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Practical REST in Grails 2.3


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Practical REST in Grails 2.3

  1. 1. PRACTICAL REST IN GRAILS 2.3 dan woods @danveloper
  2. 2. Introduction to Grails 2.3 REST The Concept of a “Resource” • Map data to a URL Endpoint • Traverse object graph through URL mappings • Provide serialization in your favorite format • Driven by the HTTP Request’s Accept header • Limitations: • The whole URL graph needs to be explicitly defined for mapping nested Resources
  3. 3. Introduction to Grails 2.3 REST Defining a Resource • • • • Decorate your domain object with the @Resource Annotation Map to a URI via Annotation or UrlMapping Use built-in, good-for-most-things RestfulController, or… Build a custom controller to handle your specific use-case
  4. 4. Introduction to Grails 2.3 REST Customizing Resource Behavior • • • Regulate response formats through the @Resource annotation Determine read/write behavior • In turn, writable actions will get 405 Customizing response
  5. 5. Introduction to Grails 2.3 REST Resource Renderers • • Provides inherent support for versioning Built-in Renderers like DefaultJsonRenderer, HalJsonRenderer offer some standard support • include/exclude properties • Handling versioning
  6. 6. Introduction to Grails 2.3 REST Resource Renderers • • • • • • Custom Renderers satisfy specific needs Intercept the response activity to influence the output Allow for changing the response structure This is the place to put business logic that responds with a nonstandard view Preferred over JSON.registerObjectMarshaller Auto-wireable Spring beans
  7. 7. Introduction to Grails 2.3 REST Resource Controllers From the JAX-RS Spec… "Adopting the MVC terminology, JAX-RS resource classes are comparable to controllers" • Grails maps a RestfulController to the Resource’s URL, so the @Resource is not the handler, it just represents the handler!
  8. 8. Beyond the Basics Custom RestfulController • • • • Overload how resources are resolved Custom binding logic Interface with services for object composition • Business Logic: “Only show me healthy applications” Using the respond method • Control the response format this way
  9. 9. Getting Practical Let’s get practical…
  10. 10. Getting Practical Obscuring Ids • • • Custom RestfulController • Overload queryForResource, listAllResources Custom Renderer • Only expose the properties that you want people to see The @RestIdProperty strategy for building HAL Navigation
  11. 11. Getting Practical Resources as a Concept • Nothing hard-ties a Resource to a domain object • Can be backed simply by a command object • Good choice for providing data in a format that is domainspecific, but brought in via service call
  12. 12. Getting Practical Using Hyper-Media Practically • Built-in Grails rendering constructs don’t favor reusability • grails-rest-renderers plugin can provide some simplifications to building pragmatic hyper-media renderers
  13. 13. Getting Practical Security? Great article about REST Security from Dave Syer (@david_syer): Summary: Oauth: "one of the key reasons for OAuth2 to exist is so that Client applications do not need to collect user credentials. Here is where the learning curve for OAuth2 gets steeper.” Form Login: Difficult to drive RESTful interactions since failures are redirected to login page Basic Auth: Maybe the best choice