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Diffstat (limited to 'src/meetingtools/mimeparse.py')
| -rw-r--r-- | src/meetingtools/mimeparse.py | 123 |
1 files changed, 0 insertions, 123 deletions
diff --git a/src/meetingtools/mimeparse.py b/src/meetingtools/mimeparse.py deleted file mode 100644 index 0fd91e7..0000000 --- a/src/meetingtools/mimeparse.py +++ /dev/null @@ -1,123 +0,0 @@ -"""MIME-Type Parser - -This module provides basic functions for handling mime-types. It can handle -matching mime-types against a list of media-ranges. See section 14.1 of -the HTTP specification [RFC 2616] for a complete explanation. - - http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1 - -Contents: - - parse_mime_type(): Parses a mime-type into its component parts. - - parse_media_range(): Media-ranges are mime-types with wild-cards and a 'q' quality parameter. - - quality(): Determines the quality ('q') of a mime-type when compared against a list of media-ranges. - - quality_parsed(): Just like quality() except the second parameter must be pre-parsed. - - best_match(): Choose the mime-type with the highest quality ('q') from a list of candidates. -""" - -__version__ = "0.1.2" -__author__ = 'Joe Gregorio' -__email__ = "joe@bitworking.org" -__credits__ = "" - -def parse_mime_type(mime_type): - """Carves up a mime-type and returns a tuple of the - (type, subtype, params) where 'params' is a dictionary - of all the parameters for the media range. - For example, the media range 'application/xhtml;q=0.5' would - get parsed into: - - ('application', 'xhtml', {'q', '0.5'}) - """ - parts = mime_type.split(";") - params = dict([tuple([s.strip() for s in param.split("=")])\ - for param in parts[1:] ]) - full_type = parts[0].strip() - # Java URLConnection class sends an Accept header that includes a single "*" - # Turn it into a legal wildcard. - if full_type == '*': full_type = '*/*' - (type, subtype) = full_type.split("/") - return (type.strip(), subtype.strip(), params) - -def parse_media_range(range): - """Carves up a media range and returns a tuple of the - (type, subtype, params) where 'params' is a dictionary - of all the parameters for the media range. - For example, the media range 'application/*;q=0.5' would - get parsed into: - - ('application', '*', {'q', '0.5'}) - - In addition this function also guarantees that there - is a value for 'q' in the params dictionary, filling it - in with a proper default if necessary. - """ - (type, subtype, params) = parse_mime_type(range) - if not params.has_key('q') or not params['q'] or \ - not float(params['q']) or float(params['q']) > 1\ - or float(params['q']) < 0: - params['q'] = '1' - return (type, subtype, params) - -def fitness_and_quality_parsed(mime_type, parsed_ranges): - """Find the best match for a given mime-type against - a list of media_ranges that have already been - parsed by parse_media_range(). Returns a tuple of - the fitness value and the value of the 'q' quality - parameter of the best match, or (-1, 0) if no match - was found. Just as for quality_parsed(), 'parsed_ranges' - must be a list of parsed media ranges. """ - best_fitness = -1 - best_fit_q = 0 - (target_type, target_subtype, target_params) =\ - parse_media_range(mime_type) - for (type, subtype, params) in parsed_ranges: - if (type == target_type or type == '*' or target_type == '*') and \ - (subtype == target_subtype or subtype == '*' or target_subtype == '*'): - param_matches = reduce(lambda x, y: x+y, [1 for (key, value) in \ - target_params.iteritems() if key != 'q' and \ - params.has_key(key) and value == params[key]], 0) - fitness = (type == target_type) and 100 or 0 - fitness += (subtype == target_subtype) and 10 or 0 - fitness += param_matches - if fitness > best_fitness: - best_fitness = fitness - best_fit_q = params['q'] - - return best_fitness, float(best_fit_q) - -def quality_parsed(mime_type, parsed_ranges): - """Find the best match for a given mime-type against - a list of media_ranges that have already been - parsed by parse_media_range(). Returns the - 'q' quality parameter of the best match, 0 if no - match was found. This function bahaves the same as quality() - except that 'parsed_ranges' must be a list of - parsed media ranges. """ - return fitness_and_quality_parsed(mime_type, parsed_ranges)[1] - -def quality(mime_type, ranges): - """Returns the quality 'q' of a mime-type when compared - against the media-ranges in ranges. For example: - - >>> quality('text/html','text/*;q=0.3, text/html;q=0.7, text/html;level=1, text/html;level=2;q=0.4, */*;q=0.5') - 0.7 - - """ - parsed_ranges = [parse_media_range(r) for r in ranges.split(",")] - return quality_parsed(mime_type, parsed_ranges) - -def best_match(supported, header): - """Takes a list of supported mime-types and finds the best - match for all the media-ranges listed in header. The value of - header must be a string that conforms to the format of the - HTTP Accept: header. The value of 'supported' is a list of - mime-types. - - >>> best_match(['application/xbel+xml', 'text/xml'], 'text/*;q=0.5,*/*; q=0.1') - 'text/xml' - """ - parsed_header = [parse_media_range(r) for r in header.split(",")] - weighted_matches = [(fitness_and_quality_parsed(mime_type, parsed_header), mime_type)\ - for mime_type in supported] - weighted_matches.sort() - return weighted_matches[-1][0][1] and weighted_matches[-1][1] or '' |