| # 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, types.StringTypes): |
| 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 + '</' + name + '>' |
| s += '</' + collection + '>' |
| s += '</' + CORS + '>' |
| s += '</' + CORS_CONFIG + '>' |
| return s |