After reading through the NGINX MAIL module code, I emailed Evan Miller (http://evanmiller.org/nginx-modules-guide.html), George Malamidis (http://nutrun.com/weblog/hello-world-nginx-module/), Joshua Zhu (http://blog.zhuzhaoyuan.com/tag/nginx/) and the mailing list (http://forum.nginx.org/read.php?2,5651,5651#msg-5651) as well as a few other module developers for some clarity on how to extend the MAIL modules. Based on the feedback I have received, I see that there isn't a clear model for easily extending the MAIL modules like there is for the HTTP modules. I want to be able to create a module to extend the MAIL functionality to include regex rewrite-like functionality like there is in the HTTP modules.

I realize that Igor is a busy man but eventually I wrote to him to ask if he has plans to add chain output buffers or similar structure to the MAIL module API to allow for more easily extending the functionality. He has yet to respond.

With the state of things in the MAIL API, there are two routes to address modifying the requests and responses proxied by NGINX:

1) add a chained out buffers and a structure to allow for registering additional modules of functionality, to which additional modules could be written to handle desired outcomes; or

2) modify the existing source code to scan line by line through the requests and responses (like NGINX does today for the NOOP, LOGIN, AUTHENTICATE commands) and handle each case individually.

I would prefer to see the option #1 taken so as to open up a whole new front for NGINX development but I am not certain there is community support for this. I would like to hear from you if you have interest in extending the MAIL API to handle Modules like the HTTP API does. Given the lack of interest thus far I am sceptical of community interest in extending the MAIL API to handle additional processing via modules like the HTTP API. If you have an interest in helping with this model, please speak up.

Short of community support for extending the MAIL API materializing, I would be interested in knowing if there are any developers willing/interested in modifying the source in ngx_mail_parse.c (and other locations as needed) to accommodate additional proxied commands. In particular, I need to at least handle intercepting the following IMAP commands:


(IMAP commands listed in order of priority) <char length>
[list]
[*] list <4> - response - substitute text during response from upstream servers
[*] select <6> - request - substitute text during request
examine <7> - request - substitute text during request
[*] status <6> - request & response - substitute text during request and response
[*] copy <4> - request - substitute text during request
[/list]

example:

[code]
switch (p - c) {
case 4:
vif ((c[0] == 'N' || c[0] == 'n')
&& (c[1] == 'O'|| c[1] == 'o')
&& (c[2] == 'O'|| c[2] == 'o')
&& (c[3] == 'P'|| c[3] == 'p'))
{
s->command = NGX_IMAP_NOOP;

} else if ((c[0] == 'C' || c[0] == 'c')
&& (c[1] == 'O'|| c[1] == 'o')
&& (c[2] == 'P'|| c[2] == 'p')
&& (c[3] == 'Y'|| c[3] == 'y'))
{
....
}

[/code]


Any takers?