RESTful Services Policy SWG
1. RESTful Service Policy Standards Working Group
The Open Geospatial Consortium (OGC) sees value in Web Services and Applications which make use of a RESTful approach to design. OGC believes that a common understanding and agreement on how to structure Resource Models and leverage uniform Web interfaces, in other words a common RESTful approach to the design and standardization of Web services, will lead to both improved interoperability and greater accessibility for these services. During the OGC Technical Committee (TC) meeting in Boulder in September 2011, the REST Subcommittee members recommended forming a standards working group to write such a policy standard.
Note: REST stands for “Representational State Transfer”, a set of principles and constraints for Web computing which optimize desirable qualities including ease of development, robustness, and scalability. The term RESTful connotes adaptation of REST for particular computing situations such as geospatial Web services.
2. Purpose of this Standards Working Group
The purpose of the RESTful Service Policy Standard Working Group is to create requirements, recommendations and examples for the creation of OGC standards for RESTful Web Services. The result of this work will be formalized in a Policy Standard for the structure and content of the implementation of geospatial standards embodying a uniform approach to RESTful principles.
The SWG will provide pragmatic and testable requirements with recommended guidelines and conventions for consistent RESTful OGC Services standards.
Note: Conventions for configuration patterns are essential to allow new developers and users to learn a service interface quickly. It promotes uniformity and simplicity, as well as reducing errors which can impact interoperability
3. Scope of Work
A large community of geospatial Web services stakeholders both within and outside of OGC is coming to recognize the value of REST principles for simplifying and unifying access to OGC services. The scope of this Standards Working Group will be to look across all existing and planned OGC services and investigate how REST principles can be applied to access their capabilities leveraging uniform interface, hypermedia, and structured resource design patterns. In other words, the goal is to reach a consensus on how these principles can best be realized for OGC service users.
New and old applications require looking at the same data in many different ways. One way in which OGC services have always been “special” is their emphasis on the importance and identity of the data behind the service interface. That same tiered pattern of data to service capability to client / user interaction will be important to reflect in an OGC – REST standards policy.
These advanced applications typically integrate several different service interfaces to provide the requested capability. Rather than requiring each application to perform repeated mediation between diverse standalone service bindings, one goal of this SWG will be to determine ways in which resource structures and uniform interface façade techniques can make this type of service integration a straightforward and easy to implement capability.
Candidate OGC Services to be considered for this type of harmonization will include WMS, WFS, WCS, SOS, SPS, WPS, CSW, WMTS, and profiles thereof.
Activities will include:
- Identify both common and distinct use cases for candidate services
- Identify mainstream IT and specialized concerns for RESTful OGC services
- Identify current software best practices
- Identify reusable design patterns
- Develop guidance regarding consequences of RESTful practices for geospatial interoperability
- Focus on HTTP/HTTPS protocol
3.1 What is out of scope?
This SWG will not try to codify RESTful service practice for the entire web, but will create a profile or adaptation of RESTful techniques specifically for OGC in order to provide a consistent design paradigm and practices across OGC Web Services. It will be desirable although not essential that these paradigms and practices coincide with many that are being developed and/or adopted in the wider Web services world.
In particular, the SWG will not engage in any discussion of “what REST is” in terms of:
- Other protocols such as XMPP…
- Definition of REST, ROA vs. SOA…
This SWG will specify policy for the development of RESTful bindings for current and emerging OGC service standards and guidance for the CITE SC on creation of tests for RESTful services. The SWG will not specify those bindings itself. The SWG’s work product will not constitute OGC policy until the TC has accepted the SWG’s contribution as policy. Since the product of this SWG is a standard on how to write OGC RESTful services standards, a direct CITE conformance test will not be created.
3.2 Specific Contribution of Existing Work as a Starting Point
The SWG will take into account the published and/or posted body of work on REST and RESTful Services in OGC project documents. In addition, the SWG will use at least the following external resources:
- · HTTP v. 1.1 specification (http://www.w3.org/Protocols/rfc2616/rfc2616.txt)
- · HTTPbis work (http://tools.ietf.org/wg/httpbis)
- · Fielding Ph.D. Thesis: Architectural Styles and the Design of Network-based Software Architectures (http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm)
- RESTful Web Services, Leonard Richardson and Sam Ruby, ©2007 O’Reilly Media
- RESTful Web Services Cookbook, Subbu Allamaraju, ©2010, Yahoo! Inc. O’Reilly Media
- · REST in Practice: Hypermedia and Systems Architecture, Jim Weber, Savas Parastatidis, Ian Robinson, © 2010 Jim Weber, Savas Parastatidis and Ian Robinson
- Atom Syndication Format (http://www.ietf.org/rfc/rfc4287.txt)
3.3 Completion of the SWG’s Work
The RESTful Services Policy Standards Working Group will dissolve after the following milestones have been achieved:
- The SWG has completed evaluation and incorporation into the candidate standard of all comments received during the OAB review and the public comment period;
- The SWG membership has approved a recommendation to submit the document to the TC for consideration as an OGC Adopted Standard;
- The candidate standard has been approved by the OGC Technical and Planning Committees as an Adopted OGC standard;
- A RESTful Services DWG has been formed to oversee the implementation of RESTful Services standards and to provide technical assistance where needed.
The main deliverable of the SWG will be a policy standard describing how RESTful Web Services standards will be structured for OGC Web services.
- Requirements and guidelines for OGC RESTful Services document as Policy Standard
- User stories for candidate services (explanatory annexes to the above document)
- Additional informative guidance on both creation and implementation of RESTful service specifications.
At the end of the process to create and adopt the Policy document, the REST SWG will act as a seed group to create a RESTful DWG that oversees and provides technical guidance for development of RESTful OGC Web service implementation standards, scope also to include:
- Reference implementations
- CITE tests and testing process
- Client implementation best practices
- Interoperability Program activities related to RESTful Web services
5. IPR Policy for this SWG
The IPR Policy for the SWG will be RAND, Royalty Free. In addition, the SWG will endeavor to make all of its work and deliberation available to OGC members as expeditiously as possible during our deliberations.
ý RAND-Royalty Free. ¨ RAND for fee
6. Anticipated Participants
The anticipated participants are those members of the Technical Committee who are currently interested in working on RESTful Web services. This would likely include the following groups:
- members of the REST SC;
- members of any SWG committee currently looking at creating a RESTful binding for their service, such as WFS, WMS, SPS, WPS, WCS, WCPS, WfCS, SOS, CSW or the GeoServices REST SWG;
- members of the OAB, the Architecture DWG;
- those who are or will be involved in the design, development, implementation, or use of RESTful Web Services, including RESTful service providers, prospective users of such services and content providers.
This is not meant as a limiting statement but instead is intended to provide guidance to interested potential participants as to whether they should consider participating in this SWG.
7. Other informative information about the work of this SWG
a. Similar or applicable standards work (OGC and elsewhere).
The following standards and projects may be relevant to the SWG's planned work, although none currently provide the functionality anticipated by this committee's deliverables:
- HTTP 1.1
- Uniform Resource Identifier (URI): Generic Syntax. IETF RFC3986
- OGC Identifiers – the case for http URIs. OGC 10-124r1
The SWG intends to seek and if possible maintain liaison with each of the organizations maintaining the above works.
b. Details of the first meeting
The first meeting of the SWG will be held by During the OGC TC meeting in Brussels the week of 28 November 2011. The particular time and location will be arranged as early as feasible. Call-in information will be provided to the SWG's e-mail list and on the portal calendar in advance of the meeting.
c. Projected on-going meeting schedule
The work of the SWG will be carried out primarily by email and conference calls, every one or two weeks, with face-to-face meetings at each OGC TC meeting to the extent possible.
d. Supporters of the Proposal
The following people support this proposal and are committed to the Charter and projected meeting schedule. These members are known as SWG Founding or Charter members. Once the SWG is officially activated, this group is immediately “opted-into” the SWG and have voting rights from the first day the SWG is officially formed. Extend the table as necessary.
Panagiotis (Peter) A. Vretanos
GeoConnections - Natural Resources Canada
interactive instruments GmbH
Jeff de La Beaujardiere
Pitney Bowes Business Insight
The Carbon Project
University Corporation for Atmospheric Research (UCAR)
Steve H. L. Liang
University of Calgary
The convener of the first meeting will be John Herring of Oracle.
The first order of business at that meeting will be to elect a permanent chair who will preside over the meeting after his election.