[RESOLVED] Can I parse XML or psuedo parse it without the MSXML library?

[weirddemon]

I can't use any dependencies for the update I'm about to push. The last thing I need to do is read some XML from an XML file.

Here is an example of the XML:

<Car DateEntered="11/14/2012" Plate="TEST" State="TX" Type="TEST" Alert="default/5" Make="TEST" Year="1988" Description="TESTETSTETST"><Car>

That's pretty much it. Anyone have any ideas? After this, I should be completely done with VB6! Yay! Then I can start converting everything to C#

[techgnome]

that's it? jsut that one line? If that's all you need and that's all you have to deal with, just that one line... as long as it's consistent, and even if it isn't to some extent, you could probably use a regex pattern to get what you need out of it... no, I don't know how... but I know it's possible... regex isn't exactly in my wheelhouse... in fact it's not even in my boat... it's still sitting on the dock somewhere... I know it's there, that's about it... but... I'm sure there's someone around here who could probably whip that up faster than I could write this reply.

-tg

[dilettante]

If the source of this XML has a robust impementation rather than creating "pidgeon XML" then no simple parsing is going to be reliable. You need to observe a large subset of the rules to be successful.

Just consider a simple example: what if one of the attributes contains a quotation mark character? So you have to handle entities.

White space can be a blank space, CR, LF, CRLF, Tab, or a number of them in any combination.

XML can use any character encoding, though UTF-8 is the most common. But playing the "let's assume UTF-8 is ANSI" game leads to failure often enough we get a wail for help on that subject alone here once a month.


Unless you can use pidgeon XML (which implies you control all partners in the data exchange) you're pretty much going to need MSXML or a good 3rd party library. Targeting MSXML 3.0 is pretty safe as it is considered the "safe fallback" for applications that don't want to deploy 6.0, the current version.

Using the right version of MSXML in Internet Explorer applies to desktop applications as well as to IE scripting.

MSXML 3.0 is our preferred “fallback” - It is installed on every OS from a fully patched Win2k SP4 installation on up, so it requires “zero-deployment” and is serviced regularly with the OS.

[weirddemon]

that's it? jsut that one line? If that's all you need and that's all you have to deal with, just that one line... as long as it's consistent, and even if it isn't to some extent, you could probably use a regex pattern to get what you need out of it... no, I don't know how... but I know it's possible... regex isn't exactly in my wheelhouse... in fact it's not even in my boat... it's still sitting on the dock somewhere... I know it's there, that's about it... but... I'm sure there's someone around here who could probably whip that up faster than I could write this reply.

-tg

Well, yes and no. There will be more lines, but that's just for additional entries. Each entry will have only one line and only those properties. So it shouldn't be so hard, I think. It's just that VB6 in general makes things so hard and the fact that I can't use a library makes it even harder.

If the source of this XML has a robust impementation rather than creating "pidgeon XML" then no simple parsing is going to be reliable. You need to observe a large subset of the rules to be successful.

Just consider a simple example: what if one of the attributes contains a quotation mark character? So you have to handle entities.

White space can be a blank space, CR, LF, CRLF, Tab, or a number of them in any combination.

XML can use any character encoding, though UTF-8 is the most common. But playing the "let's assume UTF-8 is ANSI" game leads to failure often enough we get a wail for help on that subject alone here once a month.


Unless you can use pidgeon XML (which implies you control all partners in the data exchange) you're pretty much going to need MSXML or a good 3rd party library. Targeting MSXML 3.0 is pretty safe as it is considered the "safe fallback" for applications that don't want to deploy 6.0, the current version.

Using the right version of MSXML in Internet Explorer applies to desktop applications as well as to IE scripting.

The XML is created by me. I control what is written and how it is written to the file. I just need a way to grab the data from that one line.

[weirddemon]

Duplicate

[MarkT]

Will the data always have the same fields in the same order?

[weirddemon]

Will the data always have the same fields in the same order?

Yeah. For the most part. The data for each field will always be different. But the fields will always be in that order. This solution doesn't need to be perfect. It just needs to work. When I convert it to C#, I'll make it properly.

[MarkT]

Here is something quick and dirty for you to play with. You should be able to call GetLineData within a loop to parse the entire file.

Private Type xmlData
    AttributeName As String
    AttributeValue As String
End Type

Private Sub Command1_Click()
Dim xmlValues() As xmlData
Dim strXML As String
Dim i As Integer

    strXML = "<Car DateEntered=""11/14/2012"" Plate=""TEST"" State=""TX"" Type=""TEST"" Alert=""default/5"" Make=""TEST"" Year=""1988"" Description=""TESTETSTETST""></Car>"
  
    xmlValues = GetLineData(strXML)
    
    For i = 0 To 7
        Debug.Print xmlValues(i).AttributeName & vbTab & "-" & vbTab & xmlValues(i).AttributeValue
    Next i
    
End Sub

Private Function GetLineData(ByVal xml As String) As xmlData()
Dim i As Integer
Dim xmlLineData(7) As xmlData
    
    For i = 0 To 7
        xmlLineData(i) = GetAttributeValue(i, xml)
    Next i
    
    GetLineData = xmlLineData
End Function

Private Function GetAttributeValue(ByVal AttributeIndex As Integer, ByVal xml As String) As xmlData
Dim intStartPos As Integer
Dim intEndPos As Integer
Dim intLen As Integer
Dim strFields(7) As String
Dim strValue As String

    strFields(0) = "DateEntered="
    strFields(1) = "Plate="
    strFields(2) = "State="
    strFields(3) = "Type="
    strFields(4) = "Alert="
    strFields(5) = "Make="
    strFields(6) = "Year="
    strFields(7) = "Description="
    
    intStartPos = InStr(xml, strFields(AttributeIndex)) + Len(strFields(AttributeIndex)) + 1
    
    If AttributeIndex < UBound(strFields) Then
        intEndPos = InStr(intStartPos, xml, strFields(AttributeIndex + 1))
    Else
        intEndPos = InStr(intStartPos, xml, ">")
    End If
    
    intLen = intEndPos - intStartPos - 2
    strValue = Mid(xml, intStartPos, intLen)
    
    GetAttributeValue.AttributeName = Left(strFields(AttributeIndex), Len(strFields(AttributeIndex)) - 1)
    GetAttributeValue.AttributeValue = strValue

End Function

[weirddemon]

Thanks, Mark. That looks good. But I'm getting the following error on the provided line.

User-defined type not defined

Public Function GetLineData(ByVal xml As String) As xmlData()

I copied your code as is. I haven't changed anything. I wanted to test before I started setting up the loop and what not. xmlData is clearly defined, so I'm not sure why this is coming up.

[MarkT]

You would get that error if this part was missing from your general declaratons section.

Private Type xmlData
    AttributeName As String
    AttributeValue As String
End Type

[weirddemon]

It's in the same module as the other methods. What do you mean by general declarations section?

[MarkT]

Can you attach a sample that isn't working?

[weirddemon]

Can you attach a sample that isn't working?

Err... this is strange. It won't even compile in the main app, but when I put the code in a test app, it runs just fine.

[MarkT]

What do you mean by general declarations section?

I found a quick explaination online

The General Declarations Section of a form or standard module. This section of a module is not labeled as such; it simply exists at the beginning of a code module, after the "Option Explicit" statement but prior to the first Sub or Function procedure. Declaring a variable here makes it a project-level variable (if the Public or Global keyword is used) or a module-level variable (if the Private or Dim keyword is used).

If you try to define the type outside of the general declarations section you will get a compiler error.

[weirddemon]

I found a quick explaination online
If you try to define the type outside of the general declarations section you will get a compiler error.

Oh. So declare it at the top. Gotcha. It's compiling now. Thanks, mark.