| 1 | #!/usr/bin/python |
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| 2 | |
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| 3 | import sys, struct, logging |
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| 4 | from ippattributegroup import IPPAttributeGroup |
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| 5 | from ippattribute import IPPAttribute |
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| 6 | from ippvalue import IPPValue |
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| 7 | |
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| 8 | # initialize logger |
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| 9 | logger = logging.getLogger("ippLogger") |
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| 10 | |
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| 11 | class IPPRequest(): |
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| 12 | """ |
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| 13 | From RFC 2565: |
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| 14 | |
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| 15 | The encoding for an operation request or response consists of: |
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| 16 | ----------------------------------------------- |
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| 17 | | version-number | 2 bytes - required |
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| 18 | ----------------------------------------------- |
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| 19 | | operation-id (request) | |
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| 20 | | or | 2 bytes - required |
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| 21 | | status-code (response) | |
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| 22 | ----------------------------------------------- |
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| 23 | | request-id | 4 bytes - required |
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| 24 | ----------------------------------------------------------- |
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| 25 | | xxx-attributes-tag | 1 byte | |
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| 26 | ----------------------------------------------- |-0 or more |
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| 27 | | xxx-attribute-sequence | n bytes | |
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| 28 | ----------------------------------------------------------- |
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| 29 | | end-of-attributes-tag | 1 byte - required |
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| 30 | ----------------------------------------------- |
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| 31 | | data | q bytes - optional |
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| 32 | ----------------------------------------------- |
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| 33 | """ |
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| 34 | |
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| 35 | # either give the version, operation_id, request_id, |
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| 36 | # attribute_sequence, and data, or a file handler (request) which |
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| 37 | # can be read from to get the request |
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| 38 | def __init__(self, version=None, operation_id=None, request_id=None, |
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| 39 | attribute_groups=[], data=None, request=None, length=sys.maxint): |
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| 40 | """ |
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| 41 | Create an IPPRequest. Takes either the segments of the |
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| 42 | request separately, or a file handle for the request to parse. |
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| 43 | If the file handle is passed in, all other arguments are |
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| 44 | ignored. |
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| 45 | |
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| 46 | Keyword arguments for passing in the segments of the request: |
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| 47 | |
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| 48 | version -- a tuple of two signed chars, identifying the |
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| 49 | major version and minor version numbers of the |
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| 50 | request |
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| 51 | |
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| 52 | operation_id -- a signed short, identifying the id of the |
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| 53 | requested operation |
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| 54 | |
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| 55 | request_id -- a signed int, identifying the id of the |
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| 56 | request itself. |
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| 57 | |
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| 58 | attribute_groups -- a list of IPPAttributes, at least length 1 |
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| 59 | |
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| 60 | data -- (optional) variable length, containing the actual |
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| 61 | data of the request |
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| 62 | |
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| 63 | Keyword arguments for passing in the raw request: |
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| 64 | |
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| 65 | request -- a file handle that supports the read() |
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| 66 | operation |
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| 67 | """ |
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| 68 | |
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| 69 | if request is None: |
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| 70 | # make sure the version number isn't empty |
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| 71 | assert version is not None |
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| 72 | # make sure verison is a tuple of length 2 |
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| 73 | assert isinstance(version, tuple) |
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| 74 | assert len(version) == 2 |
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| 75 | # make sure the operation id isn't empty |
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| 76 | assert operation_id is not None |
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| 77 | # make sure the request id isn't empty |
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| 78 | assert request_id is not None |
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| 79 | # make sure attribute_groups is a list of IPPAttributes |
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| 80 | assert len(attribute_groups) > 0 |
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| 81 | for a in attribute_groups: assert isinstance(a, IPPAttributeGroup) |
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| 82 | |
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| 83 | # if the request isn't None, then we'll read directly from |
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| 84 | # that file handle |
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| 85 | if request is not None: |
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| 86 | # read the version-number (two signed chars) |
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| 87 | self.version = struct.unpack('>bb', request.read(2)) |
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| 88 | length -= 2 |
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| 89 | logger.debug("version-number : (0x%X, 0x%X)" % self.version) |
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| 90 | |
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| 91 | # read the operation-id (or status-code, but that's only |
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| 92 | # for a response) (signed short) |
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| 93 | self.operation_id = struct.unpack('>h', request.read(2))[0] |
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| 94 | length -= 2 |
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| 95 | logger.debug("operation-id : 0x%X" % self.operation_id) |
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| 96 | |
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| 97 | # read the request-id (signed int) |
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| 98 | self.request_id = struct.unpack('>i', request.read(4))[0] |
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| 99 | length -= 4 |
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| 100 | logger.debug("request-id : 0x%X" % self.request_id) |
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| 101 | |
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| 102 | # now we have to read in the attributes. Each attribute |
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| 103 | # has a tag (1 byte) and a sequence of values (n bytes) |
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| 104 | self.attribute_groups = [] |
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| 105 | |
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| 106 | # read in the next byte |
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| 107 | next_byte = struct.unpack('>b', request.read(1))[0] |
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| 108 | length -=1 |
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| 109 | logger.debug("next byte : 0x%X" % next_byte) |
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| 110 | |
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| 111 | # as long as the next byte isn't signaling the end of the |
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| 112 | # attributes, keep looping and parsing attributes |
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| 113 | while next_byte != AttributeTags.END: |
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| 114 | |
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| 115 | attribute_group_tag = next_byte |
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| 116 | logger.debug("attribute-tag : %i" % attribute_group_tag) |
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| 117 | |
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| 118 | attributes = [] |
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| 119 | |
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| 120 | next_byte = struct.unpack('>b', request.read(1))[0] |
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| 121 | length -= 1 |
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| 122 | logger.debug("next byte : 0x%X" % next_byte) |
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| 123 | |
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| 124 | while next_byte > 0x0F: |
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| 125 | |
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| 126 | # read in the value tag (signed char) |
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| 127 | value_tag = next_byte |
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| 128 | logger.debug("value-tag : 0x%X" % value_tag) |
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| 129 | |
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| 130 | # read in the length of the name (signed short) |
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| 131 | name_length = struct.unpack('>h', request.read(2))[0] |
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| 132 | length -= 2 |
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| 133 | logger.debug("name-length : %i" % name_length) |
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| 134 | |
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| 135 | if name_length != AttributeTags.ZERO_NAME_LENGTH: |
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| 136 | # read the name (a string of name_length bytes) |
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| 137 | name = request.read(name_length) |
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| 138 | length -= name_length |
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| 139 | logger.debug("name : %s" % name) |
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| 140 | |
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| 141 | # read in the length of the value (signed short) |
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| 142 | value_length = struct.unpack('>h', request.read(2))[0] |
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| 143 | length -= 2 |
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| 144 | logger.debug("value-length : %i" % value_length) |
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| 145 | |
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| 146 | # read in the value (string of value_length bytes) |
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| 147 | value = request.read(value_length) |
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| 148 | length -= value_length |
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| 149 | |
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| 150 | ippvalue = IPPValue(value_tag, value) |
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| 151 | logger.debug("value : %s" % ippvalue.value) |
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| 152 | |
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| 153 | # create a new IPPAttribute from the data we just |
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| 154 | # read in, and add it to our attributes list |
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| 155 | attributes.append(IPPAttribute(name, [ippvalue])) |
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| 156 | |
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| 157 | else: |
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| 158 | # read in the length of the value (signed short) |
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| 159 | value_length = struct.unpack('>h', request.read(2))[0] |
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| 160 | length -= 2 |
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| 161 | logger.debug("value-length : %i" % value_length) |
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| 162 | |
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| 163 | # read in the value (string of value_length bytes) |
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| 164 | value = request.read(value_length) |
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| 165 | length -= value_length |
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| 166 | |
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| 167 | ippvalue = IPPValue(value_tag, value) |
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| 168 | logger.debug("value : %s" % ippvalue.value) |
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| 169 | |
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| 170 | # add another value to the last attribute |
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| 171 | attributes[-1].values.append(ippvalue) |
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| 172 | |
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| 173 | # read another byte |
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| 174 | next_byte = struct.unpack('>b', request.read(1))[0] |
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| 175 | length -= 1 |
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| 176 | |
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| 177 | self.attribute_groups.append(IPPAttributeGroup(attribute_group_tag, attributes)) |
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| 178 | |
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| 179 | # once we hit the end-of-attributes tag, the only thing |
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| 180 | # left is the data, so go ahead and read all of it |
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| 181 | assert length >= 0 |
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| 182 | self.data = request.read(length) |
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| 183 | logger.debug("data : %s" % self.data) |
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| 184 | |
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| 185 | # otherwise, just set the class variables to the keyword |
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| 186 | # arguments passed in |
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| 187 | else: |
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| 188 | self.version = (version[0], version[1]) |
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| 189 | self.operation_id = operation_id |
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| 190 | self.request_id = request_id |
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| 191 | self.attribute_groups = attribute_groups |
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| 192 | self.data = data |
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| 193 | |
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| 194 | def getAttributeGroup(self, tag): |
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| 195 | return filter(lambda x: x.attribute_group_tag == tag, |
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| 196 | self.attribute_groups) |
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| 197 | |
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| 198 | def toBinaryData(self): |
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| 199 | """ |
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| 200 | Packs the value data into binary data. |
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| 201 | """ |
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| 202 | |
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| 203 | # convert the version, operation id, and request id to binary |
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| 204 | preattributes = struct.pack('>bbhi', |
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| 205 | self.version[0], |
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| 206 | self.version[1], |
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| 207 | self.operation_id, |
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| 208 | self.request_id) |
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| 209 | |
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| 210 | # convert the attribute groups to binary |
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| 211 | attribute_groups = ''.join([a.toBinaryData() for a in self.attribute_groups]) |
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| 212 | |
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| 213 | # conver the end-of-attributes-tag to binary |
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| 214 | end_of_attributes_tag = struct.pack('>b', AttributeTags.END) |
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| 215 | |
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| 216 | # convert the data to binary |
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| 217 | if self.data is not None: |
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| 218 | data = ''.join([struct.pack('>b', x) for x in self.data]) |
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| 219 | else: |
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| 220 | data = '' |
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| 221 | |
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| 222 | # append everything together and return it |
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| 223 | return preattributes + attribute_groups + end_of_attributes_tag + data |
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