Re: [Expectperl-discuss] Help with legacy expect code

[Bob M. <ram...@gm...>]

Hi Mike,

No need for such formality, I generally respond well to Bob :)

I like your suggestions, particularly the second.  In hindsight (which
is almost always 20/20, or better), I wonder why I didn't  think of it. 
It is so obvious. :(

I will come back once I've tried it, and let you know how it worked out.

Thanks,

Bob


On 03/24/2017 04:09 PM, mike nicholas wrote:
> Or perhaps, send a carriage return from the enclosing expect call,
> after it returns back, to get another prompt back to match for and
> continue execution ?
>
> On Fri, Mar 24, 2017 at 6:04 PM, mike nicholas
> <xmi...@gm... <mailto:xmi...@gm...>> wrote:
>
>     Hi Mr. McGowan,
>
>     Just a shot in the dark, but:
>
>     # instead of this:
>     ##################
>
>       $ssh->expect(0, '-re', "$pat");
>       $ssh->log_file(\&logMethod) if $logging;
>              return $ssh->error();
>          };
>
>     # You may want to try:
>     ######################
>
>       $ssh->expect(5,
>             [ '-re', $pat => sub {  $ssh->log_file(\&logMethod) if
>     $logging;
>                                     return $ssh->error();
>                                       }],
>
>             ['-re', $contains_stuff => sub { break;
>                                        }],
>             );
>
>     Maybe try setting $contains_stuff to something you would expect on
>     success i.e. no pw being echo'd back ?
>
>     On Fri, Mar 24, 2017 at 4:52 PM, Bob McGowan <ram...@gm...
>     <mailto:ram...@gm...>> wrote:
>
>         Hello List,
>
>         I'm supporting legacy code that uses Expect, but I'm no expert
>         with this tool.  Nor can I figure out a way to pose the
>         question to the archive server to search for anything helpful,
>         so here I am, hoping for an answer. :)
>
>         Before the section that does the Expect processing, there is a
>         sub defined as follows:
>
>             $passHandler = sub {
>                 my ($ssh, $logging, $password) = @_;
>                 $ssh->log_file(undef);
>                 $ssh->stty(qw(-echo));
>                 print $ssh "$password\r";
>                 $ssh->stty(qw(echo));
>                 $pat = quotemeta($password);
>
>                 $ssh->expect(0, '-re', "$pat");
>
>                 $ssh->log_file(\&logMethod) if $logging;
>                 return $ssh->error();
>             };
>
>         There are a number of other patterns to look for besides the
>         two prompts listed below, each with appropriate logic
>         contained in other 'sub' definitions.  My problem is with the
>         second prompt.  Also, I'm not being pedantic here about format
>         or syntax, this is not intended to run (currently).
>
>             $expectObj->expect($timeout,
>                     '-re', $prompt1, sub {
>                         $failed = $passHandler->($ssh, $logging,
>         $password);
>                         if ($failed) {
>                             return "something";
>                         } else {
>                             return exp_continue_timeout();
>                         }
>                     },
>                     '-re', $prompt2, sub {
>                         $output = $ssh->exp_before();
>                         if ($secondPass) {
>                             $failed = $passHandler->($ssh, $logging,
>         $secondPass);
>                             if ($failed) {
>                                 return 'something';
>                             } else {
>                                 return exp_continue_timeout();
>                             }
>                         } else {
>                             return # an error
>                         }
>                     },
>                     ...
>                 );
>
>         I have run the original code with debugging on.
>
>         Processing $prompt1 happens before processing for $prompt2. 
>         $prompt1 is the login prompt passed through by 'ssh'.
>
>         Handling the ssh login step works fine.
>
>         Processing the second prompt looks for a string like 'Enter
>         secondary password: ' which is detected correctly and
>         processing goes into the passHandler, where the password is sent.
>
>         The function then does the 'expect' on the password "pattern",
>         which is there to be sure we don't get any echo'ed password
>         passed through.
>
>         But in the failing case, there is no password echoed, and the
>         next set of returned strings contains stuff that doesn't
>         match, within the passHandler.  So it times out.
>
>         Upon returning to the enclosing 'expect' call, expect
>         immediately begins 'waiting' for new data.  The strings that
>         were picked up in passHandler are not looked at, and
>         unfortunately they have the next string being 'waited' for, so
>         the whole thing times out and processing fails.
>
>         I'm happy to try to make something that actually runs, if that
>         is needed, but that will take a bit more time and I hope this
>         is enough to point someone in the right direction.
>
>         Many thanks,
>
>         Bob
>
>
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