Read/File From Disk Node doesn't return data

Questions
1

Hi everyone,
I’m running a self-hosted n8n (version 1.101.1) instance installed via npm (WIN11) , and I’m facing an issue with the Read/Write Files from Disk node when trying to read a .json file that was created by a Python script executed in the same workflow.

The flow download a file from Salesforce, save it into a local folder C:/n8ndata/logs in zip format and put it into a local python script. The python script generate a JSON file and save it into C:/n8ndata/extracted_data with the same name of the zip file, but replace . with _ and with JSON extension.

All run well, but when I try to read the JSON file, the flow fail. The results it’s always: No fields - item(s) exist, but they’re empty

  • The file exists, is accessible, and the content is valid JSON becausee I have checked it manually.
  • I’m using the Read/Write Files from Disk node with:
    • Operation: Read
    • File Extension: json
    • File Selector: an expression with I clean the path and file name. I’ve tried also with full absolute path to the file (e.g. C:/n8ndata/extracted_data/example_file.json)
    • Create a manual flow manually triggered by me with a txt file

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Before write here, I’ve tried to:

  • Check if the file is present and correctly saved before the read operation
  • Check if the path in n8n generated with the expression is right, and yes it works
  • Tried adding a Wait node before reading without result
  • Tried switching to .txt file format with the same data without result
  • Tried to insert an “Extract data from JSON” after the “read/write” node, but it didn’t works

Information on your n8n setup

  • **n8n version: 1.101.1
  • **Database (default: SQLite): default
  • **n8n EXECUTIONS_PROCESS setting (default: own, main): own
  • **Running n8n via (Docker, npm, n8n cloud, desktop app): npm
  • **Operating system: Windows 11
2

Hey @dura45 hope all is well, welcome to the community.

I assume when the file is saved, it remains saved. Have you tried in a separate workflow just to read it? Could you try to run Execute command node and list files in that same folder to see if that folder is even accessible?

I am not sure how npm installed n8n works and whether it has access to the host’s filesystem, or is it running in some sort of sandbox? Do you know?

3

Hi @jabbson thanks for your advice! They really helped me test, test, and retest, and I finally figured out that the problem was with the expression I was using in the path.

I was starting to lose hope, but thanks to your support and the fact that I created a separate flow to check if it was reading the file, I managed to understand everything.

Thanks, this thread is resolved for me

4

Glad I was able to give you a good idea for troubleshooting.
Cheers!