111 lines
3.0 KiB
Python
111 lines
3.0 KiB
Python
"""Defines Falcon utility functions
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Copyright 2013 by Rackspace Hosting, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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import datetime
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import six
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if six.PY3: # pragma nocover
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from urllib.parse import quote as url_quote
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else: # pragma nocover
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from urllib import quote as url_quote
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__all__ = ('dt_to_http', 'http_date_to_dt', 'to_query_str', 'percent_escape')
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def dt_to_http(dt):
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"""Converts a datetime instance to an HTTP date string.
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Args:
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dt: A datetime object, assumed to be UTC
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Returns:
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An HTTP date string, e.g., "Tue, 15 Nov 1994 12:45:26 GMT". See
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also: http://goo.gl/R7So4
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"""
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# Tue, 15 Nov 1994 12:45:26 GMT
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return dt.strftime('%a, %d %b %Y %H:%M:%S GMT')
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def http_date_to_dt(http_date):
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"""Converts an HTTP date string to a datetime instance.
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Args:
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http_date: An HTTP date string, e.g., "Tue, 15 Nov 1994 12:45:26 GMT".
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Returns:
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A UTC datetime instance corresponding to the given HTTP date.
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"""
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return datetime.datetime.strptime(
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http_date, '%a, %d %b %Y %H:%M:%S %Z')
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def to_query_str(params):
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"""Converts a dict of params to afaln actual query string.
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Args:
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params: dict of simple key-value types, where key is a string and
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value is a string or something that can be converted into a
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string.
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Returns:
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A URI query string starting with '?', or and empty string if there
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are no params (the dict is empty).
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"""
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if not params:
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return ''
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# PERF: This is faster than a list comprehension and join, mainly
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# because it allows us to inline the value transform.
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query_str = '?'
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for k, v in params.items():
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if v is True:
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v = 'true'
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elif v is False:
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v = 'false'
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else:
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v = str(v)
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query_str += k + '=' + v + '&'
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return query_str[:-1]
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def percent_escape(url):
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"""Percent-escape reserved characters in the given url.
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Args:
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url: A full or relative URL.
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Returns:
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An escaped version of the URL, excluding '/', ',' and ':'
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characters. In Python 2, unicode URL strings will be first
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encoded to a UTF-8 byte string to work around a urllib
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bug.
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"""
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# Convert the string so that urllib.quote does not complain
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# if it actually has Unicode chars in it.
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if not six.PY3 and isinstance(url, six.text_type): # pragma nocover
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url = url.encode('utf-8')
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return url_quote(url, safe='/:,=?&-_')
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