CODEWITHSUNDEEP
pythonfilehttp-status-code-500
Deffo
Deffo

Reputation: 197

Python doesn't release file after it is closed

What I need to do is to write some messages on a .txt file, close it and send it to a server. This happens in a infinite loop, so the code should look more or less like this:

from requests_toolbelt.multipart.encoder import MultipartEncoder

num = 0
while True:
    num += 1
    filename = f"example{num}.txt"
    with open(filename, "w") as f:
        f.write("Hello")
        f.close()

    mp_encoder = MultipartEncoder(
                fields={
                    'file': ("file", open(filename, 'rb'), 'text/plain')
                }
            )

    r = requests.post("my_url/save_file", data=mp_encoder, headers=my_headers)
    time.sleep(10)

The post works if the file is created manually inside my working directory, but if I try to create it and write on it through code, I receive this response message:

500 - Internal Server Error
System.IO.IOException: Unexpected end of Stream, the content may have already been read by another component.

I don't see the file appearing in the project window of PyCharm...I even used time.sleep(10) because at first, I thought it could be a time-related problem, but I didn't solve the problem. In fact, the file appears in my working directory only when I stop the code, so it seems the file is held by the program even after I explicitly called f.close(): I know the with function should take care of closing files, but it didn't look like that so I tried to add a close() to understand if that was the problem (spoiler: it was not)

Upvotes: 1

Views: 528

Answers (2)

Deffo
Deffo

Reputation: 197

I solved the problem by using another file

with open(filename, "r") as firstfile, open("new.txt", "a+") as secondfile:
        secondfile.write(firstfile.read())
with open(filename, 'w'):
    pass

r = requests.post("my_url/save_file", data=mp_encoder, headers=my_headers)
if r.status_code == requests.codes.ok:
    os.remove("new.txt")
else:
    print("File not saved")

I make a copy of the file, empty the original file to save space and send the copy to the server (and then delete the copy). Looks like the problem was that the original file was held open by the Python logging module

Upvotes: 2

sam
sam

Reputation: 1896

Firstly, can you change open(f, 'rb') to open("example.txt", 'rb'). In open, you should be passing file name not a closed file pointer.

Also, you can use os.path.abspath to show the location to know where file is written.

import os

os.path.abspath('.')

Third point, when you are using with context manager to open a file, you don't close the file. The context manger supposed to do it.

with open("example.txt", "w") as f:
    f.write("Hello")

Upvotes: 0

Related Questions