from __future__ import absolute_import
import difflib
from functools import wraps, partial
import re
from flask import request, url_for, current_app
from flask import abort as original_flask_abort
from flask.views import MethodView
from flask.signals import got_request_exception
from werkzeug.exceptions import HTTPException, MethodNotAllowed, NotFound
from werkzeug.http import HTTP_STATUS_CODES
from werkzeug.wrappers import Response as ResponseBase
from flask.ext.restful.utils import error_data, unpack
from flask.ext.restful.representations.json import output_json
import sys
from flask.helpers import _endpoint_from_view_func
from types import MethodType
try:
#noinspection PyUnresolvedReferences
from collections import OrderedDict
except ImportError:
from .utils.ordereddict import OrderedDict
__all__ = ('Api', 'Resource', 'marshal', 'marshal_with', '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 e
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
: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 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
"""
def __init__(self, app=None, prefix='',
default_mediatype='application/json', decorators=None,
catch_all_404s=False, url_part_order='bae'):
self.representations = dict(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.url_part_order = url_part_order
self.blueprint_setup = None
self.endpoints = set()
self.resources = []
self.app = 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.init_app(app)
api.add_resource(...)
"""
self.blueprint = None
# 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.
: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():
return self.handle_error(e)
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 hasattr(e, 'code') and current_app.propagate_exceptions:
exc_type, exc_value, tb = sys.exc_info()
if exc_value is e:
raise
else:
raise e
code = getattr(e, 'code', 500)
data = getattr(e, 'data', error_data(code))
if code >= 500:
# There's currently a bug in Python3 that disallows calling
# logging.exception() when an exception hasn't actually be raised
if sys.exc_info() == (None, None, None):
current_app.logger.error("Internal Error")
else:
current_app.logger.exception("Internal Error")
help_on_404 = current_app.config.get("ERROR_404_HELP", True)
if code == 404 and help_on_404 and ('message' not in data or
data['message'] == HTTP_STATUS_CODES[404]):
rules = dict([(re.sub('(<.*>)', '', rule.rule), rule.rule)
for rule in current_app.url_map.iter_rules()])
close_matches = difflib.get_close_matches(request.path, rules.keys())
if close_matches:
# If we already have a message, add punctuation and continue it.
if "message" in data:
data["message"] += ". "
else:
data["message"] = ""
data['message'] += 'You have requested this URI [' + request.path + \
'] but did you mean ' + \
' or '.join((rules[match]
for match in close_matches)) + ' ?'
resp = self.make_response(data, code)
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:`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
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 _register_view(self, app, resource, *urls, **kwargs):
endpoint = kwargs.pop('endpoint', None) or resource.__name__.lower()
self.endpoints.add(endpoint)
if endpoint in app.view_functions.keys():
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))
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.
rule = self._complete_url(url, self.blueprint_setup.url_prefix)
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."""
return url_for(resource.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 (application/json) if no transformer is found for the
requested mediatype.
:param data: Python object containing response data to be transformed
"""
for mediatype in self.mediatypes() + [self.default_mediatype]:
if mediatype in self.representations:
resp = self.representations[mediatype](data, *args, **kwargs)
resp.headers['Content-Type'] = mediatype
return resp
def mediatypes(self):
"""Returns a list of requested mediatypes sent in the Accept header"""
return [h for h, q in request.accept_mimetypes]
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 """
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.ext.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
for decorator in self.method_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 {}
#noinspection PyUnresolvedReferences
for mediatype in self.mediatypes():
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):
"""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 fields: a dict of whose keys will make up the final serialized
response output
:param data: the actual object(s) from which the fields are taken from
>>> from flask.ext.restful import fields, marshal
>>> data = { 'a': 100, 'b': 'foo' }
>>> mfields = { 'a': fields.Raw }
>>> marshal(data, mfields)
OrderedDict([('a', 100)])
"""
def make(cls):
if isinstance(cls, type):
return cls()
return cls
if isinstance(data, (list, tuple)):
return [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(items)
class marshal_with(object):
"""A decorator that apply marshalling to the return values of your methods.
>>> from flask.ext.restful import fields, marshal_with
>>> mfields = { 'a': fields.Raw }
>>> @marshal_with(mfields)
... def get():
... return { 'a': 100, 'b': 'foo' }
...
...
>>> get()
OrderedDict([('a', 100)])
see :meth:`flask.ext.restful.marshal`
"""
def __init__(self, fields):
""":param fields: a dict of whose keys will make up the final
serialized response output"""
self.fields = fields
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), code, headers
else:
return marshal(resp, self.fields)
return wrapper