DataCookie._deserialize() - Code Metrics - Inspection of "wip" - ergoithz/browsepy - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — wip-ergoithz ( cc842c )

by Felipe A.

created 2018-05-23 18:51 UTC

DataCookie._deserialize() A

↳ Parent: DataCookie

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c	0
b	0
f	0
dl	0
loc	9
rs	9.6666
cc	1

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

import re
import json
import base64
import logging
import zlib

from werkzeug.http import dump_header, dump_options_header, dump_cookie, \
                          parse_cookie
from werkzeug.datastructures import Headers as BaseHeaders

from .compat import range
from .exceptions import InvalidCookieSizeError


logger = logging.getLogger(__name__)


class Headers(BaseHeaders):
    '''
    A wrapper around :class:`werkzeug.datastructures.Headers`, allowing
    to specify headers with options on initialization.

    Headers are provided as keyword arguments while values can be either
    :type:`str` (no options) or tuple of :type:`str` and :type:`dict`.
    '''
    snake_replace = staticmethod(re.compile(r'(^|-)[a-z]').sub)

    @classmethod
    def genpair(cls, key, value):
        '''
        Extract value and options from values dict based on given key and
        options-key.

        :param key: value key
        :type key: str
        :param value: value or value/options pair
        :type value: str or pair of (str, dict)
        :returns: tuple with key and value
        :rtype: tuple of (str, str)
        '''
        rkey = cls.snake_replace(
            lambda x: x.group(0).upper(),
            key.replace('_', '-')
            )
        rvalue = (
            dump_header([value])
            if isinstance(value, str) else
            dump_options_header(*value)
            )
        return rkey, rvalue

    def __init__(self, **kwargs):
        '''
        :param **kwargs: header and values as keyword arguments
        :type **kwargs: str or (str, dict)
        '''
        items = [
            self.genpair(key, value)
            for key, value in kwargs.items()
            ]
        return super(Headers, self).__init__(items)


class DataCookie(object):
    '''
    Compressed base64 paginated cookie manager.

    Usage
    -----

    > from flask import Flask, request, make_response
    >
    > app = Flask(__name__)
    > cookie = DataCookie('my-cookie')
    >
    > @app.route('/get')
    > def get():
    >     return 'Cookie value is %s' % cookie.load(request.cookies)
    >
    > @app.route('/set')
    > def set():
    >     response = make_response('Cookie set')
    >     cookie.dump('setted', response, request.cookies)
    >     return response

    '''
    page_length = 4000
    size_error = InvalidCookieSizeError
    headers_class = BaseHeaders

    @staticmethod
    def _serialize(data):
        '''
        :type data: json-serializable
        :rtype: bytes
        '''
        serialized = zlib.compress(json.dumps(data).encode('utf-8'))
        return base64.b64encode(serialized).decode('ascii')

    @staticmethod
    def _deserialize(data):
        '''
        :type data: bytes
        :rtype: json-serializable
        '''
        decoded = base64.b64decode(data)
        serialized = zlib.decompress(decoded)
        return json.loads(serialized)

    def __init__(self, cookie_name, max_pages=1, max_age=None, path='/'):
        '''
        :param cookie_name: first cookie name and prefix for the following
        :type cookie_name: str
        :param max_pages: maximum allowed cookie parts, defaults to 1
        :type max_pages: int
        :param max_age: cookie lifetime in seconds or None (session, default)
        :type max_age: int, datetime.timedelta or None
        :param path: cookie path, defaults to /
        :type path: str
        '''
        self.cookie_name = cookie_name
        self.max_pages = max_pages
        self.max_age = max_age
        self.path = path

    def _name_cookie_page(self, page):
        '''
        Get name of cookie corresponding to given page.

        By design (see :method:`_name_page`), pages lower than 1 results on
        cookie names without a page name.

        :param page: page number or name
        :type page: int or str
        :returns: cookie name
        :rtype: str
        '''
        return '{}{}'.format(
            self.cookie_name,
            page if isinstance(page, str) else
            '-{:x}'.format(page - 1) if page else
            ''
            )

    def _available_cookie_size(self, name):
        '''
        Get available cookie size for value.

        :param name: cookie name
        :type name: str
        :return: available bytes for cookie value
        :rtype: int
        '''
        empty = 'Set-Cookie: %s' % dump_cookie(
            name,
            value=' ',  # force quotes
            max_age=self.max_age,
            path=self.path
            )
        return self.page_length - len(empty)

    def _extract_cookies(self, headers):
        '''
        Extract relevant cookies from headers.
        '''
        regex = re.compile('^%s$' % self._name_cookie_page('(-[0-9a-f])?'))
        return {
            key: value
            for header in headers.get_all('cookie')
            for key, value in parse_cookie(header).items()
            if regex.match(key)
            }

    def load_cookies(self, cookies, default=None):
        '''
        Parse data from relevant paginated cookie data given as mapping.

        :param cookies: request cookies
        :type cookies: collections.abc.Mapping
        :returns: deserialized value
        :rtype: browsepy.abc.JSONSerializable
        '''
        chunks = []
        for i in range(self.max_pages):
            name = self._name_cookie_page(i)
            cookie = cookies.get(name, '').encode('ascii')
            chunks.append(cookie)
            if len(cookie) < self._available_cookie_size(name):
                break
        data = b''.join(chunks)
        if data:
            try:
                return self._deserialize(data)
            except BaseException:
                pass
        return default

    def load_headers(self, headers, default=None):
        '''
        Parse data from relevant paginated cookie data on request headers.

        :param headers: request headers
        :type headers: werkzeug.http.Headers
        :returns: deserialized value
        :rtype: browsepy.abc.JSONSerializable
        '''
        cookies = self._extract_cookies(headers)
        return self.load_cookies(cookies)

    def dump_headers(self, data, headers=None):
        '''
        Serialize given object into a :class:`werkzeug.datastructures.Headers`
        instance.

        :param data: any json-serializable value
        :type data: browsepy.abc.JSONSerializable
        :param headers: optional request headers, used to truncate old pages
        :type headers: werkzeug.http.Headers
        :return: response headers
        :rtype: werkzeug.http.Headers
        '''
        result = self.headers_class()
        data = self._serialize(data)
        start = 0
        size = len(data)
        for i in range(self.max_pages):
            name = self._name_cookie_page(i)
            end = start + self._available_cookie_size(name)
            result.set(
                'Set-Cookie',
                dump_cookie(
                    name,
                    data[start:end],
                    max_age=self.max_age,
                    path=self.path,
                    )
                )
            if end > size:
                # incidentally, an empty page will be added after end == size
                if headers:
                    result.extend(self.truncate_headers(headers, i + 1))
                return result
            start = end
        # pages exhausted, limit reached
        raise self.size_error(max_cookies=self.max_pages)

    def truncate_headers(self, headers, start=0):
        '''
        Evict relevant cookies found on request headers, optionally starting
        from a given page number.

        :param headers: request headers, required to truncate old pages
        :type headers: werkzeug.http.Headers
        :param start: paginated cookie start, defaults to 0
        :type start: int
        :return: response headers
        :rtype: werkzeug.http.Headers
        '''
        name_cookie = self._name_cookie_page
        cookie_names = set(self._extract_cookies(headers))
        cookie_names.difference_update(name_cookie(i) for i in range(start))

        result = self.headers_class()
        for name in cookie_names:
            result.add('Set-Cookie', dump_cookie(name, expires=0))
        return result


1			#!/usr/bin/env python
2			# -- coding: UTF-8 --
3
4			import re
5			import json
6			import base64
7			import logging
8			import zlib
9
10			from werkzeug.http import dump_header, dump_options_header, dump_cookie, \
11			parse_cookie
12			from werkzeug.datastructures import Headers as BaseHeaders
13
14			from .compat import range
15			from .exceptions import InvalidCookieSizeError
16
17
18			logger = logging.getLogger(__name__)
19
20
21			class Headers(BaseHeaders):
22			'''
23			A wrapper around :class:`werkzeug.datastructures.Headers`, allowing
24			to specify headers with options on initialization.
25
26			Headers are provided as keyword arguments while values can be either
27			:type:`str` (no options) or tuple of :type:`str` and :type:`dict`.
28			'''
29			snake_replace = staticmethod(re.compile(r'(^\|-)[a-z]').sub)
30
31			@classmethod
32			def genpair(cls, key, value):
33			'''
34			Extract value and options from values dict based on given key and
35			options-key.
36
37			:param key: value key
38			:type key: str
39			:param value: value or value/options pair
40			:type value: str or pair of (str, dict)
41			:returns: tuple with key and value
42			:rtype: tuple of (str, str)
43			'''
44			rkey = cls.snake_replace(
45			lambda x: x.group(0).upper(),
46			key.replace('_', '-')
47			)
48			rvalue = (
49			dump_header([value])
50			if isinstance(value, str) else
51			dump_options_header(*value)
52			)
53			return rkey, rvalue
54
55			def __init__(self, **kwargs):
56			'''
57			:param **kwargs: header and values as keyword arguments
58			:type **kwargs: str or (str, dict)
59			'''
60			items = [
61			self.genpair(key, value)
62			for key, value in kwargs.items()
63			]
64			return super(Headers, self).__init__(items)
65
66
67			class DataCookie(object):
68			'''
69			Compressed base64 paginated cookie manager.
70
71			Usage
72			-----
73
74			> from flask import Flask, request, make_response
75			>
76			> app = Flask(__name__)
77			> cookie = DataCookie('my-cookie')
78			>
79			> @app.route('/get')
80			> def get():
81			> return 'Cookie value is %s' % cookie.load(request.cookies)
82			>
83			> @app.route('/set')
84			> def set():
85			> response = make_response('Cookie set')
86			> cookie.dump('setted', response, request.cookies)
87			> return response
88
89			'''
90			page_length = 4000
91			size_error = InvalidCookieSizeError
92			headers_class = BaseHeaders
93
94			@staticmethod
95			def _serialize(data):
96			'''
97			:type data: json-serializable
98			:rtype: bytes
99			'''
100			serialized = zlib.compress(json.dumps(data).encode('utf-8'))
101			return base64.b64encode(serialized).decode('ascii')
102
103			@staticmethod
104			def _deserialize(data):
105			'''
106			:type data: bytes
107			:rtype: json-serializable
108			'''
109			decoded = base64.b64decode(data)
110			serialized = zlib.decompress(decoded)
111			return json.loads(serialized)
112
113			def __init__(self, cookie_name, max_pages=1, max_age=None, path='/'):
114			'''
115			:param cookie_name: first cookie name and prefix for the following
116			:type cookie_name: str
117			:param max_pages: maximum allowed cookie parts, defaults to 1
118			:type max_pages: int
119			:param max_age: cookie lifetime in seconds or None (session, default)
120			:type max_age: int, datetime.timedelta or None
121			:param path: cookie path, defaults to /
122			:type path: str
123			'''
124			self.cookie_name = cookie_name
125			self.max_pages = max_pages
126			self.max_age = max_age
127			self.path = path
128
129			def _name_cookie_page(self, page):
130			'''
131			Get name of cookie corresponding to given page.
132
133			By design (see :method:`_name_page`), pages lower than 1 results on
134			cookie names without a page name.
135
136			:param page: page number or name
137			:type page: int or str
138			:returns: cookie name
139			:rtype: str
140			'''
141			return '{}{}'.format(
142			self.cookie_name,
143			page if isinstance(page, str) else
144			'-{:x}'.format(page - 1) if page else
145			''
146			)
147
148			def _available_cookie_size(self, name):
149			'''
150			Get available cookie size for value.
151
152			:param name: cookie name
153			:type name: str
154			:return: available bytes for cookie value
155			:rtype: int
156			'''
157			empty = 'Set-Cookie: %s' % dump_cookie(
158			name,
159			value=' ', # force quotes
160			max_age=self.max_age,
161			path=self.path
162			)
163			return self.page_length - len(empty)
164
165			def _extract_cookies(self, headers):
166			'''
167			Extract relevant cookies from headers.
168			'''
169			regex = re.compile('^%s$' % self._name_cookie_page('(-[0-9a-f])?'))
170			return {
171			key: value
172			for header in headers.get_all('cookie')
173			for key, value in parse_cookie(header).items()
174			if regex.match(key)
175			}
176
177			def load_cookies(self, cookies, default=None):
178			'''
179			Parse data from relevant paginated cookie data given as mapping.
180
181			:param cookies: request cookies
182			:type cookies: collections.abc.Mapping
183			:returns: deserialized value
184			:rtype: browsepy.abc.JSONSerializable
185			'''
186			chunks = []
187			for i in range(self.max_pages):
188			name = self._name_cookie_page(i)
189			cookie = cookies.get(name, '').encode('ascii')
190			chunks.append(cookie)
191			if len(cookie) < self._available_cookie_size(name):
192			break
193			data = b''.join(chunks)
194			if data:
195			try:
196			return self._deserialize(data)
197			except BaseException:
198			pass
199			return default
200
201			def load_headers(self, headers, default=None):
202			'''
203			Parse data from relevant paginated cookie data on request headers.
204
205			:param headers: request headers
206			:type headers: werkzeug.http.Headers
207			:returns: deserialized value
208			:rtype: browsepy.abc.JSONSerializable
209			'''
210			cookies = self._extract_cookies(headers)
211			return self.load_cookies(cookies)
212
213			def dump_headers(self, data, headers=None):
214			'''
215			Serialize given object into a :class:`werkzeug.datastructures.Headers`
216			instance.
217
218			:param data: any json-serializable value
219			:type data: browsepy.abc.JSONSerializable
220			:param headers: optional request headers, used to truncate old pages
221			:type headers: werkzeug.http.Headers
222			:return: response headers
223			:rtype: werkzeug.http.Headers
224			'''
225			result = self.headers_class()
226			data = self._serialize(data)
227			start = 0
228			size = len(data)
229			for i in range(self.max_pages):
230			name = self._name_cookie_page(i)
231			end = start + self._available_cookie_size(name)
232			result.set(
233			'Set-Cookie',
234			dump_cookie(
235			name,
236			data[start:end],
237			max_age=self.max_age,
238			path=self.path,
239			)
240			)
241			if end > size:
242			# incidentally, an empty page will be added after end == size
243			if headers:
244			result.extend(self.truncate_headers(headers, i + 1))
245			return result
246			start = end
247			# pages exhausted, limit reached
248			raise self.size_error(max_cookies=self.max_pages)
249
250			def truncate_headers(self, headers, start=0):
251			'''
252			Evict relevant cookies found on request headers, optionally starting
253			from a given page number.
254
255			:param headers: request headers, required to truncate old pages
256			:type headers: werkzeug.http.Headers
257			:param start: paginated cookie start, defaults to 0
258			:type start: int
259			:return: response headers
260			:rtype: werkzeug.http.Headers
261			'''
262			name_cookie = self._name_cookie_page
263			cookie_names = set(self._extract_cookies(headers))
264			cookie_names.difference_update(name_cookie(i) for i in range(start))
265
266			result = self.headers_class()
267			for name in cookie_names:
268			result.add('Set-Cookie', dump_cookie(name, expires=0))
269			return result
270

ergoithz / browsepy

Push — wip-ergoithz ( cc842c )

DataCookie._deserialize() A

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