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

Summary
• What is PHP?
• Web Services
• SOAP
• REST
• JSON
• Conclusions
PHP and Web Services 2

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
PHP and Web Services 3

How is PHP used?
• Content Management
• Forums
• Blogging
• Wiki
• CRM
PHP and Web Services 4

Who uses PHP?
Source: Zend
PHP and Web Services 5

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
PHP and Web Services 6

The PHP language
Easy syntax!
PHP and Web Services 7

Creating a function
function declaration
return value
function call
PHP and Web Services 8

Creating a class
class declaration
public method
method call
PHP and Web Services 9

Web Services
Source:The Server Side
(http://tinyurl.com/38umxt)
PHP and Web Services 10

What are Web Services?
• Interoperable interactions
• Calls are made over a network
• Lots of different standards
• Popular Web sites use them
PHP and Web Services 11

Requirements
• PHP 5.2.2
• SOAP
• simplexml
• DOM
• JSON
PHP and Web Services 12

SOAP
Source: Prentice Hall
(http://tinyurl.com/33dcch)
PHP and Web Services 13

SOAP
• Simple Object Access Protocol
• Usually an HTTP POST request
• Call is encapsulated in XML
• Response is an XML document
• PHP handles everything
PHP and Web Services 14

Server implementation
namespace
start a server
assign a class
handle incoming calls
PHP and Web Services 15

Client implementation
namespace
endpoint
display result
PHP and Web Services 16

Output
namespace
result
PHP and Web Services 17

SOAP
• Support for SOAP 1.1, 1.2 and WSDL 1.1
• Handles simple and complex types
• Very easy implementation
• Output is quite bulky
PHP and Web Services 18

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
PHP and Web Services 19

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
PHP and Web Services 20

Server implementation
handle incoming call
create an
XML document
add elements
output result
PHP and Web Services 21

Client implementation
endpoint
arguments
load XML document
output result
PHP and Web Services 22

Output
result
PHP and Web Services 23

REST
• Interaction needs to be implemented
• XML schema must be know beforehand
• Complex types not handled natively
• Output is usually RSS
PHP and Web Services 24

JSON
JSON Logo
Source: json.org
PHP and Web Services 25

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
PHP and Web Services 26

Server implementation
handle incoming call
generate result
output
JSON string
PHP and Web Services 27

Client implementation
endpoint
arguments
output result
PHP and Web Services 28

Output
result
PHP and Web Services 29

JSON
• REST approach
• Handles simple and complex types
• Calls can be made with AJAX
• Can also be used on the server side
PHP and Web Services 30

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
PHP and Web Services 31

Questions?
PHP and Web Services 32

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/
PHP and Web Services 33