Automating CGI logons - clarification & further question

[David Stern]

We are attempting to use Expect scripts to autologon to a remote 
SilverPlatter database via the internet.  We do this for other access
(Nexis, FirstSearch, Medline, etc).  

SilverPlatter requires the use of their own proprietary software (unixSPIRS)
which runs on our Solaris machine. The problem is that Expect appears to
filter the vt100 data as it returns from the unixSPIRS gateway -- rendering a
screen full of junk. 


TWO QUESTIONS:

(1) Is PERL scripting going to cause similar problems Or is this just 
  an emulation configuration problem that can be fixed in Expect?
 
(2) Is there a way to implement a similar script from a WWW browser that will
     allow for returning control to the script at the end of the session
     in order to exit the subdirectory and exit the server?

  Any advice?  SilverPlatter said that this WWW autologon approach has 
not been tried ... does that mean that all remote users have the 
unixSPIRS or WebSPIRS software on their local machines?

   


> 
> > This sounds like what I need, but I can't find any documentation
> > about "expect" -- is this an HTML tag, part of the CGI
> > specification, or what?
> 
> None of the above. Do a Lycos search for "expect." Here's one result
> (strong match):
> 
> ---
> 3) Expect-5.13 [0.9673]
> 
> Outline: Expect-5.13 Environment Variables: Documentation
> 
> Abstract: "Cures those uncontrollable fits of interaction". Expect is
> an extension to Tcl by Don Libes which allows you to use Tcl to
> interact via scripts with other interactive programs. [...]
> http://www.cs.ucsb.edu/Facilities/Software/expect.htm
> ---
> 
> Tcl is a scripting language like Perl. Anyone who's written a
> Crosstalk or Kermit script (or the like) could make their way through
> writing an expect script without knowing Tcl, though undoubtedly some
> aspects of it will remain mysterious (you'll just take them on faith
> and follow the "cookbook").
> 
> > Is there any way to do this with WWW servers that run a CGI script
> > to ask for a name and password?  Do we need to set up a CGI script
> > on our server to feed the info to the remote server? -- if so, how
> > does this work?
> 
> Here is how we use it. Web page foo advertises an on-line service. The
> anchor is something like:
> 
> <A HREF="telnet://proxy.x.edu:5013/"> ... </A>
> 
> The "telnet proxy server" is the machine that checks whether this is
> an authorized request, i.e., coming from a machine on campus. (You
> could also use .htaccess or the equivalent to protect the page
> itself.) Port 5013 (the number is arbitrary, so long as it's high
> enough that it won't be co-opted by a future canonical TCP/IP service)
> is running a telnet daemon that forks the expect script. This means
> that each telnet proxy service has an entry in /etc/services. Have I
> said enough already?  That is, this is a job for a systems person
> (whether from the computer center or the library). You must be very
> careful not to create _BIG_ security holes on your systems doing this
> (for example, you don't want a user breaking out and getting a
> shell). So you want someone doing this who's security-conscious as
> well (not just a good hacker).
> 
> The upside is that if you have a lot of these services, you can list
> them on an internal staff web page, and your web authors simply pick
> the URL for the service they want to advertise. Logons and passwords
> remain secure and hidden: your telnet proxy server should be a machine
> with restricted access, for example, open to systems administrators
> only.
> 
> At our site we use a different machine for the telnet proxy server and
> the web server, though that isn't necessary, provided you don't also
> have regular users on the server (partly for load, but mainly for
> security). Load so far has been minimal for the proxy server.
> 

***************************************************************

  David Stern
  Director of Science Libraries and Information Services
  Kline Science Library
  Yale University
  219 Prospect Street
  P.O. Box 208111
  New Haven, CT  06520-8111

  phone:  203 432-3447
  fax: 203 432-3441

  email:  dstern at minerva.cis.yale.edu