of the existing infrastructure of the web and to provide a stateless, client-server architecture where scalability, performance, and simplicity are key concerns.
Core Principles of REST
- Client-Server: By separating the user interface concerns from the data storage concerns, REST improves the portability of user interface across platforms and scalability of server components.
- Stateless: Each request from client to server must contain all the information needed to understand and process the request. The server should not store anything about the client state between requests.
- Cacheable: Responses must define themselves as cacheable or not to prevent clients from reusing stale or inappropriate data in response to further requests.
- Layered System: The architecture can be composed of multiple layers, each with a specific function, to improve scalability and security by enforcing boundaries between layers.
- Uniform Interface: RESTful services have a uniform interface to identify resources, manipulate them through representations, and communicate via self-descriptive messages. This is often achieved through standard HTTP methods.
- Code on Demand (optional): REST allows client functionality to be extended by downloading and executing code in the form of applets or scripts.
HTTP Methods in REST
- GET: Retrieve data from the server.
- POST: Submit data to be processed to the server.
- PUT: Update or create a resource on the server.
- DELETE: Remove a resource from the server.
- PATCH: Apply partial modifications to a resource.
- HEAD: Identical to GET, but only return headers.
- OPTIONS: Describe the communication options for the target resource.
Advantages of REST APIs
- Scalability - Due to its stateless nature, REST services can scale easily.
- Performance - RESTful services can leverage caching to improve response times.
- Flexibility - Can be used with any data format, although JSON and XML are most common.
- Compatibility - Works well with HTTP and the web architecture.
Limitations
- Statelessness can make managing sessions or stateful interactions more complex.
- Security - REST APIs rely on HTTPS for security, which can be resource-intensive.
- Overfetching or underfetching of data, where clients might receive more or less data than they need.
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