Web Services


Web Services: Introduction

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

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]

  • SOAP is a communication protocol
  • SOAP is for communication between applications
  • SOAP is a format for sending messages
  • SOAP is designed to communicate via Internet
  • SOAP is platform independent
  • SOAP is language independent
  • SOAP is based on XML
  • SOAP is simple and extensible
  • SOAP allows you to get around firewalls
  • SOAP will be developed as a W3C standard

Python (2.0) examples (with SOAP.py):
import SOAP
server = SOAP.SOAPProxy("http://services.xmethods.net/soap")
print server._ns("urn:xmethods-delayed-quotes").getQuote(symbol = "AMZN")
server = SOAP.SOAPProxy("http://services.xmethods.net/soap/servlet/rpcrouter")
print server._ns("urn:xmethods-EbayWatcher").getCurrentPrice(auction_id = "1304109465" )
server = SOAP.SOAPProxy("http://services.xmethods.net/soap")
print server._ns("urn:xmethods-CurrencyExchange").getRate(country1="usa", country2="canada")
print server._ns("urn:xmethods-CurrencyExchange").getRate(country1="usa", country2="japan")
server = SOAP.SOAPProxy("http://services.xmethods.net/soap/servlet/rpcrouter")
print server._ns("urn:xmethods-Temperature").getTemp(zipcode="21202")
server = SOAP.SOAPProxy("http://services.xmethods.net:80/perl/soaplite.cgi")
print server._ns("urn:xmethodsBabelFish").BabelFish(translationmode="en_fr", sourcedata="soap is good for translation")

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 cuurent us if WSDL is to describe services by SOAP
  • WSDL Version 1.2 (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.org

Created: 2003.01.07 Modified: Ichiro Fujinaga
McGill Crest