Application Hangs

[Rama1962]

Greetings all !
We are building an application S60 3rd Edn which opens Rsession Object and sends data over GPRS connection at 1 or 2 minute intervals.

However , our observation is that if GPRS connection is not there , sometimes the aplication hangs .

Following is the code ( from Nokia Forum only ! ) . Would some advanced soul point us in the right direction of what could be causing the application hang .

1) We are using HTTPGET

void CClientEngine::IssueHTTPGetL(const TDesC8& aUri)
{
SetupConnectionL();

// Parse string to URI (as defined in RFC2396)
TUriParser8 uri;
uri.Parse(aUri);

// Get request method string for HTTP GET
RStringF method = iSession.StringPool().StringF(HTTP::EGET,
RHTTPSession::GetTable());

// Open transaction with previous method and parsed uri. This class will
// receive transaction events in MHFRunL and MHFRunError.
iTransaction = iSession.OpenTransactionL(uri, *this, method);

// Set headers for request; user agent and accepted content type
RHTTPHeaders hdr = iTransaction.Request().GetHeaderCollection();
SetHeaderL(hdr, HTTP::EUserAgent, KUserAgent);
SetHeaderL(hdr, HTTP::EAccept, KAccept);

// Submit the transaction. After this the framework will give transaction
// events via MHFRunL and MHFRunError.
iTransaction.SubmitL();

iRunning = ETrue;
_LIT(KConnecting,"Connecting...");
iObserver.ClientEvent(KConnecting, 1);
}

2) for Every transmission we are creating a session

void CClientEngine::SetupConnectionL()
{
if( iConnectionSetupDone )
return;

iConnectionSetupDone = ETrue;

//open socket server and start the connection
User::LeaveIfError(iSocketServ.Connect());
User::LeaveIfError(iConnection.Open(iSocketServ));

// open the IAP communications database
CCommsDatabase* commDB = CCommsDatabase::NewL(EDatabaseTypeIAP);
CleanupStack::PushL(commDB);

// initialize a view
CCommsDbConnectionPrefTableView* commDBView =
commDB->OpenConnectionPrefTableInRankOrderLC(ECommDbConnectionDirectionUnknown);





// go to the first record
commDBView->GotoFirstRecord();
User::LeaveIfError(commDBView->GotoNextRecord());

// User::LeaveIfError(commDBView->GotoFirstRecord());

// Declare a prefTableView Object.
CCommsDbConnectionPrefTableView::TCommDbIapConnectionPref pref;

// read the connection preferences
commDBView->ReadConnectionPreferenceL(pref);
TUint32 iapID = pref.iBearer.iIapId;

// pop and destroy the IAP View
CleanupStack::PopAndDestroy(commDBView);

// pop and destroy the database object
CleanupStack::PopAndDestroy(commDB);

// Now we have the iap Id. Use it to connect for the connection.
// Create a connection preference variable.
TCommDbConnPref connectPref;

// setup preferences
connectPref.SetDialogPreference(ECommDbDialogPrefDoNotPrompt);
connectPref.SetDirection(ECommDbConnectionDirectionUnknown);
connectPref.SetBearerSet(ECommDbBearerGPRS);
//Sets the CommDb ID of the IAP to use for this connection
connectPref.SetIapId(iapID);

User::LeaveIfError(iConnection.Start(connectPref));

//set the sessions connection info
RStringPool strPool = iSession.StringPool();
RHTTPConnectionInfo connInfo = iSession.ConnectionInfo();

//to use our socket server and connection
connInfo.SetPropertyL ( strPool.StringF(HTTP::EHttpSocketServ,
RHTTPSession::GetTable() ), THTTPHdrVal (iSocketServ.Handle()) );

connInfo.SetPropertyL ( strPool.StringF(HTTP::EHttpSocketConnection,
RHTTPSession::GetTable() ),
THTTPHdrVal (REINTERPRET_CAST(TInt, &(iConnection))) );
}



3) after every transation we are destroying the object

iClient->CancelTransaction();
delete (iClient);
iClient = CClientEngine::NewL(*iAppView);

[Dattanand]

I suppose its stopping at SetupconnectionL() if it is not finding access point.
if so,you can try

TInt err = iConnection.Start(connectPref);
if(err != KErrNone)
{
iConnectionSetupDone = EFalse;
iConnection.Close();
iSocketServ.Close();
iTransaction.Close();
}

[Rama1962]

Thanks Dattanand.
but if i need to insert the code in setupconnectionL

void CClientEngine::SetupConnectionL()
{
if( iConnectionSetupDone )
TInt err = iConnection.Start();
    if(err != KErrNone)
    	{
       	iConnectionSetupDone = EFalse;
        iConnection.Close();
        iSocketServ.Close();
   	iTransaction.Close();
    	}

It works for 1 iteration but the phone hangs for the very next iteration.

[Dattanand]

Are you getting IAP selection popup in consecutive iterations?
if no,then it is trying to use the previously established connection and not trying to reconnect. try calling destructor of your engine where you are handling the error.

[Rama1962]

Thanks
Now neither the phone hangs nor the application. It is also not prompting for selection of access point. but i am getting the error message "PACKET DATA NOT AVAILABLE.PLEASE CHECK NETWORK SERVICES"this message is flashing quite often. i call IssueHTTPGetL every 1 min i.e. i want to send the data every 1 min and it happens that the application sends the data for some time say 4 transmissions. Then flashes error for other 2-3 transmissions. Then it resends some more transmissions and so on. The behaivior is not uniform.
Before inserting

TInt err = iConnection.Start(connectPref);
if(err != KErrNone)
{
iConnectionSetupDone = EFalse;
iConnection.Close();
iSocketServ.Close();
iTransaction.Close();
}

i never got this error and the application use to send data by IssueHTTPGetL continuously,at times, even for 2 days


My questions:
1. Is it some error that is uncaught in the application which is causing this OR is it error at network?
2. Can i suppress the error message that is flashing so user does not know about the error?