add simple development tile cache:

- change scene url to
  http://localhost:8000/vector.mapzen.com/osm/all/{z}/{x}/{y}.mvt
- run 'python proxy.py'
- delete .tiles to clear the cache

Author: hjanetzek

Diff for: .gitignore

@@ -12,6 +12,9 @@ Icon
 # Thumbnails
 ._*
 
+# proxy.py cache
+.tiles
+
 # Files that might appear on external disk
 .Spotlight-V100
 .Trashes

Diff for: proxy.py

@@ -0,0 +1,49 @@
+# Originally from http://sharebear.co.uk/blog/2009/09/17/very-simple-python-caching-proxy/
+#
+# Usage:
+# A call to http://localhost:8000/example.com/foo.html will cache the file
+# at http://example.com/foo.html on disc and not redownload it again.
+# To clear the cache simply do a `rm *.cached`. To stop the server simply
+# send SIGINT (Ctrl-C). It does not handle any headers or post data.
+#
+# see also: https://pymotw.com/2/BaseHTTPServer/
+
+import BaseHTTPServer
+import hashlib
+import os
+import urllib2
+
+from BaseHTTPServer import HTTPServer
+from SocketServer import ThreadingMixIn
+
+class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
+    pass
+
+class CacheHandler(BaseHTTPServer.BaseHTTPRequestHandler):
+    def do_GET(self):
+        m = hashlib.md5()
+        m.update(self.path)
+        cache_filename = ".tiles/" + m.hexdigest()
+        if os.path.exists(cache_filename):
+            print "Cache hit"
+            data = open(cache_filename).readlines()
+        else:
+            print "Cache miss"
+            data = urllib2.urlopen("http:/" + self.path, timeout=10).readlines()
+            open(cache_filename, 'wb').writelines(data)
+
+        self.send_response(200)
+        self.send_header("Content-Encoding", "gzip")
+        self.end_headers()
+        self.wfile.writelines(data)
+
+def run():
+    if not os.path.exists(".tiles"):
+        os.makedirs(".tiles")
+
+    server_address = ('', 8000)
+    httpd = ThreadedHTTPServer(server_address, CacheHandler)
+    httpd.serve_forever()
+
+if __name__ == '__main__':
+    run()