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<com:TContent ID="body" >
<h1>RPC Service</h1>
<p class="block-content">
RPC Service stands for "Remote Procedure Call" Service and is a common name used to identify a service that exposes an interface that can be called by remote programs in order to execute a procedure.
An RPC Service tipically exposes one or more APIs (Application programming interface), permitting remote clients to make requests to the available methods and receive a proper response.
The interface itself is not bound to a specific programming language, but uses a standard data exchange protocol (tipically xml or json).
PRADO provides <tt>TRpcService</tt> that makes developing a RPC server application an extremely easy task.
</p>
<p class="block-content">
To use <tt>TRpcService</tt>, configure it in the application specification like following:
</p>
<com:TTextHighlighter Language="xml" CssClass="source block-content">
<services>
<service id="rpc" class="System.Web.Services.TRpcService">
<rpcapi id="stockquote" class="path.to.StockQuote" />
<!--
<rpcapi...other api... />
-->
</service>
</services>
</com:TTextHighlighter>
<p class="block-content">
The example specifies a RPC service provider named <tt>stockquote</tt> which implements the <tt>getPrice</tt> RPC method in the provider class <tt>StockQuote</tt>,
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
class StockQuote
{
/**
* @param string $symbol the symbol of the stock
* @return float the stock price
* @soapmethod
*/
public function getPrice($symbol)
{
....return stock price for $symbol
}
/**
* Register the available methods
* @return the list of implemented methods
*/
public function registerMethods()
{
return array(
'getPrice' => array('method' => array($this, 'getPrice')),
);
}
}
</com:TTextHighlighter>
<p class="block-content">
PRADO already bundles two common protocols: <tt>TXmlRpcService</tt> and <tt>TJsonRpcService</tt>: requests made by clients using one of these protocol will be automatically resolved and will call the user-specified APIs.
</p>
<div class="note"><b class="tip">Note:</b>
<tt>TXmlRpcService</tt> is based on <a href="http://www.php.net/manual/it/book.xmlrpc.php">PHP XML-RPC extension</a> and thus requires the extension to be installed.
</div>
<p class="block-content">
With the above simple code, we already finish a simple RPC service that allows other applications to query the price of a specific stock. A client needs to know the exact url of the service, the name of the method and the list of parameters needed by the method.
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
// Assuming we're using the json-rpc php library from http://jsonrpcphp.org/
require_once 'jsonRPCClient.php';
$client=new jsonRPCClient('http://path/to/index.php?rpc=stockquote');
echo $client->getPrice('IBM');
</com:TTextHighlighter>
</com:TContent>
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