RESTful APIs
- What is REST?
- REST stands for Representational State Transfer.
- RESTful APIs follow a client-server architecture where resources are accessed using HTTP methods (GET, POST, PUT, DELETE).
- What is RAML?
- RAML (RESTful API Modeling Language) is a YAML-based language for describing RESTful APIs.
- It provides details about:
- Endpoints (URLs)
- HTTP methods supported by each endpoint
- Request and response structures (including data types)
- Status codes
- Why use RAML?
- RAML helps developers understand and use APIs.
- It promotes consistent API design within an organization.
- It can be used to generate client libraries and documentation.
RAML Concepts
- API Fragments: Reusable components containing common API elements (data types, security schemes, etc.).
- API Specifications: Documents that define the functionality and behavior of an API.
- RAML Structure: Composed of Root, Resources, Methods, URI Parameters, Query Parameters, and Responses.
- Traits vs. Resource Types:
- Traits define common behaviors for HTTP methods (e.g., filtering, sorting).
- Resource types are templates for resources, reducing code duplication.
- Replacing a Resource: Use a PUT method on the resource to replace it entirely.
- Including External Files: Use
!includedirective to reference external RAML files. - URI vs. Query Parameters:
- URI parameters identify specific resources.
- Query parameters filter or sort resources.
RAML in Anypoint Studio
- API Kit Router: Validates incoming messages against RAML specifications.
- Fragments vs. Libraries:
- Fragments are reusable components for multiple APIs.
- Libraries are single RAML files defining data types, resources, etc.
- PATCH vs. PUT vs. POST:
- POST: Creates a new resource.
- PATCH: Updates a partial resource.
- PUT: Replaces an entire resource.
Testing API Design
- Use the mocking service in Anypoint Studio to test your API design with sample requests.
RAML Details
- Multiple Request Paths: Yes, RAML allows multiple request paths.
- Same HTTP Method for a Path: No, RAML allows only one HTTP method per request path.
- Optional URI Parameters: Add a question mark (?) to the parameter name and define a default value.
- Design Center:
- Create RAML API definitions using API Designer.
- Publish API fragments for reuse.
- Design Mule applications.
- Collections in RAML: A common pattern for defining resource types.
- Required Field in Root: Title (e.g., “Employees API”).
- Optional Query Parameters: Use the
requiredkeyword (e.g.,required: false). - Resource Types: Inherit properties from other resources.
- Basic Authentication: Use
securitySchemesandsecuredBykeywords.
API vs. Web Service
- An API is an interface for accessing data and functionality from another program.
- A web service is a self-contained application that processes requests and returns responses. (SOAP-based, accessed via HTTP)
RAML vs. Swagger
- RAML focuses on API design and tooling (Mulesoft).
- Swagger focuses on API documentation, client libraries, and code generation. (Used by various clients)