Migrating from monolithic file.upload to sequential/asynchronous to files.getUploadURLExternal and

I scratched my head for hours trying to figure out the way to migrate after receiving the email from Slack's team of the future deprecation of file.upload. The message is the same as https://api.slack.com/changelog/2024-04-a-better-way-to-upload-files-is-here-to-stay

Wrote this, all is successful, but no image uploaded in the channel:

#!/bin/bashlength=$(wc -c < /tmp/img.png)curl \    -H "Authorization: Bearer XXX" \    -H "Content-Type: application/x-www-form-urlencoded; charset=utf-8" \    -d "filename=charts" \    -d "length=$length" \    https://slack.com/api/files.getUploadURLExternal > /tmp/slack.jsonupload_url=$(jq -r '.upload_url' /tmp/slack.json)img_id=$(jq -r '.file_id' /tmp/slack.json)curl \    -H "Authorization: Bearer XXX" \    -d "file=@/tmp/img.png" \    $upload_urlcurl \    https://slack.com/api/files.completeUploadExternal \    -H "Authorization: Bearer XXX" \    -H "Content-Type: application/json; charset=utf-8" \    -d @/dev/stdin << EOF | jq .    {"files": [            {"id": "$img_id","title": "charts",            }         ],"channel_id": "XYZ","initial_comment": "this is a test"    } EOF

The output:

{"ok": true,"files": [    {"id": "XXXXX","created": 1727014056,"timestamp": 1727014056,"name": "charts","title": "charts","mimetype": "","filetype": "","pretty_type": "","user": "XXXXXX","user_team": "XXXXXX","editable": false,"size": 5935,"mode": "hosted","is_external": false,"external_type": "","is_public": false,"public_url_shared": false,"display_as_bot": false,"username": "","url_private": "https://files.slack.com/files-pri/XXXX/charts","url_private_download": "https://files.slack.com/files-pri/XXXX/download/charts","media_display_type": "unknown","permalink": "https://etc-onlyview.slack.com/files/XXXX/charts","permalink_public": "https://slack-files.com/XXXX","comments_count": 0,"is_starred": false,"shares": {},"channels": [],"groups": [],"ims": [],"has_more_shares": false,"has_rich_preview": false,"file_access": "visible"    }  ]}

If I try to open URLs in a logged in browser, I get error: There was a problem when trying to open this link We're not quite sure what went wrong. You can go back, or try looking on our Help Center if you need a hand.

Or some other URLs, I get error redirected you too many times.

Looks like a under construction project.