A walk through PHP and the implementation of SOAP, REST and JSON servers and clients using only native functions.

1. PHP and Web Services
CITOT - May 20th 2007
Bruno Pedro <bpedro@computer.org>

2. Summary
• What is PHP?
• Web Services
• SOAP
• REST
• JSON
• Conclusions
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3. What is PHP?
• PHP: Hypertext Preprocessor
• Open Source Web scripting language
• Created in 1994
• Syntax inherited from C, Java and Perl
• Powerful, yet easy to learn
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4. How is PHP used?
• Content Management
• Forums
• Blogging
• Wiki
• CRM
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5. Who uses PHP?
Source: Zend
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6. Why use PHP?
• Used by 20M+ Web Sites around the globe
• Community-maintained documentation
• Code runs on UNIX, OSX and Windows
• Backed commercially by Zend
• Easy syntax
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7. The PHP language
Easy syntax!
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8. Creating a function
function declaration
return value
function call
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9. Creating a class
class declaration
public method
method call
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10. Web Services
Source:The Server Side
(http://tinyurl.com/38umxt)
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11. What are Web Services?
• Interoperable interactions
• Calls are made over a network
• Lots of different standards
• Popular Web sites use them
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12. Requirements
• PHP 5.2.2
• SOAP
• simplexml
• DOM
• JSON
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13. SOAP
Source: Prentice Hall
(http://tinyurl.com/33dcch)
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14. SOAP
• Simple Object Access Protocol
• Usually an HTTP POST request
• Call is encapsulated in XML
• Response is an XML document
• PHP handles everything
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15. Server implementation
namespace
start a server
assign a class
handle incoming calls
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16. Client implementation
namespace
endpoint
display result
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17. Output
namespace
result
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18. SOAP
• Support for SOAP 1.1, 1.2 and WSDL 1.1
• Handles simple and complex types
• Very easy implementation
• Output is quite bulky
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19. REST
«interface»
/calculator/sum/
Resource
GET - perform a calculation
GET
PUT - not used
PUT
POST - not used
POST
DELETE - not used
DELETE
http://example.com/calculator/sum/?x=121&y=233
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20. REST
• Representational State Transfer
• Usually an HTTP GET request
• Call is made through GET parameters
• Response is an XML document
• Create response with DOM
• Interpret response with simplexml
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21. Server implementation
handle incoming call
create an
XML document
add elements
output result
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22. Client implementation
endpoint
arguments
load XML document
output result
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23. Output
result
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24. REST
• Interaction needs to be implemented
• XML schema must be know beforehand
• Complex types not handled natively
• Output is usually RSS
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25. JSON
JSON Logo
Source: json.org
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26. JSON
• JavaScript Object Notation
• REST approach
• Except response is not XML
• Used on the client side
• Create response with json_encode()
• Interpret response in JavaScript
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27. Server implementation
handle incoming call
generate result
output
JSON string
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28. Client implementation
endpoint
arguments
output result
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29. Output
result
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30. JSON
• REST approach
• Handles simple and complex types
• Calls can be made with AJAX
• Can also be used on the server side
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31. Conclusions
• PHP is a powerful web scripting language
• Too many Web Services standards
• PHP handles all the internals
• REST requires more coding than SOAP
• Use JSON for client side applications
• XML-RPC support is still experimental
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32. Questions?
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33. Resources
• My blog: http://unfoldingtheweb.com/
• PHP Manual: http://www.php.net/
• SOAP: http://www.w3.org/TR/soap/
• REST: http://tinyurl.com/akhc7
• JSON: http://www.json.org/
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