What is REST API?
REST stands for Representational state transfer.
It relies on a stateless, client-server, cacheable communications protocol -- and in virtually all cases, the HTTP protocol is used.
REST is often used in mobile applications, social networking Web sites, mashup tools and automated business processes. The REST style emphasizes that interactions between clients and services is enhanced by having a limited number of operations (verbs). Flexibility is provided by assigning resources (nouns) their own unique universal resource indicators (URIs).
REST involves reading a designated Web page that contains an XML file. The XML file describes and includes the desired content.
The REST architectural style describes six constraints. The six constraints are:
- Uniform Interface
- Layered System
- Code on Demand
RESTful applications use HTTP requests to post data (create and/or update), read data (e.g., make queries), and delete data. Thus, REST uses HTTP for all four CRUD (Create/Read/Update/Delete) operations.
REST is a lightweight alternative to mechanisms like RPC (Remote Procedure Calls) and Web Services (SOAP, WSDL, et al.).
REST is not a "standard". There will never be a W3C recommendataion for REST, for example. And while there are REST programming frameworks, working with REST is so simple that you can often "roll your own" with standard library features in languages like Perl, Java, or C#.
As a programming approach, REST is a lightweight alternative to Web Services and RPC.
Much like Web Services, a REST service is:
- Standards-based (runs on top of HTTP), and
- Can easily be used in the presence of firewalls.
Like Web Services, REST offers no built-in security features, encryption, session management, QoS guarantees, etc. But also as with Web Services, these can be added by building on top of HTTP:
- For security, username/password tokens are often used.
- For encryption, REST can be used on top of HTTPS (secure sockets).... etc.
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