TL;DR: The SharePoint File triggers (e.g. 'When a file is modified) also need to return the numerical ID of the item. In addition, or as an alternative, the 'Get file metadata' activities need to return the numerical ID in the ID field, not the path (as the path is already known because it is an input parameter)
I have a very common scenario, which is a SharePoint Document Library with a number of custom columns. When a change is made I need the following information in my Flow:
Content of a custom column
Should be pretty easy, right?
Now, here is the problem. I can use the 'When a file is modified' trigger, which nicely gives me the file name. However, there is no way to get to the metadata for the item as:
'Get file metadata using path' does not return custom columns (and the ID field does not contain the numerical ID)
'Get item', which does return the custom columns, requires the numerical ID of the file, which is not available on the trigger (or on 'Get file metadata using path'.
I have tried to turn it upside down and use ‘When an existing item is modified’ as the trigger. This nicely gives me the numerical ID, but not the file name. I can get the file name using 'Get file metadata using path' if only I had the path to the item, which I don't have, I have the ID.