[fdo-trac] #276: Can't access WMS custom commands from managed code

[FDO]

#276: Can't access WMS custom commands from managed code
-----------------------+----------------------------------------------------
 Reporter:  ssakharov  |         Owner:  gregboone
     Type:  defect     |        Status:  assigned 
 Priority:  major      |     Milestone:  3.3.1    
Component:  FDO API    |       Version:  3.3.0    
 Severity:  3          |    Resolution:           
 Keywords:             |   External_id:           
-----------------------+----------------------------------------------------
Changes (by gregboone):

  * status:  new => assigned

Comment:

 This submission tests and resolves issues identified when attempting to
 access the following WMS custom commands through the FDO API managed
 interface.

 !GetFeatureClassStyles
 !GetFeatureClassCRSNames
 !GetImageFormats

 Through testing, it was discovered that no mechanism existed to allow
 custom commands created at the provider level to be exposed through the
 FDO ICommand Managed interface. The reason why these commands are not
 supported is that the creation of the managed wrapper object around the
 custom command is attempted in the FDO managed API component, where the
 WMS specific managed interfaces are unknown. Only the published non-custom
 FDO commands are known at this level.

 To resolve this issue, I fell back on the command pattern used to resolve
 a similar issue identified with the provider specific implementations of
 FDO !PhysicalSchemaMappings. In that case, it was decided that the
 provider specific implementation of the !PhysicalSchemaMapping interface
 would be exposed as a concrete class rather than a derived interface. As a
 part of the definition of the concrete class, a constructor would be
 defined that accepted the result of the call to
 IConnection::!CreateCommand. It was then the responsibility of the managed
 class to construct itself correctly in a manner by which it is able to
 interface with the underlying unmanaged object.

 For the case of the commands mentioned above, the following concrete
 classes would have to be defined and exposed for the WMS provider:

 {{{
 public __gc class GetFeatureClassStylesCommand :
     public ICommandImp,
     public IGetFeatureClassStyles
 {
    ...

 public:
     GetFeatureClassStylesCommand(ICommand* command, Boolean autoDelete);

    ...
 }

 public __gc class GetImageFormatsCommand :
     public ICommandImp,
     public IGetFeatureClassStyles
 {
    ...

 public:
     GetImageFormatsCommand(ICommand* command, Boolean autoDelete);

    ...
 }

 public __gc class GetFeatureClassCRSNamesCommand :
     public ICommandImp,
     public IGetFeatureClassStyles
 {
    ...

 public:
    GetFeatureClassCRSNamesCommand(ICommand* command, Boolean autoDelete);

    ...
 }
 }}}

 Here is an example of how the the above wrpapper classes are to be used:

 {{{
 IConnectionManager connectionManager =
 FeatureAccessManager.GetConnectionManager();
 IConnection mConnection =
 connectionManager.CreateConnection("OSGeo.WMS.3.3");
 mConnection.ConnectionString = @"FeatureServer=http://www2.dmsolutions.ca/
 cgi-bin/mswms_gmap";

 ConnectionState state = mConnection.Open();
 ICommand command = mConnection.CreateCommand(CommandType_GetImageFormats);
 GetImageFormatsCommand formatsCmd = new GetImageFormatsCommand(command,
 false);
 StringCollection strColl = formatsCmd.Execute();
 for (int i = 0; i < strColl.Count; i++) {
     StringElement strElem = strColl.get_Item(i);
     string strVal = strElem.String;
     Console.WriteLine(strVal);
 }

 mConnection.Close();
 }}}

 During the implementation of this change, it was discoverd that there was
 no means of retrieving the actual string value attached to the FDO
 StringElement interface using the managed FDO API. It looks as if the
 unmanaged 'FdoString* GetString()' method was never exposed in the managed
 API. To resolve this issue, a new interface method will need to be added
 to StringElement as follows:

 {{{
 public __sealed __gc class StringElement : public Disposable
 {
    ...

 public:
    __property System::String* get_String ();

    ...
 }

 }}}

 The following Files were modified:

 {{{
 *
 ******Fdocore******
 Modified : Fdo/Managed\Src\OSGeo\Common\mgStringElement.cpp
 Modified : Fdo/Managed\Src\OSGeo\Common\mgStringElement.h
 Modified : Fdo/Managed\Src\OSGeo\FDO\Commands\mgICommandImp.cpp
 Modified : Fdo/Managed\Src\OSGeo\FDO\Commands\mgICommandImp.h
 Modified : Fdo/Managed\Src\OSGeo\FDO\mgObjectFactory.cpp
 *
 ******WMS******
 Modified : Providers/WMS/Src\UnitTest\WmsTestCustomCommands.cpp
 Modified : Providers/WMS/Docs\doc_src\Doxyfile_WMS_managed
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\Override\stdafx.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\Override\AssemblyVersion.cpp
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassCRSNames.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassCRSNamesImp.cpp
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetImageFormats.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetImageFormatsImp.cpp
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassCRSNamesImp.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetImageFormatsImp.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassStyles.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassStylesImp.cpp
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgCommandType.h
 Modified :
 Providers/WMS/Managed\Src\OSGeo\FDO\Providers\WMS\mgIGetFeatureClassStylesImp.h
 *
 }}}

-- 
Ticket URL: <http://trac.osgeo.org/fdo/ticket/276#comment:1>
FDO <http://fdo.osgeo.org/>
Feature Data Objects