[c216863] | 1 | #!/usr/bin/python |
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| 2 | |
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[8403f61] | 3 | import sys, struct, logging |
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| 4 | |
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| 5 | # initialize logger |
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| 6 | logger = logging.getLogger("ippLogger") |
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[4ec7caa] | 7 | |
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[c216863] | 8 | class IPPRequest(): |
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[84e8137] | 9 | """ |
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| 10 | From RFC 2565: |
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[c216863] | 11 | |
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[84e8137] | 12 | The encoding for an operation request or response consists of: |
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| 13 | ----------------------------------------------- |
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| 14 | | version-number | 2 bytes - required |
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| 15 | ----------------------------------------------- |
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| 16 | | operation-id (request) | |
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| 17 | | or | 2 bytes - required |
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| 18 | | status-code (response) | |
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| 19 | ----------------------------------------------- |
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| 20 | | request-id | 4 bytes - required |
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| 21 | ----------------------------------------------------------- |
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| 22 | | xxx-attributes-tag | 1 byte | |
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| 23 | ----------------------------------------------- |-0 or more |
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| 24 | | xxx-attribute-sequence | n bytes | |
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| 25 | ----------------------------------------------------------- |
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| 26 | | end-of-attributes-tag | 1 byte - required |
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| 27 | ----------------------------------------------- |
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| 28 | | data | q bytes - optional |
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| 29 | ----------------------------------------------- |
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| 30 | """ |
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[c216863] | 31 | |
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| 32 | # either give the version, operation_id, request_id, |
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| 33 | # attribute_sequence, and data, or a file handler (request) which |
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| 34 | # can be read from to get the request |
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[8e43aa8] | 35 | def __init__(self, version=None, operation_id=None, request_id=None, |
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[89fe6da] | 36 | attribute_groups=[], data=None, request=None, length=sys.maxint): |
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[84e8137] | 37 | """ |
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| 38 | Create an IPPRequest. Takes either the segments of the |
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| 39 | request separately, or a file handle for the request to parse. |
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| 40 | If the file handle is passed in, all other arguments are |
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| 41 | ignored. |
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| 42 | |
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| 43 | Keyword arguments for passing in the segments of the request: |
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| 44 | |
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[4ec7caa] | 45 | version -- a tuple of two signed chars, identifying the |
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| 46 | major version and minor version numbers of the |
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| 47 | request |
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[84e8137] | 48 | |
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[4ec7caa] | 49 | operation_id -- a signed short, identifying the id of the |
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[84e8137] | 50 | requested operation |
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| 51 | |
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[4ec7caa] | 52 | request_id -- a signed int, identifying the id of the |
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[84e8137] | 53 | request itself. |
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[c216863] | 54 | |
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[8e43aa8] | 55 | attribute_groups -- a list of IPPAttributes, at least length 1 |
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[84e8137] | 56 | |
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| 57 | data -- (optional) variable length, containing the actual |
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| 58 | data of the request |
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| 59 | |
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| 60 | Keyword arguments for passing in the raw request: |
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| 61 | |
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| 62 | request -- a file handle that supports the read() |
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| 63 | operation |
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| 64 | """ |
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| 65 | |
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| 66 | if request is None: |
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| 67 | # make sure the version number isn't empty |
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| 68 | assert version is not None |
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[4ec7caa] | 69 | # make sure verison is a tuple of length 2 |
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| 70 | assert isinstance(version, tuple) |
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| 71 | assert len(version) == 2 |
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[84e8137] | 72 | # make sure the operation id isn't empty |
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| 73 | assert operation_id is not None |
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| 74 | # make sure the request id isn't empty |
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| 75 | assert request_id is not None |
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[8e43aa8] | 76 | # make sure attribute_groups is a list of IPPAttributes |
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| 77 | assert len(attribute_groups) > 0 |
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[c5e88d0] | 78 | for a in attribute_groups: assert isinstance(a, IPPAttributeGroup) |
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[84e8137] | 79 | |
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| 80 | # if the request isn't None, then we'll read directly from |
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| 81 | # that file handle |
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[c216863] | 82 | if request is not None: |
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[4ec7caa] | 83 | # read the version-number (two signed chars) |
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[d56a0bc] | 84 | self.version = struct.unpack('>bb', request.read(2)) |
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[89fe6da] | 85 | length -= 2 |
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[8403f61] | 86 | logger.debug("version-number : (0x%X, 0x%X)" % self.version) |
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[84e8137] | 87 | |
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| 88 | # read the operation-id (or status-code, but that's only |
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[4ec7caa] | 89 | # for a response) (signed short) |
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[8403f61] | 90 | self.operation_id = struct.unpack('>h', request.read(2))[0] |
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[89fe6da] | 91 | length -= 2 |
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[8403f61] | 92 | logger.debug("operation-id : 0x%X" % self.operation_id) |
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[84e8137] | 93 | |
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[4ec7caa] | 94 | # read the request-id (signed int) |
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[8403f61] | 95 | self.request_id = struct.unpack('>i', request.read(4))[0] |
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[89fe6da] | 96 | length -= 4 |
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[8403f61] | 97 | logger.debug("request-id : 0x%X" % self.request_id) |
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[84e8137] | 98 | |
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| 99 | # now we have to read in the attributes. Each attribute |
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| 100 | # has a tag (1 byte) and a sequence of values (n bytes) |
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[8e43aa8] | 101 | self.attribute_groups = [] |
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[84e8137] | 102 | |
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| 103 | # read in the next byte |
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[8403f61] | 104 | next_byte = struct.unpack('>b', request.read(1))[0] |
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[89fe6da] | 105 | length -=1 |
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[8403f61] | 106 | logger.debug("next byte : 0x%X" % next_byte) |
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[84e8137] | 107 | |
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| 108 | # as long as the next byte isn't signaling the end of the |
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| 109 | # attributes, keep looping and parsing attributes |
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[4ec7caa] | 110 | while next_byte != IPPTags.END_OF_ATTRIBUTES_TAG: |
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[84e8137] | 111 | |
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[8403f61] | 112 | attribute_group_tag = next_byte |
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| 113 | logger.debug("attribute-tag : %i" % attribute_group_tag) |
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| 114 | |
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[8e43aa8] | 115 | attributes = [] |
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| 116 | |
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[8403f61] | 117 | next_byte = struct.unpack('>b', request.read(1))[0] |
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[89fe6da] | 118 | length -= 1 |
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[8403f61] | 119 | logger.debug("next byte : 0x%X" % next_byte) |
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[84e8137] | 120 | |
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[8403f61] | 121 | while next_byte > 0x0F: |
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| 122 | |
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[4ec7caa] | 123 | # read in the value tag (signed char) |
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[8403f61] | 124 | value_tag = next_byte |
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| 125 | logger.debug("value-tag : 0x%X" % value_tag) |
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| 126 | |
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[4ec7caa] | 127 | # read in the length of the name (signed short) |
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[8403f61] | 128 | name_length = struct.unpack('>h', request.read(2))[0] |
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[89fe6da] | 129 | length -= 2 |
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[8403f61] | 130 | logger.debug("name-length : %i" % name_length) |
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[84e8137] | 131 | |
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[8403f61] | 132 | if name_length != IPPTags.ZERO_NAME_LENGTH: |
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| 133 | # read the name (a string of name_length bytes) |
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| 134 | name = request.read(name_length) |
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[89fe6da] | 135 | length -= name_length |
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[8403f61] | 136 | logger.debug("name : %s" % name) |
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| 137 | |
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| 138 | # read in the length of the value (signed short) |
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| 139 | value_length = struct.unpack('>h', request.read(2))[0] |
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[89fe6da] | 140 | length -= 2 |
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[8403f61] | 141 | logger.debug("value-length : %i" % value_length) |
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| 142 | |
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| 143 | # read in the value (string of value_length bytes) |
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| 144 | value = request.read(value_length) |
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[89fe6da] | 145 | length -= value_length |
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| 146 | |
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[aaa1da3] | 147 | ippvalue = IPPValue(value_tag, value) |
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| 148 | logger.debug("value : %s" % ippvalue.value) |
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[8403f61] | 149 | |
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| 150 | # create a new IPPAttribute from the data we just |
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| 151 | # read in, and add it to our attributes list |
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[aaa1da3] | 152 | attributes.append(IPPAttribute(name, [ippvalue])) |
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[8403f61] | 153 | |
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| 154 | else: |
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| 155 | # read in the length of the value (signed short) |
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| 156 | value_length = struct.unpack('>h', request.read(2))[0] |
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[89fe6da] | 157 | length -= 2 |
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[8403f61] | 158 | logger.debug("value-length : %i" % value_length) |
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| 159 | |
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| 160 | # read in the value (string of value_length bytes) |
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| 161 | value = request.read(value_length) |
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[89fe6da] | 162 | length -= value_length |
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[aaa1da3] | 163 | |
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| 164 | ippvalue = IPPValue(value_tag, value) |
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| 165 | logger.debug("value : %s" % ippvalue.value) |
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[8403f61] | 166 | |
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| 167 | # add another value to the last attribute |
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[aaa1da3] | 168 | attributes[-1].values.append(ippvalue) |
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[8403f61] | 169 | |
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| 170 | # read another byte |
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| 171 | next_byte = struct.unpack('>b', request.read(1))[0] |
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[89fe6da] | 172 | length -= 1 |
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[c216863] | 173 | |
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[8e43aa8] | 174 | self.attribute_groups.append(IPPAttributeGroup(attribute_group_tag, attributes)) |
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| 175 | |
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[84e8137] | 176 | # once we hit the end-of-attributes tag, the only thing |
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| 177 | # left is the data, so go ahead and read all of it |
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[89fe6da] | 178 | assert length >= 0 |
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| 179 | self.data = request.read(length) |
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[8403f61] | 180 | logger.debug("data : %s" % self.data) |
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[c216863] | 181 | |
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[84e8137] | 182 | # otherwise, just set the class variables to the keyword |
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| 183 | # arguments passed in |
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[c216863] | 184 | else: |
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[8e43aa8] | 185 | self.version = (version[0], version[1]) |
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| 186 | self.operation_id = operation_id |
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| 187 | self.request_id = request_id |
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| 188 | self.attribute_groups = attribute_groups |
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[c216863] | 189 | self.data = data |
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[d56a0bc] | 190 | |
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[c5e88d0] | 191 | def getAttributeGroup(self, tag): |
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| 192 | return filter(lambda x: x.attribute_group_tag == tag, |
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| 193 | self.attribute_groups) |
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| 194 | |
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[d56a0bc] | 195 | def toBinaryData(self): |
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| 196 | """ |
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| 197 | Packs the value data into binary data. |
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| 198 | """ |
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| 199 | |
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| 200 | # convert the version, operation id, and request id to binary |
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| 201 | preattributes = struct.pack('>bbhi', |
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| 202 | self.version[0], |
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| 203 | self.version[1], |
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| 204 | self.operation_id, |
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| 205 | self.request_id) |
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| 206 | |
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[8e43aa8] | 207 | # convert the attribute groups to binary |
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| 208 | attribute_groups = ''.join([a.toBinaryData() for a in self.attribute_groups]) |
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[d56a0bc] | 209 | |
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| 210 | # conver the end-of-attributes-tag to binary |
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| 211 | end_of_attributes_tag = struct.pack('>b', IPPTags.END_OF_ATTRIBUTES_TAG) |
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| 212 | |
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| 213 | # convert the data to binary |
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[8403f61] | 214 | if self.data is not None: |
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| 215 | data = ''.join([struct.pack('>b', x) for x in self.data]) |
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| 216 | else: |
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| 217 | data = '' |
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[d56a0bc] | 218 | |
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| 219 | # append everything together and return it |
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[8e43aa8] | 220 | return preattributes + attribute_groups + end_of_attributes_tag + data |
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