SSAS Stored Procedures - connecting to the transactional data source

There are often circumstances where an SSAS stored procedure needs to connect to the transactional database to perform a query.  This is certainly the case in a near-real-time OLAP solution where the cube sits directly on top of the application database and dynamic dimension security is implemented by a stored proc. Here the SSAS stored procedure has to query the transactional database in order to get the user's authorisation. Clearly the SSAS database has a data source and it uses this connection to process the cube. So how do we get the connection string?

Well the short code snippet below provides the solution. The code simply connects back to the current database using AMO and obtains the connection string from the data source object. It then removes the redundant "Provider=SQLNCLI.1;" before returning a valid SQL connection string that can be used by SqlConnection().