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wil/link_header.py

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Last active December 20, 2015 20:29
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  1. wil revised this gist Aug 9, 2013. 1 changed file with 78 additions and 36 deletions.
    114 changes: 78 additions & 36 deletions link_header.py
    View file
    Original file line number Diff line number Diff line change
    @@ -1,5 +1,7 @@
    #!/usr/bin/env python

    # source: https://gist.github.com/mnot/210535

    """
    HTTP Link Header Parsing
    @@ -50,40 +52,80 @@ def _splitstring(instr, item, split):
    link_splitter = re.compile(LINK_SPLIT)

    def parse_link_value(instr):
    """
    Given a link-value (i.e., after separating the header-value on commas),
    return a dictionary whose keys are link URLs and values are dictionaries
    of the parameters for their associated links.
    Note that internationalised parameters (e.g., title*) are
    NOT percent-decoded.
    Also, only the last instance of a given parameter will be included.
    For example,
    >>> parse_link_value('</foo>; rel="self"; title*=utf-8\'de\'letztes%20Kapitel')
    {'/foo': {'title*': "utf-8'de'letztes%20Kapitel", 'rel': 'self'}}
    """
    out = {}
    if not instr:
    return out
    for link in [h.strip() for h in link_splitter.findall(instr)]:
    url, params = link.split(">", 1)
    url = url[1:]
    param_dict = {}
    for param in _splitstring(params, PARAMETER, "\s*;\s*"):
    try:
    a, v = param.split("=", 1)
    param_dict[a.lower()] = _unquotestring(v)
    except ValueError:
    param_dict[param.lower()] = None
    out[url] = param_dict
    return out


    """
    Given a link-value (i.e., after separating the header-value on commas),
    return a dictionary whose keys are link URLs and values are dictionaries
    of the parameters for their associated links.
    Note that internationalised parameters (e.g., title*) are
    NOT percent-decoded.
    Also, only the last instance of a given parameter will be included.
    For example,
    >>> parse_link_value('</foo>; rel="self"; title*=utf-8\\'de\\'letztes%20Kapitel')
    {'/foo': {'title*': "utf-8'de'letztes%20Kapitel", 'rel': 'self'}}
    """
    out = {}
    if not instr:
    return out
    for link in [h.strip() for h in link_splitter.findall(instr)]:
    url, params = link.split(">", 1)
    url = url[1:]
    param_dict = {}
    for param in _splitstring(params, PARAMETER, "\s*;\s*"):
    try:
    a, v = param.split("=", 1)
    param_dict[a.lower()] = _unquotestring(v)
    except ValueError:
    param_dict[param.lower()] = None
    out[url] = param_dict
    return out

    def parse_link_value_by_rel(instr):
    """
    This is a must simplified version of the above for the common use-case
    of looking for a particular `rel` value in the list of Link values.
    Given a link-value (i.e., after separating the header-value on commas),
    return a dictionary whose keys are link `rel` parameter,
    and values are the corresponding URLs.
    Notes:
    - Only the last instance of a rel parameter value is included.
    - links with no `rel` parameter (or with an empty value) are ignored.
    - `rel` parameter values are converted to lowercase
    For example,
    >>> parse_link_value_by_rel('</foo>; rel="next"; title*=utf-8\\'de\\'letztes%20Kapitel, </bar>')
    {'next': '/foo'}
    """
    out = {}
    if not instr:
    return out
    for link in [h.strip() for h in link_splitter.findall(instr)]:
    url, params = link.split(">", 1)
    url = url[1:]
    param_dict = {}
    for param in _splitstring(params, PARAMETER, "\s*;\s*"):
    try:
    a, v = param.split("=", 1)
    param_dict[a.lower()] = _unquotestring(v)
    except ValueError:
    param_dict[param.lower()] = None
    rel = param_dict.get('rel')
    if not rel:
    continue
    out[rel] = url
    return out


    if __name__ == '__main__':
    import sys
    if len(sys.argv) > 1:
    print parse_link_value(sys.argv[1])
    import sys
    if len(sys.argv) > 1:
    print parse_link_value(sys.argv[1])
  2. @mnot mnot revised this gist Oct 15, 2009. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion link_header.py
    View file
    Original file line number Diff line number Diff line change
    @@ -7,7 +7,7 @@
    """

    __license__ = """
    Copyright (c) 2009 Mark Nottingham (code portions)
    Copyright (c) 2009 Mark Nottingham
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
  3. @mnot mnot created this gist Oct 15, 2009.
    89 changes: 89 additions & 0 deletions link_header.py
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,89 @@
    #!/usr/bin/env python

    """
    HTTP Link Header Parsing
    Simple routines to parse and manipulate Link headers.
    """

    __license__ = """
    Copyright (c) 2009 Mark Nottingham (code portions)
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
    """

    import re

    TOKEN = r'(?:[^\(\)<>@,;:\\"/\[\]\?={} \t]+?)'
    QUOTED_STRING = r'(?:"(?:\\"|[^"])*")'
    PARAMETER = r'(?:%(TOKEN)s(?:=(?:%(TOKEN)s|%(QUOTED_STRING)s))?)' % locals()
    LINK = r'<[^>]*>\s*(?:;\s*%(PARAMETER)s?\s*)*' % locals()
    COMMA = r'(?:\s*(?:,\s*)+)'
    LINK_SPLIT = r'%s(?=%s|\s*$)' % (LINK, COMMA)

    def _unquotestring(instr):
    if instr[0] == instr[-1] == '"':
    instr = instr[1:-1]
    instr = re.sub(r'\\(.)', r'\1', instr)
    return instr
    def _splitstring(instr, item, split):
    if not instr:
    return []
    return [ h.strip() for h in re.findall(r'%s(?=%s|\s*$)' % (item, split), instr)]

    link_splitter = re.compile(LINK_SPLIT)

    def parse_link_value(instr):
    """
    Given a link-value (i.e., after separating the header-value on commas),
    return a dictionary whose keys are link URLs and values are dictionaries
    of the parameters for their associated links.
    Note that internationalised parameters (e.g., title*) are
    NOT percent-decoded.
    Also, only the last instance of a given parameter will be included.
    For example,
    >>> parse_link_value('</foo>; rel="self"; title*=utf-8\'de\'letztes%20Kapitel')
    {'/foo': {'title*': "utf-8'de'letztes%20Kapitel", 'rel': 'self'}}
    """
    out = {}
    if not instr:
    return out
    for link in [h.strip() for h in link_splitter.findall(instr)]:
    url, params = link.split(">", 1)
    url = url[1:]
    param_dict = {}
    for param in _splitstring(params, PARAMETER, "\s*;\s*"):
    try:
    a, v = param.split("=", 1)
    param_dict[a.lower()] = _unquotestring(v)
    except ValueError:
    param_dict[param.lower()] = None
    out[url] = param_dict
    return out


    if __name__ == '__main__':
    import sys
    if len(sys.argv) > 1:
    print parse_link_value(sys.argv[1])