S_Shrum has asked for the wisdom of the Perl Monks concerning the following question:

My website uses nested tables out the wang. The problem is that older browsers lock when they try to open some of the pages. I'm thinking of writing a script that would handle redirecting browsers that passed testing, those that cannot, and those that are unknow to 4 possible locations: 
$failed = "http://failaddress";
$passed = "http://passaddress";
$untested = "http://untestedaddress";
$unknown = "http://unknownaddress";

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Here's my idea. I want to create a hash in a hash (which I never have dealt with before) to create a USER_AGENT table. Something like: 
my %agents = (    MSIE50NT    =>    {    string        =>    "Mozilla/
+4.0 (compatible; MSIE 5.0; Windows NT; DigExt) ",
                                    browser        =>    "Microsoft In
+ternet Explorer 5.0",
                                    developer    =>    "Microsoft",
                                    url            =>    "http://www.m
+icrosoft.com",
                                    tested        =>    "y",
                                    passed        =>    "y",
                MSIE55NT    =>    {    string        =>    "Mozilla/4.
+0 (compatible; MSIE 5.5; Windows NT; DigExt) ",
                                    browser        =>    "Microsoft In
+ternet Explorer 5.5",
                                    developer    =>    "Microsoft",
                                    url            =>    "http://www.m
+icrosoft.com",
                                    tested        =>    "y",
                                    passed        =>    "y",

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...and so on, and so on. Then I can do a test to see if the browser was tested and if it passed and redirect to the approprate page.

Does this seem like a good idea? And if so, does anyone want to help me make one? Am I looking to buy a extra large bottle of Advil? Should I just put this one down with a silver bullet? Or better yet, does one already exist? TIA

======================
Sean Shrum
http://www.shrum.net

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Re: Need help protecting the user - detecting and redirecting browsers the ADVANCED way...
by thpfft (Chaplain) on Mar 01, 2002 at 10:57 UTC

    HTTP::BrowserDetect is pretty good. It's just an oop implementation of netscape's old 'sniffer' javascript, but nicely done, offering methods like $browser->is_ie5plus or $browser->is_robot.

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Re: Need help protecting the user - detecting and redirecting browsers the ADVANCED way...
by particle (Vicar) on Mar 01, 2002 at 13:24 UTC
    i would suggest inverting your logic to use three hashes, my (%passed, %failed, %untested); (i'm not sure you need a fourth). once you get the browser type, test for existence of the key in the three hashes. if it doesn't exist in the third, add the key, then redirect. a lengthier example might look like:

    
my (%passed, %failed, %untested);
%passed = { 
    MSIE50NT => 1, 
    MSIE55NT => 1, 
    URI_REDIRECT => 'http://passaddress/', 
};
# set %failed and %untested

my $br_detect = 'palm'; # as found by HTTP::BrowserDetect
if( defined $passed{$br_detect} ) { redirect( $passed{URI_REDIRECT} ) 
+}
if( defined $failed{$br_detect} ) { redirect( $failed{URI_REDIRECT} ) 
+}
defined $untested{$br_detect} ? '' : %untested{$br_detect} = 1;
redirect( $untested{URI_REDIRECT} );

sub redirect {
# your redirect logic here...
}

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    ~Particle ;Þ

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      Say a user attempts to view a page and the browser is detected to have not passed. I would like to be able to list (for ( keys %passed )) the passed browsers along with formal browser names, versions, and URL info.

      I am seeing something like this forming: 

      my %passed    =    {                    # MSIE 5.0 on MS NT 4.0
                    1    =    (        HTTP_USER_AGENT    =>    "Mozil
+la/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)",
                                    NAME            =>    "MS Internet
+ Explorer"
                                    VERSION            =>    "5.0"
                                    PLATFORM        =>    "NT"

                                    MANUFACTURER    =>    "Microsoft"
                                    URL                =>    "http://w
+ww.microsoft.com"

      [download]

      Does this seem like the correct way to go with this idea? How would I structure the line to display the info like: 

      Here is a list of browsers that have passed testing:

   + MS Internet Explorer 5.0 / NT (http://www.microsoft.com)
...

      being that the info is a hash in a hash in a hash?

      ======================
      Sean Shrum
      http://www.shrum.net

[reply]
[d/l]
        since you're building this data structure manually, you have the ability to keep it in a config file, and do or eval it when neccessary. if you have unique values, for instance HTTP_USER_AGENT, you can use this as the key to the hash. i have an example below.

        if you don't have unique values, or require some combination of values for a unique key, you'll have to modify the data structure a little bit, to make sure your keys are unique.

        in any case, a read through perldsc will give you insight on working with complex data structures like hashes of hashes.

        my %passed = { 
    "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)"=> { 
        NAME        =>    "MS Internet Explorer",
        VERSION     =>    "5.0",
        PLATFORM    =>    "NT",
        # more specialized info here
    }, 
    # more HTTP_USER_AGENT strings here...
    URI_REDIRECT => 'http://passaddress/', 
};

# if $test_key is the unique browser identifier you're looking for
# you may print like...
my $message = join( ' ', 
    $passed{$test_key}->{NAME}, 
    $passed{$test_key}->{VERSION}, '/',
    $passed{$test_key}->{PLATFORM),
    # etc.
);

        [download]

        ~Particle ;Þ

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