XML Fetch -> Access Violation!

fesquivel · **Posted:** Tue Sep 28, 2004 1:29 pm

Using Teleflow Simulator with a small test application, I perform a call to a web service via the HTTP Step (Get call) and leave the result into a variable. From that variable I create a handle with XML Load and then I try to fetch some values from a specific node in the XML structure. But when XML Fetch tries to do so, it aborts with the "access violation" exception... This is part of the log file: Sep 28 14:27:01.48: ==>Main Sep 28 14:27:01.49: [1] START Sep 28 14:27:01.49: [8] Set Language Sep 28 14:27:01.49: Loading language 'E:\32\TeleFlow\Lang_Spanish.dll' Sep 28 14:27:01.51: Setting system variable '@PROMPT' to 'E:\32\TeleFlow\Languages\Spanish' Sep 28 14:27:01.52: [23] Wait for Call Sep 28 14:27:03.02: Wait for 1 rings and then pickup Sep 28 14:27:05.73: Connection delay: 500 ms Sep 28 14:27:06.23: [10] Play Sep 28 14:27:06.24: Message Code: Bienvenida Sep 28 14:27:06.24: Playing 'F:\Projects\[IVRs]\WS_Test\Vox\Eng\Scripts\Welcome.wav' Sep 28 14:27:07.94: [3] Set Local Variable Sep 28 14:27:07.94: Setting local variable '@CARD' to '00000002' Sep 28 14:27:07.94: [12] Set Local Variable Sep 28 14:27:07.94: Setting local variable '@PWD' to '4321' Sep 28 14:27:07.94: [25] Set Local Variable Sep 28 14:27:07.95: Setting local variable '@TEMP' to '' Sep 28 14:27:07.95: [5] HTTP Sep 28 14:27:07.95: Setting global variable '@RESULT_LOGIN' to '' Sep 28 14:27:07.95: Connecting to host '10.3.1.12' Sep 28 14:27:08.00: Sending request: 'GET /ivr/infrastructure.asmx/Login?p_cardNumber=00000002&p_password=4321 HTTP/1.0 User-Agent: TeleFlow Host: 10.3.1.12:80 Accept: */* ' Sep 28 14:27:08.05: Connection successful Sep 28 14:27:08.06: Request successful, waiting for reponse Sep 28 14:27:08.09: Response received: 37 Sep 28 14:27:08.09: Setting global variable '@RESULT_LOGIN' to '<?xml version="1.0" encoding="utf-8"?> <LoginResult xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://SistemasGalileo.com/Devices/IVR/"> <ResultCode>0</ResultCode> <AccType>CreditCard</AccType> <AccNumber>10000000000002</AccNumber> </LoginResult>' Sep 28 14:27:08.10: [18] XML Load Sep 28 14:27:08.30: [20] XML Fetch Sep 28 14:27:08.30: Handle 1001: Retrieving node '' Sep 28 14:27:08.30: Warning: No variable specified to capture node value Sep 28 14:27:08.30: Variable assignment scope: GLOBAL Sep 28 14:27:08.30: Fetching first node... Sep 28 14:27:08.32: 5A2C17: EXCEPTION_ACCESS_VIOLATION attempting to read at location 0. Sep 28 14:27:08.32: Exception occurred! Thread exiting. Sep 28 14:27:08.32: Shutting down... I've tried this: - Shutting down and restarting TeleFlow - Giving @TEMP a non-null value at initialization - Using different parameters for @CARD & @PWD But nothing... Does anyone know how to debug an access violation generated internally in the Simulator app?

fesquivel · **Posted:** Tue Sep 28, 2004 3:41 pm

Just to add to this request: I tested specifying a node value and storing this value into a temporary variable @TEMP, with this result: Sep 28 16:38:19.16: Connection successful Sep 28 16:38:19.17: Request successful, waiting for reponse Sep 28 16:38:19.18: Response received: 37 Sep 28 16:38:19.18: Setting global variable '@RESULT_LOGIN' to '<?xml version="1.0" encoding="utf-8"?> <LoginResult xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://SistemasGalileo.com/Devices/IVR/"> <ResultCode>0</ResultCode> <AccType>CreditCard</AccType> <AccNumber>10000000000002</AccNumber> </LoginResult>' Sep 28 16:38:19.19: [18] XML Load Sep 28 16:38:19.19: [20] XML Fetch Sep 28 16:38:19.20: Handle 1001: Retrieving node 'LoginResult' Sep 28 16:38:19.20: Save node value to '@TEMP' Sep 28 16:38:19.20: Variable assignment scope: LOCAL Sep 28 16:38:19.20: Fetching first node... Sep 28 16:38:19.20: 5A28CD: EXCEPTION_ACCESS_VIOLATION attempting to read at location 0. Sep 28 16:38:19.20: Exception occurred! Thread exiting. So, how can I parse the XML? What am I doing wrong?

Chris · **Posted:** Fri Oct 01, 2004 12:05 pm

There is a bug in the XML that occurs if you retrieve the top-level node value or attributes only. Although we are looking into this, there are a couple of things you can do to eliminate the exception and the error you will otherwise have. If you have a single extra document or "wrapper" node for the whole document, that will stop the exception. For example: <?xml version="1.0" encoding="utf-8"?> <XML> <LoginResult xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://SistemasGalileo.com/Devices/IVR/"> <ResultCode>0</ResultCode> <AccType>CreditCard</AccType> <AccNumber>10000000000002</AccNumber> </LoginResult> </XML> Next, you will have a problem getting the LoginResult node, because you are trying to gather a node value that doesn't actually exist. If you are trying to get attributes of the LoginResult node, such as the xmlnm:xsd attribute, you must populate the "Attributes:" section of the XML Fetch step with the attributes you want to get. Also, since @XMLNM:XSD is not a valid TeleFlow variable, you will need to "alias" the attribute to a valid TeleFlow variable name. All you must do for this is type AS between the attribute name and the name of the TeleFlow variable you want. So, a single attribute line in the TeleFlow step might look like this: xmlns:xsd AS XMLNSXSD That would, according to your example in the log output, create a TeleFlow variable called @XMLNSXSD which would contain <a href="http://www.w3.org/2001/XMLSchema " target="_new">http://www.w3.org/2001/XMLSchema </a> If you were looking for the value of a sub-node of LoginResult, the notation in the node field is actually: Node->Sub-node or, for one of your specific nodes, for example: LoginResult->ResultCode The -> "tells" the server to look at the sub-node.

fesquivel · **Posted:** Fri Oct 01, 2004 1:51 pm

Thanks a lot, Chris. Actually, what I intended to do is read sub-node values, not the attributes, so your second suggestion worked perfectly ;-)

I had a small confusion about "attributes" and "nodes" here... Now it's clear to me & the prototype is beginning to work. Thanks again!