Sending PNG image attachments causes utf-8 error

[EndenDragon]

Describe the bug
When responding with a PNG file attachment, I am getting a UnicodeDecodeError: 'utf-8' codec can't decode byte 0x89 in position 0: invalid start byte error.

@discord.command(name="test", description="Test command!")
def command_test(ctx):
    return Message(
        embed = Embed(
            title = "Embed Title",
            description = "Description",
            color = 2728830,
            image = {"url": "attachment://google.png"},
        ),
        file = ("google.png", open("google.png", "r"), "image/png")
    )

Stack trace:

10.0.2.2 - - [12/Nov/2022 18:42:19] "POST /discord HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 2548, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 2528, in wsgi_app
    response = self.handle_exception(e)
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 2525, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 1822, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 1820, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask/app.py", line 1796, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask_discord_interactions/discord.py", line 851, in interactions
    response, mimetype = result.encode()
  File "/home/endendragon/.local/lib/python3.7/site-packages/flask_discord_interactions/models/message.py", line 244, in encode
    return (multipart.to_string().decode(), multipart.content_type)
  File "/home/endendragon/.local/lib/python3.7/site-packages/requests_toolbelt/multipart/encoder.py", line 297, in to_string
    return self.read()
  File "/home/endendragon/.local/lib/python3.7/site-packages/requests_toolbelt/multipart/encoder.py", line 314, in read
    self._load(bytes_to_load)
  File "/home/endendragon/.local/lib/python3.7/site-packages/requests_toolbelt/multipart/encoder.py", line 203, in _load
    written += part.write_to(self._buffer, amount)
  File "/home/endendragon/.local/lib/python3.7/site-packages/requests_toolbelt/multipart/encoder.py", line 528, in write_to
    written += buffer.append(self.body.read(amount_to_read))
  File "/home/endendragon/.local/lib/python3.7/site-packages/requests_toolbelt/multipart/encoder.py", line 576, in read
    return self.fd.read(length)
  File "/usr/lib/python3.7/codecs.py", line 322, in decode
    (result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x89 in position 0: invalid start byte

Categorization
This issue impacts...

• The library itself
• Documentation
• Examples

To Reproduce
A mockup of the source is provided. To test, here is a sample image you may download and put aside next to the script: https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png

Expected behavior
Image to be sent along with the rich embed.

Environment
I am using... (check any that apply, leave unchecked if you don't know)

• Quart and/or Asyncio
• A "Bot User"
• Additional Flask extensions (SQLAlchemy, Flask-CORS, etc.)
• Additional backend services (Redis, RQ, Celery)

Additional context
I understand there is a 3 second limit in Discord. We'll look into message deferrals later. However the utf8 error is the first barrier in sending image attachments.

[alexpbrown]

This looks like the same problem I'm trying to help fix with #121

[breqdev]

Should be fixed in #121 and v2.1.2. Try pip install flask-discord-interactions --upgrade and let me know if that solves your problem!

[breqdev]

I'm going to close this for now since it seems like the issue is fixed, feel free to reopen if you're still having trouble!