Monitor Dropbox Folders for New Files with DB Comparison

Description

Here's the corrected English text:

Dropbox Folder Monitoring Workflow

As we don't have (yet?) a Dropbox node "Watching new files" or "Watching folder", I created this central workflow to do it.

How it works
Triggered by Dropbox webhook
I respond immediately to Dropbox to avoid webhook disabling
Then I add/duplicate one branch per monitored folder, according to my needs

In my case, I need to monitor several folders, like "vocal notes to process", "transcriptions to LinkedIn posts" or "quotes to add".

This workflow shows 2 types of folder monitoring:
Way #1: Each file in the monitored folder calls a sub-workflow
Way #2: We get all files from the monitored folder and compare them to a database. If the file is not listed in DB, i supposed it's new one.

Way #1 - We get all files from the monitored folder
I set a variable folder_to_watch to indicate which folder to monitor. This step is here just to be homogeneous and allow setting the folder path only once in this branch.
I list the folder files
We keep only files (exclude folders)
Then I call the specialized sub-workflow

Way #2 - We want only new files from the monitored folder
I set a variable folder_to_watch to indicate which folder to monitor
I list the folder files and keep only files
Meanwhile, I query my DB to get known files about this folder (I send the query to NocoDB (folder_to_watch,eq,{{ $json.folder_to_watch }}))
Now I can exclude old files and keep only new ones by merging (I compare from Dropbox file id - as the file could be renamed by the user)
I add the new file in DB to be sure to recognize it next time - I save the JSON Dropbox data:
{
"id":"{{ $json.id }}",
"name":"{{ $json.name }}",
"lastModifiedClient": "{{ $json.lastModifiedClient }}",
"lastModifiedServer": "{{ $json.lastModifiedServer }}",
"rev": "{{ $json.rev }}",
"contentSize": {{ $json.contentSize }},
"type": "{{ $json.type }}",
"contentHash": "{{ $json.contentHash }}",
"pathLower": "{{ $json.pathLower }}",
"pathDisplay": "{{ $json.pathDisplay }}",
"isDownloadable": {{ $json.isDownloadable }}
}
And now I can call my sub-workflow :)

My DB
Columns details:
folder_to_watch
data (json/text)
timestamp
file_id (Dropbox file ID, to ease future searches)

My vision:
I have only one workflow in my n8n that monitors Dropbox folders/files
This workflow calls the required sub-workflow specialized for the tasks required
I will have as many branches as I have folders to monitor (if I have 5 different folders to watch, I will get 5 branches and 5 sub-workflows)