# Copyright 2012 Google Inc. # # 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, dis- # tribute, sublicense, and/or sell copies of the Software, and to permit # persons to whom the Software is furnished to do so, subject to the fol- # lowing 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 MERCHANTABIL- # ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT # SHALL THE AUTHOR 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 types from boto.gs.user import User from boto.exception import InvalidCorsError from xml.sax import handler # Relevant tags for the CORS XML document. CORS_CONFIG = 'CorsConfig' CORS = 'Cors' ORIGINS = 'Origins' ORIGIN = 'Origin' METHODS = 'Methods' METHOD = 'Method' HEADERS = 'ResponseHeaders' HEADER = 'ResponseHeader' MAXAGESEC = 'MaxAgeSec' class Cors(handler.ContentHandler): """Encapsulates the CORS configuration XML document""" def __init__(self): # List of CORS elements found within a CorsConfig element. self.cors = [] # List of collections (e.g. Methods, ResponseHeaders, Origins) # found within a CORS element. We use a list of lists here # instead of a dictionary because the collections need to be # preserved in the order in which they appear in the input XML # document (and Python dictionary keys are inherently unordered). # The elements on this list are two element tuples of the form # (collection name, [list of collection contents]). self.collections = [] # Lists of elements within a collection. Again a list is needed to # preserve ordering but also because the same element may appear # multiple times within a collection. self.elements = [] # Dictionary mapping supported collection names to element types # which may be contained within each. self.legal_collections = { ORIGINS : [ORIGIN], METHODS : [METHOD], HEADERS : [HEADER], MAXAGESEC: [] } # List of supported element types within any collection, used for # checking validadity of a parsed element name. self.legal_elements = [ORIGIN, METHOD, HEADER] self.parse_level = 0 self.collection = None self.element = None def validateParseLevel(self, tag, level): """Verify parse level for a given tag.""" if self.parse_level != level: raise InvalidCorsError('Invalid tag %s at parse level %d: ' % (tag, self.parse_level)) def startElement(self, name, attrs, connection): """SAX XML logic for parsing new element found.""" if name == CORS_CONFIG: self.validateParseLevel(name, 0) self.parse_level += 1; elif name == CORS: self.validateParseLevel(name, 1) self.parse_level += 1; elif name in self.legal_collections: self.validateParseLevel(name, 2) self.parse_level += 1; self.collection = name elif name in self.legal_elements: self.validateParseLevel(name, 3) # Make sure this tag is found inside a collection tag. if self.collection is None: raise InvalidCorsError('Tag %s found outside collection' % name) # Make sure this tag is allowed for the current collection tag. if name not in self.legal_collections[self.collection]: raise InvalidCorsError('Tag %s not allowed in %s collection' % (name, self.collection)) self.element = name else: raise InvalidCorsError('Unsupported tag ' + name) def endElement(self, name, value, connection): """SAX XML logic for parsing new element found.""" if name == CORS_CONFIG: self.validateParseLevel(name, 1) self.parse_level -= 1; elif name == CORS: self.validateParseLevel(name, 2) self.parse_level -= 1; # Terminating a CORS element, save any collections we found # and re-initialize collections list. self.cors.append(self.collections) self.collections = [] elif name in self.legal_collections: self.validateParseLevel(name, 3) if name != self.collection: raise InvalidCorsError('Mismatched start and end tags (%s/%s)' % (self.collection, name)) self.parse_level -= 1; if not self.legal_collections[name]: # If this collection doesn't contain any sub-elements, store # a tuple of name and this tag's element value. self.collections.append((name, value.strip())) else: # Otherwise, we're terminating a collection of sub-elements, # so store a tuple of name and list of contained elements. self.collections.append((name, self.elements)) self.elements = [] self.collection = None elif name in self.legal_elements: self.validateParseLevel(name, 3) # Make sure this tag is found inside a collection tag. if self.collection is None: raise InvalidCorsError('Tag %s found outside collection' % name) # Make sure this end tag is allowed for the current collection tag. if name not in self.legal_collections[self.collection]: raise InvalidCorsError('Tag %s not allowed in %s collection' % (name, self.collection)) if name != self.element: raise InvalidCorsError('Mismatched start and end tags (%s/%s)' % (self.element, name)) # Terminating an element tag, add it to the list of elements # for the current collection. self.elements.append((name, value.strip())) self.element = None else: raise InvalidCorsError('Unsupported end tag ' + name) def to_xml(self): """Convert CORS object into XML string representation.""" s = '<' + CORS_CONFIG + '>' for collections in self.cors: s += '<' + CORS + '>' for (collection, elements_or_value) in collections: assert collection is not None s += '<' + collection + '>' # If collection elements has type string, append atomic value, # otherwise, append sequence of values in named tags. if isinstance(elements_or_value, str): s += elements_or_value else: for (name, value) in elements_or_value: assert name is not None assert value is not None s += '<' + name + '>' + value + '' s += '' s += '' s += '' return s