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# -*- test-case-name: nevow.test.test_useragent -*-
"""
Parsers for browser User-Agent strings.
http://en.wikipedia.org/wiki/User_agent
http://www.user-agents.org/
"""
# Internet Explorer 1.0
# Microsoft Internet Explorer/Version (Platform)
# Internet Explorer, and browsers cloaking as Internet Explorer
# Mozilla/MozVer (compatible; MSIE IEVer[; Provider]; Platform[; Extension]*) [Addition]
# MozVer
# Netscape < 6.0
# Mozilla/Version[Gold] [[Language]][Provider] (Platform; Security[; SubPlatform][StandAlone])
# Mozilla
# Mozilla/MozVer (Platform; Security; SubPlatform; Language; rv:Revision[; Extension]*) Gecko/GeckVer [Product/ProdVer]
# Opera
# Opera/Version (Platform; U) [Language]
class browsers(object):
"""
Namespace class for Browser identifiers.
"""
GECKO = u'gecko'
INTERNET_EXPLORER = u'internet explorer'
WEBKIT = u'webkit'
OPERA = u'opera'
class UserAgent(object):
"""
Structured representation of a version identifier of a web browser.
This presents only minimal structured information about the agent
currently. It could be expanded to include much more information, such a
security properties, platform, and native language.
@type browser: C{unicode}
@ivar browser: The broad category of the browser. Can only take on values
from L{browsers}.
@type version: C{str}
@ivar version: The version claimed by the browser.
"""
def __init__(self, browser, version):
"""
Initialize a new UserAgent.
The positions of the arguments to this initializer are not stable.
Only pass arguments by keyword.
"""
self.browser = browser
self.version = version
def parse_GECKO(cls, agentString):
"""
Attempt to parse the given User-Agent string as a Gecko-based browser's
user-agent.
"""
identifier = 'Gecko/'
start = agentString.find(identifier)
if start != -1:
end = agentString.find(' ', start)
if end == -1:
end = None
version = agentString[start + len(identifier):end]
try:
version = int(version)
except ValueError:
pass
else:
return cls(browsers.GECKO, (version,))
parse_GECKO = classmethod(parse_GECKO)
def parse_WEBKIT(cls, agentString):
"""
Attempt to parse the given User-Agent string as a WebKit-based
browser's user-agent.
"""
identifier = 'WebKit/'
start = agentString.find(identifier)
if start != -1:
end = start + len(identifier)
while (
end < len(agentString) and
agentString[end].isdigit() or
agentString[end] == '.'):
end += 1
version = agentString[start + len(identifier):end]
try:
version = map(int, version.split('.'))
except ValueError:
pass
else:
return cls(browsers.WEBKIT, tuple(version))
parse_WEBKIT = classmethod(parse_WEBKIT)
def parse_OPERA(cls, agentString):
"""
Attempt to parse an Opera user-agent.
"""
prefix = 'Opera/'
if agentString.startswith(prefix):
version = agentString[len(prefix):].split(None, 1)[0]
try:
version = map(int, version.split('.'))
except ValueError:
pass
else:
return cls(browsers.OPERA, tuple(version))
parse_OPERA = classmethod(parse_OPERA)
def parse_MSIE(cls, agentString):
"""
Attempt to parse an Internet Explorer user-agent.
"""
oldPrefix = 'Mozilla/4.0 (compatible; MSIE '
newPrefix = 'Mozilla/5.0 (compatible; MSIE '
for prefix in oldPrefix, newPrefix:
if agentString.startswith(prefix):
end = agentString.find(';', len(prefix))
if end == -1:
end = None
version = agentString[len(prefix):end]
try:
version = map(int, version.split('.'))
except ValueError:
pass
else:
return cls(browsers.INTERNET_EXPLORER, tuple(version))
parse_MSIE = classmethod(parse_MSIE)
def fromHeaderValue(cls, agentString):
"""
Attempt to parse an arbitrary user-agent.
@rtype: C{cls} or C{NoneType}
@return: A user agent object, or C{None} if parsing fails.
"""
# Order matters here - MSIE parser will match a ton of browsers.
for parser in ['GECKO', 'WEBKIT', 'MSIE', 'OPERA']:
agent = getattr(cls, 'parse_' + parser)(agentString)
if agent is not None:
return agent
return None
fromHeaderValue = classmethod(fromHeaderValue)
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