使用Python编码-将非英文字符转换为URL

Question

I'm trying bit for bit to write a geocoding script. There is a Danish (official and free) web service, where I enter an address in the URL and get a json file with all needed info.

I can't find the right way to translate my Danish characters (æ,ø,å) when they go into an URL. In the example I have included two different urls (containing the address info). One – where the street is 'Byvej' works fine, and I get the result I expect printed out in IDLE. (And I can get the lat/long too).

The other, where the street is 'Bispegårdsvej' gives nothing in IDLE. The returned list is empty. The url works fine in a browser, and I know, I need to add something to the script, I just can't find anything that works.

I'm using ActivePython 2.7.2.5 Thanks, Tommy

# -*- coding: cp1252 -*-
import urllib2
import json


#url='http://geo.oiorest.dk/adresser.json?postnr=4682&vejnavn=Byvej&husnr=31'
url='http://geo.oiorest.dk/adresser.json?postnr=4320&vejnavn=Bispegårdsvej&husnr=2'

try:
    data = urllib2.urlopen(url).read()
    adresser = json.loads(data)

    for adresse in adresser:
        print "%s %s, %s %s" % \
            (adresse['vejnavn']['navn'],
             adresse['husnr'],
             adresse['postnummer']['nr'],
             adresse['postnummer']['navn'])

except urllib2.HTTPError, e:
    print "HTTP error: %d" % e.code
except urllib2.URLError, e:
    print "Network error: %s" % e.reason.args[1]    

Answer 1

You need to encode the social characters with percent encoding, also known as URL encode. After percent encoding, the URL should like like this:

http://geo.oiorest.dk/adresser.json?postnr=4320&vejnavn=Bispeg%C3%A5rdsvej&husnr=2

Web services that complies with the IRI to URI mapping defined in RFC 3987 would use utf-8 for encoding after character normalization, but you should need to check the documentation the service to be sure what encoding to use.

Python has urllib.quote() in the standard library to do percent encoding from a string and urllib.urlencode() in the standard library to do percent encoding from a dictionary or an iterable of two elements tuples to produce a string for the query parameter.

Answer 2

You'll have to encode special characters properly, as eg urlencode does:

In[16]: urllib.urlencode([('postnr',4320),('vejnavn', 'Bispegårdsvej'), ('husnr',2)])
Out[16]: 'postnr=4320&vejnavn=Bispeg%C3%A5rdsvej&husnr=2'

If you then prepend the base url to this string, this should work (I at least tried it in the browser).

If you're open to get a third party package, requests would be a popular choice. It would simplify things to:

import requests
response = requests.get('http://geo.oiorest.dk/adresser.json',
                        params = dict(postnr=4320,
                                      vejnavn='Bispegårdsvej',
                                      husnr=2))