Python3 Requests "Post" Ignoring Filename when using BytesIO?

Question

I've written a simple script to expand my skills with python - however I've noticed something very strange when using BytesIO.

Here's my working script:

import requests

url = "http://MY.FAKE.IP.ADDR/Uploader.php"
file = open("test.jpg","rb")
action = {"file" : file, "name" : "test.jpg"}
requests.post(url, files=action) 

However, when I try to do the same thing with an image in the memory (for example, a screenshot), the webserver gets a blank filename?? Here's my code for this:

import requests
from PIL import ImageGrab
from io import BytesIO

url = "http://MY.FAKE.IP.ADDR/phUploader.php"

file_name = "test.jpg"

im = ImageGrab.grab()
output = BytesIO()
im.save(output, "JPEG")

file = output.getvalue()

action ={"file":file,"name":file_name}

requests.post(url,files=action)

What the file looks like on the webserver:

However the file once renamed - does contain my image as intended. I can't find anything on this, it's really confusing why this script doesn't work.

Answer 1

You're constructing your requests files argument wrong, check the official documentation on how to construct it.

In your case: action = {"file": (file_name, file)} should do the trick.