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A decorator around the WSGITileServer that allows for custom tilestache configuration.
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| from TileStache import WSGITileServer, splitPathInfo | |
| import re | |
| # | |
| # Decorator for the WSGITileServer that allows for custom tilestache configuration. | |
| # | |
| # Takes in a tilestache config file and a series of parameter names. Any that are present will be sent to the | |
| # provider and the cache classes on each call. | |
| # | |
| # If the URL is http://mytileserver.com/foo/45/bar/34/layer/x/y/z.png, | |
| # it checks the cache and then optionally calls the provider as if | |
| # http://mytileserver.com/layer/x/y/z.png were requested. | |
| # | |
| # Before the cache and/or provider is utilized for a given request, it | |
| # checks each of those classes for a function named | |
| # "set_tileserver_parameters". If it's there, it calls | |
| # "set_tileserver_parameters({foo:45, bar:34})". | |
| # | |
| # Not all parameters must be sent on any call. If the syntax of the URL doesn't match or none are | |
| # sent, it acts just like a regular WSGITileServer | |
| # | |
| # To run it, use: | |
| # gunicorn --pythonpath $PWD "TileServer:DynamicLayersTileServer('tilestache.cfg', 'foo', 'bar')" | |
| # gunicorn --pythonpath $PWD "TileServer:DynamicLayersTileServer('tilestache.cfg', 'foo', 'bar', 'baz')" | |
| # | |
| class ParameterParser(): | |
| def __init__(self, parameter_name): | |
| self.parameter_name = parameter_name | |
| #regex will parse out the parameter value from the path tilestache expects if it contains the parameter name | |
| self.regex = re.compile("(?P<prefix>^.*)\/" + parameter_name + "\/(?P<value>\w+)\/(?P<suffix>.*)$") | |
| def parse_out_parameter_value(self, string): | |
| match = self.regex.match(string) | |
| if match: | |
| reassembled = "%s/%s" % (match.group('prefix'), match.group('suffix')) | |
| return (match.group('value'), reassembled) | |
| else: | |
| return (None, string) | |
| def has_parameter(self, string): | |
| return bool(self.regex.match(string)) | |
| class DynamicLayersTileServer(): | |
| PARAMETER_SETTER_FUNCTION_NAME = "set_tileserver_parameters" | |
| def __init__(self, config, *parameter_names): | |
| self.tile_server = WSGITileServer(config) | |
| self.parameter_parsers = [ParameterParser(parameter_name) for parameter_name in parameter_names] | |
| def __call__(self, environ, start_response): | |
| path_info = environ['PATH_INFO'] or '' | |
| parameter_values = {} | |
| for parser in self.parameter_parsers: | |
| if parser.has_parameter(path_info): | |
| (value, path_info) = parser.parse_out_parameter_value(path_info) | |
| parameter_values[parser.parameter_name] = value | |
| if parameter_values: | |
| environ['PATH_INFO'] = path_info | |
| layer_name = splitPathInfo(path_info)[0] | |
| config = self.tile_server.config | |
| layer = config.layers[layer_name] | |
| self.__set_dynamic_parameters__(layer.provider, parameter_values) | |
| self.__set_dynamic_parameters__(config.cache, parameter_values) | |
| response = self.tile_server.__call__(environ, start_response) | |
| return response | |
| def __get_regex_variable_name__(self, parameter_name): | |
| return parameter_name + "_value" | |
| def __set_dynamic_parameters__(self, obj, parameter_values): | |
| if hasattr(obj, DynamicLayersTileServer.PARAMETER_SETTER_FUNCTION_NAME): | |
| getattr(obj, DynamicLayersTileServer.PARAMETER_SETTER_FUNCTION_NAME)(parameter_values) | |
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