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Make deepstream server enhance data coming to RPC

I'm looking for a way to make my deepstream server enhance data sent to an RPC endpoint with authorized client data. I wonder if it is realistic. If yes how could I achieve it?

I can see clearly I have authorized user data in canPerformAction call. I'm not sure how I can modify a message so.

Solution

  • Transform functions allow you to do so.

    https://deepstream.io/tutorials/transforming-data.html

    It provides you a hook to insert or delete data from every incoming and outgoing message from deepstream, including RPC, events and records.

    server.set( 'dataTransforms', [{
    topic: C.TOPIC.RPC,
    action: C.ACTIONS.REQUEST,
    transform: function( data, metaData ) {
        if( metaData.rpcName === 'do-something' ) {
            // Add user sensitive data to rpc
            data.userData = confidentialUserData[ metaData.sender ];
        }
        return data;
    }
}] );