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Rest Webservice
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- 2. Course Section Section1: REST API Concepts Section2: Implementation with Rest Easy
- 3. Internal | Department| 11/30/2015 | © Robert Bosch Engineering and Business Solutions Private Limited 2015. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights. Header of section Man behind REST REST was initially proposed by Roy Thomas Fielding in his 2000 PhD dissertation "Architectural Styles and the Design of Network-based Software Architectures" 3
- 4. REST REST stands forRepresentational State Transfer It is an architectural pattern for developing web services as opposed to a specification. REST web services communicate over the HTTP specification, using HTTP vocabulary: Methods (GET, POST, etc.) HTTP URI syntax (paths, parameters, etc.) Media types (xml, json, html, plain text, etc) HTTP Response codes.
- 5. Representational Clientspossess the information necessary to identify, modify, and/or delete a web resource. State All resource state information is stored on the client. Transfer Client state is passed from the client to the service through HTTP.
- 6. What is webservices? Web services are services that are exposed to the internet for programmatic access. They are online Apis that you can call from your code. Web Services
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- 9. Real time Scenarios http://maps.googleapis.com/maps/api/geocode/json?address=chicago
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- 11. Protocol There isno protocol unlike SOAP.
- 12. How the communicationhappens? HTTP Exchange 1. GET 2. POST 3. PUT 4. DELETE
- 13. Service Definition Thereis no formal service definition in REST. Unlike SOAP a WSDL is mandate.
- 14. Steps to followto create REST Resource Based URI HTTP Methods HTTP Status Code Message Headers.
- 15. Resource Based URI Old Web applications URIs look like Now Get message with id 10. Consumer is not aware of URL. /getMessages.do?id=10 Rest consumer should be aware of the URL.
- 16. Best practice toName Resources Use Nouns not Verbs Use /profiles/{profileName} /messages/{messageId} And most importantly Resourse Based URI are resistant to change.
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- 18. The HTTPrequest is sent from the client. Identifies the location of a resource. Specifies the verb, or HTTP method to use when accessing the resource. Supplies optional request headers (name-value pairs) that provide additional information the server may need when processing the request. Supplies an optional request body that identifies additional data to be uploaded to the server (e.g. form parameters, attachments, etc.)
- 19. Resource – identifiedby a URL (or uniform resource locator) Method – the action verb to perform on a resource e.g. GET, POST, PUT, DELETE, etc. Request Headers – name-value pairs of meta-information about the request e.g. Content types expected by the client Request Body – data to be streamed from the client to the server e.g. Attachments, form parameters, etc.
- 20. The HTTPresponse is sent from the server. Gives the status of the processed request. Supplies response headers (name-value pairs) that provide additional information about the response. Supplies an optional response body that identifies additional data to be downloaded to the client (html, xml, binary data, etc.)
- 21. Status –An HTTP status code and status message e.g. 404 Not Found, 200 OK Response Headers – name-value pairs of meta-information about the response e.g. Content-Type Response Body – Additional data to be streamed from the server to the client e.g. HTML document, XML document, binary data
- 22. HTTP Methods supportedby REST: GET – Requests a resource at the request URL Should not contain a request body, as it will be discarded. May be cached locally or on the server. May produce a resource, but should not modify on it. POST – Submits information to the service for processing Should typically return the new or modified resource. PUT – Add a new resource at the request URL DELETE – Removes the resource at the request URL
- 24. Its safeto make duplicate GET request. How about put, post and delete? What is difference between Put and Post?
- 26. Caching Is GET,POST , PUT Cacheable? What about browser referesh?
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- 31. Success Codes 1.200 – OK 2. 204 – No Content Client Error Codes 400 – Bad Request 401 – Unauthorized 403 – Forbidden 404 – Not Found
- 32. 500 –Internal Server Error
- 33. HATEOS HYPERMEDIA AS THEENGINE OF APPLICATION STATE
- 34. Avoid hardcodingof URI is client side. Helps like documentation of Resourse. Provides additional information to consumer for a resource. It provides links to resources in API response. URI to next steps are handed to them in response.
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- 40. Level 0– Swamp of POX One URI. Everything is defined in XML and no HTTP concepts are used. <create-message> <message-content>Hello World</message-content> </create-message>
- 41. Level 1:Resource URI Individual URI for each resource. In spite of having “what needs to done” in message itself.
- 42. Level 2– HTTP Methods Use standard HTTP Methods and error codes.
- 43. Level 3: Usage of HATEOAS. Responses have links that client can use.