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