XSL Error with document() function

[rox.scott]

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.
Why ???

VB.NET code: ** note the commented line, this is the culprit **
Dim xsl As New System.Xml.Xsl. XslTransform()
Dim xw As New System.IO.Strin gWriter()
Dim xmldoc As New System.Xml.XmlD ocument()
Dim xsldoc As New System.Xml.XmlD ocument()
xmldoc.Load("te st.xml")
xsldoc.Load("te st.xsl")
'xsldoc.LoadXml (xsldoc.OuterXm l)
xsl.Load(xsldoc .CreateNavigato r)
xsl.Transform(x mldoc.CreateNav igator, Nothing, xw)
Console.Write(x w.ToString)
XML input: (test.xml)
<xml>
<node1 val="hello world" />
</xml>

XSL input: (test.xsl)
<xsl:styleshe et version="1.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:value-of select="count(d ocument('')//*)" />
</xsl:template>
</xsl:stylesheet>

Please explain why this happens, I do not want to use any file I/O in my
program!
Thanks.

--scott

[Nigel Armstrong]

Hi

What are you trying to achieve here - is it the count of elements inside the
source document, or the stylesheet? From the MSXML reference:

If an empty string is passed to the document() function, the result is the
source XML of the XSLT document itself, unless the second argument is given
(and is not null). In the latter case, the URL of the document is the base
URL of the node contained in the second element.

So if you use an empty string for the document function, then the context is
actually the stylesheet, not the source document.

So leave the document('') function out!

HTH

Nigel

"rox.scott" wrote:

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.
Why ???

VB.NET code: ** note the commented line, this is the culprit **
Dim xsl As New System.Xml.Xsl. XslTransform()
Dim xw As New System.IO.Strin gWriter()
Dim xmldoc As New System.Xml.XmlD ocument()
Dim xsldoc As New System.Xml.XmlD ocument()
xmldoc.Load("te st.xml")
xsldoc.Load("te st.xsl")
'xsldoc.LoadXml (xsldoc.OuterXm l)
xsl.Load(xsldoc .CreateNavigato r)
xsl.Transform(x mldoc.CreateNav igator, Nothing, xw)
Console.Write(x w.ToString)
XML input: (test.xml)
<xml>
<node1 val="hello world" />
</xml>

XSL input: (test.xsl)
<xsl:styleshe et version="1.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:value-of select="count(d ocument('')//*)" />
</xsl:template>
</xsl:stylesheet>

Please explain why this happens, I do not want to use any file I/O in my
program!
Thanks.

--scott

[rox.scott]

Yes, I want count of the stylesheet nodes.
This is a simplification of my real-world case, I don't actually want a node
count, but illustrates the problem.

In either case, I should not get 0 as a result.

--scott

"Nigel Armstrong" wrote:

Hi

What are you trying to achieve here - is it the count of elements inside the
source document, or the stylesheet? From the MSXML reference:

If an empty string is passed to the document() function, the result is the
source XML of the XSLT document itself, unless the second argument is given
(and is not null). In the latter case, the URL of the document is the base
URL of the node contained in the second element.

So if you use an empty string for the document function, then the context is
actually the stylesheet, not the source document.

So leave the document('') function out!

HTH

Nigel

"rox.scott" wrote:

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.
Why ???

VB.NET code: ** note the commented line, this is the culprit **
Dim xsl As New System.Xml.Xsl. XslTransform()
Dim xw As New System.IO.Strin gWriter()
Dim xmldoc As New System.Xml.XmlD ocument()
Dim xsldoc As New System.Xml.XmlD ocument()
xmldoc.Load("te st.xml")
xsldoc.Load("te st.xsl")
'xsldoc.LoadXml (xsldoc.OuterXm l)
xsl.Load(xsldoc .CreateNavigato r)
xsl.Transform(x mldoc.CreateNav igator, Nothing, xw)
Console.Write(x w.ToString)
XML input: (test.xml)
<xml>
<node1 val="hello world" />
</xml>

XSL input: (test.xsl)
<xsl:styleshe et version="1.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:value-of select="count(d ocument('')//*)" />
</xsl:template>
</xsl:stylesheet>

Please explain why this happens, I do not want to use any file I/O in my
program!
Thanks.

--scott

[Oleg Tkachenko [MVP]]

rox.scott wrote:

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.

When you load XSLT from a string, it has no base URI and relatiev URIs
cannot be resolved therefore.
Don't load XSLT from a string or if you do need, provide base URI:
xslt.Load(new XmlTextReader(" foo.xsl", new StringReader(st rXSL)));

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Nigel Armstrong wrote:

So if you use an empty string for the document function, then the context is
actually the stylesheet, not the source document.

So leave the document('') function out!

In fact document('') is quite useful technique, which enables XSLT
introspection - a stylesheet can process itself. E.g. this is commonly
used for embedding loopup tables within a stylesheet.

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[rox.scott]

It is strange, this all works just fine using MSXML4 objects instead of XML.NET
I guess between the implementation of MSXML4 and XML.NET they forgot the
purpose of the special case document('').

Obviously if I were capable of resolving a URI then I would just use
document(URI) instead of empty string. I imagine the original programmers
thought of this case and that is why the document('') was originally offered.
I am not sure of its value anymore. When I provide a base URI as in Oleg's
code above, the content of the XSL in memory is ignored and the resolved URI
is used instead.

W3C spec or not, it is too bad that XML.NET is intrinsically tied to the
file system. My program has access neither to write nor read from the file
system. I guess I will use MSXML4.

Thank you.
"Oleg Tkachenko [MVP]" wrote:

rox.scott wrote:

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.

When you load XSLT from a string, it has no base URI and relatiev URIs
cannot be resolved therefore.
Don't load XSLT from a string or if you do need, provide base URI:
xslt.Load(new XmlTextReader(" foo.xsl", new StringReader(st rXSL)));

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Nigel Armstrong]

Hi Rox

I think this may be classed as a bug - I've done some limited testing using
the System.Xml.Quer y.XsltCommand in .NET 2.0 as well...there is an improvment
from .NET 1.0/1.1, in that the Exception messages are more clear, but I don't
think that the issue is fixed.

I know you can't have File IO, but as an alternative, could you return your
stylesheets from a URL using ASP.NET to hook into your (I guess) database
storage.

Nigel

"rox.scott" wrote:

It is strange, this all works just fine using MSXML4 objects instead of XML.NET
I guess between the implementation of MSXML4 and XML.NET they forgot the
purpose of the special case document('').

Obviously if I were capable of resolving a URI then I would just use
document(URI) instead of empty string. I imagine the original programmers
thought of this case and that is why the document('') was originally offered.
I am not sure of its value anymore. When I provide a base URI as in Oleg's
code above, the content of the XSL in memory is ignored and the resolved URI
is used instead.

W3C spec or not, it is too bad that XML.NET is intrinsically tied to the
file system. My program has access neither to write nor read from the file
system. I guess I will use MSXML4.

Thank you.
"Oleg Tkachenko [MVP]" wrote:

rox.scott wrote:

Can someone please explain why this happens?
The expected output is 3, but uncommenting line 7 makes the output 0.

When you load XSLT from a string, it has no base URI and relatiev URIs
cannot be resolved therefore.
Don't load XSLT from a string or if you do need, provide base URI:
xslt.Load(new XmlTextReader(" foo.xsl", new StringReader(st rXSL)));

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

rox.scott wrote:

It is strange, this all works just fine using MSXML4 objects instead of XML.NET
It works fine in .NET if you provide base URI for your stylesheet.
I guess between the implementation of MSXML4 and XML.NET they forgot the
purpose of the special case document('').
There is nothing special about document('') - it's just zero-length
realtive URI to be resolved.
Obviously if I were capable of resolving a URI then I would just use
document(URI) instead of empty string. I imagine the original programmers
thought of this case and that is why the document('') was originally offered.
I am not sure of its value anymore. When I provide a base URI as in Oleg's
code above, the content of the XSL in memory is ignored and the resolved URI
is used instead.
You seems to be working with MSXML too much. There is no such thing as
XSL in memory. In .NET as well as in many other XSLT implementations
XSLT is being compiled to binary representation prior to transformation
and this binary compiled stylesheet of course doesn't contain source
document.
W3C spec or not, it is too bad that XML.NET is intrinsically tied to the
file system.
It doesn't.
My program has access neither to write nor read from the file
system. I guess I will use MSXML4.

You can easily workaround this problem in .NET having source of the XSLT
stylesheet stored in some form (string or XPathDocument) and providing
custom XmlResolver, which resolves "" to that document (return it as
Stream or XPathNavigator in GetEntity() method).

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Nigel Armstrong wrote:

I think this may be classed as a bug - I've done some limited testing using
the System.Xml.Quer y.XsltCommand in .NET 2.0 as well...there is an improvment
from .NET 1.0/1.1, in that the Exception messages are more clear, but I don't
think that the issue is fixed.

I don't think that's a bug. That's by design. XSLT allows such behaviour
when compiled XSLT stylesheet has no source representation - e.g. when
you compile C++ code to exe, there is no way for exe to return you
source C++ code, right? So why in XSLT it's a bug?

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Nigel Armstrong]

Hi Oleg

I've just written some sample code supplying a base URI when loading the
stylesheet, and it doesn't seem to be working for me. Perhaps you could take
a look at it!

Nigel

test.xml
<?xml version="1.0"?>
<?xml-stylesheet type='text/xsl' href='test.xsl' ?>
<root><child>te xt</child></root>

test.xsl
<?xml version='1.0'?>
<xsl:styleshe et version='1.0'
xmlns:xsl='http ://www.w3.org/1999/XSL/Transform' >
<xsl:template match='/'>
<root><xsl:valu e-of select='count(d ocument(&apos;& apos;)//*)'/></root>
</xsl:template>
</xsl:stylesheet>

Works:
Dim r As New MyResolver

'Dim s As New Xml.XmlTextRead er("file:///C:/test.xsl", New
IO.FileStream(" ../test.xsl", IO.FileMode.Ope n))
Dim d As New Xml.XmlDocument
d.Load("../test.xml")

Dim t As New Xml.Xsl.XslTran sform
t.Load("../test.xsl", r)
't.Load(s, r, Nothing)
Dim sw As New IO.StringWriter

t.Transform(d, Nothing, sw, r)

MessageBox.Show (sw.ToString())
Doesn't work:
Dim r As New MyResolver

Dim s As New Xml.XmlTextRead er("file:///C:/test.xsl", New
IO.FileStream(" ../test.xsl", IO.FileMode.Ope n))
Dim d As New Xml.XmlDocument
d.Load("../test.xml")

Dim t As New Xml.Xsl.XslTran sform
't.Load("../test.xsl", r)
t.Load(s, r, Nothing)
Dim sw As New IO.StringWriter

t.Transform(d, Nothing, sw, r)

MessageBox.Show (sw.ToString())
Custom resolver that always returns a reference to the same stylesheet
Public Class MyResolver
Inherits Xml.XmlResolver

Public Overrides WriteOnly Property Credentials() As
System.Net.ICre dentials
Set(ByVal Value As System.Net.ICre dentials)

End Set
End Property

Public Overrides Function GetEntity(ByVal absoluteUri As System.Uri,
ByVal role As String, ByVal ofObjectToRetur n As System.Type) As Object
Return New IO.FileStream(" ..\test.xsl", IO.FileMode.Ope n)
End Function
End Class

"Oleg Tkachenko [MVP]" wrote:

rox.scott wrote:

It is strange, this all works just fine using MSXML4 objects instead of XML.NET

It works fine in .NET if you provide base URI for your stylesheet.

I guess between the implementation of MSXML4 and XML.NET they forgot the
purpose of the special case document('').

There is nothing special about document('') - it's just zero-length
realtive URI to be resolved.

Obviously if I were capable of resolving a URI then I would just use
document(URI) instead of empty string. I imagine the original programmers
thought of this case and that is why the document('') was originally offered.
I am not sure of its value anymore. When I provide a base URI as in Oleg's
code above, the content of the XSL in memory is ignored and the resolved URI
is used instead.

You seems to be working with MSXML too much. There is no such thing as
XSL in memory. In .NET as well as in many other XSLT implementations
XSLT is being compiled to binary representation prior to transformation
and this binary compiled stylesheet of course doesn't contain source
document.

W3C spec or not, it is too bad that XML.NET is intrinsically tied to the
file system.

It doesn't.

My program has access neither to write nor read from the file
system. I guess I will use MSXML4.

You can easily workaround this problem in .NET having source of the XSLT
stylesheet stored in some form (string or XPathDocument) and providing
custom XmlResolver, which resolves "" to that document (return it as
Stream or XPathNavigator in GetEntity() method).

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com