Broadening Web Service Access through REST and OData?

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1 Broadening Web Service Access through REST and OData? Presented By: Steve Pilon, OSIsoft Michael van der Veeken, Atos Origin Where PI geeks meet 9/23/2010

It has an interaction interface described in a machine WSDL processable format (WSDL).

2 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 2 What is a web service? a software system designed to support interoperable machine-to-machine interoperable interaction over machine-to-machine a network. It has an interaction interface described in a machine WSDL processable format (WSDL). Other systems interact with the Web SOAP service in a manner prescribed by its description using SOAP messages, HTTP typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.

6 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 6 In clear SOAP Exposes methods with inputs and outputs (operation-centric) Well-defined, discoverable calling sequences Thought of as "official, serious, for large enterprises" REST Exposes resources, collections, relationships (data-centric) Open format (URI with verbs and nouns) Thought of as "easy, simple, free-form"

7 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 7 SOAP Web Services (a.k.a. Big Web Services) WSDL: What can you do? (contract) Client SOAP Web Service SOAP: Do something. Return data. (operation)

8 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 8 REST Web Services (a.k.a. RESTful) Client HTTP: Do something. Return data. REST/HTTP Verbs: GET read PUT create POST update DELETE delete REST Web Service

9 Representational State Transfer Nouns (Unconstrained) e.g. sinusoid )?$filter=time gt *-1h and lt * Verbs (Constrained) e.g. GET Content Types (Constrained) e.g. XML Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 9

11 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 11 Web Feeds RSS Atom AtomPub Really Simple Syndication Pseudo-XML syndication format More organized, Atom publishing extended RSS protocol Fully-compliant Defines how to XML format play with the data * JSON is another type of web feed format

12 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 12 Open Data Protocol (OData) OData (protocol) HTTP/HTTPS (transport) AtomPub/JSON A RESTful Interface for Data (format) URI Conventions (interactions)

/AFElements('Pump 123') Member Access /AFElements('Pump 123')/EffectiveDate Link Traversal /AFElements('Pump

13 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 14 URL Conventions Addressing entities and sets Entity Set /AFElements Single Entity /AFElements('Pump 123') Member Access /AFElements('Pump 123')/EffectiveDate Link Traversal /AFElements('Pump 123')/Attributes Deep Access /AFElements('Pump 123')/Attributes('Flow Rate')/Value Presentation Options Sorting Filtering Paging /AFElements?$orderby=Name /AFElements?$filter=CreationDate gt ' ' /AFElements?$top=10&$skip=30

14 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 15 Why OData? No more silos of data Bus stops, facility buildings, schools Census data, construction projects, gas stations, hotels, metro stations

16 Another example Events, Products, Partners, etc. /events?$filter=type eq 'Regional Seminar' /events?$filter=location eq 'San Francisco' OData for OSIsoft vcampus Live! 2010 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 17

17 Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 18 In the Microsoft world WCF Services SOAP WSDL WS-* WS-Security Formerly 'ADO.NET Data WCF Data Services REST HTTP AtomPub OData Services' (codename 'Astoria') Expose IQueryable collections as part of an OData Service IUpdatable for updates/deletes/inserts

20 PI in WCF Data Services Remember WCF Data Services expose IQueryable collections as part of an OData Service PI AF SDK exposes IQueryable collections (e.g. AFElements, AFAttributes) Difficult to achieve with PI SDK LinqToPI does this for PI data Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 23

22 LinqToPI Empowers.NET developers to query the PI System using in-code, SQL-like queries Make PI "entities" IQueryable (and "OData ready") var values = from arc in context.archive.archivedata where arc.tag == tagname && arc.time.between(starttime, endtime) select arc; Where PI geeks meet 2010 OSIsoft, LLC. All Rights Reserved 25

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