Re: [Expectperl-discuss] HELP: Proper handling of escape sequences in the method set_seq()

[Dave J. <jac...@gm...>]

I have this email and the bug report it mentions open. I have not dived
into the Expect code recently, either as a maintainer or as a user, so it
will take a little bit before I can get to it.

But it is received. I will look into it.


On Fri, Nov 24, 2017 at 7:52 AM, Tom Brown <70m...@gm...> wrote:

> Dear Perl-Expect fellows,
>
> as the implementation for the interact-method within Expect.pm is far away
> from the TCL-Expect implementation
>
> (see https://rt.cpan.org/Public/Bug/Display.html?id=56997)
>
> I am trying to use the method set_seq as workaround. But there is a very
> hard
> nut I am trying to crack for two days now. I am not sure if its caused by
> a bug
> in the Expect.pm module or my understanding is wrong how to hand over
> escape sequences to the set_seq($sequence,\&function,\@parameters) method.
>
> For reproduction purposes you can find the whole script below.
>
> -------------------------------- SCRIPT BEGIN
> -------------------------------
> #!/usr/bin/perl
>
> use strict;
> use warnings;
> use Expect;
> use feature qw(say);
>
> my %OPT = (
> "login" => "tbrown",
> "host" => "rtr",
> "prompt" => "RTR#",
> "passwd" => "myPasswd",
> "timeout" => 2,
> );
>
> my @command = ("/usr/bin/ssh",
> "-o StrictHostKeyChecking=no",
> "-o PreferredAuthentications=password",
> "-o PubkeyAuthentication=no",
> "$OPT{login}\@$OPT{host}");
>
> my $exp = new Expect();
> $exp = Expect->spawn(@command) or die "Cannot spawn $command[0]: $!\n";
> $exp->expect(2,'-re',"password: ");
> $exp->send("$OPT{passwd}\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
>
> $exp->send("term length 0\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
>
> my @parameters = qw(Parameter1 Parameter2 Parameter3);
> my @tunnel_iface = 2;
>
> $exp->log_stdout(0);
> $exp->debug(3);
> $exp->exp_internal(1);
> $exp->slave->stty(qw(raw -echo));
>
>
> ### Proper handling of the following escape sequences (keys F1 ~ F3)
> $exp->set_seq('\\033OP',\&sh_clock);
> $exp->set_seq("\\033OQ",\&sh_arp_vlan, \@parameters);
> $exp->set_seq("\\033OR",\&sh_vpn, \@tunnel_iface);
>
> ### Wrong handling of the following escape sequences (function keys F5)
> ### As with beginning of F5 the escape sequence pattern starts with
> '^[[15~'
> ### it looks like something goes wrong with the second '[' and the followed
> ### '15~'
> $exp->set_seq('\\033\[15~', \&leave);
> $exp->set_seq('X', \&leave);
> #$exp->set_seq('\x1b\x5b\x31\x35\x7e', \&leave);
> #$exp->set_seq('\\033\x5b15~', \&leave);
> #$exp->set_seq('\\033\\03315~', \&leave);
> #$exp->set_seq('\\033\x5b15~', \&leave); # \x5b = [ = escape character as
> hex
>
>
> $exp->log_stdout(1);
> $exp->debug(0);
> $exp->exp_internal(0);
>
> sub sh_clock {
> $exp->send("sh clock\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
> }
>
> sub sh_arp_vlan {
> foreach my $parameter (@_) {
> say $parameter;
> }
> $exp->send("show ip arp vlan 1\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
> }
>
> sub sh_vpn {
> my $iface = shift;
> $exp->send("show crypto isakmp sa\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
> $exp->send("show crypto ipsec sa interface tunnel $iface\r");
> $exp->expect($OPT{timeout}, $OPT{prompt});
> }
>
> sub leave {
> $exp->send("exit\r");
> $exp->expect($OPT{timeout}, eof);
> }
>
> $exp->interact();
>
>
> print "##### MATCHED:";
> p $exp->exp_match();
>
> --------------------------------- SCRIPT END
> --------------------------------
>
> The output of debug on invocation and after login is the following:
>
> RTR#term length 0
> RTR#Escape seq. '\033OP' function for spawn id(6) set to
> 'CODE(0x7f88318a72b8)()'
> Escape seq. '\033OQ' function for spawn id(6) set to
> 'CODE(0x7f88318a7240)()'
> Escape seq. '\033OR' function for spawn id(6) set to
> 'CODE(0x7f88318a70f0)()'
> Escape seq. '\033\[15~' function for spawn id(6) set to
> 'CODE(0x7f88318a6f70)()'
> Escape seq. 'X' function for spawn id(6) set to 'CODE(0x7f88318a6f70)()'
>
> My investigations so far:
>
> ------------------------------------- 1 ------------------------------
> -------
>
> $exp->set_seq('\\033\[15~', \&leave);
> By pressing F5 the string '5~exit' occurs on the routers shell. Obviously,
> the escape sequence seems to be divided and the string "~5" is passed
> within @_ to the function &leave).
>
> ------------------------------------- 2 ------------------------------
> -------
>
> $exp->set_seq('X', \&leave);
> By pressing just X I get the following:
>
> Value of @_ is:[]
> exit                     ### End of @_
> Translating "Xexit"...domain server...  # < mind the "Xexit"!!!
>
> Translating "### Value of @_ is:[]
> (8.8.8.8) (217.237.150.51) (217.237.148.22) @_
> (8.8.8.8) (217.237.150.51) (217.237.148.22)
> % Unknown command or computer name,or unable to find computer address
> RTR#exit
> Connection to 192.168.3.1 closed.
>
> Conclusion: Instead calling the function &leave expect sends 'Xexit' to
> the
> router. Why???
>
> But: In case just pressing "ESC" followed by X, the function leave() is
> properly called and logged out.
>
> Conclusion: Pressing ESC before X followed by a proper function call is
> the
> proof that the method set_seq works as it should - so far at least.
>
> ------------------------------------- 3 ------------------------------
> -------
>
> The following attempts (different variants to catch the escape sequence
> properly) doesn't work neither.
>
> $exp->set_seq('\x1b\x5b\x31\x35\x7e', \&leave); # escape sequence in hex
> #$exp->set_seq('\\033\\03315~', \&leave); #
> #$exp->set_seq('\\033\[15~', \&leave);
> #$exp->set_seq('\\033\x5b15~', \&leave); # \x5b = [ = Escape Character
>
> ------------------------------------------------------------
> -----------------
>
> I am at my wits' end. Any ideas or workarounds how to invoke functions
> properly by pressing function keys (using escape sequences)?
>
> I appreciate any comments.
>
> Thanks.
>
> T.
>
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>


-- 
Dave Jacoby
jac...@gm...

Don't panic when the crisis is happening, or you won't enjoy it.