pymultimonaprs corrupts packets by re-encoding

[hessu]

pymultimonaprs makes the assumption that all packets could be decoded or encoded as ISO-8859-1 printable strings, and decodes and subsequently re-encodes them as such. In reality a lot of packets contain binary byte sequences which cannot be correctly decoded or encoded as such. Many packets also contain substrings (such as APRS text message content) which are UTF-8 encoded, but other encodings are also widely used.

Encoding and re-encoding will often fail and cause packet data corruption, and modified duplicated packets as other igates will pass these packets without corrupting them. APRS packets in transit on the network must be processed as binary byte arrays, not strings of some specific encoding.

pymultimonaprs/pymultimonaprs/frame.py

Line 19 in 96d4cf1

tnc2_frame = tnc2_frame.decode('ISO-8859-1')

pymultimonaprs/pymultimonaprs/frame.py

Line 38 in 96d4cf1

tnc2 = tnc2.encode('ISO-8859-1')

See this implementation hint for more info:

https://github.com/hessu/aprsc/blob/master/doc/IGATE-HINTS.md#packets-getting-modified-due-to-character-encoding-issues