Re: lwp proxy problem

I downloaded the file using wget, getting:

$ wget -O - http://www.tau.ac.il/tau.pac
--17:49:19--  http://www.tau.ac.il/tau.pac
           => `-'
Resolving www.tau.ac.il... 132.66.16.6
Connecting to www.tau.ac.il[132.66.16.6]:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1,187 [application/x-ns-proxy-autoconfig]
 
 0% [                                     ] 0             --.--K/s    
+function FindProxyForURL(url, host)
    {
        if ((isInNet(myIpAddress(), "132.66.90.0", "255.255.254.0")) &
+&
            !dnsDomainIs(host, "www.tau.ac.il")) {
            return "PROXY proxyslb.tau.ac.il:8080; " +
                   "PROXY proxy.tau.ac.il:8080; " +
                   "PROXY netcache.tau.ac.il:8080; " +
                   "PROXY netcache2.tau.ac.il:8080; " +
                   "PROXY proxym.tau.ac.il:8080; " +
                   "PROXY 132.66.16.12:8080; " +
                   "PROXY 132.66.16.34:8080; " +
                   "PROXY 132.66.16.23:8080";
        }
        else if (isInNet(host, "132.66.58.20", "255.255.255.255")) {
            return "PROXY proxym.tau.ac.il:8080";
        }
        else if (isPlainHostName(host) ||
            isInNet(host, "127.0.0.1", "255.255.255.255") ||
            isInNet(host, "132.66.0.0", "255.254.0.0")) {
            return "DIRECT";
        }
        else {
            return "PROXY proxyslb.tau.ac.il:8080; " +
                   "PROXY proxy.tau.ac.il:8080; " +
                   "PROXY netcache.tau.ac.il:8080; " +
                   "PROXY netcache2.tau.ac.il:8080; " +
                   "PROXY proxym.tau.ac.il:8080; " +
                   "PROXY 132.66.16.12:8080; " +
                   "PROXY 132.66.16.34:8080; " +
                   "PROXY 132.66.16.23:8080";
        }
    }
[download]

It is easy to read, so I think that once you know your IP address you can pick a proxy from the list by hand

~~Or you can write a script yourself to parse the pac file, at the moment I have no time to sketch one, sorry :-(~~

Update: see HTTP::ProxyAutoConfig

Update: ~~try this and tell me if it works. It seems I can't use that proxy, so I couldn't make any test myself, apart from checking that it parses and runs correctly.~~

use HTTP::ProxyAutoConfig ;
use LWP::Simple qw(&getstore $ua);
                                                                      
+          
my $pac = new HTTP::ProxyAutoConfig("http://www.tau.ac.il/tau.pac");
                                                                      
+          
my $url='http://www.yahoo.com';
$ua->proxy(http => $pac->FindProxy($url));
                                                                      
+          
my $file='test.html';
print "success" if (getstore($url, $file));
[download]

Update: actually, that won't work, since you need to parse the return value from FindProxy and pass it to $ua->proxy only if it matches /PROXY: host:port/ (after cleaning up the PROXY: parts, of course). Unfortunately, I am having no luck in making this module work (the FindProxyForURL function doesn't get defined). I'll update the above script as soon as I make sense of the module...

Update: Ok, I checked with ptkdb and saw that:

the module tries to parse the function contained in the pac file (javascript) to convert it to Perl
the parser in the subroutine is very buggy, and probabily expects a certain format for the PAC file, that is: is not general enough to parse any pac
the converted function is finally eval'ed, but no check is done on the $@ variable. Therefore, the user doesn't know if the pac failed to parse until he tries to use the FindProxy* functions and sees them fail because FindProxyForURL doesn't exist

Possible solutions:

write a bug report for the module and wait for the author to patch his module
write a better parsing routine, or ask for one (I can't write one, I am a JavaScript illiterate :-)
rewrite the parser routine using one of the JavaScript modules from CPAN. This one, for example, uses the SpiderMonkey engine from Mozilla, and I expect that it will know how to parse the PAC

Sorry, I can't help further :-(

Ciao!
--bronto

The very nature of Perl to be like natural language--inconsistant and full of dwim and special cases--makes it impossible to know it all without simply memorizing the documentation (which is not complete or totally correct anyway).
--John M. Dlugosz

Comment on Re: lwp proxy problem Select or Download Code

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Re: Re: lwp proxy problem by dannoura (Pilgrim) on Apr 27, 2004 at 16:15 UTC
Thanks for your help. It's not working, though. I get two errors: `Useless use of a constant in void context at C:/perl/site/lib/HTTP/Pro +xyAutoConfig.pm line 367. Undefined subroutine &HTTP::ProxyAutoConfig::FindProxyForURL called at + C:/perl/site/lib/HTTP/ProxyAutoConfig.pm line 131.` [download] ----------------------------------- Any comments about coding style are welcome.	[reply] [d/l]