XML and VW7.5 NC

Hello
I'm just getting my feet wet with XML and I'm kind of stuck. What I'd
like to do is add XML support to my app (XML will just serve as "model
interchange format"). There is basically one schema file (at
http://www.optimizationservices.org/schemas/OSiL.xsd) I need (it imports
  some others) and I have some examples XML files (locally). What I'd
like to do: parse the schema, parse the example and validate the example
(w.r.t. the schema).
I read the "WebServices.pdf" but I'm a bit lost... I started with
something like:

xmlToObjElement := XMLTypesParser url:
'http://www.optimizationservices.org/schemas/OSiL.xsd'.
binding := (XMLObjectBinding buildBindings: (Array with:
xmlToObjElement)) first.
manager := XMLObjectMarshalingManager on: binding.

However, as soon as the base schema imports other schemas, I get the
following error:

"unhandled exception" with "This URI does not contain a protocol."

I traced it down to the XML snippet <xs:include
schemaLocation="OSgL.xsd"/> in the above mentioned schema file
"http://www.optimizationservices.org/schemas/OSiL.xsd"

Is this a VW bug? An error in the XML schema? Is there a known
workaround? Or, what am I doing wrong?

Thanks a lot
Mike

For basic XML support, see BasicLibraries.pdf, the chapter on XML.  There should be (well, in theory at least) enough information there to get you started.

Bruce

----- Original Message -----
From: "Mike Bielser" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, June 14, 2007 6:42 AM
Subject: XML and VW7.5 NC


| Hello
| I'm just getting my feet wet with XML and I'm kind of stuck. What I'd
| like to do is add XML support to my app (XML will just serve as "model
| interchange format"). There is basically one schema file (at
| http://www.optimizationservices.org/schemas/OSiL.xsd) I need (it imports
|  some others) and I have some examples XML files (locally). What I'd
| like to do: parse the schema, parse the example and validate the example
| (w.r.t. the schema).
| I read the "WebServices.pdf" but I'm a bit lost... I started with
| something like:
|
| xmlToObjElement := XMLTypesParser url:
| 'http://www.optimizationservices.org/schemas/OSiL.xsd'.
| binding := (XMLObjectBinding buildBindings: (Array with:
| xmlToObjElement)) first.
| manager := XMLObjectMarshalingManager on: binding.
|
| However, as soon as the base schema imports other schemas, I get the
| following error:
|
| "unhandled exception" with "This URI does not contain a protocol."
|
| I traced it down to the XML snippet <xs:include
| schemaLocation="OSgL.xsd"/> in the above mentioned schema file
| "http://www.optimizationservices.org/schemas/OSiL.xsd"
|
| Is this a VW bug? An error in the XML schema? Is there a known
| workaround? Or, what am I doing wrong?
|
| Thanks a lot
| Mike
|

If you need to use XML to object binding you can try the following code
to create a binding and unmarshal an XML file:
(x20 := XMLTypesParser defaultBinding)
        baseURI:'http://www.optimizationservices.org/schemas/OSiL.xsd'
asURI;
        readFrom:'http://www.optimizationservices.org/schemas/OSiL.xsd'
asURI.

b := XMLObjectBinding loadFrom: x20 printString readStream.
manager := XMLObjectMarshalingManager on: b.
xml := (XMLParser on: aDataSource) validate: false; scanDocument.
doc := manager unmarshal: xml atNamespace:
'os.optimizationservices.org'.

The connection was not responding when the http client tried to read the
schema from the <include> statement.


Tamara Kogan
Smalltalk development,
Cincom Systems

> -----Original Message-----
> From: Bruce Boyer [mailto:[hidden email]]
> Sent: Thursday, June 14, 2007 9:54 AM
> To: Mike Bielser; [hidden email]
> Subject: Re: XML and VW7.5 NC
>
> For basic XML support, see BasicLibraries.pdf, the chapter on XML.
There
> should be (well, in theory at least) enough information there to get
you I'd
> | like to do is add XML support to my app (XML will just serve as
"model
> | interchange format"). There is basically one schema file (at
> | http://www.optimizationservices.org/schemas/OSiL.xsd) I need (it
imports
> |  some others) and I have some examples XML files (locally). What I'd
> | like to do: parse the schema, parse the example and validate the
example

Hi Tamara
thank you very much for your help. I started with the code snippet you
provided; this snippet was somewhat similar to mine.
However, executing your code in a workspace would bring up the hourglass
cursor, then the trash can cursor, then the GC cursor. This "cursor
sequence" repeated over and over, usually until I lost patience (at
which point VW had consumed about 180 MB of RAM and I had to kill the
workspace using the ProcessViewer).
It quickly turned out that there were cyclic imports/includes of schema
files; at least in my case the involved VW XML classes do not seem to
like this!
I downloaded all the schema files, deleted any cyclic includes and got
started. The next offending line of code seems to be

binding := XMLObjectBinding loadFrom: x20 printString readStream

which is not valid XML code but just a ByteString containing 'a
WebServices.XMLTypesParser'. So I replaced it with this code of mine:

tmpStream := (String new: 5000) readWriteStream.
x20 schemaBindings printCanonicalOn: tmpStream.
tmpStream reset.
binding := XMLObjectBinding loadBindings: tmpStream.

In the last line of code above, at some point VW yells at me saying:

Unhandled exception: Message not understood: #relations
WebServices.ChoiceMarshaler(Object)>>doesNotUnderstand:
WebServices.GroupMarshaler>>setAttributesFrom:in:
WebServices.GroupMarshaler(WebServices.XMLTypeMarshaler)>>setAttributesFrom:in:name:
WebServices.BindingBuilder>>startBinding:attributes:
WebServices.BindingBuilder>>startElement:localName:qName:attributes:

And now I'm really lost...Can I tell VW to ignore some schema elements
(like this one), to get past such errors??? Or what do I do?

Thanks a lot for your help so far!

Kind regards
Mike

> It quickly turned out that there were cyclic imports/includes of
schema
> files; at least in my case the involved VW XML classes do not seem to
> like this!

It is a bug. We should take care of cyclic references. Is these any way
to send some test case?

 
> In the last line of code above, at some point VW yells at me saying:
>
> Unhandled exception: Message not understood: #relations
> WebServices.ChoiceMarshaler(Object)>>doesNotUnderstand:
> WebServices.GroupMarshaler>>setAttributesFrom:in:
>
WebServices.GroupMarshaler(WebServices.XMLTypeMarshaler)>>setAttributesF
ro
> m:in:name:
> WebServices.BindingBuilder>>startBinding:attributes:
> WebServices.BindingBuilder>>startElement:localName:qName:attributes:
>
> And now I'm really lost...Can I tell VW to ignore some schema elements
> (like this one), to get past such errors??? Or what do I do?

It looks like we don't handle a choice inside a group element properly.
There is no way to ignore this element while loading the binding. You
can try to modify the xml to object binding and reload the binding.
If your xml looks like:
<struct name="myGroup">
<choice>
<element ref="xsd:int" name="int"/>
<element name="group2" ref="xsd:string"/>
</choice>
</struct>
<struct name="Item" tag="Item">
<group name="myGroup" ref="tns:myGroup"/>
<element ref="tns:Item" />
</struct>
You can remove the <choice> element and the group elements will be
treated as <sequence>:
<struct name="myGroup">
<element ref="xsd:int" name="int"/>
<element name="group2" ref="xsd:string"/>
</struct>

Tamara

 
> Unhandled exception: Message not understood: #relations
> WebServices.ChoiceMarshaler(Object)>>doesNotUnderstand:
> WebServices.GroupMarshaler>>setAttributesFrom:in:
>
WebServices.GroupMarshaler(WebServices.XMLTypeMarshaler)>>setAttributesF
ro
> m:in:name:
> WebServices.BindingBuilder>>startBinding:attributes:
> WebServices.BindingBuilder>>startElement:localName:qName:attributes:


Could you, please, send me the group element? I was able to load a group
with choice element in 75:

bindingSpec := XMLTypesParser readFrom:
'<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
         xmlns="http://testGroupChoice"
         targetNamespace="http://testGroupChoice">
 <xsd:element name="Item">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:group ref="myGroup"/>
        <xsd:element name="aaa" type="xsd:string"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
 
 <xsd:group name="myGroup">
    <xsd:choice>
      <xsd:element name="string" type="xsd:string"/>
     <xsd:element name="int" type="xsd:int"/>
    </xsd:choice>
  </xsd:group>

  </xsd:schema>'.
b := XMLObjectBinding loadFrom: bindingSpec printString readStream.

Tamara

Kogan, Tamara wrote:


<snip>

> Could you, please, send me the group element? I was able to load a group
> with choice element in 75:

<snip>


Here you go:

<xs:group name="DistributionGroup">
        <xs:choice>
                <xs:group ref="DiscreteDistributionGroup"/>
                <xs:group ref="ContinuousDistributionGroup"/>
        </xs:choice>
</xs:group>
<xs:group name="DiscreteDistributionGroup">
        <xs:choice>
                <xs:element ref="empiricalDiscrete"/>
                <xs:element ref="discreteUniform"/>
                <xs:element ref="bernoulli"/>
                <xs:element ref="binomial"/>
                <xs:element ref="hypergeometric"/>
                <xs:element ref="poisson"/>
                <xs:element ref="geometric"/>
                <xs:element ref="negativeBinomial"/>
        </xs:choice>
</xs:group>

The above snippet is the first occurence of element "group" in the
schema "OSgL.xsd", which actually gets imported/included by the schema
"OSiL.xsd" (the start/mother schema).
I have attached the EDITED schemas (i.e. the ones where I manually
deleted any cyclic includes). I started editing the VW code this
afternoon (well, afternoon here in Switzerland) to handle this "group"
thing, but I don't know whether I'll be able to fix it...

Kind regards
Mike

I copied your code:

into a workspace and got the following error:

Unhandled exception: Illegal volume specification
FATFilename class(PCFilename class)>>readVolumeFrom:
FATFilename class(PCFilename class)>>readBaseLocationFromStream:
FATFilename class(Filename class)>>components:

The stream (that readVolumeFrom: expects) starts with "<xsd:"

Do you have anything special loaded from the Cincom Public Repository? I
opened the Parcel Manager (tab "Suggestions", folder "Web Services" on
the left), other than "Opentalk-CGI" I have every parcel loaded into a
clean VW7.5NC image (on WinXP SP2). Really puzzling...

Mike

I changed the workspace code to

bindingSpec := XMLTypesParser readFrom:
        '<xsd:schema ... snip ... </xsd:schema>' readStream.
b := XMLObjectBinding loadFrom: bindingSpec printString readStream.

and now it works. So the missing "readStream" was the culprit in your
small example. Unfortunately, this still does not solve the group/choice
problem in my schemas...

Mike

This workspace code works (but please note I had to change all "ref" to
"name" within the choice element in order to avoid an "unresolved
reference signal"):

bindingSpec := XMLTypesParser readFrom:
'<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
         xmlns="http://testGroupChoice" targetNamespace="http://testGroupChoice">

<xs:group name="DiscreteDistributionGroup">
     <xs:choice>
         <xs:element name="empiricalDiscrete"/>
         <xs:element name="discreteUniform"/>
         <xs:element name="bernoulli"/>
         <xs:element name="binomial"/>
         <xs:element name="hypergeometric"/>
         <xs:element name="poisson"/>
         <xs:element name="geometric"/>
         <xs:element name="negativeBinomial"/>
     </xs:choice>
</xs:group>
</xs:schema>' readStream.
b := XMLObjectBinding loadFrom: bindingSpec printString readStream.

Mike

This workspace code does NOT work (at least not in my setup := clean
image + "Web Services" - "Opentalk-CGI").

bindingSpec := XMLTypesParser readFrom:
'<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
         xmlns="http://testGroupChoice" targetNamespace="http://testGroupChoice">

<xs:group name="DistributionGroup">
     <xs:choice>
         <xs:group ref="DiscreteDistributionGroup"/>
         <xs:group ref="ContinuousDistributionGroup"/>
     </xs:choice>
</xs:group>
</xs:schema>' readStream.
b := XMLObjectBinding loadFrom: bindingSpec printString readStream.

Comparing this with the former example reveals that the culprit is
"groups within a choice". As long as you have "elements within a
choice", things are fine. From my point of view, this is a bug in VW7.5NC

Mike

Hi Mike,

I was able to create x2o binding from the schemas you sent in 75. There
was no problem with the include statements.
I copied all file in one directory and did:

(parser := XMLTypesParser defaultBinding)
        baseURI: 'F:\vw7\image\bugs\OSgl\OSiL.xsd' asFilename asURI;
        readFrom:'F:\vw7\image\bugs\OSgl\OSiL.xsd' asFilename asURI.

b := XMLObjectBinding buildBindings:  parser schemaBindings
realElements.

With the attached patch the binding was loaded.
I created an AR for the case.
It took for a while to create the binding. There are more than 900
marshalers in this binding.

Tamara Kogan
Smalltalk development,
Cincom Systems

Hi Tamara
I tried the attachment, but both on WinXP as well as on MacOS 10.4 the
file "XMLObjectMarshalers.st" ( the only one within the ZIP archive)
contains (basically) nothing:

<?xml version="1.0"?>

<st-source>
<time-stamp>From VisualWorks®, Pre-Release 7.5.1 (jun07.2) of June 11,
2007 on June 19, 2007 at 8:04:54 am</time-stamp>


</st-source>

Is this really all there is in this file?

Kind regards
Mike

Indeed, that file out is empty.

-Boris

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Thank you.
11,
> 2007 on June 19, 2007 at 8:04:54 am</time-stamp>
>
>
> </st-source>
>
> Is this really all there is in this file?
>
> Kind regards
> Mike

Sorry, about it. Try the attached file.

Tamara Kogan
Smalltalk development,
Cincom Systems

Kogan, Tamara wrote:
> Sorry, about it. Try the attached file.
>
> Tamara Kogan
> Smalltalk development,
> Cincom Systems

Hi Tamara
great, it works, thanks a million! So, to recap (from my point of view):

1) I had to delete any cyclic includes/imports in the schema files
manually (not a big deal here, but I think VW should handle this
"automagically")

2) Nested "group-choice-group" constructs (and similiar ones) do not
work (without your patch).

Thanks again
Mike