Request | request.files access is too slow.

[kshitij12345]

Expected Behavior

I am getting very slow access to request.files['file'].
Below is a part of the code.

@app.route('/perspective_transform/', methods = ['POST'])
def perspective_transform():
    print(request)
    with Timer(prefix='API Execution'):
        with Timer(prefix='Loading Image File'):
            file = request.files['file']
            
        with Timer(prefix='Read File'):
            img_bytes = file.read()

        with Timer(prefix='Loading Args'):
            vertices = request.form.get('vertices')

        # Some other processing code
    return response

I would think that once request reaches the Python function, all data is available at that point.
Surprisingly most of the time is spent at file = request.files['file']
Based on my assumption it should be quick. Also the print(request) doesn't take any time at all.
The file that I am trying to get is generally in the range 1Mb to 2Mb.
On some occassion it takes very very long.
Is this the expected behavior?
Any way to mitigate it?

Loading Image File took 0.423 seconds
Read File took 0.001 seconds
Loading Args took 0.000 seconds
API Execution took 0.736 seconds

Environment

• Python version: 3.7
• Flask version: 1.1.1
• Werkzeug version: 1.0.0

[davidism]

Duplicate of pallets/werkzeug#875

[ThiefMaster]

@cauffe Don't do that again.

[kshitij12345]

@davidism Thanks for the reference and quick reply.