Adds a beforeget event to standard Deployd collections.

By default Deployd runs the on get logic on each result of a get request, even if, for example, the user is not logged in and should not receive any results.

ON GET event

cancelUnless(me, "You are not logged in", 401)

Front end

dpd.mycollection.get({}, function(res) {
    console.log(res) // res === []
})

This would fetch all entries from mycollection and check if the user is logged in repeatedly, for every result. Then return an empty result to the user. (or crash)

ON BEFOREGET event

cancelUnless(me, "You are not logged in", 401)

Front end

dpd.mycollection.get({}, function(res) {
    console.log(res) // res === {"message":"You are not logged in","statusCode":401,"status":401}
})

This time, Deployd would immediately cancel the request and return an error message to the user.