Uploaded byPete Morano
Understanding and Using Rest APIs (SocialDevCamp Chicago 2009)
RESTful APIs have become integral to technology and dominate web development. While REST is based on simple principles like using HTTP methods and representing resources, there is still a lack of standardization around documentation and discovery. WADL aims to provide a standard like WSDL for REST that would reduce errors and enable code generation.
Understanding and Using Rest APIs (SocialDevCamp Chicago 2009)
- 1. REST 11.07.2009Understanding andUsing RESTful APIs
- 2. About MeDeveloping softwarefor 15 years
- 3. Bulk of experienceon enterprise-scale applications
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- 5. KeyLimeTieOverviewAlthough REST is10 years old, APIs based on the REST model continue to become an integral part of the technology landscape. ProgrammableWeb.com lists 1051 RESTful APIs, 4422 Mashups.We’ll look atBasic REST Concepts
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- 8. REST OverviewAPIs basedon the Representational State Transfer (REST) architecture dominate web 2.0 mash-up and social media development.There are a number of frameworks available that support the development of RESTful APIs (WCF, JAX-RS, Wicket, Zend)We are still missing an established mechanism for documentation and discovery and client-side tool support for rapid implementation.
- 9. REST OverviewREST-style architecturesconsist of clients and servers. Requests and responses are built around the transfer of "representations" of "resources". A resource is any entity that can be addressed in a URI (an account, an employee, a physical file)A representation of a resource is any information that captures the current or intended state of a resource. All information necessary to process and complete a request is contained within it.
- 10. ExampleResource (Twitter PublicTimeline) http://twitter.com/statuses/public_timeline.xmlResource (Twitter User) http://twitter.com/users/petermorano.xml
- 11. REST OverviewREST-style architecturesconsist of clients and servers. Requests and responses are built around the transfer of "representations" of "resources". A resource is any entity that can be addressed in a URI (an account, an employee, a physical file)A representation of a resource is any information that captures the current or intended state of a resource. All information necessary to process and complete a request is contained within it.
- 12. Wait a MinuteIfthis sounds a lot like the Web, it’s because the Web is a REST implementationRoy Fielding, who created REST, was also one of the principal authors of HTTP
- 13. REST BasicsThe RESTarchitecture was designed around a few key principles: Use HTTP Methods (and Response Codes)
- 14. Be Statelessand Cacheable
- 15. Use AddressableResources
- 16. Support thetransfer of RepresentationsREST BasicsThe REST architecture was designed around a few key principles:Use HTTP Methods (and Response Codes)
- 17. Be Statelessand Cacheable
- 18. Use AddressableResources
- 19. Support thetransfer of RepresentationsHTTP MethodsMap to CRUD OperationsActionSQLHTTP MethodCreateInsertPostReadSelectGetUpdateUpdatePutDeleteDeleteDelete
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- 21. REST BasicsThe RESTarchitecture was designed around a few key principles: Use HTTP Methods (and Response Codes)
- 22. Be Stateless andCacheable
- 23. Use AddressableResources
- 24. Support thetransfer of RepresentationsStateless and CacheableNo State Stored on the Server
- 25. Every HTTPrequest executes in complete isolation on the server
- 26. Easier toscale because of GET methodREST BasicsThe REST architecture was designed around a few key principles: Use HTTP Methods (and Response Codes)
- 27. Be Statelessand Cacheable
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- 29. Support thetransfer of RepresentationsResourcesAny THING – person, concept, artifact
- 30. Anything youcan point to
- 31. Explicit Requestand Response – No StateREST BasicsThe REST architecture was designed around a few key principles: Use HTTP Methods (and Response Codes)
- 32. Be Stateless andCacheable
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- 34. Support the transferof RepresentationsRepresentationsA serializable description of a Resource
- 35. Resources aremodifiable through Representations
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- 38. Binary Formats (jpg,gif, mpeg)REST ProsCacheableScalableDifferent RepresentationsHuman Readable ResultsLightweight
- 39. REST ConsMust be HTTPNo Atomic TransactionsNo Standards for security except HTTPSNo Standardized Discovery
- 40. REST vs. SOAPUnlikeSOAP-based web services, there is no "official" standard for RESTful web service. Though not a standard, a RESTful implementation uses standards like HTTP, URL, XML, GIF, etc.
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- 53. Easy to workwith, Brower-testable
- 54. GET Method supportscaching
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- 58. USING RESTThink ofa REST API as another data sourceDetails depend on the language, but there are common steps:Serialize the representation (if PUT or POST)
- 59. Format the URI(parameters, variables)
- 60. Encode Authentication intothe Header
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- 62. Deserialize ResponseUSING RESTThreebasic options for consuming RESTful APIsUse the service’s toolkit (not always available)
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- 66. Code your ownimplementationCommunity BuiltUpside Ready to useDownsideIt’s not your code
- 67. You may bewaiting for the library to become available.
- 68. Enterprise clients mayhave concernsWriting Your OwnUpside You know the codeDownsideManual Discovery Process
- 69. Implementation can betediousToolsTools for testing RESTful APIsCurl
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- 73. WADLWeb Application DiscoveryLanguage (WADL)Created in 2005 by Marc Hadley of Sun MicrosystemsSubmitted to W3C on 8/31/2009REST’s Answer to WSDLSpecification: https://wadl.dev.java.net/
- 74. What WADL GetsYouReduced Errors in DiscoveryOpportunities for Code GenerationSpend more time building your application and less time implementing APIs
- 75. So Where IsIt?Currently in Submission to W3CAPI Providers are slow to adopt, so tool providers are slow to implementThere are projects underway to generate code from WADL, and at least one tool that helps in creating WADL
- 76. WADL DemoProject oncode.google.comOnline Version: http://tomayac.de/rest-describe/latest/RestDescribe.html
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