[Maposmatic-dev] [PATCH maposmatic 3/3] Query nominatim for more details + canonicalize the results

[David Decotigny]

With the "addressdetail" querty param, Nominatim allows to retrieve
the coutry, world region, etc. as well as the language code. The
latter is needed for localization. This patch uses it and correctly
pareses the new format. The patch also transforms the results so that
dict, list, etc. do not only deal with strings: we try to cast the
strings to integers, float, etc. as far as possible.
---
 www/maposmatic/nominatim.py |   38 ++++++++++++++++++++++++++++++++++----
 1 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/www/maposmatic/nominatim.py b/www/maposmatic/nominatim.py
index 9dfa1ad..3e817ec 100644
--- a/www/maposmatic/nominatim.py
+++ b/www/maposmatic/nominatim.py
@@ -54,7 +54,7 @@ def query(query_text, with_polygons = False):
       - key "admin_level": The value stored in the OSM table for admin_level
     """
     entries = _fetch_entries(query_text, with_polygons)
-    return _retrieve_missing_data_from_GIS(entries)
+    return _canonicalize_data(_retrieve_missing_data_from_GIS(entries))
 
 
 def _fetch_entries(query_text, with_polygons):
@@ -69,14 +69,44 @@ def _fetch_entries(query_text, with_polygons):
     # json. This is because we know that this xml output is correct
     # and complete (at least the "osm_id" field is missing from the
     # json output)
-    query_tags = dict(q=query_text, format='xml')
+    query_tags = dict(q=query_text, format='xml', addressdetails=1)
     if with_polygons:
         query_tags['polygon']=1
 
     qdata = urlencode(query_tags)
     f = urllib2.urlopen(url="%s?%s" % (NOMINATIM_BASE_URL, qdata))
-    return [dict(place.items())
-            for place in XMLTree(f).getroot().getchildren()]
+
+    result = []
+    for place in XMLTree(f).getroot().getchildren():
+        attribs = dict(place.attrib)
+        for elt in place.getchildren():
+            attribs[elt.tag] = elt.text
+        result.append(attribs)
+
+    return result
+
+
+def _canonicalize_data(data):
+    """
+    Take a structure containing strings (dict, list, scalars, ...)
+    and convert it into the same structure with the proper conversions
+    to float or integers, etc.
+    """
+    if type(data) is tuple:
+        return tuple(_canonicalize_data(x) for x in data)
+    elif type(data) is list:
+        return [_canonicalize_data(x) for x in data]
+    elif type(data) is dict:
+        return dict([(_canonicalize_data(k),
+                      _canonicalize_data(v)) for k,v in data.iteritems()])
+    try:
+        return int(data)
+    except ValueError:
+        try:
+            return float(data)
+        except ValueError:
+            pass
+    return data
 
 
 def _retrieve_missing_data_from_GIS(entries):
-- 
1.6.3.3