libxml + sax + schema validation

Hi,

I need to write a sax xml parser that will
validate the contents against a xml schema file.

Writing a sax parser wasn't to hard, but I have no
clue how to implement the schema validation.

Can anyone help me?
Links to some examples would be great

BR, Jovan
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On Tue, Feb 06, 2007 at 03:33:57PM +0100, Jovan Kostovski
wrote:
> Hi,
> 
> I need to write a sax xml parser that will
> validate the contents against a xml schema file.
> 
> Writing a sax parser wasn't to hard, but I have no
> clue how to implement the schema validation.
> 
> Can anyone help me?
> Links to some examples would be great

  there is an API to push a schemas validation context on
top of
a SAX event, see xmlSchemaValidateStream() use in testSAX()
in xmllint.c

Daniel

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Hi,

It seems libxml2 sometimes doesn't catch duplicate elements
(under the
same parent element) when loading a schema. (Please see the
simple
schema at the end).

  xmlSchemaParserCtxtPtr parserCtxtPtr =
xmlSchemaNewParserCtxt("./sample.xsd");  -----line
1
  xmlSchemaPtr schema = xmlSchemaParse(parserCtxtPtr);   
------------>
line 2

Line 1 creates a parser context, and line 2 creates schema
pointer.

For the schema below, there are two "ifid"
elements in "interface_type"
complexType, I expect line 2 reports an error saying
duplicate elements
defined, but instead, line 2 returns fine.

Thanks,
Yong Chen 


Sample.xsd:

<?xml version="1.0"?>
<xs:schema xmlnss=&qu
ot;http://www.w3.
org/2001/XMLSchema"
xmlns="http://www.my.com/test&q
uot; targetNamespace="http://www.my.com/test&q
uot;
elementFormDefault="qualified">
  <xs:element name="show"
type="show_type"/>
  <xs:complexType name="show_type">
    <xs:sequence>
      <xs:element name="interface"
minOccurs="1"
type="interface_type"/>
    </xs:sequence>
  </xs:complexType>
  <xs:complexType name="interface_type">
    <xs:sequence>
        <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
        <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:schema>
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One more info: it also doesn't catch duplicates in following
(slightly
modified) sample file. Basically I inserted
<xs:choice> as the parent of
those two "ifid" elements.

Thanks,
Yong Chen


<?xml version="1.0"?>
<xs:schema xmlnss=&qu
ot;http://www.w3.
org/2001/XMLSchema"
xmlns="http://www.my.com/test&q
uot; 
targetNamespace="http://www.my.com/test&q
uot;
elementFormDefault="qualified">
  <xs:element name="show"
type="show_type"/>
  <xs:complexType name="show_type">
    <xs:sequence>
      <xs:element name="interface"
minOccurs="1"
type="interface_type"/>
    </xs:sequence>
  </xs:complexType>
  <xs:complexType name="interface_type">
    <xs:sequence>
      <xs:choice>
        <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
        <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
      </xs:choice>
    </xs:sequence>
  </xs:complexType>
</xs:schema>

> -----Original Message-----
> From: xml-bouncesgnome.org [mailtoml-bo
uncesgnome.org] On 
> Behalf Of Yong Chen (yongche)
> Sent: Wednesday, February 07, 2007 3:19 PM
> To: xmlgnome.org
> Subject: [xml] Libxml not catching schema error
> 
> Hi,
> 
> It seems libxml2 sometimes doesn't catch duplicate
elements 
> (under the same parent element) when loading a schema.

> (Please see the simple schema at the end).
> 
>   xmlSchemaParserCtxtPtr parserCtxtPtr = 
> xmlSchemaNewParserCtxt("./sample.xsd"); 
-----line 1
>   xmlSchemaPtr schema = xmlSchemaParse(parserCtxtPtr); 
  
> ------------>
> line 2
> 
> Line 1 creates a parser context, and line 2 creates
schema pointer.
> 
> For the schema below, there are two "ifid"
elements in 
> "interface_type"
> complexType, I expect line 2 reports an error saying 
> duplicate elements defined, but instead, line 2 returns
fine.
> 
> Thanks,
> Yong Chen 
> 
> 
> Sample.xsd:
> 
> <?xml version="1.0"?>
> <xs:schema xmlnss=&qu
ot;http://www.w3.
org/2001/XMLSchema"
> xmlns="http://www.my.com/test&q
uot; 
> targetNamespace="http://www.my.com/test&q
uot;
> elementFormDefault="qualified">
>   <xs:element name="show"
type="show_type"/>
>   <xs:complexType name="show_type">
>     <xs:sequence>
>       <xs:element name="interface"
minOccurs="1" 
> type="interface_type"/>
>     </xs:sequence>
>   </xs:complexType>
>   <xs:complexType
name="interface_type">
>     <xs:sequence>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>     </xs:sequence>
>   </xs:complexType>
> </xs:schema>
> _______________________________________________
> xml mailing list, project page  http://xmlsoft.org/ 
> xmlgnome.org http://mai
l.gnome.org/mailman/listinfo/xml
> 
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Hi Yong,

"Yong Chen (yongche)" <chencisco.com> writes:

>   <xs:complexType
name="interface_type">
>     <xs:sequence>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>     </xs:sequence>
>   </xs:complexType>

This is valid as long as the two elements with the same name
have
the same type (XML Schema "consistent declaration
rule"). The
fragment above is equivalent to:

<xs:complexType name="interface_type">
  <xs:sequence>
    <xs:element name="ifid"
minOccurs="2" maxOccurs="2"
type="xs:string"/>
  </xs:sequence>
</xs:complexType>


hth,
-boris

-- 
Boris Kolpackov
Code Synthesis Tools CC
http://www.codesynthesis
.com
Open-Source, Cross-Platform C++ XML Data Binding

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Hi Yong,

"Yong Chen (yongche)" <chencisco.com> writes:

>   <xs:complexType
name="interface_type">
>     <xs:sequence>
>       <xs:choice>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
>       </xs:choice>
>     </xs:sequence>
>   </xs:complexType>

This is also valid though does not make much sense (e.g, a
choice
between two equivalent elements). One scenario where
repeating
the same element would me sense is something along these
lines:

<xs:complexType name="interface_type">
  <xs:sequence>
    <xs:element name="ifid"
type="xs:string"/>
    <xs:element name="foo"
type="xs:string"/>
    <xs:element name="ifid"
type="xs:string"/>
  </xs:sequence>
</xs:complexType>

I.e., you want an element ifid followed by element foo which
in turn
is followed by another element ifid.


hth,
-boris


-- 
Boris Kolpackov
Code Synthesis Tools CC
http://www.codesynthesis
.com
Open-Source, Cross-Platform C++ XML Data Binding

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Hi Boris,

Thanks a lot for the response.

But libxml2 doesn't catch the problem even if I change the
type of the
first "ifid" to "xs:integer". (with or
without "xs:choice" as the parent
of "ifid" elements).

Thanks,
Yong Chen 

> -----Original Message-----
> From: xml-bouncesgnome.org [mailtoml-bo
uncesgnome.org] On 
> Behalf Of Boris Kolpackov
> Sent: Thursday, February 08, 2007 11:27 AM
> To: xmlgnome.org
> Subject: Re: [xml] Libxml not catching schema error
> 
> Hi Yong,
> 
> "Yong Chen (yongche)" <chencisco.com> writes:
> 
> >   <xs:complexType
name="interface_type">
> >     <xs:sequence>
> >       <xs:choice>
> >         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
> >         <xs:element name="ifid"
minOccurs="1" type="xs:string"/>
> >       </xs:choice>
> >     </xs:sequence>
> >   </xs:complexType>
> 
> This is also valid though does not make much sense
(e.g, a 
> choice between two equivalent elements). One scenario
where 
> repeating the same element would me sense is something
along 
> these lines:
> 
> <xs:complexType name="interface_type">
>   <xs:sequence>
>     <xs:element name="ifid"
type="xs:string"/>
>     <xs:element name="foo"
type="xs:string"/>
>     <xs:element name="ifid"
type="xs:string"/>
>   </xs:sequence>
> </xs:complexType>
> 
> I.e., you want an element ifid followed by element foo
which 
> in turn is followed by another element ifid.
> 
> 
> hth,
> -boris
> 
> 
> --
> Boris Kolpackov
> Code Synthesis Tools CC
> http://www.codesynthesis
.com
> Open-Source, Cross-Platform C++ XML Data Binding
> 
> _______________________________________________
> xml mailing list, project page  http://xmlsoft.org/ 
> xmlgnome.org http://mai
l.gnome.org/mailman/listinfo/xml
> 
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Hi Yong,

"Yong Chen (yongche)" <chencisco.com> writes:

> But libxml2 doesn't catch the problem even if I change
the type of the
> first "ifid" to "xs:integer". (with
or without "xs:choice" as the parent
> of "ifid" elements).

This is a bug then. Note also that the XML Schema support in
libxml2 is
not yet complete.

hth,
-boris


-- 
Boris Kolpackov
Code Synthesis Tools CC
http://www.codesynthesis
.com
Open-Source, Cross-Platform C++ XML Data Binding

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:-(, I thought the schema implementation was complete!

Thanks,
Yong Chen 

> -----Original Message-----
> From: xml-bouncesgnome.org [mailtoml-bo
uncesgnome.org] On 
> Behalf Of Boris Kolpackov
> Sent: Thursday, February 08, 2007 11:03 PM
> To: xmlgnome.org
> Subject: Re: [xml] Libxml not catching schema error
> 
> Hi Yong,
> 
> "Yong Chen (yongche)" <chencisco.com> writes:
> 
> > But libxml2 doesn't catch the problem even if I
change the 
> type of the 
> > first "ifid" to "xs:integer".
(with or without "xs:choice" as the 
> > parent of "ifid" elements).
> 
> This is a bug then. Note also that the XML Schema
support in 
> libxml2 is not yet complete.
> 
> hth,
> -boris
> 
> 
> --
> Boris Kolpackov
> Code Synthesis Tools CC
> http://www.codesynthesis
.com
> Open-Source, Cross-Platform C++ XML Data Binding
> 
> _______________________________________________
> xml mailing list, project page  http://xmlsoft.org/ 
> xmlgnome.org http://mai
l.gnome.org/mailman/listinfo/xml
> 
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Hi,

I've a question regarding copying one node's properties and
namespaces.

First, I want to copy all properties of node A to B, is it
correct to do
following?

                B->properties=xmlCopyPropList(B,
A->properties)


Then, I also know that node A has several namespaces defined
(such as
xmlns:first="www.first.com"
xmlns:second="www.second.com"), I want to
copy all of them to node B, should I do both of following?

               B->ns=xmlCopyNamespaceList(A->ns);
And
              
B->nsDef=xmlCopyNamespaceList(A->nsDef);





Thanks in advance for your help,

Yong Chen
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