Packets

A HSMS packet secsgem.hsms.HsmsPacket consists of a header secsgem.hsms.HsmsHeader and a data part represented by a string. The string contains the additional data encoded as ASCII characters for transmission over TCP. The additional data is only required for a stream/function packet.

>>> secsgem.hsms.HsmsPacket(secsgem.hsms.HsmsLinktestReqHeader(2))
secsgem.hsms.HsmsPacket({'header': secsgem.hsms.HsmsLinktestReqHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 2, 'session_id': 65535, 'require_response': False, 's_type': 5}), 'data': ''})

Every header has a system id to match the response to a certain request. The system id is the first parameter to the headers constructor. The connection keeps track of the system id, a new one can be requested with the secsgem.hsms.connections.HsmsConnection.get_next_system_counter() function.

HSMS packet objects can encode themselves with the secsgem.hsms.HsmsPacket.encode() function to a string, which can be sent over the TCP connection.

>>> packet = secsgem.hsms.HsmsPacket(secsgem.hsms.HsmsLinktestReqHeader(2))
>>> secsgem.common.format_hex(packet.encode())
'00:00:00:0a:ff:ff:00:00:00:05:00:00:00:02'

The other way around, a HSMS packet object can be created from the ASCII string with the secsgem.hsms.HsmsPacket.decode() function.

>>> secsgem.hsms.HsmsPacket.decode(packetData)
secsgem.hsms.HsmsPacket({'header': secsgem.hsms.HsmsHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 2, 'session_id': 65535, 'require_response': False, 's_type': 5}), 'data': ''})

There are classes inherited from secsgem.hsms.HsmsHeader for all HSMS packet types available:

Select Request

Establish HSMS communication

>>> secsgem.hsms.HsmsSelectReqHeader(14)
secsgem.hsms.HsmsSelectReqHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 14, 'session_id': 65535, 'require_response': False, 's_type': 1})

Select Response

Result of select request

>>> secsgem.hsms.HsmsSelectRspHeader(24)
secsgem.hsms.HsmsSelectRspHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 24, 'session_id': 65535, 'require_response': False, 's_type': 2})

Deselect Request

Grateful close HSMS communication before disconnecting

>>> secsgem.hsms.HsmsDeselectReqHeader(1)
secsgem.hsms.HsmsDeselectReqHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 1, 'session_id': 65535, 'require_response': False, 's_type': 3})

Deselect Response

Result of deselect request

>>> secsgem.hsms.HsmsDeselectRspHeader(1)
secsgem.hsms.HsmsDeselectRspHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 1, 'session_id': 65535, 'require_response': False, 's_type': 4})

Linktest Request

Check the HSMS connection link is good

>>> secsgem.hsms.HsmsLinktestReqHeader(2)
secsgem.hsms.HsmsLinktestReqHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 2, 'session_id': 65535, 'require_response': False, 's_type': 5})

Linktest Response

Result of linktest request

>>> secsgem.hsms.HsmsLinktestRspHeader(10)
secsgem.hsms.HsmsLinktestRspHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 10, 'session_id': 65535, 'require_response': False, 's_type': 6})

Reject Request

Response to unsupported HSMS message

>>> secsgem.hsms.HsmsRejectReqHeader(17, 3, 4)
secsgem.hsms.HsmsRejectReqHeader({'function': 4, 'stream': 3, 'p_type': 0, 'system': 17, 'session_id': 65535, 'require_response': False, 's_type': 7})

Separate Request

Immediate termination of the HSMS connection

>>> secsgem.hsms.HsmsSeparateReqHeader(17)
secsgem.hsms.HsmsSeparateReqHeader({'function': 0, 'stream': 0, 'p_type': 0, 'system': 17, 'session_id': 65535, 'require_response': False, 's_type': 9})

Data Message

Secs stream and function message

>>> secsgem.hsms.HsmsStreamFunctionHeader(22, 1, 1, True, 100)
secsgem.hsms.HsmsStreamFunctionHeader({'function': 1, 'stream': 1, 'p_type': 0, 'system': 22, 'session_id': 100, 'require_response': True, 's_type': 0})