Debugging Navision Employee Portal

After a long time today i had a chance to work on the Navision portal the need was to debug a problem as we know the navision really is a 2-tier application and the NAS is only the Navision client running in stealth mode as a service i remember having debugged this application server in the past but was lucky enough to recapitulate the same here is how it is done.

1. Stop the NAS server from the management console
2. Create a new codeunit in the navision client
3. In the run method of the new codeunit instatiate and execute the StartNAS method of the 6810 codeunit with a parameter 'NEP-1' or whatever you have used in your instance of NAS; it should display a message stating that the service has started.
4. That's it the debug mode is now enabled within the navision client now just enable the debugger and start debugging.

Read XML Using XMLReader

Reading an XML file using the XMLReader which should be faster compared to DOM classes

    XmlReader   taskDetails;
    str attributeName, attributeValue;
    int i, j;
    ;


    //using the XML Reader class
    taskDetails = XmlTextReader::newXml( tasks.ScriptText );

    while ( taskDetails.read() )
    {
        switch ( taskDetails.nodeType() )
        {
            case XMLNodeType::Element:
                while ( taskDetails.moveToNextAttribute() )
                {
                    attributeName = taskDetails.name();
                    attributeValue = taskDetails.value();
                   
                    info( strfmt("AttributeName =%1, AttributeValue = %2", taskDetails.name(), taskDetails.value() ) );
                }
                break;

            default:
                info( strfmt("Nodetype = %1, NodeName = %2, NodeValue = %3, InnerXML = %4, readAttributeValue = %5"
                            , taskDetails.nodeType()
                            , taskDetails.name()
                            , taskDetails.value()
                            , taskDetails.readInnerXml()
                            , taskDetails.readAttributeValue()
                            ) ) ;

                while ( taskDetails.moveToNextAttribute() )
                {
                    attributeName = taskDetails.name();
                    attributeValue = taskDetails.value();

                    info( strfmt("AttributeName =%1, AttributeValue = %2", taskDetails.name(), taskDetails.value() ) );
                }

                break;

        }
    }

Read XML using DOM

Please find the X++ code snippet below to read a XML stream using DOM


    XmlDocument xmlDoc;
    XmlNode xmlRoot;
    XmlNodeList xmlRecordList;
    XmlElement xmlRecord;

    XmlNamedNodeMap attributeList;
    str attributeName, attributeValue;
    int i, j;
    ;

    xmlDoc = new XmlDocument();
    xmlDoc.loadXml( tasks.ScriptText );
    xmlRoot = xmlDoc.root();
    xmlRecordList = xmlRoot.childNodes();


    for (i=0; i < xmlRecordList.length(); i++)
    {
        xmlRecord = xmlRecordList.item( i );

        attributeList = xmlRecord.attributes();

        for (j=0; j < attributeList.length(); j++)
        {
            attributeName = attributeList.item(j).name();
            attributeValue = xmlRecord.getAttribute( attributeName ) ;
        }
    }

XML Data Model

To parse a XML string it is very important to correctly understand the data model of XML here is my understanding of the same

XMLNode is a basic object in a DOM tree
XMLDocument class extends the node class and support methods for performing operations on the document as a whole

A node can have multiple childs nodes below it however each node would only have one parent. Each node can have multiple name-value pairs which are known as Attributes. If an application does not require the structure and editing capabilities provided by DOM then XMLReader and XMLWrite classes can be used as they are faster and are meant to provide a non-cached, forward only access to an XML stream.

Further to this a node could be of different types. Identifying the node type helps to determine what actions can be performed and what properties can be set or retrieved. To understand the different types of nodes lets use the example below

There is another common question that i have encountered as to what is the difference between a node and an element as we will see in the example below that an element is infact a node type

Example
<?xml version="1.0"?>
<!-- This is a sample XML document -->
<!DOCTYPE Items [<!ENTITY number "123">]>
<Items>
  <Item>Test with an entity: &number;</Item>
  <Item>test with a child element <more/> stuff</Item>
  <Item>test with a CDATA section <![CDATA[<456>]]> def</Item>
  <Item>Test with a char entity: &#65;</Item>
  <!-- Fourteen chars in this element.-->
  <Item>1234567890ABCD</Item>
</Items>

Input	Output	Node Type
<?xml version="1.0"?>	<?xml version='1.0'?>	XmlNodeType.XmlDeclaration
<!-- This is a sample XML document -->	<!--This is a sample XML document -->	XmlNodeType.Comment
<!DOCTYPE Items [<!ENTITY number "123">]>	<!DOCTYPE Items [<!ENTITY number "123">]	XmlNodeType.DocumentType
<Items>	<Items>	XmlNodeType.Element
<Item>	<Item>	XmlNodeType.Element
Test with an entity: &number;</Item>	Test with an entity: 123	XmlNodeType.Text
</Item>	</Item>	XmlNodeType.EndElement
<Item>	<Item>	XmNodeType.Element
test with a child element	test with a child element	XmlNodeType.Text
<more>	<more>	XmlNodeType.Element
stuff	stuff	XmlNodeType.Text
</Item>	</Item>	XmlNodeType.EndElement
<Item>	<Item>	XmlNodeType.Element
test with a CDATA section	test with a CDATA section	XmlTest.Text
<![CDATA[<456>]]>	<![CDATA[<456>]]>	XmlTest.CDATA
def	def	XmlNodeType.Text
</Item>	</Item>	XmlNodeType.EndElement
<Item>	<Item>	XmlNodeType.Element
Test with a char entity: &#65;	Test with a char entity: A	XmlNodeType.Text
</Item>	</Item>	XmlNodeType.EndElement
<!-- Fourteen chars in this element.-->	<--Fourteen chars in this element.-->	XmlNodeType.Comment
<Item>	<Item>	XmlNodeType.Element
1234567890ABCD	1234567890ABCD	XmlNodeType.Text
</Item>	</Item>	XmlNodeType.EndElement
</Items>	</Items>	XmlNodeType.EndElement