Ability to check the data before updating it (single request)

[jnsougata]

Now we can only update the data but if we want to check the data before updating that's not possible currently.

Let's says we have {"a": [1, 2, 3, 4]} in our Base. Now we want to append some element in this list using update. But we also want to check if that value already exists in the list. In current way if we want to do it we have to fetch the data before hand the check and then update which takes 2 API calls.

Let's assume the user want to add 1 to the list but if 1 is already there it won't append. To do that in a single request we can send a __checks key "__checks": {"contains?" : 1} with the update payload where it will be automatically parsed and handled by backend and if the check passes 1 will be added to the list otherwise won't and request will be responded accordingly with proper status code .

Sample Payload Structure:

updates = {
  "__checks": {"contains?" : 1}
  "a": base.util.append(1) # append 1'to 'a'
}