from __future__ import absolute_import from functools import wraps, partial from flask import request, url_for, current_app from flask import abort as original_flask_abort from flask import make_response as original_flask_make_response from flask.views import MethodView from flask.signals import got_request_exception from werkzeug.datastructures import Headers from werkzeug.exceptions import HTTPException, MethodNotAllowed, NotFound, NotAcceptable, InternalServerError from werkzeug.wrappers import Response as ResponseBase from flask_restful.utils import http_status_message, unpack, OrderedDict from flask_restful.representations.json import output_json import sys from flask.helpers import _endpoint_from_view_func from types import MethodType import operator from collections import Mapping __all__ = ('Api', 'Resource', 'marshal', 'marshal_with', 'marshal_with_field', 'abort') def abort(http_status_code, **kwargs): """Raise a HTTPException for the given http_status_code. Attach any keyword arguments to the exception for later processing. """ #noinspection PyUnresolvedReferences try: original_flask_abort(http_status_code) except HTTPException as e: if len(kwargs): e.data = kwargs raise DEFAULT_REPRESENTATIONS = [('application/json', output_json)] class Api(object): """ The main entry point for the application. You need to initialize it with a Flask Application: :: >>> app = Flask(__name__) >>> api = restful.Api(app) Alternatively, you can use :meth:`init_app` to set the Flask application after it has been constructed. :param app: the Flask application object :type app: flask.Flask or flask.Blueprint :param prefix: Prefix all routes with a value, eg v1 or 2010-04-01 :type prefix: str :param default_mediatype: The default media type to return :type default_mediatype: str :param decorators: Decorators to attach to every resource :type decorators: list :param catch_all_404s: Use :meth:`handle_error` to handle 404 errors throughout your app :param serve_challenge_on_401: Whether to serve a challenge response to clients on receiving 401. This usually leads to a username/password popup in web browers. :param url_part_order: A string that controls the order that the pieces of the url are concatenated when the full url is constructed. 'b' is the blueprint (or blueprint registration) prefix, 'a' is the api prefix, and 'e' is the path component the endpoint is added with :type catch_all_404s: bool :param errors: A dictionary to define a custom response for each exception or error raised during a request :type errors: dict """ def __init__(self, app=None, prefix='', default_mediatype='application/json', decorators=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order='bae', errors=None): self.representations = OrderedDict(DEFAULT_REPRESENTATIONS) self.urls = {} self.prefix = prefix self.default_mediatype = default_mediatype self.decorators = decorators if decorators else [] self.catch_all_404s = catch_all_404s self.serve_challenge_on_401 = serve_challenge_on_401 self.url_part_order = url_part_order self.errors = errors or {} self.blueprint_setup = None self.endpoints = set() self.resources = [] self.app = None self.blueprint = None if app is not None: self.app = app self.init_app(app) def init_app(self, app): """Initialize this class with the given :class:`flask.Flask` application or :class:`flask.Blueprint` object. :param app: the Flask application or blueprint object :type app: flask.Flask :type app: flask.Blueprint Examples:: api = Api() api.add_resource(...) api.init_app(app) """ # If app is a blueprint, defer the initialization try: app.record(self._deferred_blueprint_init) # Flask.Blueprint has a 'record' attribute, Flask.Api does not except AttributeError: self._init_app(app) else: self.blueprint = app def _complete_url(self, url_part, registration_prefix): """This method is used to defer the construction of the final url in the case that the Api is created with a Blueprint. :param url_part: The part of the url the endpoint is registered with :param registration_prefix: The part of the url contributed by the blueprint. Generally speaking, BlueprintSetupState.url_prefix """ parts = { 'b': registration_prefix, 'a': self.prefix, 'e': url_part } return ''.join(parts[key] for key in self.url_part_order if parts[key]) @staticmethod def _blueprint_setup_add_url_rule_patch(blueprint_setup, rule, endpoint=None, view_func=None, **options): """Method used to patch BlueprintSetupState.add_url_rule for setup state instance corresponding to this Api instance. Exists primarily to enable _complete_url's function. :param blueprint_setup: The BlueprintSetupState instance (self) :param rule: A string or callable that takes a string and returns a string(_complete_url) that is the url rule for the endpoint being registered :param endpoint: See BlueprintSetupState.add_url_rule :param view_func: See BlueprintSetupState.add_url_rule :param **options: See BlueprintSetupState.add_url_rule """ if callable(rule): rule = rule(blueprint_setup.url_prefix) elif blueprint_setup.url_prefix: rule = blueprint_setup.url_prefix + rule options.setdefault('subdomain', blueprint_setup.subdomain) if endpoint is None: endpoint = _endpoint_from_view_func(view_func) defaults = blueprint_setup.url_defaults if 'defaults' in options: defaults = dict(defaults, **options.pop('defaults')) blueprint_setup.app.add_url_rule(rule, '%s.%s' % (blueprint_setup.blueprint.name, endpoint), view_func, defaults=defaults, **options) def _deferred_blueprint_init(self, setup_state): """Synchronize prefix between blueprint/api and registration options, then perform initialization with setup_state.app :class:`flask.Flask` object. When a :class:`flask_restful.Api` object is initialized with a blueprint, this method is recorded on the blueprint to be run when the blueprint is later registered to a :class:`flask.Flask` object. This method also monkeypatches BlueprintSetupState.add_url_rule with _blueprint_setup_add_url_rule_patch. :param setup_state: The setup state object passed to deferred functions during blueprint registration :type setup_state: flask.blueprints.BlueprintSetupState """ self.blueprint_setup = setup_state if setup_state.add_url_rule.__name__ != '_blueprint_setup_add_url_rule_patch': setup_state._original_add_url_rule = setup_state.add_url_rule setup_state.add_url_rule = MethodType(Api._blueprint_setup_add_url_rule_patch, setup_state) if not setup_state.first_registration: raise ValueError('flask-restful blueprints can only be registered once.') self._init_app(setup_state.app) def _init_app(self, app): """Perform initialization actions with the given :class:`flask.Flask` object. :param app: The flask application object :type app: flask.Flask """ app.handle_exception = partial(self.error_router, app.handle_exception) app.handle_user_exception = partial(self.error_router, app.handle_user_exception) if len(self.resources) > 0: for resource, urls, kwargs in self.resources: self._register_view(app, resource, *urls, **kwargs) def owns_endpoint(self, endpoint): """Tests if an endpoint name (not path) belongs to this Api. Takes in to account the Blueprint name part of the endpoint name. :param endpoint: The name of the endpoint being checked :return: bool """ if self.blueprint: if endpoint.startswith(self.blueprint.name): endpoint = endpoint.split(self.blueprint.name + '.', 1)[-1] else: return False return endpoint in self.endpoints def _should_use_fr_error_handler(self): """ Determine if error should be handled with FR or default Flask The goal is to return Flask error handlers for non-FR-related routes, and FR errors (with the correct media type) for FR endpoints. This method currently handles 404 and 405 errors. :return: bool """ adapter = current_app.create_url_adapter(request) try: adapter.match() except MethodNotAllowed as e: # Check if the other HTTP methods at this url would hit the Api valid_route_method = e.valid_methods[0] rule, _ = adapter.match(method=valid_route_method, return_rule=True) return self.owns_endpoint(rule.endpoint) except NotFound: return self.catch_all_404s except: # Werkzeug throws other kinds of exceptions, such as Redirect pass def _has_fr_route(self): """Encapsulating the rules for whether the request was to a Flask endpoint""" # 404's, 405's, which might not have a url_rule if self._should_use_fr_error_handler(): return True # for all other errors, just check if FR dispatched the route if not request.url_rule: return False return self.owns_endpoint(request.url_rule.endpoint) def error_router(self, original_handler, e): """This function decides whether the error occured in a flask-restful endpoint or not. If it happened in a flask-restful endpoint, our handler will be dispatched. If it happened in an unrelated view, the app's original error handler will be dispatched. In the event that the error occurred in a flask-restful endpoint but the local handler can't resolve the situation, the router will fall back onto the original_handler as last resort. :param original_handler: the original Flask error handler for the app :type original_handler: function :param e: the exception raised while handling the request :type e: Exception """ if self._has_fr_route(): try: return self.handle_error(e) except Exception: pass # Fall through to original handler return original_handler(e) def handle_error(self, e): """Error handler for the API transforms a raised exception into a Flask response, with the appropriate HTTP status code and body. :param e: the raised Exception object :type e: Exception """ got_request_exception.send(current_app._get_current_object(), exception=e) if not isinstance(e, HTTPException) and current_app.propagate_exceptions: exc_type, exc_value, tb = sys.exc_info() if exc_value is e: raise else: raise e headers = Headers() if isinstance(e, HTTPException): code = e.code default_data = { 'message': getattr(e, 'description', http_status_message(code)) } headers = e.get_response().headers else: code = 500 default_data = { 'message': http_status_message(code), } # Werkzeug exceptions generate a content-length header which is added # to the response in addition to the actual content-length header # https://github.com/flask-restful/flask-restful/issues/534 remove_headers = ('Content-Length',) for header in remove_headers: headers.pop(header, None) data = getattr(e, 'data', default_data) if code and code >= 500: exc_info = sys.exc_info() if exc_info[1] is None: exc_info = None current_app.log_exception(exc_info) error_cls_name = type(e).__name__ if error_cls_name in self.errors: custom_data = self.errors.get(error_cls_name, {}) code = custom_data.get('status', 500) data.update(custom_data) if code == 406 and self.default_mediatype is None: # if we are handling NotAcceptable (406), make sure that # make_response uses a representation we support as the # default mediatype (so that make_response doesn't throw # another NotAcceptable error). supported_mediatypes = list(self.representations.keys()) fallback_mediatype = supported_mediatypes[0] if supported_mediatypes else "text/plain" resp = self.make_response( data, code, headers, fallback_mediatype = fallback_mediatype ) else: resp = self.make_response(data, code, headers) if code == 401: resp = self.unauthorized(resp) return resp def mediatypes_method(self): """Return a method that returns a list of mediatypes """ return lambda resource_cls: self.mediatypes() + [self.default_mediatype] def add_resource(self, resource, *urls, **kwargs): """Adds a resource to the api. :param resource: the class name of your resource :type resource: :class:`Type[Resource]` :param urls: one or more url routes to match for the resource, standard flask routing rules apply. Any url variables will be passed to the resource method as args. :type urls: str :param endpoint: endpoint name (defaults to :meth:`Resource.__name__.lower` Can be used to reference this route in :class:`fields.Url` fields :type endpoint: str :param resource_class_args: args to be forwarded to the constructor of the resource. :type resource_class_args: tuple :param resource_class_kwargs: kwargs to be forwarded to the constructor of the resource. :type resource_class_kwargs: dict Additional keyword arguments not specified above will be passed as-is to :meth:`flask.Flask.add_url_rule`. Examples:: api.add_resource(HelloWorld, '/', '/hello') api.add_resource(Foo, '/foo', endpoint="foo") api.add_resource(FooSpecial, '/special/foo', endpoint="foo") """ if self.app is not None: self._register_view(self.app, resource, *urls, **kwargs) else: self.resources.append((resource, urls, kwargs)) def resource(self, *urls, **kwargs): """Wraps a :class:`~flask_restful.Resource` class, adding it to the api. Parameters are the same as :meth:`~flask_restful.Api.add_resource`. Example:: app = Flask(__name__) api = restful.Api(app) @api.resource('/foo') class Foo(Resource): def get(self): return 'Hello, World!' """ def decorator(cls): self.add_resource(cls, *urls, **kwargs) return cls return decorator def _register_view(self, app, resource, *urls, **kwargs): endpoint = kwargs.pop('endpoint', None) or resource.__name__.lower() self.endpoints.add(endpoint) resource_class_args = kwargs.pop('resource_class_args', ()) resource_class_kwargs = kwargs.pop('resource_class_kwargs', {}) # NOTE: 'view_functions' is cleaned up from Blueprint class in Flask 1.0 if endpoint in getattr(app, 'view_functions', {}): previous_view_class = app.view_functions[endpoint].__dict__['view_class'] # if you override the endpoint with a different class, avoid the collision by raising an exception if previous_view_class != resource: raise ValueError('This endpoint (%s) is already set to the class %s.' % (endpoint, previous_view_class.__name__)) resource.mediatypes = self.mediatypes_method() # Hacky resource.endpoint = endpoint resource_func = self.output(resource.as_view(endpoint, *resource_class_args, **resource_class_kwargs)) for decorator in self.decorators: resource_func = decorator(resource_func) for url in urls: # If this Api has a blueprint if self.blueprint: # And this Api has been setup if self.blueprint_setup: # Set the rule to a string directly, as the blueprint is already # set up. self.blueprint_setup.add_url_rule(url, view_func=resource_func, **kwargs) continue else: # Set the rule to a function that expects the blueprint prefix # to construct the final url. Allows deferment of url finalization # in the case that the associated Blueprint has not yet been # registered to an application, so we can wait for the registration # prefix rule = partial(self._complete_url, url) else: # If we've got no Blueprint, just build a url with no prefix rule = self._complete_url(url, '') # Add the url to the application or blueprint app.add_url_rule(rule, view_func=resource_func, **kwargs) def output(self, resource): """Wraps a resource (as a flask view function), for cases where the resource does not directly return a response object :param resource: The resource as a flask view function """ @wraps(resource) def wrapper(*args, **kwargs): resp = resource(*args, **kwargs) if isinstance(resp, ResponseBase): # There may be a better way to test return resp data, code, headers = unpack(resp) return self.make_response(data, code, headers=headers) return wrapper def url_for(self, resource, **values): """Generates a URL to the given resource. Works like :func:`flask.url_for`.""" endpoint = resource.endpoint if self.blueprint: endpoint = '{0}.{1}'.format(self.blueprint.name, endpoint) return url_for(endpoint, **values) def make_response(self, data, *args, **kwargs): """Looks up the representation transformer for the requested media type, invoking the transformer to create a response object. This defaults to default_mediatype if no transformer is found for the requested mediatype. If default_mediatype is None, a 406 Not Acceptable response will be sent as per RFC 2616 section 14.1 :param data: Python object containing response data to be transformed """ default_mediatype = kwargs.pop('fallback_mediatype', None) or self.default_mediatype mediatype = request.accept_mimetypes.best_match( self.representations, default=default_mediatype, ) if mediatype is None: raise NotAcceptable() if mediatype in self.representations: resp = self.representations[mediatype](data, *args, **kwargs) resp.headers['Content-Type'] = mediatype return resp elif mediatype == 'text/plain': resp = original_flask_make_response(str(data), *args, **kwargs) resp.headers['Content-Type'] = 'text/plain' return resp else: raise InternalServerError() def mediatypes(self): """Returns a list of requested mediatypes sent in the Accept header""" return [h for h, q in sorted(request.accept_mimetypes, key=operator.itemgetter(1), reverse=True)] def representation(self, mediatype): """Allows additional representation transformers to be declared for the api. Transformers are functions that must be decorated with this method, passing the mediatype the transformer represents. Three arguments are passed to the transformer: * The data to be represented in the response body * The http status code * A dictionary of headers The transformer should convert the data appropriately for the mediatype and return a Flask response object. Ex:: @api.representation('application/xml') def xml(data, code, headers): resp = make_response(convert_data_to_xml(data), code) resp.headers.extend(headers) return resp """ def wrapper(func): self.representations[mediatype] = func return func return wrapper def unauthorized(self, response): """ Given a response, change it to ask for credentials """ if self.serve_challenge_on_401: realm = current_app.config.get("HTTP_BASIC_AUTH_REALM", "flask-restful") challenge = u"{0} realm=\"{1}\"".format("Basic", realm) response.headers['WWW-Authenticate'] = challenge return response class Resource(MethodView): """ Represents an abstract RESTful resource. Concrete resources should extend from this class and expose methods for each supported HTTP method. If a resource is invoked with an unsupported HTTP method, the API will return a response with status 405 Method Not Allowed. Otherwise the appropriate method is called and passed all arguments from the url rule used when adding the resource to an Api instance. See :meth:`~flask_restful.Api.add_resource` for details. """ representations = None method_decorators = [] def dispatch_request(self, *args, **kwargs): # Taken from flask #noinspection PyUnresolvedReferences meth = getattr(self, request.method.lower(), None) if meth is None and request.method == 'HEAD': meth = getattr(self, 'get', None) assert meth is not None, 'Unimplemented method %r' % request.method if isinstance(self.method_decorators, Mapping): decorators = self.method_decorators.get(request.method.lower(), []) else: decorators = self.method_decorators for decorator in decorators: meth = decorator(meth) resp = meth(*args, **kwargs) if isinstance(resp, ResponseBase): # There may be a better way to test return resp representations = self.representations or OrderedDict() #noinspection PyUnresolvedReferences mediatype = request.accept_mimetypes.best_match(representations, default=None) if mediatype in representations: data, code, headers = unpack(resp) resp = representations[mediatype](data, code, headers) resp.headers['Content-Type'] = mediatype return resp return resp def marshal(data, fields, envelope=None): """Takes raw data (in the form of a dict, list, object) and a dict of fields to output and filters the data based on those fields. :param data: the actual object(s) from which the fields are taken from :param fields: a dict of whose keys will make up the final serialized response output :param envelope: optional key that will be used to envelop the serialized response >>> from flask_restful import fields, marshal >>> data = { 'a': 100, 'b': 'foo' } >>> mfields = { 'a': fields.Raw } >>> marshal(data, mfields) OrderedDict([('a', 100)]) >>> marshal(data, mfields, envelope='data') OrderedDict([('data', OrderedDict([('a', 100)]))]) """ def make(cls): if isinstance(cls, type): return cls() return cls if isinstance(data, (list, tuple)): return (OrderedDict([(envelope, [marshal(d, fields) for d in data])]) if envelope else [marshal(d, fields) for d in data]) items = ((k, marshal(data, v) if isinstance(v, dict) else make(v).output(k, data)) for k, v in fields.items()) return OrderedDict([(envelope, OrderedDict(items))]) if envelope else OrderedDict(items) class marshal_with(object): """A decorator that apply marshalling to the return values of your methods. >>> from flask_restful import fields, marshal_with >>> mfields = { 'a': fields.Raw } >>> @marshal_with(mfields) ... def get(): ... return { 'a': 100, 'b': 'foo' } ... ... >>> get() OrderedDict([('a', 100)]) >>> @marshal_with(mfields, envelope='data') ... def get(): ... return { 'a': 100, 'b': 'foo' } ... ... >>> get() OrderedDict([('data', OrderedDict([('a', 100)]))]) see :meth:`flask_restful.marshal` """ def __init__(self, fields, envelope=None): """ :param fields: a dict of whose keys will make up the final serialized response output :param envelope: optional key that will be used to envelop the serialized response """ self.fields = fields self.envelope = envelope def __call__(self, f): @wraps(f) def wrapper(*args, **kwargs): resp = f(*args, **kwargs) if isinstance(resp, tuple): data, code, headers = unpack(resp) return marshal(data, self.fields, self.envelope), code, headers else: return marshal(resp, self.fields, self.envelope) return wrapper class marshal_with_field(object): """ A decorator that formats the return values of your methods with a single field. >>> from flask_restful import marshal_with_field, fields >>> @marshal_with_field(fields.List(fields.Integer)) ... def get(): ... return ['1', 2, 3.0] ... >>> get() [1, 2, 3] see :meth:`flask_restful.marshal_with` """ def __init__(self, field): """ :param field: a single field with which to marshal the output. """ if isinstance(field, type): self.field = field() else: self.field = field def __call__(self, f): @wraps(f) def wrapper(*args, **kwargs): resp = f(*args, **kwargs) if isinstance(resp, tuple): data, code, headers = unpack(resp) return self.field.format(data), code, headers return self.field.format(resp) return wrapper