Event based Jabber/XMPP bot

Some time ago I wrote superb Jabber/XMPP client based on the ideas of even more superb IRC client ii. I named the client jj and put the source code to github. Since then me and my friends have been using jj for our Jabber MUC (multiuser chat room, something like channel in IRC). And it has been serving us nicely.

Our jj bot resolves URL titles and aggregates Twitter, Google Plus and some RSS feeds to our MUC. The process how this is done is quite easy. Jj has outfile and input FIFO for each channel it sits on. The bot functionality can be distinguished into two different tasks: 1) reacting to input and 2) cron jobs:

  1. URL resolving is done by reacting to what input is coming in. There is one shell script that listens our mucs outfile with inotify. When it gets notified that something is said on the MUC it will inspect the line. If it finds URL on that line, it will call the title resolver and write the resolved title to the MUC in file.

    Here is pseudo bash for it (external tools fecho and gettitle.py are used), note also that I divided the long greps to multiple lines without testing the code:

    while true; do
        inotifywait -e modify $outfile
        line=$(tail -1 "$outfile" |\
               grep -v "^[0-9][0-9][0-9][0-9]\-[0-9][0-9]\-[0-9][0-9]\
               [0-9][0-9]:[0-9][0-99][0-9] <$nickname>" |\
               grep "^[0-9][0-9]"|\
               grep -v "[0-9] -\!-" |\
               grep -m 1 -i -E "https?://")
        if [ ! -z "$line" ]; then
            url=$(echo "$line"| grep -o -i -E "https?://.*" | cut -d" " -f1)
            title=$(echo "$url" | gettitle.py)
            fecho "$title" $infile

    Basically this can be used for any kind of reaction tasks. For example for the classic sed like line "s/from/to".

  2. Feeds (Twitter, Google Plus, RSS etc.) are done with cron jobs. Here is pseudo bash example for that (it uses external tools feedcheck and fecho):
    feedlist=$(cat <<EOF
    # Set IFS to newline only. See BASH(1) manpage for details on IFS.
    for feed in $feedlist; do
         for x in $(feedcheck $feed); do
             fecho "$x" jabber.tld/mucs/conf@conference.jabber.tld/in
             sleep 5

Sadly I had to write the external tools fecho, gettitle.py and feedcheck, since there we no proper ones available. Fecho is already in jj source code repository, but the other ones are not yet. For fecho source see here.

Hopefully these examples will illustrate how to make jj bots. I will try to polish the instructions later and add these to jj source code repository as examples.

Categories: Jabber, English, Jj, Avoin
Date: 2012-07-13 14:13:28