RESTful OGC Services

RESTful OGC Services User-Centric Resource Oriented Architecture (ROA) Approach Pat Cappelaere, pat@vightel.com Linda Derezinski, linda@i-sol.biz John Mettraux, john@openwfe.org Keith Swenson, KSwenson@us.fujitsu.com Andrew Turner, Mapufacture Version 4 1 DRAFT Aug 13, 2007

OGC Services SOAPful REST (Classic) RESTful GetCapabilities GetFeasibilities GetObservation DescribeTasking Submit... Mandatory RPC/Hybrid Option

GEO - GEOSS [G]EO-Web 2.0 Movie http://blog.geobliki.com

GEOSS Use-Case South Africa Transmission Power Grid (Red) [G]EO-Web 2.0

Fire Season MODIS Fires (every 4 hours) Population Overlay Power Grid [G]EO-Web 2.0

Notify Me: Subscription PowerLineThreat within 10km (6nm) in my area of interest (BBOX) [G]EO-Web 2.0 use Twitter, IM and SMS

User Receives Alert Alert PowerLineThreat within 10km (6nm) in BBOX [G]EO-Web 2.0 use email, Twitter, IM and SMS User clicks on url

Feed Publication / Aggregation [G]EO-Web 2.0

KML Feed Visualization in GE [G]EO-Web 2.0 Threat: Fire at 3nm lat=xxx long=xxx Do You Want to Image?

Custom Data Product To The DeskTop [G]EO-Web 2.0

Problem Statement [G]EO-Web 2.0 • Many National & International Organizations • Scarce Resources • Money • Time • Engineering Resources • We Need All Of the OGC Services

Market Positioning RESTful SOAPful Web Services Service Oriented Architecture Market NO IT Infrastructure Big IT Infrastructure Mass Market Corporate 100 America Users Neo-Geographers Corporate Developers/Engineers Capability 80% 100% Cost 10% 100% Time 10% 100% Risk Low HIgh

Technical Differences RESTful SOAPful Everything is a URL Expose Resources Expose Functions and Attributes and Inputs/Outputs WADL Discovery APP service Document WSDL Spec Size Very small if existent Very Large Schemas non-existent extensive Language Html / Javascript / Ruby Java, C++. .NET Framework Ruby on-Rails EJB Security OpenID/PKI, OpenAuth... WS-Security (Geo-DRM)

SOAP - WSDL ... xsd wsdl common 0.3.20 9 context 1 2 csw 2.0.2 6 6 ebxml-regrep 3 1 ﬁlter 1.2 4 gml 3.2 94 hma 0.95 5 ols 1.1 11 ows 1 9 phr 0.81 2 sld 1 1 swecommon 1.0.3 2 wcs 1.0.2 7 wfs 1.2 2 5 wms 1.3 3 wrs 1.0. 4 wsdl 4 xlink 1.0. 1 xml 2 Total 165 15

Unique Opportunity For System-Level Architectural Change

RESTful Services For ROA Everything is a url! • http://www.oreilly.com/catalog/9780596529260/index.html “to codify the folklore, deﬁne what’s been left undeﬁned, and try to move past the theological arguments.” HTTP with Five Operations: HEAD, GET, PUT, POST and DELETE 17

Other Technologies For Successful ROA • Publishing Formats: GeoRSS/Atom, KML • Atom Publishing Protocol (APP) • GData • OpenSearch • Security

Resource URI Patterns and Nested Resources • Resource Collections Are Plural • GET /recipes Retrieve all available recipes • GET /recipes/{id} Retrieve specific recipe by id • GET /recipes/{name} Retrieve specific recipe by name • Nested Collections (recipes have many ingredients) • GET /recipes/{id}/ingredients/ Retrieve all available ingredients for that particular recipe • GET /recipes/{id}/ingredients/{id} Retrieve specific ingredient for that particular recipe • same as: GET /ingredients/{id | name} Retrieve specific ingredient by id or name Note: Last 2 GET’s return the same data. BUT first one keeps track of context. Try to backtrack the URL to see what you would get 19

APP: Atom Publishing Protocol Format draft-ietf-atompub-protocol-17.txt • The Atom Publishing Protocol is an application-level protocol for publishing and editing Web Resources using HTTP [RFC2616] and XML 1.0 [REC-xml]. The protocol supports the creation of Web Resources and provides facilities for: * Collections: Sets of Resources, which can be retrieved in whole or in part. * Services: Discovery and description of Collections. * Editing: Creating, editing, and deleting Resources. Geo/Atom In - Geo/Atom Out http://bitworking.org/projects/atom/draft-ietf-atompub-protocol-17.html

Google GData • The Google data APIs (quot;GDataquot; for short) provide a simple standard protocol for reading and writing data on the web. • GData uses either of two standard XML-based syndication formats: Atom or RSS. It also has a feed-publishing system that consists of the Atom publishing protocol plus some extensions (using Atom's standard extension model) for handling queries (including geoqueries) • Items of type Products containing the terms digital and camera in the area of San Francisco: digital camera [item type: products] [location: @quot;San Francisco, CAquot; + 50mi] snippets/-/products?bq=digital+camera+%5blocation:@%22San+Francisco,CA%22%2b50mi% 5d

OpenSearch http://www.opensearch.org • OpenSearch 1.1 • OpenSearch description document • Discoverable by Browser • Geo Extension Draft

Security • OpenID 2.0 + Auth or PKI • OpenAuth (AOL) • That’s another topic of discussion!

Goal Consistent User Experience Across All OGC Services

What OGC Services Are We Looking At? • Workﬂow Chaining Service (WfCS) • Sensor Planning Service (SPS) • Web Processing Service (WPS) • Web Coordinate Transfer Service (WCTS) • Web Feature Service (WFS) • Web Notiﬁcation Service (WNS) or OGC Publish/Subscribe (OPS-B) • Sensor Observation Service (SOS) • WCS (Steven Keens, PCI) 25

WfCS • It Is The Most Complex Service, Let’s Do It First • It Requires Asynchronous Services • Patterns Can Be Used For SPS, WPS And WCTS • Similar Patterns Can Be Inferred For WFS & SOS • It Can Use WNS Or OPS-B 26

WfMC Reference Model http://www.wfmc.org/ Workﬂow Chaining Service (WfCS) XPDL 2.0: Serialization Mechanism for the Business Process Modeling Notation (BPMN 1.0) 27

Workflow Interoperability Real-time Offline Workflow Model Workflow GUI Internal Persistence Engines Layer Representation Layer BPEL A XPDL P OpenWFE BPMN 1.0 2.0 I SensorML WfCS Level 0 Level 1 Level 2 28

WfCS Resources • Users Are Resources, OpenID is Their URI. • Note: You Always Know Your User and Have Access to Her Profile Information • Users Create Workflows. • Each Workflow Can Have one or more Definitions (or version). • A Workflow Definition Orchestrates Activities Handled By Participants • A Specific Workflow Is Instantiated (or Launched). • A Particular Instance Has Traces (history) Related To Its Various Activities (start/ end). Think of a Workflow as a blueprint that goes through the versioning process as time goes by. A Workflow is a mere entry in a registry to maintain its name consistent over time. The definitions are the modified versions of the flow as designed by the engineer and uploaded to the server. These different versions can be enabled, disabled and eventually deleted. Another to think of it is that a workflow is akin to a catalog entry with one or more definitions attached to it as different versions 29

WfCS Resources Are: • Users • Workﬂows • Deﬁnitions • Instances • Activities • Traces • Participants

Discovery • WADL • APP Service Document • http://geobpms.geobliki.com/wfcs/app

Web Application Description Document: WADL https://wadl.dev.java.net/ http://weblogs.java.net/blog/mhadley/archive/2005/05/introducing_wad.html GET /wfcs.wadl Returns the WADL document for workﬂow resource REST Equivalent of OGC GetCapabilities or WSDL 32

Resource Metadata • HEAD /wfcs/workflows • GET /wfcs/workflows.metadata • GET /wfcs/instances.metadata • GET /wfcs/definitions.metadata See Google GData 33

Retrieving Workflows • GET /wfcs/workflows Retrieve all available workflows • GET /wfcs/workflows.atom Retrieve all available workflows in atom output • GET /wfcs/workflows/11 Retrieve specific workflow by id • GET /wfcs/workflows/get_sa_threats Retrieve specific workflow by name 34

Threat Generation Flowchart Acquire MODIS Generate Polyons EO-1 SPS Generate Threats ASTER SPS Get Feasibilities SPOT-5 SPS Get Cloud Coverage Publish WFS-B Threats

BPMN Workﬂow

Workflow Definitions • Uses XPDL 2.0 [generated from an external GUI] • GET /wfcs/workflows/get_sa_threats/definitions • GET /wfcs/workflows/get_sa_threats/definitions/v1_0 • To create/upload a new definition to be versioned: • POST /wfcs/workflows/get_sa_threats/definitions With XML Payload 37

Starting Workflow Instance POST /wfcs/workflows/get_sa_threats/instances Launch specific workflow by name, and use latest enabled version <entry xmlns:g='...' xmlns='http://www.w3.org/2005/Atom'> <title>Get SA Fire Threats</title> <category term='sa,fire,threats' scheme='http://geopbms/1.0'/> <content>Get South African Fire Threats workflow</content> <g:item_type>instances</g:item_type> <g:command>start</g:command> <g:context_data> <scenario>2</scenario> <all_threats>data/sa_all_threats.kml</all_threats> <final_threats>data/sa_final_threats.kml</final_threats> <feed_file>data/sa_threat_feed_file.xml</feed_file> <send_to_draper>0</send_to_draper> </g:context_data> </entry> Instance Location is returned 38

Dealing With Workflow Instances • GET /wfcs/instances.atom • Returns Atom Feed • Returns Instance Attributes, Status, ContextData and ResultData <entry> <title>Get SA Fire Threats</title> <link href=quot;http://geobliki.com/wfcs/instances/294quot; rel=quot;editquot;/> <link href=quot;http://geobliki.com/wfcs/definitions/11quot; rel=quot;alternatequot;/> <id>http://geobliki.com/wfcs/instances/294</id> <created>2007-09-12T14:15:55Z</created> <updated>2007-09-12T14:15:55Z</updated> <author> <name>cappelaere</name> </author> <content>Get South African Fire Threats workflow</content> <g:item_type>instances</g:item_type> <g:command>start now</g:command> <g:status>scheduled</g:status> <g:context_data> <feed_file>data/sa_threat_feed_file.xml</feed_file> <send_to_draper>0</send_to_draper> <all_threats>data/sa_all_threats.kml</all_threats> <final_threats>data/sa_final_threats.kml</final_threats> <scenario>2</scenario> </g:context_data> <g:result_data> </g:result_data> <g:traces> </g:traces> </entry> 39

Modifying Workﬂow Instances • PUT /wfcs/instances/294 <entry xmlns:g='http://geopbms/1.0' xmlns='http://www.w3.org/2005/Atom'> <g:command>terminate</g:command> </entry • PUT /wfcs/instances/294 <entry xmlns:g='http://geopbms/1.0' xmlns='http://www.w3.org/2005/Atom'> <g:command>suspend</g:command> </entry • PUT /wfcs/instances/294 <entry xmlns:g='http://geopbms/1.0' xmlns='http://www.w3.org/2005/Atom'> <g:command>resume</g:command> </entry 40

Sensor Planning Service (SPS) -- Old Way • User can submit a task request and get an ID back • Submit • User can get status information about that task and change some task attributes • GetStatus, UpdateRequest • User can cancel request • CancelRequest • Service allows users to get access to ﬁles generated as a result of the task • DescribeAccess • Service allows users to check feasibilities • GetFeasibility 41

RESTful SPS • POST /wfcs/workflows/eo1-tasking/instances Creates new task, input parameters are defined in definition file • <entry>...</entry> • GET /wfcs/instances/24.atom Retrieves Task Instance Information (status and result data if available) • PUT /wfcs/instances/24.atom Updates Task Instance Information • <entry>..</entry> • DELETE /wfcs/instances/24.atom Cancels Task Instance • POST /wfcs/workflows/eo1-feasibility/instances Submits a GetFeasility Request • <entry>...</entry> Rerieves the GetFeasility Response • GET /wfcs/workflows/instances/25.atom in result_data 42

RESTful SPS - Page 2 • DescribeTasking • GET /wfcs/workﬂows/eo1-tasking • DescribeFeasibility Retrieves XPDL for EO-1 Tasking • GET /wfcs/workﬂows/eo1-feasibility Retrieves XPDL for EO-1 GetFeasibility 43

WPS & WCTS • They are processes which map directly to named workﬂows 44

WFS Page-1 • RESOURCES ARE THE FEATURES • GET /wfs/app Retrieves WFS APP Service Document • GET /wfs/{feature}.atom Generates an atom feed with all features of that type • GET /wfs/{feature}.metadata Generates Metadata document for that feature type 45

WFS with Transactions (WFS-T) Page 2 • POST /wfs/{feature} XML Payload: <entry>...</entry> • PUT /wfs/{feature}/{id} XML Payload <entry>...</entry> • DELETE /wfs/{feature}/{id} 46

WFS Filter Page-3 • Uses OpenSearch • Keywords • BBOX • Timespan queries • Create Your Custom OpenSearch Template • Browser will discover it automatically 47

WNS / OPS-B • Web Notiﬁcation Service / OGC Publish/Subscribe • Receives Atom Feeds • Matches entries with user-based subscriptions • Delivers custom feed using user-selected notiﬁcation preferences

Resource Notification Service • Every Resource Has An URI That Follows A Simple Pattern • When A Resource Operation Takes Place, An Event Is Generated For That URI • You Can Subscribe For Those Events • For That Specific Resource • For That Specific Collection 49

Subscriptions POST /wns/subscriptions To create a new subscription Examples POST /wns/subscriptions Subscribe to all workflow events (CRUD) <path>uri</path> Subscribe to specific workflow event by name uri = /wfcs/workflows/eo1-tasking Subscribe to all workflow definitions events (CRUD) uri = /wfcs/definitions/* uri = /wfcs/instances/* Subscribe to all workflow Instances events (CRUD) uri = /wfcs/instances/*/traces/* Subscribe to specific workflow instance trace events use DELETE to unsubscribe 50

Notifications POST /wns/notifications <email_address>pat@cappelaere.com</email_address> <im_address>cappelaere@gmail.com</im_address> <twitter_address>cappelaere</twitter_address> PUT /wns/notifications <email>disabled | enabled</email> <im>disabled | enabled</im> <twitter>disabled | enabled</twitter> <notifications>enabled | disabled </notifications> 51

Sensor Observation Service (SOS) • GET /sos/app • Sensor Collection • GET /sos/sensors/ Retrieve all available sensors (html) • GET /sos/sensors.atom Retrieve all sensors in atom format • GET /sos/sensors/{id|name} Retrieve speciﬁc sensor by id or name • GET /sos/sensors/{id|name}.atom Retrieve speciﬁc sensor by id or name in atom format 52

SOS (cont) • Getting Observations • GET /sos/observations[.atom] Retrieve all observations html/atom • GET /sos/observations.metadata Retrieve all observations metadata • GET/sos/observations/{id|name}[.atom] Retrieve a specific observation by id or name html/atom • GET /sos/observations/{id|name}.metadata Retrieve specific sensor by id or name in atom format • GET /sos/observations/{id|name}/offering/{id|name}.{format} Retrieve specific offering by id/name in a specific format (.tiff/.tar.gz/.jpg, etc) • GET /sos/observations/{id|name}/offering/{id|name}.metadata Retrieve specific offering by id/name meta data

SOS Search, Exactly like WFS’s Search • Uses OpenSearch • Keywords • BBOX • Timespan queries • Create Your Custom OpenSearch Template • Browser will discover it automatically

SOS-T • PUT /sos/observations/{name} XML Payload <xml>...</xml> • PUT /sos/observations/{name}/offering/{name} XML Payload <xml>...</xml> • DELETE /sos/observations/{id|name} • DELETE /sos/observations/{id|name}/offerings/{id|name}

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RESTful OGC Services

by cappelaere on Sep 21, 2007

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RESTful OGC Services — Presentation Transcript