How to write a check in python to see if file is valid UTF-8?

Question

As stated in title, I would like to check in given file object (opened as binary stream) is valid UTF-8 file.

Anyone?

Thanks

Answer 1

def try_utf8(data):
    "Returns a Unicode object on success, or None on failure"
    try:
       return data.decode('utf-8')
    except UnicodeDecodeError:
       return None

data = f.read()
udata = try_utf8(data)
if udata is None:
    # Not UTF-8.  Do something else
else:
    # Handle unicode data

Answer 2

You could do something like

import codecs
try:
    f = codecs.open(filename, encoding='utf-8', errors='strict')
    for line in f:
        pass
    print "Valid utf-8"
except UnicodeDecodeError:
    print "invalid utf-8"

Answer 3

If anyone needed a script to find all non utf-8 files in current dir: import os

def try_utf8(data):
    try:
        return data.decode('utf-8')
    except UnicodeDecodeError:
        return None


for root, _, files in os.walk('.'):
    if root.startswith('./.git'):
        continue
    for file in files:
        if file.endswith('.pyc'):
            continue
        path = os.path.join(root, file)
        with open(path, 'rb') as f:
            data = f.read()
            data = try_utf8(data)
            if data is None:
                print(path)

Answer 4

In Python 3, you can do something like this:

with open(filename, 'rb') as f:
    try:
        f.read().decode('UTF-8')
        is_utf8 = True
    except UnicodeDecodeError:
        is_utf8 = False

print(is_utf8)