Bug 1471389

Since version 3.0 Calibre includes a new Content server [1]. Trying to interface with this server using the command line tool calibredb leads to the following error:

$ calibredb search XXX --username XXX --password XXX --with-library "http://localhost:8080/#calibre-library"
Traceback (most recent call last):
  File "/usr/bin/calibredb", line 20, in <module>
    sys.exit(main())
  File "/usr/lib64/calibre/calibre/db/cli/main.py", line 250, in main
    return run_cmd(cmd, opts, args[1:], DBCtx(opts))
  File "/usr/lib64/calibre/calibre/db/cli/main.py", line 54, in run_cmd
    ret = m.main(opts, args, dbctx)
  File "/usr/lib64/calibre/calibre/db/cli/cmd_search.py", line 45, in main
    ids = dbctx.run('search', q)
  File "/usr/lib64/calibre/calibre/db/cli/main.py", line 188, in run
    return self.remote_run(name, m, *args)
  File "/usr/lib64/calibre/calibre/db/cli/main.py", line 208, in remote_run
    res = self.br.open_novisit(rq)
  File "/usr/lib/python2.7/site-packages/mechanize/_mechanize.py", line 199, in open_novisit
    return self._mech_open(url, data, visit=False, timeout=timeout)
  File "/usr/lib/python2.7/site-packages/mechanize/_mechanize.py", line 230, in _mech_open
    response = UserAgentBase.open(self, request, data)
  File "/usr/lib/python2.7/site-packages/mechanize/_opener.py", line 193, in open
    response = urlopen(self, req, data)
  File "/usr/lib/python2.7/site-packages/mechanize/_urllib2_fork.py", line 344, in _open
    '_open', req)
  File "/usr/lib/python2.7/site-packages/mechanize/_urllib2_fork.py", line 332, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/site-packages/mechanize/_urllib2_fork.py", line 1142, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "/usr/lib/python2.7/site-packages/mechanize/_urllib2_fork.py", line 1115, in do_open
    h.request(req.get_method(), req.get_selector(), req.data, headers)
  File "/usr/lib64/python2.7/httplib.py", line 1042, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib64/python2.7/httplib.py", line 1082, in _send_request
    self.endheaders(body)
  File "/usr/lib64/python2.7/httplib.py", line 1038, in endheaders
    self._send_output(message_body)
  File "/usr/lib64/python2.7/httplib.py", line 880, in _send_output
    msg += message_body
UnicodeDecodeError: 'utf8' codec can't decode byte 0x91 in position 0: invalid start byte

According to Kovid Goyal this is caused by an outdated version of python-mechanize [2]. Fedora still ships version 0.2.5 (which was released in 2011). As of today, the latest version is 0.3.5 [3].

Bug 1432447 already tracks new releases of python-mechanize, but nobody seems to care.

[1] https://calibre-ebook.com/new-in/twelve
[2] https://www.mobileread.com/forums/showpost.php?p=3520402&postcount=151
[3] https://github.com/python-mechanize/mechanize