API hangs when filter contains variable starting with $

[ohmoses]

When I send a request with a filter containing a variable that starts with a $, e.g. GET /cloud/articles/?filter={"$selected":true}, API probably passes is onto Mongo as a selection operator and the request hangs.

Expected behavior

If a field with that name doesn't exist and it's not a valid Mongo operator either, API should return the appropriate 4xx code (?) To be discussed (e.g. do we allow field names starting with $?)

[eduardoboucas]

This was an issue caused by the MongoDB connector not propagating an error. It has been fixed in dadi/api-mongodb#67 and released as version 5.0.3 of @dadi/api-mongodb.

Additionally, #585 adds the correct status code and error message for this case.