323 lines
9.6 KiB
Python
323 lines
9.6 KiB
Python
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"""AMQP Table Encoding/Decoding"""
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import struct
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import decimal
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import calendar
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import warnings
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from datetime import datetime
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from pika import exceptions
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from pika.compat import PY2, PY3
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from pika.compat import unicode_type, long, as_bytes
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def encode_short_string(pieces, value):
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"""Encode a string value as short string and append it to pieces list
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returning the size of the encoded value.
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:param list pieces: Already encoded values
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:param value: String value to encode
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:type value: str or unicode
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:rtype: int
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"""
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encoded_value = as_bytes(value)
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length = len(encoded_value)
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# 4.2.5.3
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# Short strings, stored as an 8-bit unsigned integer length followed by zero
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# or more octets of data. Short strings can carry up to 255 octets of UTF-8
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# data, but may not contain binary zero octets.
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# ...
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# 4.2.5.5
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# The server SHOULD validate field names and upon receiving an invalid field
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# name, it SHOULD signal a connection exception with reply code 503 (syntax
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# error).
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# -> validate length (avoid truncated utf-8 / corrupted data), but skip null
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# byte check.
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if length > 255:
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raise exceptions.ShortStringTooLong(encoded_value)
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pieces.append(struct.pack('B', length))
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pieces.append(encoded_value)
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return 1 + length
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if PY2:
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def decode_short_string(encoded, offset):
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"""Decode a short string value from ``encoded`` data at ``offset``.
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"""
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length = struct.unpack_from('B', encoded, offset)[0]
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offset += 1
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# Purely for compatibility with original python2 code. No idea what
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# and why this does.
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value = encoded[offset:offset + length]
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try:
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value = bytes(value)
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except UnicodeEncodeError:
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pass
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offset += length
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return value, offset
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else:
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def decode_short_string(encoded, offset):
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"""Decode a short string value from ``encoded`` data at ``offset``.
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"""
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length = struct.unpack_from('B', encoded, offset)[0]
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offset += 1
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value = encoded[offset:offset + length]
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try:
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value = value.decode('utf8')
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except UnicodeDecodeError:
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pass
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offset += length
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return value, offset
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def encode_table(pieces, table):
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"""Encode a dict as an AMQP table appending the encded table to the
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pieces list passed in.
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:param list pieces: Already encoded frame pieces
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:param dict table: The dict to encode
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:rtype: int
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"""
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table = table or {}
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length_index = len(pieces)
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pieces.append(None) # placeholder
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tablesize = 0
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for (key, value) in table.items():
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tablesize += encode_short_string(pieces, key)
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tablesize += encode_value(pieces, value)
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pieces[length_index] = struct.pack('>I', tablesize)
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return tablesize + 4
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def encode_value(pieces, value):
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"""Encode the value passed in and append it to the pieces list returning
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the the size of the encoded value.
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:param list pieces: Already encoded values
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:param any value: The value to encode
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:rtype: int
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"""
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if PY2:
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if isinstance(value, basestring):
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if isinstance(value, unicode_type):
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value = value.encode('utf-8')
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pieces.append(struct.pack('>cI', b'S', len(value)))
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pieces.append(value)
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return 5 + len(value)
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else:
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# support only str on Python 3
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if isinstance(value, str):
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value = value.encode('utf-8')
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pieces.append(struct.pack('>cI', b'S', len(value)))
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pieces.append(value)
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return 5 + len(value)
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if isinstance(value, bytes):
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pieces.append(struct.pack('>cI', b'x', len(value)))
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pieces.append(value)
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return 5 + len(value)
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if isinstance(value, bool):
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pieces.append(struct.pack('>cB', b't', int(value)))
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return 2
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if isinstance(value, long):
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pieces.append(struct.pack('>cq', b'l', value))
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return 9
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elif isinstance(value, int):
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with warnings.catch_warnings():
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warnings.filterwarnings('error')
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try:
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p = struct.pack('>ci', b'I', value)
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pieces.append(p)
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return 5
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except (struct.error, DeprecationWarning):
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p = struct.pack('>cq', b'l', long(value))
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pieces.append(p)
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return 9
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elif isinstance(value, decimal.Decimal):
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value = value.normalize()
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if value.as_tuple().exponent < 0:
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decimals = -value.as_tuple().exponent
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raw = int(value * (decimal.Decimal(10) ** decimals))
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pieces.append(struct.pack('>cBi', b'D', decimals, raw))
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else:
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# per spec, the "decimals" octet is unsigned (!)
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pieces.append(struct.pack('>cBi', b'D', 0, int(value)))
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return 6
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elif isinstance(value, datetime):
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pieces.append(struct.pack('>cQ', b'T',
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calendar.timegm(value.utctimetuple())))
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return 9
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elif isinstance(value, dict):
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pieces.append(struct.pack('>c', b'F'))
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return 1 + encode_table(pieces, value)
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elif isinstance(value, list):
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p = []
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for v in value:
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encode_value(p, v)
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piece = b''.join(p)
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pieces.append(struct.pack('>cI', b'A', len(piece)))
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pieces.append(piece)
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return 5 + len(piece)
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elif value is None:
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pieces.append(struct.pack('>c', b'V'))
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return 1
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else:
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raise exceptions.UnsupportedAMQPFieldException(pieces, value)
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def decode_table(encoded, offset):
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"""Decode the AMQP table passed in from the encoded value returning the
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decoded result and the number of bytes read plus the offset.
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:param str encoded: The binary encoded data to decode
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:param int offset: The starting byte offset
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:rtype: tuple
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"""
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result = {}
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tablesize = struct.unpack_from('>I', encoded, offset)[0]
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offset += 4
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limit = offset + tablesize
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while offset < limit:
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key, offset = decode_short_string(encoded, offset)
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value, offset = decode_value(encoded, offset)
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result[key] = value
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return result, offset
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def decode_value(encoded, offset):
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"""Decode the value passed in returning the decoded value and the number
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of bytes read in addition to the starting offset.
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:param str encoded: The binary encoded data to decode
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:param int offset: The starting byte offset
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:rtype: tuple
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:raises: pika.exceptions.InvalidFieldTypeException
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"""
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# slice to get bytes in Python 3 and str in Python 2
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kind = encoded[offset:offset + 1]
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offset += 1
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# Bool
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if kind == b't':
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value = struct.unpack_from('>B', encoded, offset)[0]
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value = bool(value)
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offset += 1
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# Short-Short Int
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elif kind == b'b':
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value = struct.unpack_from('>B', encoded, offset)[0]
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offset += 1
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# Short-Short Unsigned Int
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elif kind == b'B':
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value = struct.unpack_from('>b', encoded, offset)[0]
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offset += 1
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# Short Int
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elif kind == b'U':
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value = struct.unpack_from('>h', encoded, offset)[0]
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offset += 2
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# Short Unsigned Int
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elif kind == b'u':
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value = struct.unpack_from('>H', encoded, offset)[0]
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offset += 2
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# Long Int
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elif kind == b'I':
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value = struct.unpack_from('>i', encoded, offset)[0]
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offset += 4
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# Long Unsigned Int
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elif kind == b'i':
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value = struct.unpack_from('>I', encoded, offset)[0]
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offset += 4
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# Long-Long Int
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elif kind == b'L':
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value = long(struct.unpack_from('>q', encoded, offset)[0])
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offset += 8
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# Long-Long Unsigned Int
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elif kind == b'l':
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value = long(struct.unpack_from('>Q', encoded, offset)[0])
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offset += 8
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# Float
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elif kind == b'f':
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value = long(struct.unpack_from('>f', encoded, offset)[0])
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offset += 4
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# Double
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elif kind == b'd':
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value = long(struct.unpack_from('>d', encoded, offset)[0])
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offset += 8
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# Decimal
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elif kind == b'D':
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decimals = struct.unpack_from('B', encoded, offset)[0]
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offset += 1
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raw = struct.unpack_from('>i', encoded, offset)[0]
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offset += 4
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value = decimal.Decimal(raw) * (decimal.Decimal(10) ** -decimals)
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# Short String
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elif kind == b's':
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value, offset = decode_short_string(encoded, offset)
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# Long String
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elif kind == b'S':
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length = struct.unpack_from('>I', encoded, offset)[0]
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offset += 4
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value = encoded[offset:offset + length]
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try:
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value = value.decode('utf8')
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except UnicodeDecodeError:
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pass
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offset += length
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elif kind == b'x':
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length = struct.unpack_from('>I', encoded, offset)[0]
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offset += 4
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value = encoded[offset:offset + length]
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offset += length
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# Field Array
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elif kind == b'A':
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length = struct.unpack_from('>I', encoded, offset)[0]
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offset += 4
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offset_end = offset + length
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value = []
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while offset < offset_end:
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v, offset = decode_value(encoded, offset)
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value.append(v)
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# Timestamp
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elif kind == b'T':
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value = datetime.utcfromtimestamp(struct.unpack_from('>Q', encoded,
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offset)[0])
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offset += 8
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# Field Table
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elif kind == b'F':
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(value, offset) = decode_table(encoded, offset)
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# Null / Void
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elif kind == b'V':
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value = None
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else:
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raise exceptions.InvalidFieldTypeException(kind)
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return value, offset
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