[OTR-users] my own messages appear encrypted

[Paul Aurich]

And Doug Breaux spoke on 12/31/2009 08:15 AM, saying:
> Interesting. I'd not gotten back to debugging my OTR delivery problems:
> 
> http://lists.cypherpunks.ca/pipermail/otr-users/2009-March/001624.html
> 
> But this sounds like it could be relevant. However I can't find any
> documentation on the messagesplitter plugin. The Purple Pidgin Pack's
> wiki page doesn't seem to have a link/page for it.

Hmm, it's not documented on the wiki, you're right :-(.

I think Ian was correct about what the problem was; Pidgin's Yahoo PRPL
lowered the maximum message size a while ago (in the 2.5. line, I think) to
bring it in line with what the servers accepted at that point.  Setting the
otr.max_message_size to something lower /should/ work.

For the record, the values currently used in Pidgin 2.6.4 (which haven't
changed in a little while) are:

/*
 * Current Maximum Length for Instant Messages
 *
 * This was found by experiment.
 *
 * The YMSG protocol allows a message of up to 948 bytes, but the official
client
 * limits to 800 characters.  According to experiments I conducted, it
seems that
 * the discrepancy is to allow some leeway for messages with mixed single- and
 * multi-byte characters, as I was able to send messages of 840 and 932 bytes
 * by using some multibyte characters (some random Chinese or Japanese
characters,
 * to be precise). - rekkanoryo
 */
#define YAHOO_MAX_MESSAGE_LENGTH_BYTES 948
#define YAHOO_MAX_MESSAGE_LENGTH_CHARS 800

The reason the message 'disappears' is that OTR injects messages directly
(to bypass loops, or other plugins trying to munge the encoded message),
but it doesn't check the result of `serv_send_im`, which returns -E2BIG in
this case.  The standard sending routine in libpurple does check that
result and prints "Unable to send message: The message is too large".

~Paul

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