[Maposmatic-dev] [PATCH maposmatic 1/2] Extend the rendering_already_exists method

[Maxime Petazzoni]

In preparation for the "Recreate Map" feature, extend the
rendering_already_exists method to work on bounding boxes as well,
making it possible to redirect to a recent rendering for the exact same
bounding box.

The original method was split in two distinct methods,
rendering_already_exists_by_osmid and rendering_already_exists_by_bbox,
each working in one of the map selection modes. A new
rendering_already_exists method replaces the old one, now working on on
MapRenderingJob object, and handling the dispatch between the two new
rendering_already_exists_by_{osmid,bbox} methods.

Signed-off-by: Maxime Petazzoni <address@hidden>
---
 www/maposmatic/helpers.py |   48 ++++++++++++++++++++++++++++++++++++++++++++-
 www/maposmatic/views.py   |   11 ++++-----
 2 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/www/maposmatic/helpers.py b/www/maposmatic/helpers.py
index 8faa240..0a70e26 100644
--- a/www/maposmatic/helpers.py
+++ b/www/maposmatic/helpers.py
@@ -69,7 +69,7 @@ def check_osm_id(osm_id, table='polygon'):
     finally:
         conn.close()
 
-def rendering_already_exists(osmid):
+def rendering_already_exists_by_osmid(osmid):
     """Returns the ID of a rendering matching the given OpenStreetMap city ID
     from the last 24 hours, or None if no rendering can be found matching this
     criteria."""
@@ -100,6 +100,52 @@ def rendering_already_exists(osmid):
     # No rendering found
     return None
 
+def rendering_already_exists_by_bbox(lat_upper_left, lon_upper_left,
+                                     lat_bottom_right, lon_bottom_right):
+    """Returns the ID of a rendering matching the given bounding box from the
+    last 24 hours, or None if no rendering can be found matching this
+    criteria."""
+
+    # First try to find rendered items
+    rendered_items = (MapRenderingJob.objects
+                      .filter(submission_time__gte=(datetime.datetime.now()
+                                                   - datetime.timedelta(1)))
+                      .filter(lat_upper_left=lat_upper_left)
+                      .filter(lon_upper_left=lon_upper_left)
+                      .filter(lat_bottom_right=lat_bottom_right)
+                      .filter(lon_bottom_right=lon_bottom_right)
+                      .filter(status=2)
+                      .filter(resultmsg="ok")
+                      .order_by("-submission_time")[:1])
+
+    if len(rendered_items) and rendered_items[0].has_output_files():
+        return rendered_items[0].id
+
+    # Then try to find items being rendered or waiting for rendering
+    rendered_items = (MapRenderingJob.objects
+                      .filter(submission_time__gte=(datetime.datetime.now()
+                                                   - datetime.timedelta(1)))
+                      .filter(lat_upper_left=lat_upper_left)
+                      .filter(lon_upper_left=lon_upper_left)
+                      .filter(lat_bottom_right=lat_bottom_right)
+                      .filter(lon_bottom_right=lon_bottom_right)
+                      .filter(status__in=[0,1])
+                      .order_by("-submission_time")[:1])
+
+    if len(rendered_items):
+        return rendered_items[0].id
+
+    # No rendering found
+    return None
+
+def rendering_already_exists(job):
+    if job.administrative_osmid:
+        return rendering_already_exists_by_osmid(job.administrative_osmid)
+    return rendering_already_exists_by_bbox(job.lat_upper_left,
+                                            job.lon_upper_left,
+                                            job.lat_bottom_right,
+                                            job.lon_bottom_right)
+
 def get_letters():
     """Returns the list of map first-letter selectors. For now, it only returns
     the ASCII letters of the latin alphabet. This should be improved for
diff --git a/www/maposmatic/views.py b/www/maposmatic/views.py
index 76f7684..5cc02ae 100644
--- a/www/maposmatic/views.py
+++ b/www/maposmatic/views.py
@@ -70,12 +70,11 @@ def new(request):
             job = form.save(commit=False)
             job.administrative_osmid = 
form.cleaned_data.get('administrative_osmid')
 
-            if job.administrative_osmid:
-                existing = 
helpers.rendering_already_exists(job.administrative_osmid)
-                if existing:
-                    request.session['redirected'] = True
-                    return HttpResponseRedirect(reverse('job-by-id',
-                                                        args=[existing]))
+            existing = helpers.rendering_already_exists(job)
+            if existing:
+                request.session['redirected'] = True
+                return HttpResponseRedirect(reverse('job-by-id',
+                                                    args=[existing]))
 
             job.status = 0 # Submitted
             job.submitterip = request.META['REMOTE_ADDR']
-- 
1.6.3.3.341.g9b22d