network error during dtd validation

[Galen Harris]

I'm getting weird errors during transformations --
"System.Net.WebException. The remote server returned an error: (500)
Internal Server Error."

I'm on the 1.0 Framework. I've looked through the stack trace and it seems
to be happending at a call to .Transform as follows (see stack trace below):
oXslTransform.Transform(myXPathDocument,plist,stWr ite);

These XML documents are 3rd party and include a doctype that refers to a dtd
across the network. I'm also getting these sometimes in IE, so it seems
that the vendors DTD is timing out. Is there anyway to disable the
validation of the document, so it doesn't try to call out to the DTD?

Thanks,
Galen

Here's a part of the stack trace:
at System.Net.HttpWebRequest.CheckFinalStatus()
at System.Net.HttpWebRequest.EndGetResponse(IAsyncRes ult asyncResult)
at System.Net.HttpWebRequest.GetResponse()
at System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials
credentials)
at System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials
credentials)
at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type
ofObjectToReturn)
at System.Xml.Schema.DtdParser.ParseDocTypeDecl()
at System.Xml.Schema.DtdParser.Parse()
at System.Xml.XmlTextReader.ParseDtd(XmlScanner scanner)
at System.Xml.XmlTextReader.ParseTag()
at System.Xml.XmlTextReader.ParseRoot()
at System.Xml.XmlTextReader.Read()
at System.Xml.XmlValidatingReader.ReadWithCollectText Token()
at System.Xml.XmlValidatingReader.Read()
at System.Xml.XPath.XPathDocument.ReadChildNodes(XPat hContainer parent,
String parentBaseUri, XmlReader reader, PositionInfo positionInfo)
at System.Xml.XPath.XPathDocument.Load(XmlReader reader)
at System.Xml.XPath.XPathDocument.Init(XmlReader reader)
at System.Xml.XPath.XPathDocument..ctor(TextReader reader)

[Oleg Tkachenko]

Galen Harris wrote:

I'm getting weird errors during transformations --
"System.Net.WebException. The remote server returned an error: (500)
Internal Server Error."

I'm on the 1.0 Framework. I've looked through the stack trace and it seems
to be happending at a call to .Transform as follows (see stack trace below):
oXslTransform.Transform(myXPathDocument,plist,stWr ite);

These XML documents are 3rd party and include a doctype that refers to a dtd
across the network. I'm also getting these sometimes in IE, so it seems
that the vendors DTD is timing out. Is there anyway to disable the
validation of the document, so it doesn't try to call out to the DTD?

In your scenario XML document is not validated actually. DTD is not only about
validation and XPathDocument class has additional requirements about entities
expansion etc, so I don't think it's good idea (if it's feasible at all) to
disable the above behaviour. Instead you can have local version of the DTD in
a file and just to redirect reader to it instead of remote version. Here is
small example:

static void Main(string[] args) {
string xml =
@"<!DOCTYPE root SYSTEM ""http://nowhere.com/my.dtd"">
<root>
<foo/>
<bar/>
</root>";
XmlReader reader = new XmlTextReader(new StringReader(xml));

XmlValidatingReader vr = new XmlValidatingReader(reader);
vr.XmlResolver = new MyResolver();
vr.ValidationType = ValidationType.None;
XPathDocument doc = new XPathDocument(vr);
...
}

public class MyResolver : XmlUrlResolver {
public override object GetEntity(Uri absoluteUri, string role, Type
ofObjectToReturn) {
if (absoluteUri.AbsoluteUri.StartsWith("http://nowhere.com"))
return File.OpenRead(@"c:\local.dtd");
else
return null;
}
}

--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel

[Galen Harris]

thanks for the response.

what would you suggest, if the xml documents were 3rd party, and i couldn't
edit their contents to change the reference to a local copy of the DTD?
"Oleg Tkachenko" <oleg@NO_SPAM_PLEASEtkachenko.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Galen Harris wrote:

I'm getting weird errors during transformations --
"System.Net.WebException. The remote server returned an error: (500)
Internal Server Error."

I'm on the 1.0 Framework. I've looked through the stack trace and it seems to be happending at a call to .Transform as follows (see stack trace below): oXslTransform.Transform(myXPathDocument,plist,stWr ite);

These XML documents are 3rd party and include a doctype that refers to a dtd across the network. I'm also getting these sometimes in IE, so it seems
that the vendors DTD is timing out. Is there anyway to disable the
validation of the document, so it doesn't try to call out to the DTD?
In your scenario XML document is not validated actually. DTD is not only

about validation and XPathDocument class has additional requirements about entities expansion etc, so I don't think it's good idea (if it's feasible at all) to disable the above behaviour. Instead you can have local version of the DTD in a file and just to redirect reader to it instead of remote version. Here is small example:

static void Main(string[] args) {
string xml =
@"<!DOCTYPE root SYSTEM ""http://nowhere.com/my.dtd"">
<root>
<foo/>
<bar/>
</root>";
XmlReader reader = new XmlTextReader(new StringReader(xml));

XmlValidatingReader vr = new XmlValidatingReader(reader);
vr.XmlResolver = new MyResolver();
vr.ValidationType = ValidationType.None;
XPathDocument doc = new XPathDocument(vr);
...
}

public class MyResolver : XmlUrlResolver {
public override object GetEntity(Uri absoluteUri, string role, Type
ofObjectToReturn) {
if (absoluteUri.AbsoluteUri.StartsWith("http://nowhere.com"))
return File.OpenRead(@"c:\local.dtd");
else
return null;
}
}

--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel

[Oleg Tkachenko]

Galen Harris wrote:

thanks for the response.

what would you suggest, if the xml documents were 3rd party, and i couldn't
edit their contents to change the reference to a local copy of the DTD?

Sorry, but you don't have to edit their content! Reread my post, the
whole idea is just to redirect the XML reader to local copy of DTD
instead on remote one, based on DTD URL.
It's well known and well proven technology (derived from SGML catalogs
and XCatalogs), it's standard when working with big DTDs like Docbook DTD.
--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel

[Galen Harris]

went back and looked at your posting again. i tried it, and it works great.
also, i noticed that i could set the XMLResolver property to null, and that
did the trick as well. i guess this would be easier in cases where i didn't
need anything from the DTD.

thanks for your help!

[Galen Harris]

went back and looked at your posting again. i tried it, and it works great.
also, i noticed that i could set the XMLResolver property to null, and that
did the trick as well. i guess this would be easier in cases where i didn't
need anything from the DTD.

thanks for your help!