ONVIF: How to implement filter in EventBindingService::CreatePullPointSubscription

Question

We're using gSoap 2.8.106 (since that's what Yocto Kirkstone provides). We've taken https://github.com/KoynovStas/onvif_srvd as a base and started implementing ONVIF S and T Profile. T Profile requires additional event filtering as can be seen in tests like EVENT-2-1-26-v17.06 BASIC NOTIFICATION INTERFACE – TOPIC SUB-TREE IN PULLMESSAGES FILTER. In EventBindingService::CreatePullPointSubscription you receive a _tev__CreatePullPointSubscription pointer. There's a member Filter which points to wsnt__FilterType:

/* complex XML schema type 'tev:CreatePullPointSubscription': */
class SOAP_CMAC _tev__CreatePullPointSubscription {
      public:
        /// Optional element 'tev:Filter' of XML schema type 'wsnt:FilterType'
        wsnt__FilterType *Filter;

But wsnt__FilterType doesn't have anything in it:

/* complex XML schema type 'wsnt:FilterType': */
class SOAP_CMAC wsnt__FilterType : public soap_dom_element {
      public:
        /// XML DOM element node graph
        std::vector<struct soap_dom_element> __any;

On gSOAP - ONVIF examples: ONVIF_Extensibility it explains:

ONVIF data types may be extensible, permitting additional elements and/or attributes. However, most scenarios associated with profiles do not require these extensions so we remove them by default to reduce the size of the generated source code.

If specific element and/or attribute extensions to a complexType are still required in specific cases, then we simply use the typemap.dat file to add these as additional optional members to the generated classes/structs.

Likewise, we add the following line to typemap.dat to add the wsnt:TopicExpression element to the tt:Filter element of tt:Events of the Events ONVIF WSDL:

tt__EventFilter = $ wsnt__TopicExpressionType *wsnt__TopicExpression;

If I do that then tt__EventFilter changes to:

class SOAP_CMAC tt__EventFilter : public wsnt__FilterType {
      public:
        /// XML DOM attribute list
        /// Typedef xsd__anyAttribute with custom serializer for struct soap_dom_attribute
        struct soap_dom_attribute __anyAttribute;
        /// Optional element 'wsnt:TopicExpression' of XML schema type 'wsnt:TopicExpressionType'
        wsnt__TopicExpressionType *wsnt__TopicExpression;

But that's not wsnt__FilterType which is what I'm getting from _tev__CreatePullPointSubscription. So what's the intention here?

I can change the line in typemap.dat to:

wsnt__FilterType = $ wsnt__TopicExpressionType *wsnt__TopicExpression;

then wsnt__FilterType becomes:

class SOAP_CMAC wsnt__FilterType : public soap_dom_element {
      public:
        /// XML DOM element node graph
        std::vector<struct soap_dom_element> __any;
        /// Optional element 'wsnt:TopicExpression' of XML schema type 'wsnt:TopicExpressionType'
        wsnt__TopicExpressionType *wsnt__TopicExpression;

Using wsnt__TopicExpressionType I can read Dialect but that's all there is. How can I read the rest of the filter details?

Once I read the filter, is there an implementation for it anywhere or do I have to write this from scratch?

Steven Dillingham · Accepted Answer · 2024-03-20 12:50:13Z

1

Add the following lines to the wsdl/typemap.dat file passed into wsdl2h:

wsnt__FilterType = $ std::vector<wsnt__TopicExpressionType*> TopicExpression            0;  ///< Multiple elements.
wsnt__FilterType = $ std::vector<wsnt__QueryExpressionType*> MessageContent             0;  ///< Multiple elements.

This will include serialization and deserialization code for the specified elements.

You should be able to get the Topic Expression from the soap_dom_element __any:

std::string topic = topicExpression->__any.get_text();

edited Mar 20, 2024 at 12:50

answered Mar 20, 2024 at 12:45

Steven Dillingham

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