terom@135: """
terom@135:     Raw tile handling.
terom@135: """
terom@135: 
terom@135: from werkzeug import Request, Response, exceptions
terom@165: from werkzeug.utils import redirect
terom@167: import werkzeug.urls
terom@135: 
terom@167: import pngtile.application
terom@135: import pypngtile
terom@135: 
terom@172: import datetime
terom@172: 
terom@135: ## Coordinates
terom@135: # width of a tile
terom@140: TILE_SIZE = 256
terom@140: 
terom@140: # maximum zoom out
terom@140: MAX_ZOOM = 4
terom@135: 
terom@135: # max. output resolution to allow
terom@135: MAX_PIXELS = 1920 * 1200
terom@135: 
terom@135: def scale (val, zoom):
terom@135:     """
terom@135:         Scale dimension by zoom factor
terom@135: 
terom@135:         zl > 0 -> bigger
terom@135:         zl < 0 -> smaller
terom@135:     """
terom@135: 
terom@135:     if zoom > 0:
terom@135:         return val << zoom
terom@135: 
terom@135:     elif zoom < 0:
terom@135:         return val >> -zoom
terom@135: 
terom@135:     else:
terom@135:         return val
terom@135: 
terom@135: def scale_center (val, dim, zoom):
terom@135:     """
terom@135:         Scale value about center by zoom.
terom@135:     """
terom@135: 
terom@175:     return scale(val - dim / 2, zoom)
terom@135: 
terom@167: class TileApplication (pngtile.application.PNGTileApplication):
terom@173:     # age in seconds for caching an unknown-mtime image for revalidates
terom@173:     MIN_AGE = 10 # 10 seconds
terom@173: 
terom@172:     # age in seconds for caching a known-mtime image
terom@172:     MAX_AGE = 7 * 24 * 60 * 60 # 1 week
terom@172: 
terom@165:     def __init__ (self, image_server, **opts):
terom@165:         """
terom@165:             image_server:       http://.../ url to image-server frontend
terom@165:         """
terom@165: 
terom@167:         super(TileApplication, self).__init__(**opts)
terom@165: 
terom@165:         self.image_server = image_server
terom@135:         
terom@167:     def image_url (self, name):
terom@167:         return werkzeug.urls.Href(self.image_server)(path)
terom@167: 
terom@135:     def render_region (self, request, image):
terom@135:         """
terom@135:             Handle request for an image region
terom@135:         """
terom@135: 
terom@135:         width = int(request.args['w'])
terom@135:         height = int(request.args['h'])
terom@135:         x = int(request.args['x'])
terom@135:         y = int(request.args['y'])
terom@135:         zoom = int(request.args.get('zoom', "0"))
terom@135: 
terom@140:         # safety limit
terom@135:         if width * height > MAX_PIXELS:
terom@135:             raise exceptions.BadRequest("Image size: %d * %d > %d" % (width, height, MAX_PIXELS))
terom@135: 
terom@140:         if zoom > MAX_ZOOM:
terom@140:             raise exceptions.BadRequest("Image zoom: %d > %d" % (zoom, MAX_ZOOM))
terom@140: 
terom@144:         x = scale_center(x, width, zoom)
terom@144:         y = scale_center(y, height, zoom)
terom@135:         
terom@135:         try:
terom@135:             return image.tile_mem(width, height, x, y, zoom)
terom@135: 
terom@135:         except pypngtile.Error as error:
terom@167:             raise exceptions.InternalServerError(str(error))
terom@135:         
terom@135:     def render_tile (self, request, image):
terom@135:         """
terom@135:             Handle request for image tile
terom@135:         """
terom@135: 
terom@140:         width = TILE_SIZE
terom@140:         height = TILE_SIZE
terom@140:         x = int(request.args['x'])
terom@140:         y = int(request.args['y'])
terom@135:         zoom = int(request.args.get('zoom', "0"))
terom@140:         
terom@140:         if zoom > MAX_ZOOM:
terom@140:             raise exceptions.BadRequest("Image zoom: %d > %d" % (zoom, MAX_ZOOM))
terom@135: 
terom@140:         x = scale(x * width, zoom)
terom@140:         y = scale(y * height, zoom)
terom@135: 
terom@135:         try:
terom@135:             return image.tile_mem(width, height, x, y, zoom)
terom@135: 
terom@135:         except pypngtile.Error as error:
terom@167:             raise exceptions.InternalServerError(str(error))
terom@135: 
terom@165:     def handle_dir (self, request, name, path):
terom@135:         """
terom@165:             Redirect to the image frontend for a non-tile request.
terom@135:         """
terom@165: 
terom@165:         if not name.endswith('/'):
terom@165:             # avoid an additional redirect
terom@165:             name += '/'
terom@165: 
terom@167:         return redirect(self.image_url(name))
terom@165: 
terom@165:     def handle_image (self, request, name, path):
terom@165:         """
terom@165:             Redirect to the image frontend for a non-tile request.
terom@165:         """
terom@165: 
terom@167:         return redirect(self.image_url(name))
terom@165: 
terom@165:     def handle (self, request):
terom@165:         """
terom@165:             Handle request for an image
terom@165:         """
terom@167:         
terom@167:         name, path, type = self.lookup(request.path)
terom@165:         
terom@165:         # determine handler
terom@165:         if not type:
terom@165:             return self.handle_dir(request, name, path)
terom@165: 
terom@165:         elif not request.args:
terom@165:             return self.handle_image(request, name, path)
terom@165: 
terom@165:         elif 'w' in request.args and 'h' in request.args and 'x' in request.args and 'y' in request.args:
terom@171:             render_func = self.render_region
terom@135: 
terom@140:         elif 'x' in request.args and 'y' in request.args:
terom@171:             render_func = self.render_tile
terom@135: 
terom@135:         else:
terom@135:             raise exceptions.BadRequest("Unknown args")
terom@171:         
terom@171:         # handle image
terom@171:         image, name = self.open(request.path)
terom@135: 
terom@171:         # http caching
terom@171:         mtime = image.cache_mtime()
terom@171: 
terom@172:         if 't' in request.args:
terom@172:             try:
terom@172:                 ttime = datetime.datetime.utcfromtimestamp(int(request.args['t']))
terom@172:             except ValueError:
terom@172:                 ttime = None
terom@172:         else:
terom@172:             ttime = None
terom@172: 
terom@171:         if request.if_modified_since and mtime == request.if_modified_since:
terom@174:             response = Response(status=304)
terom@174:         else:
terom@174:             # render 
terom@174:             png = render_func(request, image)
terom@171:         
terom@174:             response = Response(png, content_type='image/png')
terom@174:         
terom@174:         # cache out
terom@171:         response.last_modified = mtime
terom@171: 
terom@172:         if not ttime:
terom@172:             # cached item may change while url stays the same
terom@173:             response.headers['Cache-Control'] = 'max-age={min_age:d}'.format(min_age=self.MIN_AGE)
terom@172: 
terom@172:         elif ttime == mtime:
terom@172:             # url will change if content changes
terom@172:             response.headers['Cache-Control'] = 'max-age={max_age:d}'.format(max_age=self.MAX_AGE)
terom@172: 
terom@172:         else:
terom@172:             # XXX: mismatch wtf
terom@172:             response.headers['Cache-Control'] = 'must-revalidate'
terom@172: 
terom@171:         return response
terom@171: 
terom@171: