RPC Service
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 TRpcService that makes developing a RPC server application an extremely easy task.
To use TRpcService, configure it in the application specification like following:
<services>
<service id="rpc" class="System.Web.Services.TRpcService">
<rpcapi id="stockquote" class="path.to.StockQuote" />
<!--
<rpcapi...other api... />
-->
</service>
</services>
The example specifies a RPC service provider named stockquote which implements the getPrice RPC method in the provider class StockQuote,
class StockQuote extends TRpcApiProvider
{
/**
* @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')),
);
}
}
PRADO already bundles two common protocols: TXmlRpcService and TJsonRpcService: requests made by clients using one of these protocol will be automatically resolved and will call the user-specified APIs.
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.
// 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');