[Maposmatic-dev] [PATCH] New separate api to query nominatim

[David Decotigny]

Nominatim queries now performed in their own module, together with the
relevant OSM queries to retrieve the osm_id from the DB.
---
 www/maposmatic/nominatim.py |   93 +++++++++++++++++++++++++++++++++++++++++++
 www/maposmatic/views.py     |   27 +-----------
 2 files changed, 95 insertions(+), 25 deletions(-)
 create mode 100644 www/maposmatic/nominatim.py

diff --git a/www/maposmatic/nominatim.py b/www/maposmatic/nominatim.py
new file mode 100644
index 0000000..e22c034
--- /dev/null
+++ b/www/maposmatic/nominatim.py
@@ -0,0 +1,93 @@
+# coding: utf-8
+
+# maposmatic, the web front-end of the MapOSMatic city map generation system
+# Copyright (C) 2009  David Decotigny
+# Copyright (C) 2009  Frédéric Lehobey
+# Copyright (C) 2009  David Mentré
+# Copyright (C) 2009  Maxime Petazzoni
+# Copyright (C) 2009  Thomas Petazzoni
+# Copyright (C) 2009  Gaël Utard
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Nominatim parsing + json export
+# Note: we query nominatim in XML format because otherwise we cannot
+# access the osm_id tag. Then we format it as json back to the
+# javascript routines
+
+import www.settings
+import psycopg2
+from urllib import urlencode
+import urllib2
+from xml.etree.ElementTree import parse as XMLTree
+
+
+NOMINATIM_BASE_URL = "http://nominatim.openstreetmap.org/search/";
+
+
+def query(query_text, with_polygons = False):
+    entries = _fetch_entries(query_text, with_polygons)
+    return _retrieve_missing_data_from_GIS(entries)
+
+
+def _fetch_entries(query_text, with_polygons):
+    """
+    Return a list of entries for the given squery (eg. "Paris"). Each entry
+    is a dictionary key -> value.
+    """
+    query_tags = dict(q=query_text, format='xml')
+    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()]
+
+
+def _retrieve_missing_data_from_GIS(entries):
+    if not www.settings.has_gis_database():
+        return entries
+
+    try:
+        conn = psycopg2.connect("dbname='%s' user='%s' host='%s' 
password='%s'" %
+                                (www.settings.GIS_DATABASE_NAME,
+                                 www.settings.DATABASE_USER,
+                                 www.settings.DATABASE_HOST,
+                                 www.settings.DATABASE_PASSWORD))
+        cursor = conn.cursor()
+    except psycopg2.OperationalError:
+        return entries
+
+    retval = []
+    for entry in entries:
+        if ( (entry.get("class", None) != "boundary")
+             or (entry.get("type", None) != "administrative") ):
+            continue
+
+        for table_name in ("polygon", "line"):
+            cursor.execute("""select osm_id, admin_level
+                              from planet_osm_%s
+                              where osm_id in (%s,-%s)""" \
+                               % (table_name,
+                                  entry["osm_id"],entry["osm_id"]))
+            result = tuple(set(cursor.fetchall()))
+            if len(result) == 1:
+                entry["ocitysmap_params"] = dict(table=table_name,
+                                                 id=result[0][0],
+                                                 admin_level=result[0][1])
+                retval.append(entry)
+                break
+
+    return retval
diff --git a/www/maposmatic/views.py b/www/maposmatic/views.py
index 7e5b654..6dff29d 100644
--- a/www/maposmatic/views.py
+++ b/www/maposmatic/views.py
@@ -39,14 +39,8 @@ import www.settings
 import math
 from www.maposmatic.widgets import AreaField
 from ocitysmap.coords import BoundingBox as OCMBoundingBox
+from www.maposmatic import nominatim
 
-# Nominatim parsing + json export
-# Note: we query nominatim in XML format because otherwise we cannot
-# access the osm_id tag. Then we format it as json back to the
-# javascript routines
-from urllib import urlencode
-import urllib2
-from xml.etree.ElementTree import parse as XMLTree
 try:
     from json import dumps as json_encode
 except ImportError:
@@ -269,22 +263,6 @@ def all_maps(request):
                               context_instance=RequestContext(request))
 
 
-def _parse_nominatim_xml(squery,
-                         
nominatim_url="http://nominatim.openstreetmap.org/search/";,
-                         with_polygons = False):
-    """
-    Return a list of entries for the given squery (eg. "Paris"). Each entry
-    is a dictionary key -> value.
-    """
-    query_tags = dict(q=squery, format='xml')
-    if with_polygons:
-        query_tags['polygon']=1
-
-    qdata = urlencode(query_tags)
-    f = urllib2.urlopen(url="%s?%s" % (nominatim_url, qdata))
-    return [dict(place.items()) for place in 
XMLTree(f).getroot().getchildren()]
-
-
 def query_nominatim(request, format, squery):
     if not format:
         format = "json"
@@ -295,8 +273,7 @@ def query_nominatim(request, format, squery):
         return HttpResponseBadRequest("Invalid format: %s" % format)
 
     try:
-        contents = _parse_nominatim_xml(squery,
-                                        with_polygons=False)
+        contents = nominatim.query(squery, with_polygons=False)
     except:
         contents = []
 
-- 
1.6.3.3