gistfile1.pyw

import tornado.httpserver
import tornado.ioloop
import tornado.web

import mapnik
from twcache import TWCache
from sphericalmercator import SphericalMercator

class TileHandler(tornado.web.RequestHandler):
    def get(self, datafile, mapfile, z, x, y):
        z, x, y = map(int, [z, x, y])
        merc = SphericalMercator(levels=23, size=256)
        mapfile_cache = TWCache('mapfiles')
        datafile_cache = TWCache('data')
        envelope = merc.xyz_to_envelope(x, y, z)
        _mapnik_map = mapnik.Map(256, 256)
        im = mapnik.Image(256, 256)

        mapnik.load_map(_mapnik_map, 
            mapfile_cache.filecache(mapfile))

        for layer in _mapnik_map.layers:
            layer.datasource = datafile_cache.dscache(datafile)

        _mapnik_map.layers.append(layer)
        _mapnik_map.zoom_to_box(envelope)
        _mapnik_map.buffer_size = 128

        mapnik.render(_mapnik_map, im)
        self.set_header("Content-Type", "image/png")
        self.write(im.tostring('png'))

class Application(tornado.web.Application):
    def __init__(self):
        handlers = [
            (r"/", MainHandler),
            (r"/tile/([^/]+)/([^/]+)/([0-9]+)/([0-9]+)/([0-9]+)", TileHandler),
        ]
        tornado.web.Application.__init__(self, handlers)

def main():
    http_server = tornado.httpserver.HTTPServer(Application())
    http_server.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

if __name__ == "__main__":
    main()