Extending multiprovider

TileStache/Config.py

@@ -124,6 +124,10 @@ def __init__(self, cache, dirpath):
         self.dirpath = dirpath
         self.layers = {}
 
+        # adding custom_layer to extend multiprovider to support comma separated layernames
+        self.custom_layer_name = ","
+        self.custom_layer_dict = {'provider': {'class': 'TileStache.Goodies.VecTiles:MultiProvider', 'kwargs': {'names': []}}}
+
         self.index = 'text/plain', 'TileStache bellows hello.'
 
 class Bounds:
@@ -204,7 +208,7 @@ def buildConfiguration(config_dict, dirpath='.'):
         URL including the "file://" prefix.
     """
     scheme, h, path, p, q, f = urlparse(dirpath)
-    
+
     if scheme in ('', 'file'):
         sys.path.insert(0, path)
 
@@ -216,6 +220,8 @@ def buildConfiguration(config_dict, dirpath='.'):
     for (name, layer_dict) in config_dict.get('layers', {}).items():
         config.layers[name] = _parseConfigfileLayer(layer_dict, config, dirpath)
 
+    config.layers[config.custom_layer_name] = _parseConfigfileLayer(config.custom_layer_dict, config, dirpath)
+
     if 'index' in config_dict:
         index_href = urljoin(dirpath, config_dict['index'])
         index_body = urlopen(index_href).read()

TileStache/Goodies/VecTiles/server.py

@@ -195,7 +195,11 @@ class MultiProvider:
     def __init__(self, layer, names):
         self.layer = layer
         self.names = names
-
+
+    def __call__(self, layer, names):
+        self.layer = layer
+        self.names = names
+
     def renderTile(self, width, height, srs, coord):
         ''' Render a single tile, return a Response instance.
         '''

TileStache/__init__.py

@@ -46,6 +46,9 @@
 _pathinfo_pat = re.compile(r'^/?(?P<l>\w.+)/(?P<z>\d+)/(?P<x>-?\d+)/(?P<y>-?\d+)\.(?P<e>\w+)$')
 _preview_pat = re.compile(r'^/?(?P<l>\w.+)/(preview\.html)?$')
 
+# symbol used to separate layers when specifying more than one layer
+_delimiter = ','
+
 def getTile(layer, coord, extension, ignore_cached=False):
     ''' Get a type string and tile binary for a given request layer tile.
 
@@ -138,6 +141,19 @@ def mergePathInfo(layer, coord, extension):
 
     return '/%(layer)s/%(z)d/%(x)d/%(y)d.%(extension)s' % locals()
 
+def isValidLayer(layer, config):
+    if not layer:
+        return False
+    if (layer not in config.layers):
+        if (layer.find(_delimiter) != -1):
+            multi_providers = list(ll for ll in config.layers if hasattr(config.layers[ll].provider, 'names'))
+            for l in layer.split(_delimiter):
+                if ((l not in config.layers) or (l in multi_providers)):
+                    return False
+            return True
+        return False
+    return True
+
 def requestLayer(config, path_info):
     """ Return a Layer.
 
@@ -175,9 +191,16 @@ def requestLayer(config, path_info):
 
     layername = splitPathInfo(path_info)[0]
 
-    if layername not in config.layers:
+    if not isValidLayer(layername, config):
         raise Core.KnownUnknown('"%s" is not a layer I know about. Here are some that I do know about: %s.' % (layername, ', '.join(sorted(config.layers.keys()))))
 
+    custom_layer = layername.find(_delimiter)!=-1
+
+    if custom_layer:
+        config.layers[layername] = config.layers[config.custom_layer_name]
+        config.layers[layername].provider(config.layers[layername], **{'names': layername.split(_delimiter)})
+        del config.layers[config.custom_layer_name]
+
     return config.layers[layername]
 
 def requestHandler(config_hint, path_info, query_string=None):
@@ -369,7 +392,7 @@ def __call__(self, environ, start_response):
         # WSGI behavior is different from CGI behavior, because we may not want
         # to return a chatty rummy for likely-deployed WSGI vs. testing CGI.
         #
-        if layer and layer not in self.config.layers:
+        if not isValidLayer(layer, self.config):
             return self._response(start_response, 404)
 
         path_info = environ.get('PATH_INFO', None)