Implementing webservices with PHP

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Implementing webservices with PHP
Dr. Tarique Sani CTO, SANIsoft Nagpur, India
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Who this talk is for?

• PHP developers with moderate degree of PHP
  expertise
• PHP developers wanting to implement SOAP based
  webservice
• PHP developers who think webservices is rocket
  science
• It is not intended for ASP.NET developers

3
What will be covered

• What are web services
• Basics of SOAP
• Implementing a simple webservice using NuSOAP

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What is a webservice?

• Loosely coupled, reusable software components
  that semantically encapsulate discrete
  functionality and are distributed and
  programmatically accessible over standard
  Internet protocols

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What is a webservice??

• Remote Procedure Calling protocol that works
  over HTTP.

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Where to use Webservices?

• Retrieve information dynamically over web
• Stock Quotes
• Price comparisions
• Hotel bookings
• Web applications requiring integration with
  diverse programming languages

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Why use PHP

• Already a very popular for web development
• XML support
• CURL support
• OOP
• Potential SOAP extension

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SOAP

• Simple Object Access Protocol
• HTTP XML SOAP

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SOAP Message

• Simple Object Access Protocol
• HTTP XML SOAP

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SOAP Request

• POST /examples HTTP/1.1
• User-Agent Radio UserLand/7.0 (WinNT)
• Host localhost81
• Content-Type text/xml charsetutf-8
• Content-length 474
• SOAPAction "/examples"
• lt?xml version"1.0"?gt
• ltSOAP-ENVEnvelope SOAP-ENVencodingStyle"http//
  schemas.xmlsoap.org/soap/encoding/"
  xmlnsSOAP-ENC"http//schemas.xmlsoap.org/soap/en
  coding/" xmlnsSOAP-ENV"http//schemas.xmlsoap.or
  g/soap/envelope/" xmlnsxsd"http//www.w3.org/199
  9/XMLSchema" xmlnsxsi"http//www.w3.org/1999/XML
  Schema-instance"gt
• ltSOAP-ENVBodygt
• ltmgetStateName xmlnsm"http//www.soapware
  .org/"gt
• ltstatenum xsitype"xsdint"gt41lt/statenum
  gt
• lt/mgetStateNamegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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SOAP Response

• HTTP/1.1 200 OK
• Connection close
• Content-Length 499
• Content-Type text/xml charsetutf-8
• Date Wed, 28 Mar 2001 050504 GMT
• Server UserLand Frontier/7.0-WinNT
• lt?xml version"1.0"?gt
• ltSOAP-ENVEnvelope SOAP-ENVencodingStyle"http//
  schemas.xmlsoap.org/soap/encoding/"
  xmlnsSOAP-ENC"http//schemas.xmlsoap.org/soap/en
  coding/" xmlnsSOAP-ENV"http//schemas.xmlsoap.or
  g/soap/envelope/" xmlnsxsd"http//www.w3.org/199
  9/XMLSchema" xmlnsxsi"http//www.w3.org/1999/XML
  Schema-instance"gt
• ltSOAP-ENVBodygt
• ltmgetStateNameResponse xmlnsm"http//www.
  soapware.org/"gt
• ltResult xsitype"xsdstring"gtSouth
  Dakotalt/Resultgt
• lt/mgetStateNameResponsegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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SOAP Fault

• HTTP/1.1 500 Server Error
• Connection close
• Content-Length 511
• Content-Type text/xml charsetutf-8
• Date Wed, 28 Mar 2001 050632 GMT
• Server UserLand Frontier/7.0-WinNT
• lt?xml version"1.0"?gt
• ltSOAP-ENVEnvelope SOAP-ENVencodingStyle"http//
  schemas.xmlsoap.org/soap/encoding/"
  xmlnsSOAP-ENV"http//schemas.xmlsoap.org/soap/en
  velope/" xmlnsxsd"http//www.w3.org/1999/XMLSche
  ma" xmlnsxsi"http//www.w3.org/1999/XMLSchema-in
  stance"gt
• ltSOAP-ENVBodygt
• ltSOAP-ENVFaultgt
• ltfaultcodegtSOAP-ENVClientlt/faultcodegt
• ltfaultstringgtCan't call getStateName
  because there are too many parameters.lt/faultstrin
  ggt
• lt/SOAP-ENVFaultgt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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WAKE UP!!!!The next slide has pics of naked
ladies I took in Thailand
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Sorry!! but...

• XML output is not always simplest to put in PHP
  code
• The XML output is repetitive
• Most of us are lazy
• Less work is better
• In-Short what is needed is a class which
  abstracts the SOAP messages for us

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NuSOAP Toolkit

• Several PHP toolkits available for SOAP
• NuSOAP usage is simple and efficient
• Object Oriented ...
• URL - http//dietrich.ganx4.com/nusoap/
• Author - Dietrich Ayala
• Has support for WSDL generation as well

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A PHP Function

• // Return the STD code for the City.
• function getSTD (city)
• global db
• query"SELECT Code FROM cities WHERE
  cityNamecity"
• db-gtquery(query)
• return db-gtf("Code")

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SOAP Server

• require_once('nusoap.php')
• server new soap_server
• server-gtregister('getSTD')
• server-gtservice (_SERVER'HTTP_RAW_POST_DATA')
  
• exit()

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SOAP Client

• require_once('nusoap.php')
• param array('city'gt_GET'city')
• client new soapclient ('http//sanisoft.com/
  getSTD.php')
• response client-gtcall('getSTD', param)
• response will now have the STD code for the city
  passed as parameter... ...

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What is missing?

• What if you don't pass a City name?
• What if you don't get a result?
• What if....
• SOAP Fault generation

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PHP Function revisted

• / Return the STD code for the City.
• function getSTD (city)
• global db
• if (city '')
• / Return a SOAP fault indicating a blank
  city name /
• return new soap_fault(
• 'Client', '',
• 'Must supply a city name',''
• )
• query"SELECT Code FROM cities WHERE
  cityNamecity"
• db-gtquery(query)
• return db-gtf("Code")

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SOAP Client revisted

• require_once('nusoap.php')
• param array('city'gt_GET'city')
• client new soapclient ('http//sanisoft.com/
  getSTD.php')
• response client-gtcall('getSTD', param)
• if(client-gtfault)echo "FAULT ltpgtCode
  client-gtfaultcode ltbr /gt" echo "String
  client-gtfaultstring lt/pgt"
• else
• echo response

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Some considerations

• SOAP vs XML-RPC
• SOAP transactions/session
• SOAP authentication and security

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SOAP Resources

• Other PHP SOAP implementations
• PHP-SOAP Extension
• Activestate SWSAPI for PHP
• PEAR
• Krysalis
• Manuel Lemos SOAP class

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SOAP Resources

• SOAP and web services reference sites
• http//www.xml.com/pub/a/2001/04/04/webservices/
  XML.com A Web Services Primer
• http//www.w3c.org/tr/soap - SOAP 1.1
  specification
• http//www-106.ibm.com/developerworks/webservices
  / - IBM developerWorks Web Services Zone