[asterisk-dev] GMail Support

[Marc Smith]

Hi,

Using imap.gmail.com (GMail / Google Apps) for the IMAP server has a
few problems (app_voicemail w/ IMAP storage). I'm pretty sure these
issues are more likely with Google's IMAP implementation, not c-client
or asterisk; when I change the IMAP server setting to a dovecot IMAP
server, it works perfectly.

UW IMAP version: imap-2007b
Asterisk: 1.4.21.1
Linux asterisk_test 2.6.23-hardened-r7 #2 SMP Thu Jul 10 10:35:52 EDT
2008 x86_64 Intel(R) Xeon(R) CPU X5355 @ 2.66GHz GenuineIntel
GNU/Linux

1) Out of the box, voicemail messages are saved correctly through
IMAP. One of the problems arises when attempting to retrieve voicemail
messages. Also, the MWI is never "active" -- asterisk reports no
voicemail messages (old or new).
The problem appears to be that when the mail_search_full function is
called. The SEARCHPGM that contains the header criteria
("X-Asterisk-VM-Extension") is never matched. When that criteria is
changed to something else, say the header "From" and the value being
"Asterisk PBX" then I get some voicemails. Changing this in both the
messagecount and open_mailbox functions will make it so my MWI updates
correctly and also will play the voicemails correctly when I dial the
voicemail app. I'm not sure why Google's IMAP does not return any
matches when the search is performed. When I connect to imap.gmail.com
with mtest and retrieve the message, I see the
"X-Asterisk-VM-Extension" exists in the header (along with all the
others). I turned on mail_debug for the mail stream and I see exactly
what it issues to the IMAP server (along with its response):
NOTICE[32142] app_voicemail.c: 00000007 SEARCH UNDELETED UNSEEN HEADER
X-Asterisk-VM-Extension 20001
NOTICE[32142] app_voicemail.c: * SEARCH
NOTICE[32142] app_voicemail.c: 00000007 OK SEARCH completed (Success)

2) Next, I noticed after listening to voicemails (through my phone)
the messages are not marked as "seen" so they still appear as new
messages in the GMail web interface (and I'm sure through IMAP too). I
believe when mail_fetchstructure is called in play_message, that
normally sets the "seen" flag or the IMAP server sets the "seen" flag.
This is not happening with Google Mail, so I used mail_setflag to
"manually" set the flag after mail_fetchstructure is called. This
fixed it so the messages are marked as read after listening to them.

I have a couple quick workarounds that solve these problems when using
GMail with IMAP storage. I grabbed app_voicemail.c revision 129158
from /branches/1.4/apps to work with.

1) For this first problem with no results being returned from the
search for voicemail messages, I just changed two lines:
Line 2560 (function messagecount)
Old: hdr = mail_newsearchheader ("X-Asterisk-VM-Extension", (char *)mailbox);
New: hdr = mail_newsearchheader ("From", "Asterisk PBX");
Line 4910 (function open_mailbox)
Old: hdr = mail_newsearchheader ("X-Asterisk-VM-Extension", vmu->mailbox);
New: hdr = mail_newsearchheader ("From", "Asterisk PBX");
This is definitely not a good solution. With this, sharing a single
IMAP mailbox for all users would be out of the question. Thats not my
situation, so its getting me by for my testing. Ideas? If the problem
is Google's IMAP, I doubt we're going to get them to change (at least
not any time soon). It could be something else, but again, I don't
have any problems when I switch to a dovecot IMAP server and I haven't
heard anyone else having this problem.

2) This fix took took a couple more lines, but I think this could
probably stay in without affecting other users; more testing needed to
confirm.
Starting after line 4590 (function play_message)
Inserted this:
char tmp[10];
snprintf(tmp, sizeof(tmp), "%lu", vms->msgArray[vms->curmsg]);
mail_setflag(vms->mailstream, tmp, "\\Seen");
This then sets messages to read in GMail. Again, I'm not sure if this
is caused by Google's IMAP or what. This may also be a bit neater
(better?) in a function like its brother vm_imap_delete.

I'm set for my testing and I'll update if I run into anything else.
What do you think about merging changes in so GMail users can be
happy? Maybe even using some kind of 'gmail=yes' option in
voicemail.conf to enable these "special" changes to app_voicemail.c.
Thoughts? Ideas?

--Marc