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pamqp.encode

pamqp.encode

Functions for encoding data of various types including field tables and arrays

DEPRECATED_RABBITMQ_SUPPORT = False module-attribute

Toggle to support older versions of RabbitMQ.

support_deprecated_rabbitmq(enabled=True)

Toggle the data types available in field-tables

If called with True, than RabbitMQ versions, the field-table integer types will not support the full AMQP spec.

Parameters:

Name Type Description Default
enabled bool

Specify if deprecated RabbitMQ versions are supported

 True
Source code in pamqp/encode.py 
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def support_deprecated_rabbitmq(enabled: bool = True) -> None:
    """Toggle the data types available in field-tables

    If called with `True`, than RabbitMQ versions, the field-table integer
    types will not support the full AMQP spec.

    :param enabled: Specify if deprecated RabbitMQ versions are supported

    """
    global DEPRECATED_RABBITMQ_SUPPORT

    DEPRECATED_RABBITMQ_SUPPORT = enabled

by_type(value, data_type)

Takes a value of any type and tries to encode it with the specified encoder.

Parameters:

Name Type Description Default
value FieldValue

The value to encode

 required
data_type str

The data type name to use for encoding

 required

Raises:

Type Description
TypeError

when the :data:data_type is unknown
Source code in pamqp/encode.py 
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def by_type(value: common.FieldValue, data_type: str) -> bytes:
    """Takes a value of any type and tries to encode it with the specified
    encoder.

    :param value: The value to encode
    :type value: :const:`pamqp.common.FieldValue`
    :param data_type: The data type name to use for encoding
    :raises TypeError: when the :data:`data_type` is unknown

    """
    try:
        return METHODS[str(data_type)](value)
    except KeyError as err:
        raise TypeError(f'Unknown type: {data_type}') from err

bit(value, byte, position)

Encode a bit value

Parameters:

Name Type Description Default
value int

Value to encode

 required
byte int

The byte to apply the value to

 required
position int

The position in the byte to set the bit on

 required
Source code in pamqp/encode.py 
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def bit(value: int, byte: int, position: int) -> int:
    """Encode a bit value

    :param value: Value to encode
    :param byte: The byte to apply the value to
    :param position: The position in the byte to set the bit on

    """
    return byte | (value << position)

boolean(value)

Encode a boolean value

Parameters:

Name Type Description Default
value bool

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
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def boolean(value: bool) -> bytes:
    """Encode a boolean value

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, bool):
        raise TypeError(f'bool required, received {type(value)}')
    return common.Struct.short_short_uint.pack(int(value))

byte_array(value)

Encode a byte array value

Parameters:

Name Type Description Default
value bytearray

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
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def byte_array(value: bytearray) -> bytes:
    """Encode a byte array value

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, bytearray):
        raise TypeError(f'bytearray required, received {type(value)}')
    return common.Struct.integer.pack(len(value)) + value

decimal(value)

Encode a decimal.Decimal value

Parameters:

Name Type Description Default
value Decimal

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def decimal(value: _decimal.Decimal) -> bytes:
    """Encode a decimal.Decimal value

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, _decimal.Decimal):
        raise TypeError(f'decimal.Decimal required, received {type(value)}')
    exponent = value.as_tuple().exponent
    if not isinstance(exponent, int):  # NaN, Infinity, sNaN
        raise TypeError(f'Cannot encode {value} as a decimal')
    elif exponent > 0:  # scale a positive exponent up into the mantissa
        scale = 0
        mantissa = int(value)
    else:  # value == mantissa * 10 ** -scale
        scale = -exponent
        mantissa = int(value.scaleb(scale))
    if not (0 <= scale <= 255):
        raise TypeError('Decimal scale range: 0 to 255')
    elif not (-2147483648 <= mantissa <= 2147483647):
        raise TypeError('Decimal mantissa range: -2147483648 to 2147483647')
    return struct.pack('>Bi', scale, mantissa)

double(value)

Encode a floating point value as a double

Parameters:

Name Type Description Default
value float

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
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def double(value: float) -> bytes:
    """Encode a floating point value as a double

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, float):
        raise TypeError(f'float required, received {type(value)}')
    return common.Struct.double.pack(value)

floating_point(value)

Encode a floating point value

Parameters:

Name Type Description Default
value float

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
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def floating_point(value: float) -> bytes:
    """Encode a floating point value

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, float):
        raise TypeError(f'float required, received {type(value)}')
    return common.Struct.float.pack(value)

long_int(value)

Encode a long integer

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
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def long_int(value: int) -> bytes:
    """Encode a long integer

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    elif not (-2147483648 <= value <= 2147483647):
        raise TypeError('Long integer range: -2147483648 to 2147483647')
    return common.Struct.long.pack(value)

long_uint(value)

Encode a long unsigned integer

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
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def long_uint(value: int) -> bytes:
    """Encode a long unsigned integer

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    elif not (0 <= value <= 4294967295):
        raise TypeError('Long unsigned-integer range: 0 to 4294967295')
    return common.Struct.ulong.pack(value)

long_long_int(value)

Encode a long-long int

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
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def long_long_int(value: int) -> bytes:
    """Encode a long-long int

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    elif not (-9223372036854775808 <= value <= 9223372036854775807):
        raise TypeError(
            'long-long integer range: '
            '-9223372036854775808 to 9223372036854775807'
        )
    return common.Struct.long_long_int.pack(value)

long_string(value)

Encode a "long string"

Parameters:

Name Type Description Default
value str

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def long_string(value: str) -> bytes:
    """Encode a "long string"

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    return _string(common.Struct.integer, value)

octet(value)

Encode an octet value

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def octet(value: int) -> bytes:
    """Encode an octet value

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    return common.Struct.byte.pack(value)

short_int(value)

Encode a short integer

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
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def short_int(value: int) -> bytes:
    """Encode a short integer

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    elif not (-32768 <= value <= 32767):
        raise TypeError('Short integer range: -32768 to 32767')
    return common.Struct.short.pack(value)

short_uint(value)

Encode an unsigned short integer

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
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def short_uint(value: int) -> bytes:
    """Encode an unsigned short integer

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if not isinstance(value, int):
        raise TypeError(f'int required, received {type(value)}')
    elif not (0 <= value <= 65535):
        raise TypeError('Short unsigned integer range: 0 to 65535')
    return common.Struct.ushort.pack(value)

short_string(value)

Encode a string

Parameters:

Name Type Description Default
value str

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def short_string(value: str) -> bytes:
    """Encode a string

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    return _string(common.Struct.byte, value)

timestamp(value)

Encode a datetime.datetime object or time.struct_time

Parameters:

Name Type Description Default
value datetime | struct_time

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
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def timestamp(
    value: datetime.datetime | time.struct_time,
) -> bytes:
    """Encode a datetime.datetime object or time.struct_time

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type

    """
    if isinstance(value, datetime.datetime):
        if value.tzinfo is None or value.tzinfo.utcoffset(value) is None:
            # assume datetime object is UTC
            value = value.replace(tzinfo=datetime.UTC)
        return common.Struct.timestamp.pack(int(value.timestamp()))
    if isinstance(value, time.struct_time):
        return common.Struct.timestamp.pack(calendar.timegm(value))
    raise TypeError(
        f'datetime.datetime or time.struct_time required, received {type(value)}'
    )

field_array(value)

Encode a field array from a list of values

Parameters:

Name Type Description Default
value FieldArray

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def field_array(value: common.FieldArray) -> bytes:
    """Encode a field array from a list of values

    :param value: Value to encode
    :type value: :const:`pamqp.common.FieldArray`
    :raises TypeError: when the value is not the correct type

    """
    if not isinstance(value, list):
        raise TypeError(f'list of values required, received {type(value)}')
    data = []
    for item in value:
        data.append(encode_table_value(item))
    output = b''.join(data)
    return common.Struct.integer.pack(len(output)) + output

field_table(value)

Encode a field table from a dict

Parameters:

Name Type Description Default
value FieldTable

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type
Source code in pamqp/encode.py 
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def field_table(value: common.FieldTable) -> bytes:
    """Encode a field table from a dict

    :param value: Value to encode
    :type value: :const:`pamqp.common.FieldTable`
    :raises TypeError: when the value is not the correct type

    """
    if not value:  # If there is no value, return a standard 4 null bytes
        return common.Struct.integer.pack(0)
    elif not isinstance(value, dict):
        raise TypeError(f'dict required, received {type(value)}')
    data = []
    for key, item in sorted(value.items()):
        encoded_key = key.encode('utf-8')
        if len(encoded_key) > 128:  # field names have a 128 byte max
            LOGGER.warning('Truncating key %s to 128 bytes', key)
            # ``ignore`` drops a multi-byte character split at the boundary
            key = encoded_key[0:128].decode('utf-8', 'ignore')
        data.append(short_string(key))
        try:
            data.append(encode_table_value(item))
        except TypeError as err:
            raise TypeError(f'{key} error: {err}') from err
    output = b''.join(data)
    return common.Struct.integer.pack(len(output)) + output

table_integer(value)

Determines the best type of numeric type to encode value as, preferring the smallest data size first.

Parameters:

Name Type Description Default
value int

Value to encode

 required

Raises:

Type Description
TypeError

when the value is not the correct type or outside the acceptable range for the data type
Source code in pamqp/encode.py 
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def table_integer(value: int) -> bytes:
    """Determines the best type of numeric type to encode value as, preferring
    the smallest data size first.

    :param value: Value to encode
    :raises TypeError: when the value is not the correct type or outside the
        acceptable range for the data type

    """
    if DEPRECATED_RABBITMQ_SUPPORT:
        return _deprecated_table_integer(value)
    if -128 <= value <= 127:
        return b'b' + common.Struct.short_short_int.pack(value)
    elif -32768 <= value <= 32767:
        return b's' + short_int(value)
    elif 0 <= value <= 65535:
        return b'u' + short_uint(value)
    elif -2147483648 <= value <= 2147483647:
        return b'I' + long_int(value)
    elif 0 <= value <= 4294967295:
        return b'i' + long_uint(value)
    elif -9223372036854775808 <= value <= 9223372036854775807:
        return b'l' + long_long_int(value)
    raise TypeError(f'Unsupported numeric value: {value}')

encode_table_value(value)

Takes a value of any type and tries to encode it with the proper encoder

Parameters:

Name Type Description Default
value FieldArray | FieldTable | FieldValue

Value to encode

 required

Raises:

Type Description
TypeError

when the type of the value is not supported
Source code in pamqp/encode.py 
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def encode_table_value(
    value: common.FieldArray | common.FieldTable | common.FieldValue,
) -> bytes:
    """Takes a value of any type and tries to encode it with the proper encoder

    :param value: Value to encode
    :type value: :const:`pamqp.common.FieldArray` or
                 :const:`pamqp.common.FieldTable` or
                 :const:`pamqp.common.FieldValue`
    :raises TypeError: when the type of the value is not supported

    """
    if isinstance(value, bool):
        return b't' + boolean(value)
    elif isinstance(value, int):
        return table_integer(value)
    elif isinstance(value, _decimal.Decimal):
        return b'D' + decimal(value)
    elif isinstance(value, float):
        return b'f' + floating_point(value)
    elif isinstance(value, str):
        return b'S' + long_string(value)
    elif isinstance(value, (datetime.datetime, time.struct_time)):
        return b'T' + timestamp(value)
    elif isinstance(value, dict):
        return b'F' + field_table(value)
    elif isinstance(value, list):
        return b'A' + field_array(value)
    elif isinstance(value, bytearray):
        return b'x' + byte_array(value)
    elif value is None:
        return b'V'
    raise TypeError(f'Unknown type: {type(value)} ({value!r})')