Added support for CORS headers

pull/1930/head
Sander van Kasteel 2 years ago committed by GitHub
parent a36b3ce2ba
commit 0d39928a7b
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@ -1,6 +1,9 @@
# coding=utf-8
from flask import Flask, redirect
import os
from flask_cors import CORS
from flask_socketio import SocketIO
from .get_args import args
@ -18,6 +21,9 @@ def create_app():
app.config['JSONIFY_PRETTYPRINT_REGULAR'] = True
app.config['JSON_AS_ASCII'] = False
if settings.get('cors', 'enabled'):
CORS(app)
if args.dev:
app.config["DEBUG"] = True
else:

@ -85,6 +85,9 @@ defaults = {
'username': '',
'password': ''
},
'cors': {
'enabled': 'False'
},
'backup': {
'folder': os.path.join(args.config_dir, 'backup'),
'retention': '31',

@ -115,6 +115,14 @@ const SettingsGeneralView: FunctionComponent = () => {
}
settingKey={settingApiKey}
></Text>
<Check
label="Enable CORS headers"
settingKey="settings-cors-enabled"
></Check>
<Message>
Allow third parties to make requests towards your Bazarr installation.
Requires a restart of Bazarr when changed
</Message>
</Section>
<Section header="Proxy">
<Selector

@ -0,0 +1,27 @@
# -*- coding: utf-8 -*-
"""
flask_cors
~~~~
Flask-CORS is a simple extension to Flask allowing you to support cross
origin resource sharing (CORS) using a simple decorator.
:copyright: (c) 2016 by Cory Dolphin.
:license: MIT, see LICENSE for more details.
"""
from .decorator import cross_origin
from .extension import CORS
from .version import __version__
__all__ = ['CORS', 'cross_origin']
# Set default logging handler to avoid "No handler found" warnings.
import logging
from logging import NullHandler
# Set initial level to WARN. Users must manually enable logging for
# flask_cors to see our logging.
rootlogger = logging.getLogger(__name__)
rootlogger.addHandler(NullHandler())
if rootlogger.level == logging.NOTSET:
rootlogger.setLevel(logging.WARN)

@ -0,0 +1,383 @@
# -*- coding: utf-8 -*-
"""
core
~~~~
Core functionality shared between the extension and the decorator.
:copyright: (c) 2016 by Cory Dolphin.
:license: MIT, see LICENSE for more details.
"""
import re
import logging
try:
# on python 3
from collections.abc import Iterable
except ImportError:
# on python 2.7 and pypy
from collections import Iterable
from datetime import timedelta
from six import string_types
from flask import request, current_app
from werkzeug.datastructures import Headers, MultiDict
LOG = logging.getLogger(__name__)
# Response Headers
ACL_ORIGIN = 'Access-Control-Allow-Origin'
ACL_METHODS = 'Access-Control-Allow-Methods'
ACL_ALLOW_HEADERS = 'Access-Control-Allow-Headers'
ACL_EXPOSE_HEADERS = 'Access-Control-Expose-Headers'
ACL_CREDENTIALS = 'Access-Control-Allow-Credentials'
ACL_MAX_AGE = 'Access-Control-Max-Age'
# Request Header
ACL_REQUEST_METHOD = 'Access-Control-Request-Method'
ACL_REQUEST_HEADERS = 'Access-Control-Request-Headers'
ALL_METHODS = ['GET', 'HEAD', 'POST', 'OPTIONS', 'PUT', 'PATCH', 'DELETE']
CONFIG_OPTIONS = ['CORS_ORIGINS', 'CORS_METHODS', 'CORS_ALLOW_HEADERS',
'CORS_EXPOSE_HEADERS', 'CORS_SUPPORTS_CREDENTIALS',
'CORS_MAX_AGE', 'CORS_SEND_WILDCARD',
'CORS_AUTOMATIC_OPTIONS', 'CORS_VARY_HEADER',
'CORS_RESOURCES', 'CORS_INTERCEPT_EXCEPTIONS',
'CORS_ALWAYS_SEND']
# Attribute added to request object by decorator to indicate that CORS
# was evaluated, in case the decorator and extension are both applied
# to a view.
FLASK_CORS_EVALUATED = '_FLASK_CORS_EVALUATED'
# Strange, but this gets the type of a compiled regex, which is otherwise not
# exposed in a public API.
RegexObject = type(re.compile(''))
DEFAULT_OPTIONS = dict(origins='*',
methods=ALL_METHODS,
allow_headers='*',
expose_headers=None,
supports_credentials=False,
max_age=None,
send_wildcard=False,
automatic_options=True,
vary_header=True,
resources=r'/*',
intercept_exceptions=True,
always_send=True)
def parse_resources(resources):
if isinstance(resources, dict):
# To make the API more consistent with the decorator, allow a
# resource of '*', which is not actually a valid regexp.
resources = [(re_fix(k), v) for k, v in resources.items()]
# Sort by regex length to provide consistency of matching and
# to provide a proxy for specificity of match. E.G. longer
# regular expressions are tried first.
def pattern_length(pair):
maybe_regex, _ = pair
return len(get_regexp_pattern(maybe_regex))
return sorted(resources,
key=pattern_length,
reverse=True)
elif isinstance(resources, string_types):
return [(re_fix(resources), {})]
elif isinstance(resources, Iterable):
return [(re_fix(r), {}) for r in resources]
# Type of compiled regex is not part of the public API. Test for this
# at runtime.
elif isinstance(resources, RegexObject):
return [(re_fix(resources), {})]
else:
raise ValueError("Unexpected value for resources argument.")
def get_regexp_pattern(regexp):
"""
Helper that returns regexp pattern from given value.
:param regexp: regular expression to stringify
:type regexp: _sre.SRE_Pattern or str
:returns: string representation of given regexp pattern
:rtype: str
"""
try:
return regexp.pattern
except AttributeError:
return str(regexp)
def get_cors_origins(options, request_origin):
origins = options.get('origins')
wildcard = r'.*' in origins
# If the Origin header is not present terminate this set of steps.
# The request is outside the scope of this specification.-- W3Spec
if request_origin:
LOG.debug("CORS request received with 'Origin' %s", request_origin)
# If the allowed origins is an asterisk or 'wildcard', always match
if wildcard and options.get('send_wildcard'):
LOG.debug("Allowed origins are set to '*'. Sending wildcard CORS header.")
return ['*']
# If the value of the Origin header is a case-sensitive match
# for any of the values in list of origins
elif try_match_any(request_origin, origins):
LOG.debug("The request's Origin header matches. Sending CORS headers.", )
# Add a single Access-Control-Allow-Origin header, with either
# the value of the Origin header or the string "*" as value.
# -- W3Spec
return [request_origin]
else:
LOG.debug("The request's Origin header does not match any of allowed origins.")
return None
elif options.get('always_send'):
if wildcard:
# If wildcard is in the origins, even if 'send_wildcard' is False,
# simply send the wildcard. Unless supports_credentials is True,
# since that is forbidded by the spec..
# It is the most-likely to be correct thing to do (the only other
# option is to return nothing, which almost certainly not what
# the developer wants if the '*' origin was specified.
if options.get('supports_credentials'):
return None
else:
return ['*']
else:
# Return all origins that are not regexes.
return sorted([o for o in origins if not probably_regex(o)])
# Terminate these steps, return the original request untouched.
else:
LOG.debug("The request did not contain an 'Origin' header. This means the browser or client did not request CORS, ensure the Origin Header is set.")
return None
def get_allow_headers(options, acl_request_headers):
if acl_request_headers:
request_headers = [h.strip() for h in acl_request_headers.split(',')]
# any header that matches in the allow_headers
matching_headers = filter(
lambda h: try_match_any(h, options.get('allow_headers')),
request_headers
)
return ', '.join(sorted(matching_headers))
return None
def get_cors_headers(options, request_headers, request_method):
origins_to_set = get_cors_origins(options, request_headers.get('Origin'))
headers = MultiDict()
if not origins_to_set: # CORS is not enabled for this route
return headers
for origin in origins_to_set:
headers.add(ACL_ORIGIN, origin)
headers[ACL_EXPOSE_HEADERS] = options.get('expose_headers')
if options.get('supports_credentials'):
headers[ACL_CREDENTIALS] = 'true' # case sensative
# This is a preflight request
# http://www.w3.org/TR/cors/#resource-preflight-requests
if request_method == 'OPTIONS':
acl_request_method = request_headers.get(ACL_REQUEST_METHOD, '').upper()
# If there is no Access-Control-Request-Method header or if parsing
# failed, do not set any additional headers
if acl_request_method and acl_request_method in options.get('methods'):
# If method is not a case-sensitive match for any of the values in
# list of methods do not set any additional headers and terminate
# this set of steps.
headers[ACL_ALLOW_HEADERS] = get_allow_headers(options, request_headers.get(ACL_REQUEST_HEADERS))
headers[ACL_MAX_AGE] = options.get('max_age')
headers[ACL_METHODS] = options.get('methods')
else:
LOG.info("The request's Access-Control-Request-Method header does not match allowed methods. CORS headers will not be applied.")
# http://www.w3.org/TR/cors/#resource-implementation
if options.get('vary_header'):
# Only set header if the origin returned will vary dynamically,
# i.e. if we are not returning an asterisk, and there are multiple
# origins that can be matched.
if headers[ACL_ORIGIN] == '*':
pass
elif (len(options.get('origins')) > 1 or
len(origins_to_set) > 1 or
any(map(probably_regex, options.get('origins')))):
headers.add('Vary', 'Origin')
return MultiDict((k, v) for k, v in headers.items() if v)
def set_cors_headers(resp, options):
"""
Performs the actual evaluation of Flas-CORS options and actually
modifies the response object.
This function is used both in the decorator and the after_request
callback
"""
# If CORS has already been evaluated via the decorator, skip
if hasattr(resp, FLASK_CORS_EVALUATED):
LOG.debug('CORS have been already evaluated, skipping')
return resp
# Some libraries, like OAuthlib, set resp.headers to non Multidict
# objects (Werkzeug Headers work as well). This is a problem because
# headers allow repeated values.
if (not isinstance(resp.headers, Headers)
and not isinstance(resp.headers, MultiDict)):
resp.headers = MultiDict(resp.headers)
headers_to_set = get_cors_headers(options, request.headers, request.method)
LOG.debug('Settings CORS headers: %s', str(headers_to_set))
for k, v in headers_to_set.items():
resp.headers.add(k, v)
return resp
def probably_regex(maybe_regex):
if isinstance(maybe_regex, RegexObject):
return True
else:
common_regex_chars = ['*', '\\', ']', '?', '$', '^', '[', ']', '(', ')']
# Use common characters used in regular expressions as a proxy
# for if this string is in fact a regex.
return any((c in maybe_regex for c in common_regex_chars))
def re_fix(reg):
"""
Replace the invalid regex r'*' with the valid, wildcard regex r'/.*' to
enable the CORS app extension to have a more user friendly api.
"""
return r'.*' if reg == r'*' else reg
def try_match_any(inst, patterns):
return any(try_match(inst, pattern) for pattern in patterns)
def try_match(request_origin, maybe_regex):
"""Safely attempts to match a pattern or string to a request origin."""
if isinstance(maybe_regex, RegexObject):
return re.match(maybe_regex, request_origin)
elif probably_regex(maybe_regex):
return re.match(maybe_regex, request_origin, flags=re.IGNORECASE)
else:
try:
return request_origin.lower() == maybe_regex.lower()
except AttributeError:
return request_origin == maybe_regex
def get_cors_options(appInstance, *dicts):
"""
Compute CORS options for an application by combining the DEFAULT_OPTIONS,
the app's configuration-specified options and any dictionaries passed. The
last specified option wins.
"""
options = DEFAULT_OPTIONS.copy()
options.update(get_app_kwarg_dict(appInstance))
if dicts:
for d in dicts:
options.update(d)
return serialize_options(options)
def get_app_kwarg_dict(appInstance=None):
"""Returns the dictionary of CORS specific app configurations."""
app = (appInstance or current_app)
# In order to support blueprints which do not have a config attribute
app_config = getattr(app, 'config', {})
return {
k.lower().replace('cors_', ''): app_config.get(k)
for k in CONFIG_OPTIONS
if app_config.get(k) is not None
}
def flexible_str(obj):
"""
A more flexible str function which intelligently handles stringifying
strings, lists and other iterables. The results are lexographically sorted
to ensure generated responses are consistent when iterables such as Set
are used.
"""
if obj is None:
return None
elif(not isinstance(obj, string_types)
and isinstance(obj, Iterable)):
return ', '.join(str(item) for item in sorted(obj))
else:
return str(obj)
def serialize_option(options_dict, key, upper=False):
if key in options_dict:
value = flexible_str(options_dict[key])
options_dict[key] = value.upper() if upper else value
def ensure_iterable(inst):
"""
Wraps scalars or string types as a list, or returns the iterable instance.
"""
if isinstance(inst, string_types):
return [inst]
elif not isinstance(inst, Iterable):
return [inst]
else:
return inst
def sanitize_regex_param(param):
return [re_fix(x) for x in ensure_iterable(param)]
def serialize_options(opts):
"""
A helper method to serialize and processes the options dictionary.
"""
options = (opts or {}).copy()
for key in opts.keys():
if key not in DEFAULT_OPTIONS:
LOG.warning("Unknown option passed to Flask-CORS: %s", key)
# Ensure origins is a list of allowed origins with at least one entry.
options['origins'] = sanitize_regex_param(options.get('origins'))
options['allow_headers'] = sanitize_regex_param(options.get('allow_headers'))
# This is expressly forbidden by the spec. Raise a value error so people
# don't get burned in production.
if r'.*' in options['origins'] and options['supports_credentials'] and options['send_wildcard']:
raise ValueError("Cannot use supports_credentials in conjunction with"
"an origin string of '*'. See: "
"http://www.w3.org/TR/cors/#resource-requests")
serialize_option(options, 'expose_headers')
serialize_option(options, 'methods', upper=True)
if isinstance(options.get('max_age'), timedelta):
options['max_age'] = str(int(options['max_age'].total_seconds()))
return options

@ -0,0 +1,135 @@
# -*- coding: utf-8 -*-
"""
decorator
~~~~
This unit exposes a single decorator which should be used to wrap a
Flask route with. It accepts all parameters and options as
the CORS extension.
:copyright: (c) 2016 by Cory Dolphin.
:license: MIT, see LICENSE for more details.
"""
from functools import update_wrapper
from flask import make_response, request, current_app
from .core import *
LOG = logging.getLogger(__name__)
def cross_origin(*args, **kwargs):
"""
This function is the decorator which is used to wrap a Flask route with.
In the simplest case, simply use the default parameters to allow all
origins in what is the most permissive configuration. If this method
modifies state or performs authentication which may be brute-forced, you
should add some degree of protection, such as Cross Site Forgery
Request protection.
:param origins:
The origin, or list of origins to allow requests from.
The origin(s) may be regular expressions, case-sensitive strings,
or else an asterisk
Default : '*'
:type origins: list, string or regex
:param methods:
The method or list of methods which the allowed origins are allowed to
access for non-simple requests.
Default : [GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE]
:type methods: list or string
:param expose_headers:
The header or list which are safe to expose to the API of a CORS API
specification.
Default : None
:type expose_headers: list or string
:param allow_headers:
The header or list of header field names which can be used when this
resource is accessed by allowed origins. The header(s) may be regular
expressions, case-sensitive strings, or else an asterisk.
Default : '*', allow all headers
:type allow_headers: list, string or regex
:param supports_credentials:
Allows users to make authenticated requests. If true, injects the
`Access-Control-Allow-Credentials` header in responses. This allows
cookies and credentials to be submitted across domains.
:note: This option cannot be used in conjuction with a '*' origin
Default : False
:type supports_credentials: bool
:param max_age:
The maximum time for which this CORS request maybe cached. This value
is set as the `Access-Control-Max-Age` header.
Default : None
:type max_age: timedelta, integer, string or None
:param send_wildcard: If True, and the origins parameter is `*`, a wildcard
`Access-Control-Allow-Origin` header is sent, rather than the
request's `Origin` header.
Default : False
:type send_wildcard: bool
:param vary_header:
If True, the header Vary: Origin will be returned as per the W3
implementation guidelines.
Setting this header when the `Access-Control-Allow-Origin` is
dynamically generated (e.g. when there is more than one allowed
origin, and an Origin than '*' is returned) informs CDNs and other
caches that the CORS headers are dynamic, and cannot be cached.
If False, the Vary header will never be injected or altered.
Default : True
:type vary_header: bool
:param automatic_options:
Only applies to the `cross_origin` decorator. If True, Flask-CORS will
override Flask's default OPTIONS handling to return CORS headers for
OPTIONS requests.
Default : True
:type automatic_options: bool
"""
_options = kwargs
def decorator(f):
LOG.debug("Enabling %s for cross_origin using options:%s", f, _options)
# If True, intercept OPTIONS requests by modifying the view function,
# replicating Flask's default behavior, and wrapping the response with
# CORS headers.
#
# If f.provide_automatic_options is unset or True, Flask's route
# decorator (which is actually wraps the function object we return)
# intercepts OPTIONS handling, and requests will not have CORS headers
if _options.get('automatic_options', True):
f.required_methods = getattr(f, 'required_methods', set())
f.required_methods.add('OPTIONS')
f.provide_automatic_options = False
def wrapped_function(*args, **kwargs):
# Handle setting of Flask-Cors parameters
options = get_cors_options(current_app, _options)
if options.get('automatic_options') and request.method == 'OPTIONS':
resp = current_app.make_default_options_response()
else:
resp = make_response(f(*args, **kwargs))
set_cors_headers(resp, options)
setattr(resp, FLASK_CORS_EVALUATED, True)
return resp
return update_wrapper(wrapped_function, f)
return decorator

@ -0,0 +1,190 @@
# -*- coding: utf-8 -*-
"""
extension
~~~~
Flask-CORS is a simple extension to Flask allowing you to support cross
origin resource sharing (CORS) using a simple decorator.
:copyright: (c) 2016 by Cory Dolphin.
:license: MIT, see LICENSE for more details.
"""
from flask import request
from .core import *
try:
from urllib.parse import unquote_plus
except ImportError:
from urllib import unquote_plus
LOG = logging.getLogger(__name__)
class CORS(object):
"""
Initializes Cross Origin Resource sharing for the application. The
arguments are identical to :py:func:`cross_origin`, with the addition of a
`resources` parameter. The resources parameter defines a series of regular
expressions for resource paths to match and optionally, the associated
options to be applied to the particular resource. These options are
identical to the arguments to :py:func:`cross_origin`.
The settings for CORS are determined in the following order
1. Resource level settings (e.g when passed as a dictionary)
2. Keyword argument settings
3. App level configuration settings (e.g. CORS_*)
4. Default settings
Note: as it is possible for multiple regular expressions to match a
resource path, the regular expressions are first sorted by length,
from longest to shortest, in order to attempt to match the most
specific regular expression. This allows the definition of a
number of specific resource options, with a wildcard fallback
for all other resources.
:param resources:
The series of regular expression and (optionally) associated CORS
options to be applied to the given resource path.
If the argument is a dictionary, it's keys must be regular expressions,
and the values must be a dictionary of kwargs, identical to the kwargs
of this function.
If the argument is a list, it is expected to be a list of regular
expressions, for which the app-wide configured options are applied.
If the argument is a string, it is expected to be a regular expression
for which the app-wide configured options are applied.
Default : Match all and apply app-level configuration
:type resources: dict, iterable or string
:param origins:
The origin, or list of origins to allow requests from.
The origin(s) may be regular expressions, case-sensitive strings,
or else an asterisk
Default : '*'
:type origins: list, string or regex
:param methods:
The method or list of methods which the allowed origins are allowed to
access for non-simple requests.
Default : [GET, HEAD, POST, OPTIONS, PUT, PATCH, DELETE]
:type methods: list or string
:param expose_headers:
The header or list which are safe to expose to the API of a CORS API
specification.
Default : None
:type expose_headers: list or string
:param allow_headers:
The header or list of header field names which can be used when this
resource is accessed by allowed origins. The header(s) may be regular
expressions, case-sensitive strings, or else an asterisk.
Default : '*', allow all headers
:type allow_headers: list, string or regex
:param supports_credentials:
Allows users to make authenticated requests. If true, injects the
`Access-Control-Allow-Credentials` header in responses. This allows
cookies and credentials to be submitted across domains.
:note: This option cannot be used in conjunction with a '*' origin
Default : False
:type supports_credentials: bool
:param max_age:
The maximum time for which this CORS request maybe cached. This value
is set as the `Access-Control-Max-Age` header.
Default : None
:type max_age: timedelta, integer, string or None
:param send_wildcard: If True, and the origins parameter is `*`, a wildcard
`Access-Control-Allow-Origin` header is sent, rather than the
request's `Origin` header.
Default : False
:type send_wildcard: bool
:param vary_header:
If True, the header Vary: Origin will be returned as per the W3
implementation guidelines.
Setting this header when the `Access-Control-Allow-Origin` is
dynamically generated (e.g. when there is more than one allowed
origin, and an Origin than '*' is returned) informs CDNs and other
caches that the CORS headers are dynamic, and cannot be cached.
If False, the Vary header will never be injected or altered.
Default : True
:type vary_header: bool
"""
def __init__(self, app=None, **kwargs):
self._options = kwargs
if app is not None:
self.init_app(app, **kwargs)
def init_app(self, app, **kwargs):
# The resources and options may be specified in the App Config, the CORS constructor
# or the kwargs to the call to init_app.
options = get_cors_options(app, self._options, kwargs)
# Flatten our resources into a list of the form
# (pattern_or_regexp, dictionary_of_options)
resources = parse_resources(options.get('resources'))
# Compute the options for each resource by combining the options from
# the app's configuration, the constructor, the kwargs to init_app, and
# finally the options specified in the resources dictionary.
resources = [
(pattern, get_cors_options(app, options, opts))
for (pattern, opts) in resources
]
# Create a human readable form of these resources by converting the compiled
# regular expressions into strings.
resources_human = {get_regexp_pattern(pattern): opts for (pattern,opts) in resources}
LOG.debug("Configuring CORS with resources: %s", resources_human)
cors_after_request = make_after_request_function(resources)
app.after_request(cors_after_request)
# Wrap exception handlers with cross_origin
# These error handlers will still respect the behavior of the route
if options.get('intercept_exceptions', True):
def _after_request_decorator(f):
def wrapped_function(*args, **kwargs):
return cors_after_request(app.make_response(f(*args, **kwargs)))
return wrapped_function
if hasattr(app, 'handle_exception'):
app.handle_exception = _after_request_decorator(
app.handle_exception)
app.handle_user_exception = _after_request_decorator(
app.handle_user_exception)
def make_after_request_function(resources):
def cors_after_request(resp):
# If CORS headers are set in a view decorator, pass
if resp.headers is not None and resp.headers.get(ACL_ORIGIN):
LOG.debug('CORS have been already evaluated, skipping')
return resp
normalized_path = unquote_plus(request.path)
for res_regex, res_options in resources:
if try_match(normalized_path, res_regex):
LOG.debug("Request to '%s' matches CORS resource '%s'. Using options: %s",
request.path, get_regexp_pattern(res_regex), res_options)
set_cors_headers(resp, res_options)
break
else:
LOG.debug('No CORS rule matches')
return resp
return cors_after_request

@ -0,0 +1 @@
__version__ = '3.0.10'

@ -8,6 +8,7 @@ dogpile.cache==1.1.5
enzyme==0.4.1
fese==0.1.2
ffsubsync==0.4.20
flask-cors==3.0.10
flask-restful==0.3.9
Flask-SocketIO==5.1.1
Flask==2.0.2

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