service component architecture for php konferenz 2006 begin end

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Service ComponentArchitecture for PHPReusable components and effort-free web servicesMatthew Peters, IBM Hursley Park

[email protected]


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Background IBM Hursley Park, Winchester, UK

http://www5.ibm.com/uk/locations/hursley_explore.html

2-3K people

Services, outsourcing

Product development: CICS, MQSeries, Java Incubator group:

Porting, experimenting with technologies from

Java world, implementing and simplifying in PHP


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How to find us Google for OSOA

(Open Service Oriented Architecture)


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Agenda Two slide-overview Some simple SCA components (hello worldstyle)

Components calling each other locally Make them all run as web services (Slides and Zend Studio)

More SCA: Interoperability with other web services Exceptions Data Structures

Work in progress: DOJO, JSON-RPC and SCA Summary, Futures and Links


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SWG AB IncubatorsService Component Architecture

for PHP SCA for PHP allows a PHP programmer to write reusable

components (classes) in PHP, which can be calledeither locally, or remotely via Web Services, with anidentical interface.

Components use PHP annotations both to declare theirdependencies on other components, and to define theinterface which they expose as a service. Business logicis kept separate from interface and dependencies.

Deploying a PHP component as a web service can be as

simple as copying it into a web servers document root.


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Making your component reusable

Do not entangle the business logic with the wiring

1. Be flexible about how you are called

Expose as many bindings as needed make sure your business logic does notneed to know how it was called

2. Be flexible about your dependencies Declare the dependencies but make sure your business logic does not need to

know how to resolve these Ideally get something else to wire up the components (Inversion of Control;

Dependency Injection patterns)

JSON-RPC binding

A component,containing

business logic

A local component,Same call stack

A web service

2. Be flexible aboutyour dependencies1. Be flexible about

how you are called

Local binding

Web service binding


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Four scenarios1. One component called locally

2. One component calling two others3. Make the single component expose aWeb service binding

4. Make them all use web services

Same interface, minimal effort


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Scenario 1. Simplest A client script calling one local

component What does the simplest SCA componentlook like?

GreetingComponentclient


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Our first simple SCA component A PHP class

@service annotation include for SCA.php

GreetingComponent


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Calling an SCA component from a

client script Client script

Includes SCA.php But is not itself a

component Uses SCA::getService()

getService takes apath

Absolute or relative

Relative paths areresolved against thelocation of the script

getService returns aproxy object:

Enforces pass-by-

value

GreetingComponent

client

"hello PHP"


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Scenario 2. Multiple A local component calling other local

components How are the dependencies wired up?

ReversingComponent

ReversedGreetingComponent

GreetingComponent

client

"PHP olleh"


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Add a second component Like GreetingComponent:

@service

Include for SCA.php

ReversingComponent


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Dependencies Dependencies are declared annotated with @reference

The instance variable

following will be assigned aproxy Hence needs to be public Initialised before any

business logic

@binding.php

indicates how to find thecomponent and that it is local same rules as getService



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What have we got so far? Sample call stack:

ReversingComponent


GreetingComponent

client

reverse( $in ) C:\Program Files\Apache Group\Apache2\htdocs\Konferenz\ReversingComponent.php line 13__call( $method_name, $arguments ) c:\php\PEAR\SCA\SCA_LocalProxy.php line 109greet( $name ) C:\Program Files\Apache Group\Apache2\htdocs\Konferenz\ReversedGreetingComponent.php line 24

__call( $method_name, $arguments ) c:\php\PEAR\SCA\SCA_LocalProxy.php line 109main( ) C:\Program Files\Apache Group\Apache2\htdocs\Konferenz\client2.php line 7

SCA_Localproxy

breakpoint

"PHP olleh"


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Scenario 3. Web Service A client script calling one remote

component How to expose a web service binding

GreetingComponentclient

= SOAP Web service request/response


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Exposing a web service binding @binding

Expose a web servicebinding

Public methods are in theinterface

@param/@return Need more information

about each method

GreetingComponent



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Generating the WSDL Generated in response to HTTP GET with ?wsdl

http://www.example.com/GreetingComponent.php?wsdl

Do it in a browser file_get_contents('http://www.example.com/GreetingCom

ponent.php?wsdl');

Currently cached in the same directory as the

component http://www.example.com/GreetingComponent.wsdl

(in future need to do something different to avoidneed for write access into htdocs)


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Generated WSDL

Document/literalwrapped style Message

formats areexplicit withinthe schema

...


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Generated WSDL message

post binding

...

...


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Generated WSDL Location attribute is decided once the file is in place

Currently using the URL to determine the location with respect to thedocument root

(in future need to do something different to cope with proxies,rewriting, firewalls)

Ends with a distinctive comment Special handling of exceptions when one component talks to another

...


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Calling a remote SCA component from

a script SCA::getService() takes the

location of the WSDL Once again, $service is a

proxy: SCA_SoapProxy Proxy contains within it an

instance of the ext/SOAPclient

Location can be a URL In which case the soap

extension will probablycache it

Location can be a path Relative paths resolved

against location of script

Greeting

Componentclient

= SCA_SoapProxy


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Sample Soap request Document/literal wrapped, so

element enclosing element

PHP


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Scenario 4. Multiple web service Everything separated

ReversingComponent


GreetingComponent

client



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A second remote component Annotations

@binding @param @return

And generate WSDL asbefore

ReversingComponent


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Remote dependencies

@binding.ws

for remotecomponent

locates wsdl



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What have we got now? What have we achieved? Client local local Client remote remote

What had to change? Arguments to getService(), or @binding.php to @binding.ws Annotatations to describe the interface in more detail Generating WSDL on demand; otherwise deployment is just copying the component

But the business logic remains unchanged

ReversingComponent


GreetingComponent

client

SOAP Web service request/response


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Interlude But, you have to change the files

themselves True, but changing an annotation in an interpretedfile is that different from a line in a config file?

Essential point is that wiring and business

logic are separated Same file, but in different worlds Wiring is declarative, in annotations Business logic is imperative, in code


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Futures Annotation overriding

Changing service targets, bindings,properties from outside

PHP classes rather than xsds for datastructures

Simple database services

Other bindings

Atompub, REST (XML and JSON), RSS


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DOJO, JSON-RPC and SCA DOJO is a user interface widget set written in JavaScript Can talk back to the server asynchronously - AJAX style Can use JSON-RPC to do so

JSON = JavaScript Object Notation Like a simplified XML Name/value pairs { for structure [ array

A JSON-RPC interface can be defined in SMD = Service Method Description

Like a simplified WSDL Also written in JSON

SCA components can expose a JSON-RPC binding too


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A component exposing a JSON

binding @binding.jsonrpc

Generates .smd

?smd

smd = service methoddescription


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HelloService.php?smd Defines a service that has:

One method sayHello(), with

One parameter, name{"SMDVersion":".1","serviceType":"JSON-RPC","serviceURL":"http://localhost/Samples/JsonRpc/hello/HelloService.php",

"methods": [ {"name":"sayHello","parameters": [ {

"name":"name","type":"string

} ],"return": {"type":"string"}

} ]}


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A DOJO function to call sayHello

Obtain .smd

Issue the call

function sayHello(){

var SCA = new dojo.rpc.JsonService({smdUrl: "HelloService.php?smd"});var inputfield = document.getElementById("hellotext").value;SCA.sayHello(inputfield).addCallback(handleResponse);

}


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JSON-RPC - POST POST Style - Request

POST Style - Response

POST /json-rpc/HelloService.php HTTP/1.1

Host: localhost:8081

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.7) Gecko/20060909 Firefox/1.5.0.7

Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

Content-Type: application/json-rpc

Content-Length: 48

Pragma: no-cache

Cache-Control: no-cache

{"params":["Hello!"],"method":"sayHello","id":1}

HTTP/1.1 200 OK

Date: Tue, 03 Oct 2006 18:14:35 GMT

Server: Apache/2.0.55 (Win32) PHP/5.2.0RC5-dev

X-Powered-By: PHP/5.2.0RC5-dev

Content-Length: 27

Keep-Alive: timeout=15, max=89

Connection: Keep-Alive

Content-Type: application/json-rpc

{return":"Hello "}


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Links

SCA for PHP homepage http://osoa.org/display/PHP/SOA+PHP+Homepage

Discussion Group http://groups.google.com/group/phpsoa/

Blog http://www.ibm.com/developerworks/blogs/page/phpblog

SDO for PHP

http://www.php.net/sdo


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Acknowledgements

Other members of the SCA for PHP team

Graham Charters, Megan Beynon, ChrisMiller, Caroline Maynard, Simon Laws

Special thanks to Dmitry Stogov for help

with the SOAP extension, serialising andde-serialising SDOs


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