Representational State Transfer (REST) Web services, or “RESTful” Web services describes any simple interface that transmits data over a standardized interface (such as HTTP) without an additional messaging layer, such as SOAP.
There is no client context being stored server side (no Sessions). REST is a stateless.
REST is easier to build and consume than using SOAP-services.
REST provides a set of design rules for creating stateless services that are viewed as resources, or sources of specific information, and can be identified by their unique URIs. A client accesses the resource using the URI, a standardized fixed set of methods, and a representation of the resource is returned. The client is said to transfer state with each new resource representation.
Rest is often the base technology behind micro-services
Objects in a typical REST system are addressable by URI and interacted with using verbs in the HTTP protocol.
- An HTTP GET to a particular URI fetches an object and returns a server-specified set of fields.
- An HTTP PUT edits an object;
- An HTTP DELETE deletes an object; and so on.
Because of multiple round-trips and over-fetching, applications built in the REST style inevitably end up building ad hoc endpoints.
Ad Hoc Endpoints
Many applications have no formalized client-server contract. Product developers access server capabilities through ad hoc endpoints and write custom code to fetch the data they need. (They end up with a custom endpoint per view).
HTTP Request Method
REST makes use of the HTTP request methods:
- GET - Read requests
- PUT- Modify Request
- POST- Create Request
- DELETE - Delete Request
Context and security
A RESTful interface does not store any information about a particular user's session.
Every request authentication is basic. See Http - Authorization Header (authentication entries)
version can be specified:
- in the url
- or as a query string. example: api-version: 2015-06-15
There is actually two schema file format that may defines your Rest API:
- The openapi file format.
- the schema file is defined first.
- boilerplate code (ie POJOs) is generated from it
- client / documentation (known as console) is generated from it
- and /or every request can be also be controlled from it
- the schema file must be kept up-to-date.
- once generated, you can't regenerate the boilerplate code
- not really flexible
In a code first development:
- the code is annotated with annotation or comment
- client / documentation (known as console) can be generated from:
- the comment / annotation
- the schema file
see Java - Rest
- https://api-platform.com/ - REST and GraphQL framework
- Google Chrome plugin REST client
- Fetch Mock - library fetch-mock
Via the setting of a proxy, you can set up what's called a mock-server