files_upload failing to upload custom FormData object

[GerhardOfRivia]

Description

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What type of issue is this? (place an x in one of the [ ])

• bug
• enhancement (feature request)
• question
• documentation related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

---

Bug Report

I am trying to upload a in memory string to slack as a file. Probably something inside of using an io.BytesIO object.

Reproducible in:

slackclient version: 2.5.0

python version: 3.6.10

OS version(s): Docker Alpine

$ cat /etc/alpine-release 
3.11.5

Steps to reproduce:

        try:
            buff = io.BytesIO(b'here is my data but not sure what is wrong.......')
            buff.seek(0)
            data = FormData()
            data.add_field('file', buff, filename='output.txt', content_type='text')
            client = slack.WebClient(token=os.environ['SLACK_API_TOKEN'])
            response = client.files_upload(channels='#my-random-channel', file=data)
            logger.info('html slack post complete %s', response)
        except Exception as err:
            logger.exception(err)

Expected result:

What you expected to happen, the file to be uploaded?

Actual result:

     response = client.files_upload(channels='#my-random-channel', file=data)
   File "/usr/local/lib/python3.6/site-packages/slack/web/client.py", line 970, in files_upload
     return self.api_call("files.upload", files={"file": file}, data=kwargs)
   File "/usr/local/lib/python3.6/site-packages/slack/web/base_client.py", line 171, in api_call
     return self._event_loop.run_until_complete(future)
   File "/usr/local/lib/python3.6/asyncio/base_events.py", line 488, in run_until_complete
     return future.result()
   File "/usr/local/lib/python3.6/site-packages/slack/web/base_client.py", line 226, in _send
     return SlackResponse(**{**data, **res}).validate()
   File "/usr/local/lib/python3.6/site-packages/slack/web/slack_response.py", line 176, in validate
     raise e.SlackApiError(message=msg, response=self)
 slack.errors.SlackApiError: The request to the Slack API failed.
 The server responded with: {'ok': False, 'error': 'no_file_data'}

Attachments:

Logs, screenshots, screencast, sample project, funny gif, etc.

[seratch]

Hello @AsynchronousGillz 👋

Do you have some reason to directly use aiohttp.FormData to construct the form data? If not, just passing io.BytesIO data as file parameter works for you. Here is a minimum working example.

import io
import logging
import os

logger = logging.getLogger(__name__)
bot_token = os.environ["SLACK_BOT_TOKEN"]
client: WebClient = WebClient(token=bot_token)
channel_ids = self.sync_client, self.logger, ",".join(["C123456789"])
buff = io.BytesIO(b'here is my data but not sure what is wrong.......')
buff.seek(0)
upload = client.files_upload(
    file=buff,
    filename="output.text",
    filetype="text",
    channels=channel_ids,
)
logger.debug("File uploaded - %s", upload)

If you need to use aiohttp.FormData for some reason, unfortunately, the WebClient doesn't accept the value and we're not planning to support the type.

[GerhardOfRivia]

I did not think I could just use the BytesIO object like that..... That worked perfectly Thank You!