Add subscription name to query result

help
#1

In a situation where more than one subscription might be in effect, I’d like to make sure that I only query data from a certain subscription, not among all data that might be currently available for that particular collection and user.

So I thought I’d do something like
SELECT field1, field2, "value" as "myXtraField" FROM myTable;
but of course in MongoDb, in my publish function.

That way I could do a simple
myCollection.find({myXtraField: "value"})
without the risk that other subscriptions come into play.

I’d like to do that without iterating through the entire query result in the publication.

Is there a good way to achieve this?

#2

Just replicate the query on the client side.

If one subscription is

return Whatever.find({ count: { $gt: 10 } })

and another subscription is

return Whatever.find({ count: {$lt: 10 } });

Then you can query a specific subscription by repeating that query on the client.

Meteor.subscribe('greaterThan10');
Meteor.subscribe('lessThan10');
Whatever.find({ count: { $gt: 10 } });
# => Would only return results from greaterThan10 subscription
#3

The data from both subscriptions would be available to my client side find().

#4

Correct. You would filter the result in your client side find.

#5

Yes, I could replicate the query, but I’d prefer not to. Partly because of efficiency and partly because the duplicated code would have to be kept manually in sync until forever.

#6

You don’t duplicate the code. You would write the query once, and export it.

// whatever.js

export const someQuery = {
  count: {
    $gt: 10
  }
}

Meteor.publish('greaterThan10', function() {
  return Whatever.find(someQuery);
});

// SomeComponent.js
import { someQuery } from '/imports/api/whatever.js'

Meteor.subscribe('greaterThan10');
Whatever.find(someQuery);
#7

Yes, that is true and it would work. Still, I’d have to execute a very heavy query twice

#8

Have you looked at percolate:find-from-publication?

#9

@cereal
Oh, I just realized why I got into this situation to begin with: I cannot use $text client side. So the duplicate query will not work.

#10

@robfallows
maybe that could work, but it looks like a pretty… strange workaround.
If I don’t find another way, I’ll try it though.

#11

Does the data need to be reactive?

If not, just return the data from a method

#12

It needs to be reactive, yes.

I find it strange that there seem to be no simple way of doing something that is pretty standard in SQL.