Source code for lwr.web.framework

Tiny framework used to power LWR application, nothing in here is specific to running
or staging jobs. Mostly deals with routing web traffic and parsing parameters.
from webob import Request
from webob import Response
from webob import exc

import inspect
from os.path import exists
import re

from json import dumps
from six import Iterator

[docs]class RoutingApp(object): """ Abstract definition for a python web application. """ def __init__(self): self.routes = []
[docs] def add_route(self, route, controller, **args): route_regex = self.__template_to_regex(route) self.routes.append((route_regex, controller, args))
def __call__(self, environ, start_response): req = Request(environ) = self for route, controller, args in self.routes: match = route.match(req.path_info) if match: request_args = dict(args) route_args = match.groupdict() request_args.update(route_args) return controller(environ, start_response, **request_args) return exc.HTTPNotFound()(environ, start_response) def __template_to_regex(self, template): var_regex = re.compile(r''' \{ # The exact character "{" (\w+) # The variable name (restricted to a-z, 0-9, _) (?::([^}]+))? # The optional :regex part \} # The exact character "}" ''', re.VERBOSE) regex = '' last_pos = 0 for match in var_regex.finditer(template): regex += re.escape(template[last_pos:match.start()]) var_name = expr = or '[^/]+' expr = '(?P<%s>%s)' % (var_name, expr) regex += expr last_pos = match.end() regex += re.escape(template[last_pos:]) regex = '^%s$' % regex return re.compile(regex)
[docs]def build_func_args(func, *arg_dicts): args = {} def add_args(func_args, arg_values): for func_arg in func_args: if func_arg not in args and func_arg in arg_values: args[func_arg] = arg_values[func_arg] func_args = inspect.getargspec(func).args for arg_dict in arg_dicts: add_args(func_args, arg_dict) return args
[docs]class Controller(object): """ Wraps python functions into controller methods. """ def __init__(self, response_type='OK'): self.response_type = response_type def __get_client_address(self, environ): """ """ try: return environ['HTTP_X_FORWARDED_FOR'].split(',')[-1].strip() except KeyError: return environ['REMOTE_ADDR'] def __add_args(self, args, func_args, arg_values): for func_arg in func_args: if func_arg not in args and func_arg in arg_values: args[func_arg] = arg_values[func_arg] def __handle_access(self, req, environ, start_response): access_response = None if hasattr(self, '_check_access'): access_response = self._check_access(req, environ, start_response) return access_response def __build_args(self, func, args, req, environ): args = build_func_args(func, args, req.GET, self._app_args(args, req)) func_args = inspect.getargspec(func).args for func_arg in func_args: if func_arg == "ip": args["ip"] = self.__get_client_address(environ) if 'body' in func_args: args['body'] = req.body_file return args def __execute_request(self, func, args, req, environ): args = self.__build_args(func, args, req, environ) try: result = func(**args) except exc.HTTPException as e: result = e return result def __build_response(self, result): if self.response_type == 'file': resp = file_response(result) else: resp = Response(body=self.body(result)) return resp def __call__(self, func): def controller_replacement(environ, start_response, **args): req = Request(environ) access_response = self.__handle_access(req, environ, start_response) if access_response: return access_response result = self.__execute_request(func, args, req, environ) resp = self.__build_response(result) return resp(environ, start_response) controller_replacement.func = func controller_replacement.response_type = self.response_type controller_replacement.body = self.body controller_replacement.__name__ = func.__name__ controller_replacement.__controller__ = True return controller_replacement
[docs] def body(self, result): body = 'OK' if self.response_type == 'json': body = dumps(result) return body
def _prepare_controller_args(self, req, args): pass
[docs]def file_response(path): resp = Response() if exists(path): resp.app_iter = FileIterator(path) else: raise exc.HTTPNotFound("No file found with path %s." % path) return resp
[docs]class FileIterator(Iterator): def __init__(self, path): self.input = open(path, 'rb') def __iter__(self): return self def __next__(self): buffer = if(buffer == ""): raise StopIteration return buffer