| 1 | from .attribute import Attribute |
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| 2 | import sys |
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| 3 | import struct |
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| 4 | import logging |
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| 5 | |
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| 6 | # initialize logger |
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| 7 | logger = logging.getLogger(__name__) |
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| 8 | |
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| 9 | class AttributeGroup(object): |
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| 10 | """An AttributeGroup consists of an attribute-group-tag, followed |
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| 11 | by a sequence of Attributes. According to RFC 2565, 'Within an |
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| 12 | attribute-sequence, if two attributes have the same name, the |
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| 13 | first occurrence MUST be ignored.', so we can effectively treat |
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| 14 | this as an ordered dictionary. |
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| 15 | |
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| 16 | """ |
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| 17 | |
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| 18 | def __init__(self, tag=None, attributes=[]): |
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| 19 | """Initialize an AttributeGroup. An AttributeGroup can be |
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| 20 | initialized in three ways: |
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| 21 | |
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| 22 | AttributeGroup() |
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| 23 | AttributeGroup(tag) |
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| 24 | AttributeGroup(tag, attributes) |
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| 25 | |
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| 26 | Arguments: |
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| 27 | |
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| 28 | tag -- a signed char, holds the tag of the |
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| 29 | attribute group |
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| 30 | |
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| 31 | attributes -- a list of attributes |
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| 32 | |
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| 33 | """ |
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| 34 | |
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| 35 | if tag is not None: |
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| 36 | assert isinstance(tag, int), \ |
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| 37 | "tag must be a character!" |
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| 38 | |
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| 39 | self.tag = tag |
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| 40 | self.attributes = [] |
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| 41 | self.extend(attributes) |
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| 42 | |
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| 43 | def __getitem__(self, name): |
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| 44 | """Returns a list of attributes which have name 'name'. |
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| 45 | |
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| 46 | """ |
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| 47 | |
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| 48 | attribute = filter(lambda x: x.name == name, self.attributes) |
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| 49 | if attribute: |
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| 50 | return attribute[0] |
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| 51 | else: |
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| 52 | raise KeyError("Attribute %r not found" % name) |
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| 53 | |
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| 54 | def __contains__(self, name): |
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| 55 | return len(filter(lambda x: x.name == name, self.attributes)) |
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| 56 | |
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| 57 | def __iter__(self): |
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| 58 | return (a.name for a in self.attributes) |
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| 59 | |
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| 60 | iterkeys = __iter__ |
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| 61 | |
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| 62 | def __setitem__(self, name, attribute): |
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| 63 | """Sets an attribute in the attribute group. Note that the key |
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| 64 | is ignored and the attribute is queried for its name. |
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| 65 | |
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| 66 | """ |
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| 67 | |
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| 68 | return self.append(attribute) |
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| 69 | |
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| 70 | def __delitem__(self, name): |
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| 71 | self.attributes = filter(lambda x: x.name != name, |
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| 72 | self.attributes) |
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| 73 | |
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| 74 | def append(self, attribute): |
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| 75 | return self.extend([attribute]) |
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| 76 | |
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| 77 | def extend(self, attributes): |
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| 78 | """Sets the attributes for the attribute group. |
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| 79 | |
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| 80 | """ |
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| 81 | |
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| 82 | for a in attributes: |
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| 83 | assert isinstance(a, Attribute), \ |
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| 84 | "attribute must be of type Attribute!" |
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| 85 | |
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| 86 | for a in attributes: |
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| 87 | # XXX: Instead of replacing the attribute, do we want to |
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| 88 | # append the value to the attribute here? |
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| 89 | del self[a.name] |
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| 90 | self.attributes.append(a) |
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| 91 | |
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| 92 | @property |
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| 93 | def packed_value(self): |
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| 94 | """Convert the AttributeGroup to binary. |
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| 95 | |
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| 96 | """ |
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| 97 | |
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| 98 | # convert the tag to binary |
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| 99 | tag = struct.pack('>b', self.tag) |
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| 100 | |
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| 101 | # convert each of the attributes to binary |
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| 102 | attributes = [a.packed_value for a in self.attributes] |
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| 103 | |
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| 104 | # concatenate everything and return |
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| 105 | return tag + ''.join(attributes) |
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| 106 | |
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| 107 | def __repr__(self): |
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| 108 | return '<IPPAttributeGroup (%r, %r)>' % (self.tag, self.attributes) |
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