In WSO2 API Manager we can provide wsdl when we create API. And users may be able to access it from UI. When we store API in registry we will rewrite endpoints to match with API created. But still users can type API url and wsdl and hit backend wsdl. For this we can suggest synapse configuration based solution. For this i added filter on top of resource and check request is coming for wsdl. If it contains wsdl url then we can forward request to registry path of internal wsdl. Sometimes editing synapse configurations manually will cause to some problems(when we update through publisher it will discard changes etc). So we normally dont recommend that but in this case we do not have other option.
As a solution for that we can automate this using velosity template file. Then we don't have to do this per each API Manually. For this we can use API name, context and version parameters inside velosity configuration and generate filter according to that. Sample configuration would be something like this. Please note here we should have connection to registry ( some of our clients don't mount registry for gateway). We need to explain limitations of this approach when we reply to client.
<filter source="get-property('To')" regex=".*?wsdl.*"> <log level="custom"> <property name="end" expression="get-property('To')"/> </log> <send> <endpoint> <address uri="http://10.100.1.65:9763 /registry/resource/_system/governance/apimgt/applicationdata/wsdls/admin--rrr1.0.0.wsdl"/> </endpoint> </send> </filter>