Andrea Aime wrote: > Justin Deoliveira ha scritto: >> Hi Andrea, >> >> Finally got a chance to look your proposal over, i must say this looks >> pretty darn cool. I had an idea about how to extend the protocol. >> >> Instead of modifying any of the existing wfs schema files, could we >> define all of the needed functionality to support versioning in terms of >> new operations? If so, then we could create a new schema which just >> imports the wfs schemas proper, and extends any types that it needs to. >> >> For instance, consider the type for a GetFeature reqquest from the wfs >> schema: >> >> WFS-basic.xsd: >> >> <xsd:complexType name="GetFeatureType"> >> <xsd:sequence> >> <xsd:element ref="wfs:Query" maxOccurs="unbounded"/> >> </xsd:sequence> >> <xsd:attribute name="version" >> type="xsd:string" use="required" fixed="1.0.0"/> >> <xsd:attribute name="service" >> type="xsd:string" use="required" fixed="WFS"/> >> <xsd:attribute name="handle" >> type="xsd:string" use="optional"/> >> <xsd:attribute name="outputFormat" >> type="xsd:string" use="optional" default="GML2"> >> </xsd:attribute> >> <xsd:attribute name="maxFeatures" type="xsd:positiveInteger" >> use="optional"> >> </xsd:attribute> >> </xsd:complexType> >> >> >> In our schema we create a new type of request, GetFeatureAtRevision (for >> lack of a better name) which extends the normal operation type just >> adding an additional >> >> WFS-version.xsd: >> >> <xsd:complexType name="GetFeatureAtRevisionType"> >> <extenstion base="wfs:GetFeatureType"> >> <xsd:attribute name="revision" type="xsd:string"/> >> </extension> >> </xsd:complexType> >> >> An idea, it would make extending the schema nice and clean. However it >> hinges on being able to create all the needed operations by xml schema >> extension and restriction. Not sure if that is possible. > > Yeah, I was thinking about it myself too... seems like a good plan > indeed, and for operations where I cannot cleanly extend the WFS XSD, > I'll just have to copy and hack. > Restriction allows me to better constraint existing element/attributes, > but does not allow me to wipe out existing attributes, right? Not sure, this is bordering on my knowledge of xml schema but i beleive you are correct. > > I'm also considering this from the point of view of someone that already > implemented WFS-T, and wants to support versioning as well... would the > copy and paste approach from a GetFeature request work for GetDiff? > I don't want to support everything GetFeature has in that call, for > example. The same goes for GetLog.
> This seems the only clean way, yet it seems more work for > implementors... having the protocol dead easy to implement is key, since > we don't have a OpenGIS spec for it (and having "revision" around, we > cannot even try to turn this into a spec, because global revision > numbers do expose an implementation detail I guess). > Considering that not many people implement wfs altogether, I dont think a ton of people will implement wfs-t. I agree that a simple protocol is a big win, but not if it starts to reek havoc with existing clients. Having two instances of a single schema (one modified) could quickly turn into a nightmare. > Cheers > Andrea > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Geotools-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geotools-devel > > !DSPAM:1004,456b2294224852207481331! > -- Justin Deoliveira [EMAIL PROTECTED] The Open Planning Project http://topp.openplans.org ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
