This adds python3 compatibility for blocking.transcribe and
blocking.transit, enough to allow the four
"wormhole (send|receive)-(text|file)" commands to work. These are all
tested by travis (via "trial wormhole").
"wormhole server" runs under py3, but only with --no-daemon (until
twisted.python.logfile is ported).
twisted.transcribe doesn't work yet (it needs twisted.web.client.Agent,
plus more local porting work).
This roughly parallels the way that blocking/eventsource.py and the pypi
"requests" modules work: the server can set the encoding (with
"Content-Type: text/event-stream; charset=utf-8"), and the EventSource
parser will decode accordingly. However eventsource_twisted.py *always*
returns unicode (on both py2/py3), even when the server hasn't set an
encoding. blocking/eventsource.py returns bytes (on py3, and str on py2)
when the server doesn't set an encoding.
In the future, eventsource_twisted.py should return bytes when the
server doesn't set an encoding.
eventsource_twisted.py includes an alternate approach that might be
necessary (a to_unicode() function instead of always using .decode), but
I won't be sure until enough of Twisted has been ported to allow the
EventSourceParser to be tested.
Also fix demo.py for python3.
* declare transit records and handshake keys are bytes, not str
* declare transit connection hints to be str
* use six.moves.socketserver, six.moves.input for Verifier query
* argparse "--version" writes to stderr on py2, stdout on py3
* avoid xrange(), use subprocess.Popen(universal_newlines=True)
* use modern/portable "next(iter)" instead of "iter.next()"
* use six.moves.input() instead of raw_input()
* tell requests' Response.iter_lines that we want str, not bytes
The main wormhole code is str (unicode in py3, bytes in py2). Most
everything else must be passed as bytes in both py2/py3.
Keep the internal "side" string as a str, to make it easier to merge
with other URL pieces.
The twisted.python.logfile in Twisted-15.4.0 is not yet compatible with
py3, but can be bypassed by not daemonizing the server (so it doesn't
write to a logfile). This has been fixed in twisted trunk, so when
15.4.1 or 15.5.0 comes out, this will no longer be needed. But I think
we'll leave it in place, since sometimes it's handy to run a server
without daemonization.
magic-wormhole now only uses the "SPAKE2_Symmetric" protocol, which does
not require the two participants to decide ahead of time which one is
which.
Previously, the blocking form used an asymmetric protocol, and the
non-blocking/Twisted form used a symmetric protocol (however it used an
earlier+slower version from SPAKE2-0.2.0, which is not compatible with
the current SPAKE2-0.3.0 one).
This breaks compatibility for the built-in "wormhole" script: a sender
using 0.3.0 will get errors when talking to a recipient running this
version or newer (including the upcoming 0.4.0 release).
