RESTful Web Processing Service
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This document proposes a RESTful approach to implementing OGC Web Processing Services (WPS). It discusses representing geoprocessing operations as addressable resources that can be invoked via HTTP verbs like GET and POST. Operations return job resources that can then be monitored. Formats like JSON, KML and GML are supported through content negotiation. An example humanitarian relief workflow is presented to demonstrate chaining processes through their RESTful interfaces. The design aims to provide seamless integration of WPS capabilities into RESTful geospatial web services and applications.
![REST – architectural style “ ... a hybrid style derived from several of the network-based architectural styles [...] and combined with additional constraints that define a uniform connector interface.” (Fielding, 2000) REST properties Addressability, statelessness, connectedness, uniform interface Resources accessible through URLs HTTP Verbs GET, POST, PUT, DELETE,… Hypermedia approach Representations & content negotiation](https://image.slidesharecdn.com/restfulwpsagile-110420110953-phpapp01/85/RESTful-Web-Processing-Service-4-320.jpg)
![HTTP verbs - Examples Perform process GET: processes/[process_ID]?[parameters] Jobs POST: processes/[process_ID]/jobs GET: processes/[process_ID]/jobs Job GET: processes/[process_ID]/jobs/[job_ID] DELETE: processes/[process_ID]/jobs/[job_ID]](https://image.slidesharecdn.com/restfulwpsagile-110420110953-phpapp01/85/RESTful-Web-Processing-Service-8-320.jpg)
![Thanks for your attention! swsl.uni-muenster.de Theodor Foerster [email_address]](https://image.slidesharecdn.com/restfulwpsagile-110420110953-phpapp01/85/RESTful-Web-Processing-Service-17-320.jpg)
RESTful Web Processing Service
- 1. RESTful Web Processing Service Theodor Foerster, Andre Bruehl, Bastian Schaeffer AGILE 2011, Utrecht, the Netherlands
- 2. Why RESTful WPS? Representational State Transfer (Fielding, 2000) RESTful Web Services are available For mapping & data GeoWeb & Mashups Producers = Consumers Processing missing, but essential Seamless integration OGC WPS compatibility
- 3. Web-based Geoprocessing Data Information GetCapabilities Execute WPS Process 1 Process 2 Process n DescribeProcess
- 4. REST – architectural style “ ... a hybrid style derived from several of the network-based architectural styles [...] and combined with additional constraints that define a uniform connector interface.” (Fielding, 2000) REST properties Addressability, statelessness, connectedness, uniform interface Resources accessible through URLs HTTP Verbs GET, POST, PUT, DELETE,… Hypermedia approach Representations & content negotiation
- 5. REST for Geo Services available Google, Yahoo, GeoCommons, etc. Documents & specifications too
- 6. Design approach Identify resources What are the relevant resources? Link resources How does the client navigate between the resources? Interaction with HTTP verbs How to build the functionality Multiple representations for the resources Which are the relevant representations?
- 7. Resources Links & navigation Jobs & processes
- 8. HTTP verbs - Examples Perform process GET: processes/[process_ID]?[parameters] Jobs POST: processes/[process_ID]/jobs GET: processes/[process_ID]/jobs Job GET: processes/[process_ID]/jobs/[job_ID] DELETE: processes/[process_ID]/jobs/[job_ID]
- 9. Representations ATOM, KML, GML, OGC WPS, JSON Example – processes/buffer
- 10. WPS Compatibility Processes modelled as resources OGC WPS return formats possible through content negotiation OGC WPS functionality fully reflected Process by reference Synchronous & asynchronous processing
- 11. Implementation
- 12. Client JavaScript & RESTful APIs
- 13. Humanitarian relief workflow Evaluating campsites for medical access Inspired by OGC testbed GeoCommons Medical facilities Campsites Interactive & client-based chaining Buffer, intersection & symDifference
- 14. Qualitative evaluation Addressability Each process & job is a resource and addressed via URL Statelessness Required information available at runtime Connectedness Resources are connected Uniform interface HTTP
- 15. Discussion & Outlook Difference to ESRI GeoServices Towards modular specifications at OGC Incorporating WPS-T Link to open linked data to be investigated
- 16. Conclusion REST is a hot topic GeoWeb & APIs Process as a resource Seamless integration through REST OGC compatibility Humanitarian relief use case
- 17. Thanks for your attention! swsl.uni-muenster.de Theodor Foerster [email_address]