problem with unicode decoding

Question

This is funny.. I am trying to read geographic lookup data from openstreetmap. The code that performs the query looks like this

params = urllib.urlencode({'q': ",".join([e for e in full_address]), 'format': "json", "addressdetails" : "1"})
query = "http://nominatim.openstreetmap.org/search?%s" % params
print query
time.sleep(5)
response = json.loads(unicode(urllib.urlopen(query).read(), "UTF-8"), encoding="UTF-8")
print response

The query for Zürich is correctly URL-encoded on UTF-8 data. No wonders here.

http://nominatim.openstreetmap.org/search?q=Z%C3%BCrich%2CSWITZERLAND&addressdetails=1&format=json

When I print the response, the u with umlaut is encoded latin1 (0xFC)

[{u'display_name': u'Z\xfcrich, Bezirk Z\xfcrich, Z\xfcrich, Schweiz, Europe', u'place_id': 588094, u'lon': 8.540443

but that's nonsense because openstreetmap returns the JSON data in UTF-8

Connecting to nominatim.openstreetmap.org (nominatim.openstreetmap.org)|128.40.168.106|:80... connected.
HTTP request sent, awaiting response... 
  HTTP/1.1 200 OK
  Date: Wed, 26 Jan 2011 13:48:33 GMT
  Server: Apache/2.2.14 (Ubuntu)
  Content-Location: search.php
  Vary: negotiate
  TCN: choice
  X-Powered-By: PHP/5.3.2-1ubuntu4.7
  Access-Control-Allow-Origin: *
  Content-Length: 3342
  Keep-Alive: timeout=15, max=100
  Connection: Keep-Alive
  Content-Type: application/json; charset=UTF-8
Length: 3342 (3.3K) [application/json]

which is also confirmed by the file contents, and then I explicitly say that it's UTF-8 both at read and json parsing.

What's going on here ?

EDIT : apparently it's the json.loads that screws up somehow.

Answer 1

When I go and print the response, the u with umlaut is encoded latin1 (0xFC)

You are just misinterpreting the output. It's a unicode string (you can tell by the u in prefix), there's no encoding "attached" - the \xFC means there it's the codepoint with number 0xFC, which happens to be the U-Umlaut (see http://www.fileformat.info/info/unicode/char/fc/index.htm). The reason why this happens is that the numbering of the first 256 unicode codepoints coincides with the latin1 encoding.

In short, you did everything right - you have a unicode object with the right content (that is agnostic to encodings), you can choose the encoding you want when you use that content for output somewhere by doing unicodestr.encode("utf-8") or by using codecs, see http://docs.python.org/howto/unicode.html#reading-and-writing-unicode-data