Web Services

Web Services: Introduction

• Building blocks for constructing distributed Web-based applicaitons
• Independence:
  • platform
  • object model
  • language
• Based on open Internet standards: http, XML
• Web Services Architecture (W3C)
• REstful State Transfer (REST)

SOAP: Simple Object Access Protocol

"SOAP Version 1.2 provides the definition of the XML-based information which can be used for exchanging structured and typed information between peers in a decentralized, distributed environment." [W3C]

WSDL: Web Services Description Language

• Describe XML-based services
• A collection of metadata about an XML-based service
• Desribes functionality and how that functionality is made available
• Most prominent use of WSDL is to describe services by SOAP
• WSDL Version 2.0 (W3C)

UDDI: Universal Description, Discovery and Integration

• A specification for distributed Web-based information registries of Web services
• A publicly accessible registries of services
• Allow businesses to register information about the Web services they offer so that other busines can find them
• uddi.xml.org

RESTful (Representational State Transfer) API

last.fm: http://www.last.fm/api/intro

• http://ws.audioscrobbler.com/2.0/?method=artist.getSimilar&artist=Madonna&api_key=

Echonest: http://developer.echonest.com (disconitinued 2016/10)

• http://developer.echonest.com/api/v4/artist/similar?api_key=FILDTEOIK2HBORODV&name=Madonna [no longer works]

Spotify: https://developer.spotify.com/web-api