GraphQLDataSourceProvider.cls

global with sharing class GraphQLDataSourceProvider extends DataSource.Provider{

    global GraphQLDataSourceProvider(){} 

        override global List<DataSource.AuthenticationCapability> getAuthenticationCapabilities() {
        List<DataSource.AuthenticationCapability> capabilities = new List<DataSource.AuthenticationCapability>();
            capabilities.add(DataSource.AuthenticationCapability.OAUTH);
        		capabilities.add(DataSource.AuthenticationCapability.ANONYMOUS); 
        		capabilities.add(DataSource.AuthenticationCapability.BASIC);
        return capabilities;
    }

    override global List<DataSource.Capability> getCapabilities()
    { 
    List<DataSource.Capability> capabilities = new
        List<DataSource.Capability>();
    capabilities.add(DataSource.Capability.ROW_QUERY);
    capabilities.add(DataSource.Capability.REQUIRE_ENDPOINT);
    //capabilities.add(DataSource.Capability.SEARCH); 
    //capabilities.add(DataSource.Capability.ROW_CREATE);
    //capabilities.add(DataSource.Capability.ROW_UPDATE);
    //capabilities.add(DataSource.Capability.ROW_DELETE);
    return capabilities;
    }

    override global DataSource.Connection getConnection(DataSource.ConnectionParams connectionParams) {
            return new GraphQLDataSourceConnection(connectionParams);
        }
}