Handling Errors

Errors can occur for any number of reasons. If the request cannot find the service, an error will occur. If the request makes it to the server but the server rejects it, an error will occur. If the SOAP server detects an error, it should return a SOAP response that contains a SOAP fault. This will contain a description of the problem. Any error will be reported as a standard DataFlex error. If the error is a SOAP Fault error, the error description provided by the service will be displayed.

The property peTransferStatus can be tested after a call to see if your web-service call succeeded. If the property’s value is wssOk, the call succeeded. All possible, and some less desirable, values for peTransferStatus are:

wssOk
Request succeeded
wssHttpRequestFailed
HTTP request failed
wssBadRequest
Bad or missing data sent
wssInvalidContentType
Invalid contentType received
wssNoData
No data was received
wssNotXml
Received data not in proper XML format
wssNotSoap
Received XML data not in proper SOAP format
wssInvalidSoap
Received SOAP data not formatted according to service description
wssSoapFault
SOAP Fault Returned.
Fault-code returned in psFaultCode
Fault-description returned in psFaultString

You can use this status to properly handle failed service calls. For example:

Procedure OnClick
    string sFirst sLast sReply
    Integer eStatus

    Get Value of oFirst to sFirst
    Get Value of oLast to sLast
    Get wsHello of oWSHelloService sFirst sLast to sReply
    Get peTransferStatus of oWSHelloService to eStatus

    If (eStatus = wssOk) begin
        Set Value of oReply to sReply
    End
    Else begin
        Set Value of oReply to "Error"
    end
End_Procedure // OnClick

Under some circumstances, you may wish to trap an error and handle it yourself. You can suppress errors by setting the client web-service property pbSuppressLastError to true. When true, errors are not reported, and it is up to you to determine how to handle the error. If peTransferStatus is not wssOk, you can manually generate an error by getting the error text for the last error and creating your own error. The error text for any error status is obtained by sending the TransferErrorDescription message. For example:

Procedure OnClick
    string sFirst sLast sReply
    string sError
    Integer eStatus

    Get Value of oFirst to sFirst
    Get Value of oLast to sLast
    Get wsHello of oWSHelloService sFirst sLast to sReply
    Get peTransferStatus of oWSHelloService to eStatus

    If (eStatus = wssOk) begin
        Set Value of oReply to sReply
    End
    Else begin
        // we know we have an error and we know the type.
        // Get the error message for this error
        Get TransferErrorDescription eStatus to sError
        Set Value of oReply to sError
    end
End_Procedure // OnClick

Under certain circumstances, you may need to see the actual SOAP requests and responses to determine the source of errors. A helper object is provided to do that and is described below. In addition, the client object maintains the XML request, response, and return object of the last call. Those are maintained as XML DOM objects and are pointed to by the properties phoSoapRequest and phoSoapResponse. These are for advanced use only.

Handling Errors

See Also