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REpresentational State Transfer (REST)

  • refers to a group of software architecture design constraints that bring about efficient, reliable, and scalable systems

6 constraints of REST​

  • if a web-based API meets these 6 constraints, it can be considered a RESTful API
  1. Client-server architecture
    • the client manages user interface concerns while the server manages data storage concerns
      • this allows a highly portable system where 1 REST server can serve multiple clients
    • have a complete separation between the content and its presentation and interaction
  2. Statelessness
    • no client context or information (state) can be stored on the server between requests
    • the client is responsible for keeping track of its own session state
    • all requests sent from a client must be self-contained and complete
    • if the client's session state is relevant, it must be sent along with a request
    • if the server needs to store the state, it must pass it on to a database or similar service for a specific time
  3. Cacheability
    • all REST responses must be clearly marked as cacheable or not cacheable
  4. Layered system
    • the client cannot know, and shouldn't care, whether it's connected directly to the server or to an intermediary like a CDN or mirror
      • ensures scalability and helps with security
  5. Code on demand
    • servers are allowed to transfer executable code like JavaScript and compiled components to clients
    • less commonly used of REST
  6. Uniform interface
    1. Resource identification in request
      • the URI request must specify what resource it is looking for and what format the response should use
    2. Resource manipulation through representations
      • once a client has a representation of a resource, it can modify or delate the resource
    3. Self-descriptive messages
      • a uniform interface must issue self-descriptive messages for both sending and receiving REST data
      • each representation must describe its own data format
    4. Hypermedia as the engine of application state
      • a uniform interface must use hypermedia as the engine of application state
      • once a client has access to a REST service, it should be able to discover all available resources and methods through the hyperlinks provided