App gives UnicodeDecodeError when uploading new frames to the network

[crespum]

After the app identifies a new KISS packet and calls the RPC method communications.gs.storePassiveMessage the following error is returned by the server:

{ code: 104, 
message: "UnicodeDecodeError('utf8', '\x82\xa0\x00\x00HUMDE\x000\n%\x07)\xa3?\x91\x18\x01\x12\x1f\xf8\x07)\xa3?\x06\x0e\x01\x11\x07)\xa39n\x18\x01\x10\x1f\xf8\nX0\xde\xa7\x19\xb8', 0, 1, 'invalid start byte')", 
name: "JSONRPCError" }

This happened when using a recording of a HumSat pass, although a similar result was observed in a live pass of UniSat-6 and TigriSat.

[crespum]

This happens because the server tries to parse all frames as AX.25 whereas HUMSAT uses CSP, so the first byte of the message is not a 0x7E as specified in the first protocol.

In case of TigriSat, which uses AX.25, the message received in the Chrome App was (base64):

hqJAQEBAYJKSYKqmQOED8FVTNngURQkBOGsAh0M1AuBzAVUDAvr/xf9HAIb9O/+rAPsADxwzQDx8eD43ACYAkQKBAskCAACyAoMCAAAPAAAFrQ==

This indicates that the first byte is not a 0x7E, so the problem can be found either in the kiss parser or in the conversion to base64.

[crespum]

The problem was that the TNC I am using removes the first and the last byte of the AX.25 packets (0x7E). Packets should not be automatically decoded in the server because not every satellite uses AX.25 and not every TNC leaves the flag bytes.