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classPiiNetworkInputOperation

#include <PiiNetworkInputOperation.h>

An operation that receives objects through a network connection with the HTTP protol.

Inherits PiiNetworkOperation, PiiHttpProtocol::UriHandler

Description

PiiNetworkInputOperation registers itself as a handler into a PiiHttpServer's protocol. It accepts many different input formats and is able to automatically decode data in various formats.

Inputs

statusan optional input for HTTP status code (int). The default status code is 200. 
 // This code implements a complete HTTP/1.1 server that calculates
 // the sum of two numerical query arguments. The server supports
 // both GET and POST queries.
 // Start the server and browse to http://localhost:8080/sum?arg1=2&arg2=4.
 // The server will respond with "6".

 #include <QCoreApplication>
 #include <PiiHttpServer.h>
 #include <PiiEngine.h>

 int main(int argc, char* argv[])
 {
   QCoreApplication app(argc, argv);

   PiiEngine engine;
   try
     {
       PiiEngine::loadPlugin("piinetwork");
       PiiEngine::loadPlugin("piibase");

       // Create a configuration
       PiiOperation* net = engine.createOperation("PiiNetworkInputOperation");
       net->setProperty("outputNames", QStringList() << "arg1" << "arg2");
       net->setProperty("httpServer", "myServer");
       net->setObjectName("sum");
       PiiOperation* sum = engine.createOperation("PiiArithmeticOperation");
       net->connectOutput("arg1", sum, "input0");
       net->connectOutput("arg2", sum, "input1");
       sum->connectOutput("output", net, "body");

       // Start the HTTP server
       PiiHttpServer* pServer = PiiHttpServer::addServer("myServer", "tcp://0.0.0.0:8080");
       if (!pServer->start())
         return 1;

       // Start the execution engine
       engine.execute();
     }
   catch (PiiException& ex)
     {
       qDebug(ex.message().toUtf8().constData());
       return 1;
     }
   // Run eternally
   return app.exec();
 }

Input decoding

The operation does its best in guessing the type of the input data, if the type is not explicitly specified. The operation supports HTML form submissions (GET and POST with application/x-www-form-urlencoded and multipart/form-data encodings). If the string representing the value of a submitted form field can be converted to an int, it will be converted. double will be tried next, and if that is not successful, the value will be used as a string.

Properties

QString
httpServer

The name of the HTTP server you want to handle incoming requests to this operation.

QString
interruptedResponse

The message sent to the HTTP client if the operation is interrupted while processing a request.

QString
timeoutResponse

The message sent to the HTTP client if the operation fails to receive a response object within time limits.

QString
uri

The URI of the operation within the server.

Constructors and destructor
PiiNetworkInputOperation
( )
~PiiNetworkInputOperation
( )

Public member functions

virtual void
check
(
  • bool reset
)

Checks the operation for execution.

virtual void
handleRequest
( )

Handles a request.

QString
httpServer
( )
QString
interruptedResponse
( )
virtual void
pause
( )

Prepares the operation for pausing.

void
setHttpServer
( )
void
setInterruptedResponse
(
  • const QString & interruptedResponse
)
void
setTimeoutResponse
( )
void
setUri
( )
virtual void
stop
( )

Prepares the operation for stopping.

QString
timeoutResponse
( )
QString
uri
( )

Protected member functions

virtual void
process
( )

Executes one round of processing.

Property details

  • QString httpServer

    [read, write]

    The name of the HTTP server you want to handle incoming requests to this operation.

    The server must be previously created with PiiHttpServer::addServer(). If you want to create a server for this operation only, use a URI here. See PiiHttpServer::addServer() for URI syntax.

     PiiOperation* pReceiver = engine.createOperation("PiiNetworkInputOperation");
 pReceiver->setProperty("httpServer", "tcp://0.0.0.0:8080/");

  • QString interruptedResponse

    [read, write]

    The message sent to the HTTP client if the operation is interrupted while processing a request.

    The default is "The operation was interrupted."

  • QString timeoutResponse

    [read, write]

    The message sent to the HTTP client if the operation fails to receive a response object within time limits.

    The default is "Timed out while waiting for response."

    PiiNetworkOperation::responseTimeout

  • QString uri

    [read, write]

    The URI of the operation within the server.

    Note that each operation must have a unique URI in the context of a HTTP server. If uri is empty, /objectName will be used as the URI.

Function details

  • PiiNetworkInputOperation

    ()

  • ~PiiNetworkInputOperation

    ()

  • virtual void check

    (
    • bool reset
    )
    [virtual]

    Checks the operation for execution.

    This function creates a suitable flow controller by calling createFlowController(). It then sets the flow controller to the active processor and sets the processor as the input controller for all inputs.

    If you change socket groupings in your overridden implementation, please call PiiDefaultOperation::check() after that. Otherwise, your new groupings will not be in effect.

    Reimplemented from PiiNetworkOperation.

  • virtual void handleRequest

    ()
    [virtual]

    Handles a request.

    This function must be thread-safe.

     void MyHandler::handleRequest(const QString& uri, PiiHttpDevice* dev, TimeLimiter*)
 {
   // Find the path of the request wrt to the "root" of this handler
   QString strRequestPath(dev->requestPath(uri));
   if (strRequestPath == "index.html" && dev->requestMethod() == "GET")
     dev->print("<html><head><title>Hello world!</title></head><body><!-- Secret message --></body></html>");
 }

    Parameters
    uri

    the URI the handler was registered at. Use the PiiHttpDevice::requestUri() function to fetch the full request URI.

    dev

    the communication device. PiiHttpProtocol has already fetched request headers, and the device is positioned at the beginning of request data.

    controller

    a progress controller. Call the PiiProgressController::canContinue() with no parameters time to time to ensure you are still allowed to continue communication. Returning from this function will automatically flush the output pending in dev.

    Exceptions
    The

    function may throw a PiiHttpException on error. PiiHttpProtocol sets the response header correspondingly and writes message to the response body.

    Reimplemented from PiiHttpProtocol::UriHandler.

  • QString httpServer

    ()

  • QString interruptedResponse

    ()

  • virtual void pause

    ()
    [virtual]

    Prepares the operation for pausing.

    The functioning is dependent on the type of the processor. In threaded mode, the operation will be turned into Pausing state, and processing will pause once the thread has finished its current processing round. In simple mode, the processor will check if the operation has connected inputs. If it does, the operation will turn into Pausing state and wait until it receives pause signals from previous operations in the pipeline. If there are no connected inputs, the operation will immediately turn into Paused state.

    Reimplemented from PiiDefaultOperation.

  • void setHttpServer

    ()

  • void setInterruptedResponse

    (
    • const QString & interruptedResponse
    )

  • void setTimeoutResponse

    ()

  • void setUri

    ()

  • virtual void stop

    ()
    [virtual]

    Prepares the operation for stopping.

    Works analogously to pause().

    Reimplemented from PiiDefaultOperation.

  • QString timeoutResponse

    ()

  • QString uri

    ()

  • virtual void process

    ()
    [protected, virtual]

    Executes one round of processing.

    This function is invoked by the processor if the necessary preconditions for a new processing round are met. This function does all the necessary calculations to create output objects and sends them to output sockets.

    Calls to process(), syncEvent(), and setProperty() are synchronized and cannot occur simultaneously. PiiDefaultOperation ensures this by locking processLock() for reading before calling process().

    Note: With time-consuming operations, one should occasionally check that the operation hasn't been interrupted, i.e. that state() returns Running.

    Exceptions
    PiiExecutionException

    whenever an unrecoverable error occurs during a processing round, the operation is interrupted, or finishes execution due to end of input data.

    Reimplemented from PiiDefaultOperation.

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