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werkzeug-main / werkzeug / _internal.py

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# -*- coding: utf-8 -*-
"""
    werkzeug._internal
    ~~~~~~~~~~~~~~~~~~

    This module provides internally used helpers and constants.

    :copyright: (c) 2009 by the Werkzeug Team, see AUTHORS for more details.
    :license: BSD, see LICENSE for more details.
"""
import inspect
from weakref import WeakKeyDictionary
from cStringIO import StringIO
from Cookie import BaseCookie, Morsel, CookieError
from time import gmtime
from datetime import datetime


_logger = None
_empty_stream = StringIO('')
_signature_cache = WeakKeyDictionary()


HTTP_STATUS_CODES = {
    100:    'Continue',
    101:    'Switching Protocols',
    102:    'Processing',
    200:    'OK',
    201:    'Created',
    202:    'Accepted',
    203:    'Non Authoritative Information',
    204:    'No Content',
    205:    'Reset Content',
    206:    'Partial Content',
    207:    'Multi Status',
    226:    'IM Used',              # see RFC 3229
    300:    'Multiple Choices',
    301:    'Moved Permanently',
    302:    'Found',
    303:    'See Other',
    304:    'Not Modified',
    305:    'Use Proxy',
    307:    'Temporary Redirect',
    400:    'Bad Request',
    401:    'Unauthorized',
    402:    'Payment Required',     # unused
    403:    'Forbidden',
    404:    'Not Found',
    405:    'Method Not Allowed',
    406:    'Not Acceptable',
    407:    'Proxy Authentication Required',
    408:    'Request Timeout',
    409:    'Conflict',
    410:    'Gone',
    411:    'Length Required',
    412:    'Precondition Failed',
    413:    'Request Entity Too Large',
    414:    'Request URI Too Long',
    415:    'Unsupported Media Type',
    416:    'Requested Range Not Satisfiable',
    417:    'Expectation Failed',
    418:    'I\'m a teapot',        # see RFC 2324
    422:    'Unprocessable Entity',
    423:    'Locked',
    424:    'Failed Dependency',
    426:    'Upgrade Required',
    449:    'Retry With',           # propritary MS extension
    500:    'Internal Server Error',
    501:    'Not Implemented',
    502:    'Bad Gateway',
    503:    'Service Unavailable',
    504:    'Gateway Timeout',
    505:    'HTTP Version Not Supported',
    507:    'Insufficient Storage',
    510:    'Not Extended'
}


class _Missing(object):

    def __repr__(self):
        return 'no value'

    def __reduce__(self):
        return '_missing'

_missing = _Missing()


def _proxy_repr(cls):
    def proxy_repr(self):
        return '%s(%s)' % (self.__class__.__name__, cls.__repr__(self))
    return proxy_repr


def _log(type, message, *args, **kwargs):
    """Log into the internal werkzeug logger."""
    global _logger
    if _logger is None:
        import logging
        _logger = logging.getLogger('werkzeug')
        if _logger.level == logging.NOTSET:
            _logger.setLevel(logging.INFO)
            handler = logging.StreamHandler()
            _logger.addHandler(handler)
    getattr(_logger, type)(message.rstrip(), *args, **kwargs)


def _parse_signature(func):
    """Return a signature object for the function."""
    if hasattr(func, 'im_func'):
        func = func.im_func

    # if we have a cached validator for this function, return it
    parse = _signature_cache.get(func)
    if parse is not None:
        return parse

    # inspect the function signature and collect all the information
    positional, vararg_var, kwarg_var, defaults = inspect.getargspec(func)
    defaults = defaults or ()
    arg_count = len(positional)
    arguments = []
    for idx, name in enumerate(positional):
        if isinstance(name, list):
            raise TypeError('cannot parse functions that unpack tuples '
                            'in the function signature')
        try:
            default = defaults[idx - arg_count]
        except IndexError:
            param = (name, False, None)
        else:
            param = (name, True, default)
        arguments.append(param)
    arguments = tuple(arguments)

    def parse(args, kwargs):
        new_args = []
        missing = []
        extra = {}

        # consume as many arguments as positional as possible
        for idx, (name, has_default, default) in enumerate(arguments):
            try:
                new_args.append(args[idx])
            except IndexError:
                try:
                    new_args.append(kwargs.pop(name))
                except KeyError:
                    if has_default:
                        new_args.append(default)
                    else:
                        missing.append(name)
            else:
                if name in kwargs:
                    extra[name] = kwargs.pop(name)

        # handle extra arguments
        extra_positional = args[arg_count:]
        if vararg_var is not None:
            new_args.extend(extra_positional)
            extra_positional = ()
        if kwargs and not kwarg_var is not None:
            extra.update(kwargs)
            kwargs = {}

        return new_args, kwargs, missing, extra, extra_positional, \
               arguments, vararg_var, kwarg_var
    _signature_cache[func] = parse
    return parse


def _patch_wrapper(old, new):
    """Helper function that forwards all the function details to the
    decorated function."""
    try:
        new.__name__ = old.__name__
        new.__module__ = old.__module__
        new.__doc__ = old.__doc__
        new.__dict__ = old.__dict__
    except:
        pass
    return new


def _decode_unicode(value, charset, errors):
    """Like the regular decode function but this one raises an
    `HTTPUnicodeError` if errors is `strict`."""
    fallback = None
    if errors.startswith('fallback:'):
        fallback = errors[9:]
        errors = 'strict'
    try:
        return value.decode(charset, errors)
    except UnicodeError, e:
        if fallback is not None:
            return value.decode(fallback, 'ignore')
        from werkzeug.exceptions import HTTPUnicodeError
        raise HTTPUnicodeError(str(e))


def _iter_modules(path):
    """Iterate over all modules in a package."""
    import os
    import pkgutil
    if hasattr(pkgutil, 'iter_modules'):
        for importer, modname, ispkg in pkgutil.iter_modules(path):
            yield modname, ispkg
        return
    from inspect import getmodulename
    from pydoc import ispackage
    found = set()
    for path in path:
        for filename in os.listdir(path):
            p = os.path.join(path, filename)
            modname = getmodulename(filename)
            if modname and modname != '__init__':
                if modname not in found:
                    found.add(modname)
                    yield modname, ispackage(modname)


def _dump_date(d, delim):
    """Used for `http_date` and `cookie_date`."""
    if d is None:
        d = gmtime()
    elif isinstance(d, datetime):
        d = d.utctimetuple()
    elif isinstance(d, (int, long, float)):
        d = gmtime(d)
    return '%s, %02d%s%s%s%s %02d:%02d:%02d GMT' % (
        ('Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun')[d.tm_wday],
        d.tm_mday, delim,
        ('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
         'Oct', 'Nov', 'Dec')[d.tm_mon - 1],
        delim, str(d.tm_year), d.tm_hour, d.tm_min, d.tm_sec
    )


_timegm = None
def _date_to_unix(arg):
    """Converts a timetuple, integer or datetime object into the seconds from
    epoch in utc.
    """
    global _timegm
    if isinstance(arg, datetime):
        arg = arg.utctimetuple()
    elif isinstance(arg, (int, long, float)):
        return int(arg)
    if _timegm is None:
        from calendar import timegm as _timegm
    return _timegm(arg)


class _ExtendedMorsel(Morsel):
    _reserved = {'httponly': 'HttpOnly'}
    _reserved.update(Morsel._reserved)

    def __init__(self, name=None, value=None):
        Morsel.__init__(self)
        if name is not None:
            self.set(name, value, value)

    def OutputString(self, attrs=None):
        httponly = self.pop('httponly', False)
        result = Morsel.OutputString(self, attrs).rstrip('\t ;')
        if httponly:
            result += '; HttpOnly'
        return result


class _ExtendedCookie(BaseCookie):
    """Form of the base cookie that doesn't raise a `CookieError` for
    malformed keys.  This has the advantage that broken cookies submitted
    by nonstandard browsers don't cause the cookie to be empty.
    """

    def _BaseCookie__set(self, key, real_value, coded_value):
        morsel = self.get(key, _ExtendedMorsel())
        try:
            morsel.set(key, real_value, coded_value)
        except CookieError:
            pass
        dict.__setitem__(self, key, morsel)


class _DictAccessorProperty(object):
    """Baseclass for `environ_property` and `header_property`."""
    read_only = False

    def __init__(self, name, default=None, load_func=None, dump_func=None,
                 read_only=None, doc=None):
        self.name = name
        self.default = default
        self.load_func = load_func
        self.dump_func = dump_func
        if read_only is not None:
            self.read_only = read_only
        self.__doc__ = doc

    def __get__(self, obj, type=None):
        if obj is None:
            return self
        storage = self.lookup(obj)
        if self.name not in storage:
            return self.default
        rv = storage[self.name]
        if self.load_func is not None:
            try:
                rv = self.load_func(rv)
            except (ValueError, TypeError):
                rv = self.default
        return rv

    def __set__(self, obj, value):
        if self.read_only:
            raise AttributeError('read only property')
        if self.dump_func is not None:
            value = self.dump_func(value)
        self.lookup(obj)[self.name] = value

    def __delete__(self, obj):
        if self.read_only:
            raise AttributeError('read only property')
        self.lookup(obj).pop(self.name, None)

    def __repr__(self):
        return '<%s %s>' % (
            self.__class__.__name__,
            self.name
        )


def _easteregg(app):
    """Like the name says.  But who knows how it works?"""
    gyver = '\n'.join([x + (77 - len(x)) * ' ' for x in '''
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mj2Z/FM1vQWgDynsRwNvrWnJHlespkrp8+vO1jNaibm+PhqXPPv30YwDZ6jApe3wUjFQobghvW9p
7f2zLkGNv8b191cD/3vs9Q833z8t'''.decode('base64').decode('zlib').splitlines()])
    def easteregged(environ, start_response):
        def injecting_start_response(status, headers, exc_info=None):
            headers.append(('X-Powered-By', 'Werkzeug'))
            return start_response(status, headers, exc_info)
        if environ.get('QUERY_STRING') != 'macgybarchakku':
            return app(environ, injecting_start_response)
        injecting_start_response('200 OK', [('Content-Type', 'text/html')])
        return ['''<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<title>About Werkzeug</>
<style type="text/css">
  body { font: 15px Georgia, serif; text-align: center; }
  a { color: #333; text-decoration: none; }
  h1 { font-size: 30px; margin: 20px 0 10px 0; }
  p { margin: 0 0 30px 0; }
  pre { font: 11px 'Consolas', 'Monaco', monospace; line-height: 0.95; }
</style>
<h1><a href="http://werkzeug.pocoo.org/">Werkzeug</a></h1>
<p>the Swiss Army knife of Python web development.
<pre>%s\n\n\n</>''' % gyver]
    return easteregged