[i18n/postcodes] Fetching postcode regexes from the data source used by Google's libaddressinput, caches requests for the length of the running program (e.g. generating parser data, so the regexes will get updated over time).

scripts/geodata/i18n/google.py

@@ -0,0 +1,60 @@
+import re
+import requests
+import six.moves.urllib_parse as urlparse
+import ujson
+
+requests.models.json = ujson
+
+
+GOOGLE_I18N_API = 'http://i18napis.appspot.com'
+GOOGLE_ADDRESS_DATA_API = urlparse.urljoin(GOOGLE_I18N_API, 'address/data/')
+
+
+class GoogleI18N(object):
+    '''
+    Fetches data from e.g. http://i18napis.appspot.com/address/data/GB
+    and caches it in a dictionary for each country. These requests are
+    lightweight, so for a given run of a program, max 250 requests
+    will be made.
+    '''
+    def __init__(self):
+        self.responses = {}
+
+    def get(self, country_code):
+        ret = self.responses.get(country_code.lower())
+
+        if ret is None:
+            url = urlparse.urljoin(GOOGLE_ADDRESS_DATA_API, country_code.upper())
+            response = requests.get(url)
+            if response.ok:
+                ret = response.json()
+                self.responses[country_code.lower()] = ret
+            else:
+                self.responses[country_code.lower()] = {}
+        return ret
+
+
+google_i18n = GoogleI18N()
+
+
+class PostcodeRegexes(object):
+    def __init__(self):
+        self.responses = {}
+        self.postcode_regexes = {}
+
+    def get(self, country_code):
+        ret = self.postcode_regexes.get(country_code.lower())
+        if ret is None:
+            response = google_i18n.get(country_code)
+            if response:
+                postcode_expression = response.get('zip')
+                if not postcode_expression:
+                    self.postcode_regexes[country_code.lower()] = None
+                    return None
+                ret = re.compile(postcode_expression, re.I)
+                self.postcode_regexes[country_code.lower()] = ret
+
+        return ret
+
+
+postcode_regexes = PostcodeRegexes()