ltr presentaion 2
DESCRIPTION
Web Services and Service-Oriented ArchitectureTRANSCRIPT
Web Services and the Service-Oriented Architecture
November 5, 2009
Jessica NgJing YangJill Baron
Ruben Balderas
Basic Concepts
• Service-Oriented Architecture SOA is an organizing principle for an
organization's technical infrastructure to support the needs of the organization's software users.
• Web services are the dominant approach for implementing SOA.
Web Services Are Not
Web interfacesWeb-based information resourcesWeb-based “services”Software as serviceApplication service providerWeb Service Librarian
Web Services
• DefinitionA Web service is a software system designed to support
interoperable machine-to-machine interaction over a network.
It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.
(World Wide Web Consortium)
Communication Path for Web Services
Web-Service Components and Protocols
eXtensible Markup Language (XML)
Web-Service Components and Protocols
eXtensible Markup Language (XML)
Simple Object Access Protocol (SOAP)
Web-Service Components and Protocols
eXtensible Markup Language (XML)
Simple Object Access Protocol (SOAP)
Web Services Description Language (WSDL)
Web-Service Components and Protocols
eXtensible Markup Language (XML)
Simple Object Access Protocol (SOAP)
Web Services Description Language (WSDL)
Universal Description, Discovery and Integration (UDDI)
Open Source Protocol Substitutes• Representational State Transfer (REST)
- Substitute for SOAP
-Response as an XML Stream
Easier and faster to implement
Better Performance and response time
Really Simple Syndication (RSS)
Second-Generation Specifications• WS-Security
Second-Generation Specifications• WS-Security
• WS-AtomicTransaction/WS-BusinessActivity
Second-Generation Specifications• WS-Security
• WS-AtomicTransaction/WS-BusinessActivity
• WS-Coordination
Second-Generation Specifications• WS-Security
• WS-AtomicTransaction/WS-BusinessActivity
• WS-Coordination
• WS-Reliable Messaging
Second-Generation Specifications• WS-Security
• WS-AtomicTransaction/WS-BusinessActivity
• WS-Coordination
• WS-Reliable Messaging
• WS-Attachments
Second-Generation Specifications• WS-Security
• WS-AtomicTransaction/WS-BusinessActivity
• WS-Coordination
• WS-Reliable Messaging
• WS-Attachments
• Business Process Execution Language for Web Services (BPEL4WS)
Web Services in the Library Environment
• The VIEWS Initiative Vendor Initiative for Enabling Web Services
(VIEWS). A consortium of vendors formed to facilitate the
development of interoperable Web services related to library applications.
Goal: Provide a forum in which library-automation vendors could establish a set of Web services that can be used in library applications.
Specific implementation of Web services.
Controversy
• Originally not a National Information Standards Organization (NISO) sponsored group.
• Not all vendors chose to participate• Much of the work intertwined with NISO’s
initiatives.• Replaced by NISO Web Services and Practices
Working Group in August 2005.
• Mission: Developing best practices for designing and
deploying web services Produce and maintain a “Web Services Best
Practices” document for general use in assessing new and ongoing Web-service applications
Provide and maintain “Web Services Interoperability Mechanisms
Non-Web-Service Library Standards and Protocols
• Z39.50– Search-and-retrieval protocol– Performs search operations and returns results in
MARC cimmunications format.– Based on Abstract Syntax Notation (ASN.1) and
Basic Encoding Rules (BER),– Maintained by the Library of Congress.
• ISO 10160/10161 and ISO ILL Provides set of standard protocols for the interoperable
exchange of ILL transactions. Open Systems Interconnect style of communication based
on ASN.1 and BER Maintained by the Library and Archives Canada
• UN/EDIFACT and ANSI x12 Electronic Data Interchange (EDI) standards intended for
the exchange of messages related to business transactions International standard employed across many industries Used between libraries and suppliers
• Electronic ordering• Making claims for items expected and received• Transfer of invoices
• MARC 21 Format– Most widely accepted adapted library standard– Formats store bibliographic records in a compact
format. – MARCXML – Provides XML Structure for MARC 21
data.• Metadata Object Description Standard (MODS)
– XML schema for MARC 21 bibliographic records
• Metadata Authority Description Schema (MADS)– XML schema for selected tags of the MARC 21 authority
format.
• Encoded Archival Description (EAD)– Standard for creating finding aids of archival collections in
XML.
• Dublin Core– Metadata format expressed in XML.• Provides simplified approach for describing information
objects.
– Widely used as a metadata format describing electronic resources or other application in which MARC format is not needed.
• OpenURL– Provides a mechanism for linking to resources
independently of their physical locations.
Library Protocols based on Web Services
• Z39.50 International: Next Generation (ZING)– Established to take the concepts and functionality
embodied in Z39.50 forward.– Development of a version of Z39.50 in the
framework of Web services – search-and-retrieval protocol.
– SRU: Search/Retrieve via URL– SRW: Search/Retrieve Web Service
• SRU and SRW supports three operations:– SearchRetrieve– Scan– Explain
• Implementation of SRU and SRW– OCLC Research
• Index Data• The Cheshire Project
Open Archives Initiative Protocol for Metadata Harvesting
• Supports federated-search model– Harvesting metadata from multiple information
repositories– Create centralized search services– Provides alternative to those based on
simultaneous queries.• Relies on data providers and service providers. • Web harvesting: Provides means to harvest
new and changed pages.
Standardized Usage Statistics Harvesting Initiative (SUSHI)
• Deals with issue of transferring statistics that assess an institution’s use of an electronic resource that the library subscribes to.
• Project COUNTER– Initiative to develop set of standard practices
regarding how publishes will produce use statistics related to library subscriptions.
When we think of architecture we think of
or
“Service-oriented” architecture might be more like
INTEROPERABILITY
or,
many moving parts
Why this matters
Services make life easier
We want to do things here:
Research
Architectural Repository, aka SOA
SOA allows the library or archive:
• Manage materials effectively• Build on resources• Greater collaboration with other organizations
and businesses• Provide services within campus or municipal
portal environments or other non-traditional channels
• Enhance research experience
SOA allows the user:
• Ease of access• Multimedia resources• More resources = a more global
understanding of a subject• Opportunity to consider relationships
between items• More fun