try: from simplejson import dumps, loads except ImportError: # pragma: no cover from json import dumps, loads # noqa from inspect import Arguments from itertools import chain, tee from mimetypes import guess_type, add_type from os.path import splitext import logging import operator import types import six from webob import (Request as WebObRequest, Response as WebObResponse, exc, acceptparse) from webob.multidict import NestedMultiDict from .compat import urlparse, izip from .secure import handle_security from .templating import RendererFactory from .routing import lookup_controller, NonCanonicalPath from .util import _cfg, encode_if_needed, getargspec from .middleware.recursive import ForwardRequestException if six.PY3: from .compat import is_bound_method as ismethod else: from inspect import ismethod # make sure that json is defined in mimetypes add_type('application/json', '.json', True) state = None logger = logging.getLogger(__name__) class RoutingState(object): def __init__(self, request, response, app, hooks=[], controller=None, arguments=None): self.request = request self.response = response self.app = app self.hooks = hooks self.controller = controller self.arguments = arguments class Request(WebObRequest): def __getattribute__(self, name): try: return WebObRequest.__getattribute__(self, name) except UnicodeDecodeError as e: logger.exception(e) abort(400) class Response(WebObResponse): pass def proxy(key): class ObjectProxy(object): explanation_ = AttributeError( "`pecan.state` is not bound to a context-local context.\n" "Ensure that you're accessing `pecan.request` or `pecan.response` " "from within the context of a WSGI `__call__` and that " "`use_context_locals` = True." ) def __getattr__(self, attr): try: obj = getattr(state, key) except AttributeError: raise self.explanation_ return getattr(obj, attr) def __setattr__(self, attr, value): obj = getattr(state, key) return setattr(obj, attr, value) def __delattr__(self, attr): obj = getattr(state, key) return delattr(obj, attr) def __dir__(self): obj = getattr(state, key) return dir(obj) return ObjectProxy() request = proxy('request') response = proxy('response') def override_template(template, content_type=None): ''' Call within a controller to override the template that is used in your response. :param template: a valid path to a template file, just as you would specify in an ``@expose``. :param content_type: a valid MIME type to use for the response.func_closure ''' request.pecan['override_template'] = template if content_type: request.pecan['override_content_type'] = content_type def abort(status_code=None, detail='', headers=None, comment=None, **kw): ''' Raise an HTTP status code, as specified. Useful for returning status codes like 401 Unauthorized or 403 Forbidden. :param status_code: The HTTP status code as an integer. :param detail: The message to send along, as a string. :param headers: A dictionary of headers to send along with the response. :param comment: A comment to include in the response. ''' raise exc.status_map[status_code]( detail=detail, headers=headers, comment=comment, **kw ) def redirect(location=None, internal=False, code=None, headers={}, add_slash=False, request=None): ''' Perform a redirect, either internal or external. An internal redirect performs the redirect server-side, while the external redirect utilizes an HTTP 302 status code. :param location: The HTTP location to redirect to. :param internal: A boolean indicating whether the redirect should be internal. :param code: The HTTP status code to use for the redirect. Defaults to 302. :param headers: Any HTTP headers to send with the response, as a dictionary. :param request: The :class:`pecan.Request` instance to use. ''' request = request or state.request if add_slash: if location is None: split_url = list(urlparse.urlsplit(request.url)) new_proto = request.environ.get( 'HTTP_X_FORWARDED_PROTO', split_url[0] ) split_url[0] = new_proto else: split_url = urlparse.urlsplit(location) split_url[2] = split_url[2].rstrip('/') + '/' location = urlparse.urlunsplit(split_url) if not headers: headers = {} if internal: if code is not None: raise ValueError('Cannot specify a code for internal redirects') request.environ['pecan.recursive.context'] = request.context raise ForwardRequestException(location) if code is None: code = 302 raise exc.status_map[code](location=location, headers=headers) def render(template, namespace, app=None): ''' Render the specified template using the Pecan rendering framework with the specified template namespace as a dictionary. Useful in a controller where you have no template specified in the ``@expose``. :param template: The path to your template, as you would specify in ``@expose``. :param namespace: The namespace to use for rendering the template, as a dictionary. :param app: The instance of :class:`pecan.Pecan` to use ''' app = app or state.app return app.render(template, namespace) def load_app(config, **kwargs): ''' Used to load a ``Pecan`` application and its environment based on passed configuration. :param config: Can be a dictionary containing configuration, a string which represents a (relative) configuration filename returns a pecan.Pecan object ''' from .configuration import _runtime_conf, set_config set_config(config, overwrite=True) for package_name in getattr(_runtime_conf.app, 'modules', []): module = __import__(package_name, fromlist=['app']) if hasattr(module, 'app') and hasattr(module.app, 'setup_app'): app = module.app.setup_app(_runtime_conf, **kwargs) app.config = _runtime_conf return app raise RuntimeError( 'No app.setup_app found in any of the configured app.modules' ) class PecanBase(object): SIMPLEST_CONTENT_TYPES = ( ['text/html'], ['text/plain'] ) def __init__(self, root, default_renderer='mako', template_path='templates', hooks=lambda: [], custom_renderers={}, extra_template_vars={}, force_canonical=True, guess_content_type_from_ext=True, context_local_factory=None, request_cls=Request, response_cls=Response, **kw): if isinstance(root, six.string_types): root = self.__translate_root__(root) self.root = root self.request_cls = request_cls self.response_cls = response_cls self.renderers = RendererFactory(custom_renderers, extra_template_vars) self.default_renderer = default_renderer # pre-sort these so we don't have to do it per-request if six.callable(hooks): hooks = hooks() self.hooks = list(sorted( hooks, key=operator.attrgetter('priority') )) self.template_path = template_path self.force_canonical = force_canonical self.guess_content_type_from_ext = guess_content_type_from_ext def __translate_root__(self, item): ''' Creates a root controller instance from a string root, e.g., > __translate_root__("myproject.controllers.RootController") myproject.controllers.RootController() :param item: The string to the item ''' if '.' in item: parts = item.split('.') name = '.'.join(parts[:-1]) fromlist = parts[-1:] module = __import__(name, fromlist=fromlist) kallable = getattr(module, parts[-1]) msg = "%s does not represent a callable class or function." if not six.callable(kallable): raise TypeError(msg % item) return kallable() raise ImportError('No item named %s' % item) def route(self, req, node, path): ''' Looks up a controller from a node based upon the specified path. :param node: The node, such as a root controller object. :param path: The path to look up on this node. ''' path = path.split('/')[1:] try: node, remainder = lookup_controller(node, path, req) return node, remainder except NonCanonicalPath as e: if self.force_canonical and \ not _cfg(e.controller).get('accept_noncanonical', False): if req.method == 'POST': raise RuntimeError( "You have POSTed to a URL '%s' which " "requires a slash. Most browsers will not maintain " "POST data when redirected. Please update your code " "to POST to '%s/' or set force_canonical to False" % (req.pecan['routing_path'], req.pecan['routing_path']) ) redirect(code=302, add_slash=True, request=req) return e.controller, e.remainder def determine_hooks(self, controller=None): ''' Determines the hooks to be run, in which order. :param controller: If specified, includes hooks for a specific controller. ''' controller_hooks = [] if controller: controller_hooks = _cfg(controller).get('hooks', []) if controller_hooks: return list( sorted( chain(controller_hooks, self.hooks), key=operator.attrgetter('priority') ) ) return self.hooks def handle_hooks(self, hooks, hook_type, *args): ''' Processes hooks of the specified type. :param hook_type: The type of hook, including ``before``, ``after``, ``on_error``, and ``on_route``. :param \*args: Arguments to pass to the hooks. ''' if hook_type not in ['before', 'on_route']: hooks = reversed(hooks) for hook in hooks: result = getattr(hook, hook_type)(*args) # on_error hooks can choose to return a Response, which will # be used instead of the standard error pages. if hook_type == 'on_error' and isinstance(result, WebObResponse): return result def get_args(self, state, all_params, remainder, argspec, im_self): ''' Determines the arguments for a controller based upon parameters passed the argument specification for the controller. ''' args = [] varargs = [] kwargs = dict() valid_args = argspec.args[:] if ismethod(state.controller) or im_self: valid_args.pop(0) # pop off `self` pecan_state = state.request.pecan remainder = [x for x in remainder if x] if im_self is not None: args.append(im_self) # grab the routing args from nested REST controllers if 'routing_args' in pecan_state: remainder = pecan_state['routing_args'] + list(remainder) del pecan_state['routing_args'] # handle positional arguments if valid_args and remainder: args.extend(remainder[:len(valid_args)]) remainder = remainder[len(valid_args):] valid_args = valid_args[len(args):] # handle wildcard arguments if [i for i in remainder if i]: if not argspec[1]: abort(404) varargs.extend(remainder) # get the default positional arguments if argspec[3]: defaults = dict(izip(argspec[0][-len(argspec[3]):], argspec[3])) else: defaults = dict() # handle positional GET/POST params for name in valid_args: if name in all_params: args.append(all_params.pop(name)) elif name in defaults: args.append(defaults[name]) else: break # handle wildcard GET/POST params if argspec[2]: for name, value in six.iteritems(all_params): if name not in argspec[0]: kwargs[encode_if_needed(name)] = value return args, varargs, kwargs def render(self, template, namespace): if template == 'json': renderer = self.renderers.get('json', self.template_path) elif ':' in template: renderer_name, template = template.split(':', 1) renderer = self.renderers.get( renderer_name, self.template_path ) else: renderer = self.renderers.get( self.default_renderer, self.template_path ) return renderer.render(template, namespace) def find_controller(self, state): ''' The main request handler for Pecan applications. ''' # get a sorted list of hooks, by priority (no controller hooks yet) req = state.request pecan_state = req.pecan # store the routing path for the current application to allow hooks to # modify it pecan_state['routing_path'] = path = req.path_info # handle "on_route" hooks self.handle_hooks(self.hooks, 'on_route', state) # lookup the controller, respecting content-type as requested # by the file extension on the URI pecan_state['extension'] = None # attempt to guess the content type based on the file extension if self.guess_content_type_from_ext \ and not pecan_state['content_type'] \ and '.' in path: new_path, extension = splitext(path) # preface with a letter to ensure compat for 2.5 potential_type = guess_type('x' + extension)[0] if potential_type is not None: path = new_path pecan_state['extension'] = extension pecan_state['content_type'] = potential_type controller, remainder = self.route(req, self.root, path) cfg = _cfg(controller) if cfg.get('generic_handler'): raise exc.HTTPNotFound # handle generic controllers im_self = None if cfg.get('generic'): im_self = six.get_method_self(controller) handlers = cfg['generic_handlers'] controller = handlers.get(req.method, handlers['DEFAULT']) handle_security(controller, im_self) cfg = _cfg(controller) # add the controller to the state so that hooks can use it state.controller = controller # if unsure ask the controller for the default content type content_types = cfg.get('content_types', {}) if not pecan_state['content_type']: # attempt to find a best match based on accept headers (if they # exist) accept = getattr(req.accept, 'header_value', '*/*') if accept == '*/*' or ( accept.startswith('text/html,') and list(content_types.keys()) in self.SIMPLEST_CONTENT_TYPES): pecan_state['content_type'] = cfg.get( 'content_type', 'text/html' ) else: best_default = acceptparse.MIMEAccept( accept ).best_match( content_types.keys() ) if best_default is None: msg = "Controller '%s' defined does not support " + \ "content_type '%s'. Supported type(s): %s" logger.error( msg % ( controller.__name__, pecan_state['content_type'], content_types.keys() ) ) raise exc.HTTPNotAcceptable() pecan_state['content_type'] = best_default elif cfg.get('content_type') is not None and \ pecan_state['content_type'] not in content_types: msg = "Controller '%s' defined does not support content_type " + \ "'%s'. Supported type(s): %s" logger.error( msg % ( controller.__name__, pecan_state['content_type'], content_types.keys() ) ) raise exc.HTTPNotFound # fetch any parameters if req.method == 'GET': params = req.GET elif req.content_type in ('application/json', 'application/javascript'): try: if not isinstance(req.json, dict): raise TypeError('%s is not a dict' % req.json) params = NestedMultiDict(req.GET, req.json) except (TypeError, ValueError): params = req.params else: params = req.params # fetch the arguments for the controller args, varargs, kwargs = self.get_args( state, params.mixed(), remainder, cfg['argspec'], im_self ) state.arguments = Arguments(args, varargs, kwargs) # handle "before" hooks self.handle_hooks(self.determine_hooks(controller), 'before', state) return controller, args + varargs, kwargs def invoke_controller(self, controller, args, kwargs, state): ''' The main request handler for Pecan applications. ''' cfg = _cfg(controller) content_types = cfg.get('content_types', {}) req = state.request resp = state.response pecan_state = req.pecan # If a keyword is supplied via HTTP GET or POST arguments, but the # function signature does not allow it, just drop it (rather than # generating a TypeError). argspec = getargspec(controller) keys = kwargs.keys() for key in keys: if key not in argspec.args and not argspec.keywords: kwargs.pop(key) # get the result from the controller result = controller(*args, **kwargs) # a controller can return the response object which means they've taken # care of filling it out if result is response: return elif isinstance(result, WebObResponse): state.response = result return raw_namespace = result # pull the template out based upon content type and handle overrides template = content_types.get(pecan_state['content_type']) # check if for controller override of template template = pecan_state.get('override_template', template) or ( 'json' if self.default_renderer == 'json' else None ) pecan_state['content_type'] = pecan_state.get( 'override_content_type', pecan_state['content_type'] ) # if there is a template, render it if template: if template == 'json': pecan_state['content_type'] = 'application/json' result = self.render(template, result) # If we are in a test request put the namespace where it can be # accessed directly if req.environ.get('paste.testing'): testing_variables = req.environ['paste.testing_variables'] testing_variables['namespace'] = raw_namespace testing_variables['template_name'] = template testing_variables['controller_output'] = result # set the body content if result and isinstance(result, six.text_type): resp.text = result elif result: resp.body = result if pecan_state['content_type']: # set the content type resp.content_type = pecan_state['content_type'] def _handle_empty_response_body(self, state): # Enforce HTTP 204 for responses which contain no body if state.response.status_int == 200: # If the response is a generator... if isinstance(state.response.app_iter, types.GeneratorType): # Split the generator into two so we can peek at one of them # and determine if there is any response body content a, b = tee(state.response.app_iter) try: next(a) except StopIteration: # If we hit StopIteration, the body is empty state.response.status = 204 finally: state.response.app_iter = b else: text = None if state.response.charset: # `response.text` cannot be accessed without a valid # charset (because we don't know which encoding to use) try: text = state.response.text except UnicodeDecodeError: # If a valid charset is not specified, don't bother # trying to guess it (because there's obviously # content, so we know this shouldn't be a 204) pass if not any((state.response.body, text)): state.response.status = 204 if state.response.status_int in (204, 304): state.response.content_type = None def __call__(self, environ, start_response): ''' Implements the WSGI specification for Pecan applications, utilizing ``WebOb``. ''' # create the request and response object req = self.request_cls(environ) resp = self.response_cls() state = RoutingState(req, resp, self) controller = None # handle the request try: # add context and environment to the request req.context = environ.get('pecan.recursive.context', {}) req.pecan = dict(content_type=None) controller, args, kwargs = self.find_controller(state) self.invoke_controller(controller, args, kwargs, state) except Exception as e: # if this is an HTTP Exception, set it as the response if isinstance(e, exc.HTTPException): # if the client asked for JSON, do our best to provide it best_match = acceptparse.MIMEAccept( getattr(req.accept, 'header_value', '*/*') ).best_match(('text/plain', 'text/html', 'application/json')) state.response = e if best_match == 'application/json': json_body = dumps({ 'code': e.status_int, 'title': e.title, 'description': e.detail }) if isinstance(json_body, six.text_type): e.text = json_body else: e.body = json_body state.response.content_type = best_match environ['pecan.original_exception'] = e # if this is not an internal redirect, run error hooks on_error_result = None if not isinstance(e, ForwardRequestException): on_error_result = self.handle_hooks( self.determine_hooks(state.controller), 'on_error', state, e ) # if the on_error handler returned a Response, use it. if isinstance(on_error_result, WebObResponse): state.response = on_error_result else: if not isinstance(e, exc.HTTPException): raise # if this is an HTTP 405, attempt to specify an Allow header if isinstance(e, exc.HTTPMethodNotAllowed) and controller: allowed_methods = _cfg(controller).get('allowed_methods', []) if allowed_methods: state.response.allow = sorted(allowed_methods) finally: # handle "after" hooks self.handle_hooks( self.determine_hooks(state.controller), 'after', state ) self._handle_empty_response_body(state) # get the response return state.response(environ, start_response) class ExplicitPecan(PecanBase): def get_args(self, state, all_params, remainder, argspec, im_self): # When comparing the argspec of the method to GET/POST params, # ignore the implicit (req, resp) at the beginning of the function # signature if hasattr(state.controller, '__self__'): _repr = '.'.join(( state.controller.__self__.__class__.__module__, state.controller.__self__.__class__.__name__, state.controller.__name__ )) else: _repr = '.'.join(( state.controller.__module__, state.controller.__name__ )) signature_error = TypeError( 'When `use_context_locals` is `False`, pecan passes an explicit ' 'reference to the request and response as the first two arguments ' 'to the controller.\nChange the `%s` signature to accept exactly ' '2 initial arguments (req, resp)' % _repr ) try: positional = argspec.args[:] positional.pop(1) # req positional.pop(1) # resp argspec = argspec._replace(args=positional) except IndexError: raise signature_error args, varargs, kwargs = super(ExplicitPecan, self).get_args( state, all_params, remainder, argspec, im_self ) if ismethod(state.controller): args = [state.request, state.response] + args else: # generic controllers have an explicit self *first* # (because they're decorated functions, not instance methods) args[1:1] = [state.request, state.response] return args, varargs, kwargs class Pecan(PecanBase): ''' Pecan application object. Generally created using ``pecan.make_app``, rather than being created manually. Creates a Pecan application instance, which is a WSGI application. :param root: A string representing a root controller object (e.g., "myapp.controller.root.RootController") :param default_renderer: The default template rendering engine to use. Defaults to mako. :param template_path: A relative file system path (from the project root) where template files live. Defaults to 'templates'. :param hooks: A callable which returns a list of :class:`pecan.hooks.PecanHook` :param custom_renderers: Custom renderer objects, as a dictionary keyed by engine name. :param extra_template_vars: Any variables to inject into the template namespace automatically. :param force_canonical: A boolean indicating if this project should require canonical URLs. :param guess_content_type_from_ext: A boolean indicating if this project should use the extension in the URL for guessing the content type to return. :param use_context_locals: When `True`, `pecan.request` and `pecan.response` will be available as thread-local references. :param request_cls: Can be used to specify a custom `pecan.request` object. Defaults to `pecan.Request`. :param response_cls: Can be used to specify a custom `pecan.response` object. Defaults to `pecan.Response`. ''' def __new__(cls, *args, **kw): if kw.get('use_context_locals') is False: self = super(Pecan, cls).__new__(ExplicitPecan, *args, **kw) self.__init__(*args, **kw) return self return super(Pecan, cls).__new__(cls) def __init__(self, *args, **kw): self.init_context_local(kw.get('context_local_factory')) super(Pecan, self).__init__(*args, **kw) def __call__(self, environ, start_response): try: state.hooks = [] state.app = self state.controller = None state.arguments = None return super(Pecan, self).__call__(environ, start_response) finally: del state.hooks del state.request del state.response del state.controller del state.arguments del state.app def init_context_local(self, local_factory): global state if local_factory is None: from threading import local as local_factory state = local_factory() def find_controller(self, _state): state.request = _state.request state.response = _state.response controller, args, kw = super(Pecan, self).find_controller(_state) state.controller = controller state.arguments = _state.arguments return controller, args, kw def handle_hooks(self, hooks, *args, **kw): state.hooks = hooks return super(Pecan, self).handle_hooks(hooks, *args, **kw)