cache tiles on disk

src/c3nav/mapdata/views.py

@@ -1,3 +1,6 @@
+import os
+
+from django.conf import settings
 from django.http import Http404, HttpResponse, HttpResponseNotModified
 from shapely.geometry import box
 
@@ -32,21 +35,44 @@ def tile(request, level, zoom, x, y, format):
     if if_none_match == etag:
         return HttpResponseNotModified()
 
+    f = None
+    if settings.CACHE_TILES:
+        dirname = os.path.sep.join((settings.TILES_ROOT, update_cache_key, level, str(zoom), str(x), str(y)))
+        filename = os.path.sep.join((dirname, access_cache_key+'.'+format))
+
+        try:
+            f = open(filename, 'rb')
+        except FileNotFoundError:
+            pass
+
+    content_type = 'image/svg+xml' if format == 'svg' else 'image/png'
+
+    if not settings.CACHE_TILES or f is None:
         try:
             renderer.check_level()
         except Level.DoesNotExist:
             raise Http404
 
         svg = renderer.render()
-
         if format == 'svg':
-        response = HttpResponse(svg.get_xml(), 'image/svg+xml')
+            data = svg.get_xml()
+            filemode = 'w'
         elif format == 'png':
-        response = HttpResponse(content_type='image/png')
+            data = svg.get_png()
-        svg.get_png(f=response)
+            filemode = 'wb'
         else:
             raise ValueError
 
+        if settings.CACHE_TILES:
+            # noinspection PyUnboundLocalVariable
+            os.makedirs(dirname, exist_ok=True)
+            # noinspection PyUnboundLocalVariable
+            with open(filename, filemode) as f:
+                f.write(data)
+    else:
+        data = f.read()
+
+    response = HttpResponse(data, content_type)
     response['ETag'] = etag
     response['Cache-Control'] = 'no-cache'
 

src/c3nav/settings.py

@@ -21,6 +21,7 @@ MEDIA_ROOT = os.path.join(DATA_DIR, 'media')
 SOURCES_ROOT = os.path.join(DATA_DIR, 'sources')
 MAP_ROOT = os.path.join(DATA_DIR, 'map')
 RENDER_ROOT = os.path.join(DATA_DIR, 'render')
+TILES_ROOT = os.path.join(DATA_DIR, 'tiles')
 
 if not os.path.exists(DATA_DIR):
     os.mkdir(DATA_DIR)
@@ -34,6 +35,8 @@ if not os.path.exists(MAP_ROOT):
     os.mkdir(MAP_ROOT)
 if not os.path.exists(RENDER_ROOT):
     os.mkdir(RENDER_ROOT)
+if not os.path.exists(TILES_ROOT):
+    os.mkdir(TILES_ROOT)
 
 if config.has_option('django', 'secret'):
     SECRET_KEY = config.get('django', 'secret')
@@ -55,6 +58,7 @@ debug_fallback = "runserver" in sys.argv
 DEBUG = config.getboolean('django', 'debug', fallback=debug_fallback)
 RENDER_SCALE = float(config.get('c3nav', 'render_scale', fallback=20.0))
 SVG_RENDERER = config.get('c3nav', 'svg_renderer', fallback='rsvg-convert')
+CACHE_TILES = config.get('c3nav', 'cache_tiles', fallback=not DEBUG)
 
 db_backend = config.get('database', 'backend', fallback='sqlite3')
 DATABASES = {