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OurNet::BBSAgent
Scriptable telnet-based virtual users

OurNet::BBSAgent - Scriptable telnet-based virtual users


NAME

OurNet::BBSAgent - Scriptable telnet-based virtual users


SYNOPSIS


    #!/usr/local/bin/perl

    # To run it, make sure you have a 'elixus.bbs' file in the same

    # directory. The actual content is listed just below this section.

    use strict;

    use OurNet::BBSAgent;

    my $remote  = 'elixus.bbs';         # template name

    my $timeout = undef;                # no timeout

    my $logfile = 'elixus.log';         # log file

    my $bbs     = OurNet::BBSAgent->new($remote, $timeout, $logfile);

    my ($user, $pass) = @ARGV;

    $user = 'guest' unless defined($user);

    $bbs->{debug} = 1;                  # debugging flag

    $bbs->login($user, $pass);          # username and password

    # callback($bbs->message) while 1;  # procedural interface

    $bbs->Hook('message', \&callback);  # callback-based interface

    $bbs->Loop(undef, 10);              # loop indefinitely, send Ctrl-L

                                        # every 10 seconds (anti-idle)

    sub callback {

        my ($caller, $message) = @_;

        print "Received: $message\n";

        ($bbs->logoff, exit) if ($message eq '!quit');

        $bbs->message_reply("$caller: $message");

    }


DESCRIPTION

OurNet::BBSAgent provides an object-oriented interface to TCP/IP based interactive services, by simulating as a virtual user with action defined by a script language.

The developer could then use the same methods to access different services, to easily implement interactive robots, spiders, or other cross-service agents.

The scripting language of OurNet::BBSAgent features both flow-control and event-driven capabilities, makes it especially well-suited for dealing with automation tasks involved with Telnet-based BBS systems.

This module is the foundation of the BBSAgent back-end described in the OurNet::BBS manpage. Please consult its man page for more information.

Site Description File

This module has its own scripting language, which looks like this in a site description file:


    Elixus BBS

    elixus.org:23

    =login

    wait \e[7m

    send $[username]\n

    doif $[password]

        wait \e[7m

        send $[password]\nn\n

    endo

    # login failure, unsaved article, kick multi-logins

    send \n\n\n

    # skips splash screens (if any)

    send \x20\x20\x20

    =main

    send qqqqqqee

    wait \e[;H\e[2J\e[1;44;37m

    till ]\e[31m

    =logoff

    call main

    send g\ng\ny\ny\n\n\n

    exit

    =message

    wait \e[1;33;46m

    wait m/../

    till \x20\e[37;45m\x20

    till \x20\e[m

    exit

    =message_reply

    send \x12

    wait \e[m

    wait \e[23;1H

    send $[message]\n

    wait [Y]

    send \n

    wait \e[37;45m

    wait \e[m

    exit

The first two lines describe the service's title, its IP address and port number. Any number of procedures then begins with a = sign (e.g. =procname), which could be called as $object->procname([arguments]) in the program.

Directives

All procedures are consisted of following directives:

load FILENAME
This directive must be used before any procedures. It loads another BBS definition file under the same directory (or current directory).

If the FILENAME has an extension other than .bbs (eg. .board, .session), BBSAgent will try to locate additional modules by expanding . into /, and look for the required module with an .inc extension. For example, load maple3.board will look for maple3/board.inc in the same directory.

wait STRING
till STRING
or STRING
Tells the agent to wait until STRING is sent by remote host. May time out after $self->{timeout} seconds. Each trailing or directives specifies an alternative string to match.

If STRING matches the regex m/.*/[imsx]*, it will be treated as a regular expression. Capturing parentheses are silently ignored.

The till directive is functionally equivalent to wait, except that it will puts anything between the last wait or till and STRING into the return list.

send STRING
Sends STRING to remote host.

doif CONDITION
elif CONDITION
else
endo
The usual flow control directives. Nested doif...endos are supported.

goto PROCEDURE
call PROCEDURE
Executes another procedure in the site description file. A goto never returns, while a call always does. Also, a call will not occur if the destination was the last executed procedure, which does not end with exit.

exit
Marks the termination of a procedure; also denotes that this procedure is not a state - that is, multiple calls to it will all be executed.

setv VAR STRING
Sets a global, non-overridable variable (see below).

idle NUMBER
Sleep that much seconds.

Variable Handling

Whenever a variable in the form of $[name] is encountered as part of a directive, it will be looked up in the global setv hash $self->{var} first, then at the procedure-scoped variable hash, then finally shift()ed from the argument list if none are found.

For example:


    setv foo World!

    =login

    send $[bar] # sends the first argument

    send $[foo] # sends 'World!'

    send $[baz] # sends the second argument

    send $[bar] # sends the first argument again

A notable exception are digits-only subscripts (e.g. $[1]), which contains the matched string in the previous wait or till directive. If there are multiple strings via or directives, the subscript correspond to the matched alternative.

For example:


    =match

    wait foo

      or m/baz+/

    doif $[1] # 'foo' matched

        send $[1] # sends 'foo'

    else

        send $[2] # sends 'bazzzzz...'

    endo

Event Hooks

In addition to call the procedures one-by-one, you can Hook those that begins with wait (optionally preceded by call) so whenever the strings they expected are received, the responsible procedure is immediately called. You may also supply a call-back function to handle its results.

For example, the code in SYNOPSIS above hooks a callback function to procedure message, then enters a event loop by calling Loop, which goes on forever until the agent receives !quit via the message procedure.

The internal hook table could be accessed by $obj->{hook}.


METHODS

Following methods are offered by OurNet::BBSAgent:

new($class, $bbsfile, [$timeout], [$logfile])

Constructor class method. Takes the BBS description file's name and two optional arguments, and returns a OurNet::BBSAgent object.

If no files are found at $bbsfile, the method will try to locate it on the OurNet/BBSAgent sub-directory of each @INC entries.

loadfile($self, $bbsfile, [$path])

Reads in a BBS description file, parse its contents, and return the object itself. The optional $path argument may be used to specify a root directory where files included by the load directive should be found.

Hook($self, $procedure, [\&callback], [@args])

Adds a procedure to the trigger table, with an optional callback function and parameters on invoking that procedure.

If specified, the callback function will be invoked after the hooked procedure's execution, using its return value as arguments.

Unhook($self, $procedure)

Unhooks the procedure from event table. Raises an error if the specified procedure did not exist.

Loop($self, [$timeout], [$refresh])

Causes a Expect loop to be executed for $timeout seconds, or indefinitely if not specified. If the $refresh argument is specified, BBSAgent will send out a Ctrl-L (\cL) upon entering the loop, and then every $refresh seconds during the Loop.

Expect($self, [$string], [$timeout])

Implements the wait and till directives; all hooked procedures are also checked in parallel.

Note that multiple strings could be specified in one $string by using \n as the delimiter.

AUTOLOAD($self, [@args])

The actual implementation of named procedures. All method calls made to a OurNet::BBSAgent object would resolve to the corresponding procedure defined it its site description file, which pushes values to the return stack through the till directive.

An error is raised if the procedure called is not found.


SEE ALSO

the Net::Telnet manpage, the OurNet::BBS manpage


AUTHORS

Autrijus Tang <autrijus@autrijus.org>


COPYRIGHT

Copyright 2001, 2003 by Autrijus Tang <autrijus@autrijus.org>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html

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