[xsde-users] Why xml_schema::schema exception is thrown when the xml document is not well formed

[Jiang, Bin (Bin)]

Hi, Boris and all,

I found in some cases, xml_schema::schema will be thrown when the xml document is not well-formed. Take the example library in the xsde release 1.1.0 as an example:

<lib:catalog xmlns:lib="http://www.codesynthesis.com/library"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://www.codesynthesis.com/library library.xsd">

  book id="MM" available="false" >
    <isbn>0679760806</isbn>
    <title>The Master and Margarita</title>
    <genre>fiction1</genre>
...
</lib:catalog>

If I remove the "<" of book, the parser would say:
schema error: line[15] column[34] unexpected characters encountered

while I think this should be an xml_schema::xml exception.

Thanks,
Jiang Bin (Bin)
GLMS Developer
Alcatel-Lucent

> -----Original Message-----
> From: Jiang, Bin (Bin)
> Sent: 2007年10月25日 0:41
> To: 'Boris Kolpackov'
> Cc: xsde-users at codesynthesis.com
> Subject: RE: [xsde-users] How to config xsde to parse without namespace
> check / How to gain a better error message
> 
> Hi Boris,
> 
> Really appreciate your timely and detailed response, thank you!
> Please see my more questions below.
> 
> Thanks,
> Jiang Bin (Bin)
> GLMS Developer
> Alcatel-Lucent
> 
> > -----Original Message-----
> > From: Boris Kolpackov [mailto:boris at codesynthesis.com]
> > Sent: 2007年10月23日 0:05
> > To: Jiang, Bin (Bin)
> > Cc: xsde-users at codesynthesis.com
> > Subject: Re: [xsde-users] How to config xsde to parse without namespace
> > check / How to gain a better error message
> >
> > Hi Bin,
> >
> > Jiang, Bin (Bin) <binjiang at alcatel-lucent.com> writes:
> >
> > > Sometimes I need parsing a xml fragment without checking the namespace,
> > > it there any convenient way to do this?
> > > I've used XSD 2.1.1 2.3.0, and now xsde 1.1.0, my way is modifiy the
> xsd
> > > library files and the generated parser files.
> >
> > I think there is a more elegant way to accomplish this. The idea is
> > to override the _start_element (and _start_attribute if necessary)
> > low-level hook on the root parser and call the original version with
> > a proper namespace when necessary:
> >
> > virtual void
> > _start_element (const xml_schema::ro_string& ns,
> >                 const xml_schema::ro_string& name)
> > {
> >   if (need_to_add_namespace)
> >   {
> >     xml_schema::ro_string ns ("urn:oma:xml:poc:list-service");
> >     base::_start_element (ns, name);
> >   }
> >   else
> >   {
> >     base::_start_element (ns, name);
> >   }
> > }
> >
> > This will work because all events are going through the root
> > element parser. This can get a bit more complicated if your
> > vocabulary mixes qualified and unqualified elements. But
> > normally it is either all qualified or only root element that
> > is qualified and both of these cases are easy to handle with
> > this method.
> >
> 
> [Jiang, Bin (Bin)]
> [Jiang, Bin (Bin)] This may not work if there is more than one namespace
> definitions in a instance document, right?
> 
> > > Another question is when there is an exception, like unexpected
> element
> > > or attribute, how to get the namespace and name of the encountered
> > > element or attribute, I only find there is line/column and text().
> >
> > The current error propagation architecture makes it costly to pass
> > this information up to the caller. Because of that we decided not
> > to provide it. However, we are planning to change the inner workings
> > of C++/Parser which will also make it fairly cheap to pass extra
> > error information around and we will add support for names and
> > namespaces then. Unfortunately, this is not planned for XSD/e 2.0.0
> > (due in a couple of weeks) and will be implemented in XSD/e 2.1.0
> > which is scheduled for the end of 2007 - beginning of 2008. How
> > urgent is this feature for your project?
> 
> [Jiang, Bin (Bin)]
> [Jiang, Bin (Bin)] It's not so urgent now, since there is line/column
> information and we can always locate the error position. But if I can
> provide name or namespace, the error message would be more user-friendly
> and complete. Is there any work-around I can use? Performance is not a big
> issue for me at this moment, since from our performance testing results,
> xsde1.1.0(with --no-iostream) is good than xsd 2.1.1 which we used before.
> 
> >
> > Boris