[xsd-users] Cxx-tree parsers not generated for all global elements
Laurence Davies
laurence.davies at unsw.edu.au
Sun Jul 5 20:06:44 EDT 2015
Hi Boris,
I've extracted this issue from my last email to this list since it is currently a bottleneck for me that I can't currently solve:
I have global elements that substitute for a global abstract element, and the parsers (documented here: http://www.codesynthesis.com/projects/xsd/documentation/cxx/tree/manual/#3) don't seem to be generated for these elements. Am I missing a crucial option to enable the generation of these parsers? For example, the following extract from my schema does not produce a parser for neither AbstractPosition nor Position. Is this because of the substitution group and the lack of a type for AbstractPosition?
<element name="AbstractPosition" substitutionGroup="gml:AbstractFeature"/>
<element name="Position" type="geo:PositionType" substitutionGroup="geo:AbstractPosition"/>
<complexType name="PositionType">
<complexContent>
<extension base="gml:AbstractFeatureType">
....
</extension>
</complexContent>
</complexType>
Thank you again and kind regards,
Laurence Davies
Laurence Davies
____________________
Research Assistant in eGeodesy
CRC-SI, UNSW
Desk phone: (03) 8636 2373
Mobile: 0427 519 289
________________________________________
From: Laurence Davies
Sent: Monday, 29 June 2015 11:51 AM
To: xsd-users at codesynthesis.com
Subject: RE: [xsd-users] Resolving xlinks in a GML file
Hi Boris,
Thanks for your reply.
You've noted the xlink that points to raw data, so perhaps I provided a bad example.
In GML there is the concept of the property type (if you're interested, it is discussed here: https://www.seegrid.csiro.au/wiki/AppSchemas/GmlImplementation#Implementation_of_properties ) which is my main concern at present. The below XML should illustrate the URLs that I need to resolve and parse if the resolution succeeds:
<geo:PositionTimeSeries gml:id="ID_PTS_1" srsName="http://www.opengis.net/gml/srs/epsg.xml#4938">
<geo:atNode xlink:href="http://wfs.geodesyml.org/nodes?identifer" />
...
</geo:PositionTimeSeries>
HTTP result from the hypothetical web service http://wfs.geodesyml.org/nodes?hashidentifer would look like:
<wfs:FeatureCollection numberMatched="1" numberReturned="1" timeStamp="2015-06-29T00:06:01.221Z" xsi:schemaLocation="urn:xml-gov-au:icsm:egeodesy:0.2 http://icsm.govspace.gov.au/files/2015/05/GeodesyML.xsd http://www.opengis.net/gml/3.2 http://schemas.opengis.net/gml/3.2.1/gml.xsd http://www.opengis.net/wfs/2.0 http://schemas.opengis.net/wfs/2.0/wfs.xsd">
<wfs:member>
<geo:Node gml:id="node_11328">
<gml:name codeSpace="urn:vic-gov-au:icsm:egeodesy:geodesyml_node-name">node_11328</gml:name>
...
</geo:Node>
</wfs:member>
</wfs:FeatureCollection>
Would the added layer of parsing a WFS response pose a problem? If the URL just returns a <geo:Node>...</geo:Node> perhaps I could use the following template:
/* second argument takes the form:
* std::[auto|unique]_ptr<type> name (const std::basic_string<C>& uri, xml_schema::flags = 0, const xml_schema::properties& = xml_schema::properties ());
*/
template<class P, class T>
std::auto_ptr<T> PropertyResolver(P &p,
std::auto_ptr<T> (*create_global_element) (const ::std::string& uri, xml_schema::flags, const xml_schema::properties&)
)
{
typedef ::xlink::hrefType href_type;
typedef ::xsd::cxx::tree::optional< href_type > href_optional;
href_optional ho = p.href();
if (ho.present()) {
href_type h = ho.get();
if (h.at(0) == '#')
{
xml_schema::idref ref(h.substr(1), 0, &p);
return ref.get();
}
else
{
/* Resolve the URI externally */
xercesc::XMLUri xuri(xercesc::XMLString::transcode(h));
if (xuri.isValidURI())
{
/* @todo Is this an XPointer? Split at the # and resolve the base,
* then the XPointer expression */
/* Try parsing using the xsd type */
return create_global_element(h,0,xml_schema::properties ());
}
else
{
throw runtime_error("URI for xlink:href is not valid.");
}
}
}
return std::auto_ptr<T>(null);
}
This leads to another issue that I'm having: The generation of parsers for global elements. I have global elements that substitute for a global abstract element, and the parsers (documented here: http://www.codesynthesis.com/projects/xsd/documentation/cxx/tree/manual/#3) don't seem to be generated for these elements. Am I missing a crucial option to enable the generation of these parsers? For example, consider the following extract from my schema:
<element name="AbstractPosition" substitutionGroup="gml:AbstractFeature"/>
<element name="Position" type="geo:PositionType" substitutionGroup="geo:AbstractPosition"/>
<complexType name="PositionType">
<complexContent>
<extension base="gml:AbstractFeatureType">
....
</extension>
</complexContent>
</complexType>
Thank you again and kind regards,
Laurence Davies
____________________
Research Assistant in eGeodesy
CRC-SI, UNSW
Desk phone: (03) 8636 2373
Mobile: 0427 519 289
________________________________________
From: Boris Kolpackov [boris at codesynthesis.com]
Sent: Saturday, 27 June 2015 3:46 AM
To: Laurence Davies
Cc: xsd-users at codesynthesis.com
Subject: Re: [xsd-users] Resolving xlinks in a GML file
Hi Laurence,
Laurence Davies <laurence.davies at unsw.edu.au> writes:
> I found a relevant solution you provided in 2008 on this subject in
> the email below that covers the gml:id case but not the latter. Would
> you know what call I would need to make to resolve a URL and, if
> possible, a URN?
If href is to a gml:id, it means it is to a node in the same object
model (or to some element in the same document, in XML terms). If
href is a URL/URN like below, what does it point to?
xlink:href="ftp://ftp.ga.gov.au/geodesy-outgoing/gnss/solutions/apref/apr18287.snx"
When you say "what call I would need to make to resolve a URL" what
do you want it to be resolved to? A byte stream? A file (that got
downloaded) on disk? Maybe, if it is always an image, you want this
call to display the image on the user's computer?
Boris
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