In this short post I will help you to build your Nintex for Office 365 workflow that will allow you to copy attachments that were added to a task to a related list item attachments. The list item is of course the one around which the whole workflow is running.

Approval task form

First you need to create an approval form.

It really doesn’t matter which type of a designer will you choose – each allows you to use Task attachments control (or in the modern designer – File upload control):

Configure the form the way you need it. After you’re done, get back to the approval action.

Approval action

Whether you use “Assign a task” or “Start a task process” action, you need to configure the field that returns task (or tasks) ID:

You will later use those IDs to get attachments from the related tasks (or task).

Workflow

First get the workflow a moment to wait after the approval is completed. I noticed, that sometimes workflow was resuming much faster than the attachments were uploaded to the task item. In result, workflow was resumed with information about e.g. just one attachments from 3 uploaded.

Then for each generated task do the following:

1. Prepare headers for the HTTP request:
   
   
2. Perform a GET HTTP request to the following request URL:
   
   {SITE URL}/_api/lists/getbytitle('Workflow Tasks')/items(TASK ID FOR CURRENT LOOP RUN)/AttachmentFiles?$select=FileName,ServerRelativeUrl
   
   
3. The response body will be of the following structure: {"value": [{"FileName": "xyz.jpg", "ServerRelativeUrl": "somepath/xyz.jpg"}]} – you need to extract the table only.
   
   
4. Then perform action for each item from the extracted table.

Next for each extracted attachment (in the loop iterate over the var_Data_dict dictionary and save item as eg. var_Item_dict):

1. Get filename from the dictionary
2. Get path from the dictionary
   
   
3. Prepare request headers (like above, optionally you can add second item as Content-Type: application/json)
4. And perform the copy POST request to:
   ‍{Workflow Context:Current site URL}‍/_api/web/getfilebyserverrelativeurl(@v0)/copyto(strnewurl=@v1,boverwrite=true)?@v0='‍{Variable:var_Path_txt}‍'&@v1='/SITE RELATIVE URL TO LIST/Attachments/‍{Current Item:ID}‍/‍{Variable:var_Filename_txt}‍'
   

And that’s it! Task attachment is now added to the related list item’s attachments list. Good luck!