What is a nice, reliable short way to get the char

Question

I'm a bit surprised that it's so complicated to get a charset of a webpage with Python. Am I missing a way? The HTTPMessage has loads of functions, but not this.

>>> google = urllib2.urlopen('http://www.google.com/')
>>> google.headers.gettype()
'text/html'
>>> google.headers.getencoding()
'7bit'
>>> google.headers.getcharset()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: HTTPMessage instance has no attribute 'getcharset'

So you have to get the header, and split it. Twice.

>>> google = urllib2.urlopen('http://www.google.com/')
>>> charset = 'ISO-8859-1'
>>> contenttype = google.headers.getheader('Content-Type', '')
>>> if ';' in contenttype:
...     charset = contenttype.split(';')[1].split('=')[1]
>>> charset
'ISO-8859-1'

That's a surprising amount of steps for such a basic function. Am I missing something?

Answer 1

I would go with chardet Universal Encoding Detector.

>>> import urllib
>>> urlread = lambda url: urllib.urlopen(url).read()
>>> import chardet
>>> chardet.detect(urlread("http://google.cn/"))
{'encoding': 'GB2312', 'confidence': 0.99}

You are doing right but your approach would fail for pages where charset is declared on meta tag or is not declared at all.
If you look closer at Chardet sources, it has a charsetprober/charsetgroupprober modules that deals with this problem nicely.

Answer 2

Have you checked this?

How to download any(!) webpage with correct charset in python?

Answer 3

I did some research and came up with this solution:

response = urllib.request.urlopen(url)
encoding = response.headers.get_content_charset()

This is how I would do it in Python 3. I haven't tested it in Python 2 but I am guessing that you would have to use urllib2.request instead of urllib.request.

Here is how it works, since the official Python documentation doesn't explain it very well: the result of urlopen is an http.client.HTTPResponse object. The headers property of this object is an http.client.HTTPMessage object, which, according to the documentation, "is implemented using the email.message.Message class", which has a method called get_content_charset, which tries to determine and return the character set of the response.

By default, this method returns None if it is unable to determine the character set, but you can override this behavior instead by passing a failobj parameter:

encoding = response.headers.get_content_charset(failobj="utf-8")

Answer 4

You're not missing anything. It's doing the right thing - encoding of a HTTP response is a subpart of Content-Type.

Note also that some pages might send only Content-Type: text/html and then set the encoding via <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> - that's an ugly hack though (on the part of the page author) and is not too common.