trying to force stdout to utf-8 with errors='ignore' or 'replace'

[Adam Funk]

I'm fiddling with a program that reads articles in the news spool
using email.parser (standard library) &
email_reply_parser.EmailReplyParser (installed with pip).  Reading is
fine, & I don't get any errors writing output extracted from article
bodies *until* I try to suppress invalid characters.  This works:

    if message.is_multipart():
        body = message.get_payload(0, True)
    else:
        body = message.get_payload()
    main_body = EmailReplyParser.parse_reply(body)
    # fix quoted-printable stuff
    if equals_regex.search(main_body):
        main_body = quopri.decodestring(main_body)
    # suppress attribution before quoted text
    main_body = attrib_regex.sub('>', main_body)
    # suppress sig
    main_body = sig_regex.sub('\n', main_body)
    main_body.strip()
    stdout.write(main_body + '\n\n')

but the stdout includes invalid characters.  I tried adding this at
the beginning

    if stdout.encoding is None:
       writer = codecs.getwriter("utf-8")
       stdout = writer(stdout, errors='replace')

and changing the output line to 

    stdout.write(main_body.encode('utf-8', errors='replace') + '\n\n')

but with either or both of those, I get the dreaded
"UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position
562: ordinal not in range(128)".  How can I force the output to be in
UTF-8 & silently suppress invalid characters?


-- 
Unit tests are like the boy who cried wolf.