def decode_mms_header(byte_iter):
"""
Decodes the MMS header pointed by ``byte_iter``
This method takes into account the assigned number values for MMS
field names, as specified in [4], section 7.3, table 8.
From [4], section 7.1::
MMS-header = MMS-field-name MMS-value
MMS-field-name = Short-integer
MMS-value = Bcc-value | Cc-value | Content-location-value | Content-type-value | etc
:raise wsp_pdu.DecodeError: The MMS field name could not be parsed.
``byte_iter`` will not be modified.
:return: The decoded MMS header, in the format:
(<str:MMS-field-name>, <str:MMS-value>)
:rtype: tuple
"""
# Get the MMS-field-name
mms_field_name = ''
preview = byte_iter.preview()
byte = wsp_pdu.Decoder.decode_short_integer_from_byte(preview)
if byte in mms_field_names:
byte_iter.next()
mms_field_name = mms_field_names[byte][0]
else:
byte_iter.reset_preview()
raise wsp_pdu.DecodeError('Invalid MMS Header: could '
'not decode MMS field name')
# Now get the MMS-value
mms_value = ''
try:
name = mms_field_names[byte][1]
mms_value = getattr(MMSDecoder, 'decode_%s' % name)(byte_iter)
except wsp_pdu.DecodeError as msg:
raise wsp_pdu.DecodeError('Invalid MMS Header: Could '
'not decode MMS-value: %s' % msg)
except:
raise RuntimeError('A fatal error occurred, probably due to an '
'unimplemented decoding operation. Tried to '
'decode header: %s' % mms_field_name)
return mms_field_name, mms_value
def decode_sender_visibility_value(byte_iter):
"""
Decodes the sender visibility value pointed by ``byte_iter``
Defined in [4], section 7.2.22::
Sender-visibility-value = Hide | Show
Hide = <Octet 128>
Show = <Octet 129>
:raise wsp_pdu.DecodeError: The sender visibility value could not be
parsed. ``byte_iter`` will not be modified
in this case.
:return: The sender visibility: 'Hide' or 'Show'
:rtype: str
"""
byte = byte_iter.preview()
if byte not in (128, 129):
byte_iter.reset_preview()
raise wsp_pdu.DecodeError('Error parsing sender visibility '
'value for byte: %s' % hex(byte))
byte = byte_iter.next()
value = 'Hide' if byte == 128 else 'Show'
return value
def decode_boolean_value(byte_iter):
"""
Decodes the boolean value pointed by ``byte_iter``
From [4], section 7.2.6::
Delivery-report-value = Yes | No
Yes = <Octet 128>
No = <Octet 129>
A lot of other yes/no fields use this encoding (read-reply,
report-allowed, etc)
:raise wsp_pdu.DecodeError: The boolean value could not be parsed.
``byte_iter`` will not be modified.
:return: The value for the field
:rtype: bool
"""
byte = byte_iter.preview()
if byte not in (128, 129):
byte_iter.reset_preview()
raise wsp_pdu.DecodeError('Error parsing boolean value '
'for byte: %s' % hex(byte))
byte = byte_iter.next()
return byte == 128
def decode_delivery_time_value(byte_iter):
value_length = wsp_pdu.Decoder.decode_value_length(byte_iter)
token = byte_iter.next()
value = wsp_pdu.Decoder.decode_long_integer(byte_iter)
if token == 128:
token_type = 'absolute'
elif token == 129:
token_type = 'relative'
else:
raise wsp_pdu.DecodeError('Delivery-Time type token value is undefined'
' (%s), should be either 128 or 129' % token)
return (token_type, value)
def decode_priority_value(byte_iter):
"""
Decode the "Priority" value pointed by ``byte_iter``
Defined in [4], section 7.2.17
:raise wsp_pdu.DecodeError: The priority value could not be decoded;
``byte_iter`` is not modified in this case.
:return: The decoded priority value
:rtype: str
"""
priorities = {128: 'Low', 129: 'Normal', 130: 'High'}
byte = byte_iter.preview()
if byte in priorities:
byte = byte_iter.next()
return priorities[byte]
byte_iter.reset_preview()
raise wsp_pdu.DecodeError('Error parsing Priority value '
'for byte: %s' % byte)
def decode_expiry_value(byte_iter):
"""
Used to decode the "Expiry" MMS header.
From [4], section 7.2.10::
Expiry-value = Value-length (Absolute-token Date-value | Relative-token Delta-seconds-value)
Absolute-token = <Octet 128>
Relative-token = <Octet 129>
:raise wsp_pdu.DecodeError: The Expiry-value could not be decoded
:return: The decoded Expiry-value, either as a date, or as a delta-seconds value
:rtype: str or int
"""
value_length = MMSDecoder.decode_value_length(byte_iter)
token = byte_iter.next()
if token == 0x80: # Absolute-token
return MMSDecoder.decode_date_value(byte_iter)
elif token == 0x81: # Relative-token
return MMSDecoder.decode_delta_seconds_value(byte_iter)
raise wsp_pdu.DecodeError('Unrecognized token value: %s' % hex(token))