from xlsxmetadata.metadata import get_dimensions, get_sheet_names

my_big_file = '/path/to/my/real_big_file.xlsx'

sheet_names = get_sheet_names(my_big_file)
print(sheet_names)

>>> {'test_sheet': 1}

dimensions = get_dimensions('/path/to/my/real_big_workbook.xlsx', 'test_sheet')
print(dimensions['end_column'])

>>> 16834

print(dimensions['end_row'])

>>> 1200000

from io import BytesIO
from xlsxmetadata.metadata import get_dimensions, get_sheet_names

my_big_file = request.files.get('my_big_file')

sheet_names = get_sheet_names(BytesIO(my_big_file.read()))
print(sheet_names)

>>> {'test_sheet': 1}

# you will probably have to reset the read-head
my_big_file.seek(0)

dimensions = get_dimensions(BytesIO(my_big_file.read()), 'test_sheet')
print(dimensions['end_column'])

>>> 16834

print(dimensions['end_row'])

>>> 1200000