What is HATEOAS?
HATEOAS is one of the constraints of the REST architectural style. It essentially means that a client interacting with a RESTful application can entirely navigate the API by interacting with hypermedia provided dynamically by the application servers.
Key Concepts
- Hypermedia Controls: These are the available actions provided dynamically in the response from the server. They guide the client on what actions are possible next. They may include links, embedded resources, forms, and other controls.
- Stateless Interaction: Each request from the client to the server must contain all the information needed to understand and process the request. The server retains no knowledge of client state between requests.
- Affordances: This is a concept where the server provides information about what the client can do next. If a resource can be updated or deleted, the server provides the corresponding URIs to perform those actions.
Benefits
- Discoverability: Clients can discover functionality in the application by navigating the provided links.
- Loose Coupling: By using HATEOAS, the client and server become more loosely coupled, promoting long-term compatibility between different versions of the application.
- Self-Documenting: The responses include information about the possible actions, making it easier for developers to understand the application's functionality.
Challenges
- Complexity: Implementing HATEOAS may add complexity to both client and server code.
- Limited Client Support: Not all clients are designed to take full advantage of HATEOAS principles.
Implementation
HATEOAS can be implemented using various media types, such as:
- HAL (Hypertext Application Language)
- Siren
- JSON-LD
These formats define specific structures for embedding links and actions within responses.