Logic App Sharepoint Create File not working as expected - dynamics-crm

Question

I created a set of logic apps to have a very specialized integration between D365 CE (CRM) and SharePoint. I am using the Notes entity in CRM to allow the user to upload a docx file using the native CRM UI. The Logic app finds the file (using CRM List Items action) and returns the file as a base64 encoded string. I was able to view the Logic App execution logs to see the base64 string and I was able to successfully decode it and open it in Word so I know that much is working perfectly.
The problem is when I try to create or update a SharePoint document using LA Create File or Update File actions. The file that results in SharePoint has the correct name, but I get an error when I try to open the file using Word (any version). I inspected the docx file before uploading to CRM and downloading from SharePoint and there is some differences in the bytes between the files - my guess is that something is not handling a Unicode conversion somewhere. In this picture, you see the PK signature (thanks Phil Katz) of the docx appears in the first two bytes and several other strings appear, but (what I think is high-order characters) is not converted correctly (the original file on top, and after downloading from SP on the bottom):
A few more technical details...
I tried to use a base64toBinary() in the logic app to upload the file to SharePoint:
and since the UI is hiding the actual expression, the code for this action looks like this (see line 5):
The problem is that either the base64toBinary() is not returning a faithful representation of the file, or the Create File is not happy about getting a docx file as binary as a parameter. I have tried passing the original base64 string directly to SP, but it just stores it as base64 and requires me to download/convert it before I can open it, and yes, I have tried using base64toString(). I have also tested the process with a plain text file, and that works just fine.
I am using D365 v8.2.2 and O365 SharePoint.

Answer 1

Naturally, after posting a question to the world and then getting a good nights sleep, I found the answer. The problem is in the JSON notation that the Designer generates. In my code above, you see where I used the base64toBody() function. I realized that it had curly braces around the entire function which turned the binary file into an object. By removing the braces, the file is now passed to SP as a binary correctly:
"body": "#base64toBinary(items('For_each_file_attached')?['documentbody'])",
So if you want this to work, I had to use the Code View in the editor to make it correct. I would be interested in knowing if there is a way to do the transformation from base64 to binary between retrieving it from CRM and before using the Create File action so that it could be more OOTB Designer.