A shorter IF statement

[wkdown]

Hello all, looking for the shorter version of an IF statement. I am formatting a CGI script based on the user's browser. The obvious IF statement is:


if ( ($ENV['HTTP_USER_AGENT'] =~ 'Mozilla') || ($ENV['HTTP_USER_AGENT'] =~ 'MSIE') || ...


Is there a way to make it more concise? Say like:


if ( $ENV['HTTP_USER_AGENT'] =~ ('Mozilla','MSIE','Safari','Opera') ) {


... or something to this effect?

[brad211987]

I'm not that familiar with Perl/CGI but can you create a list holding the different browsers you are checking for, and then do a check to see if '$ENV['HTTP_USER_AGENT']' is in the list? This would clean the code up, I know how to do it in ruby but not perl so much.

[wkdown]

I'm guessing you mean put them into an array and loop through, right?


my @browsers = [ 'Mozilla', 'MSIE', 'Safari', 'Opera' ];
for ($foo=0; $foo<@browsers; $foo++) {
next unless ($ENV{HTTP_USER_AGENT} =~ $browsers[$foo]);
$mobile=1;
}


That makes the issue moot since this is even longer. I want to keep it to just the IF statement.

[wkdown]

Actually, I figured it out using regular expressions. For anyone who cares to know...


if ($ENV{HTTP_USER_AGENT} !~ /Mozilla|MSIE|Safari|Opera/ ) { $mobileUser = 1 }


The pipes | are regular expression ORs, so it will look for equivalence with any of the four.

[FishMonger]

There are several approaches that can be taken, but you didn't provide enough info on exactly what you want to accomplish so I can't say which of the approaches will best suite your needs.

See if this what you're after.
if( $ENV{'HTTP_USER_AGENT'} =~ /(Mozilla|MSIE|Safari|Opera)/ )

[FishMonger]

Good, you figured it out. I guess I should always refresh before posting a solution.

[wkdown]

Yes I got it, thanks alot though.

Note to anyone who Googles this: This is not an end-all solution for mobile browsers. These are only the four major browsers on PCs which account for ~95% of browsers used to view pages. Two exceptions I've found already (which may be major down the road)...

1. Apple iPhone and iPod Touch users; their browsers use a form of Safari
2. PSP users; PSP uses a form of Mozilla

Blackberrys (the most common handheld browsers) use their own proprietary browser. Example USER AGENT data:

BlackBerry8830/4.2.2 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104

[FishMonger]

Another thing to keep in mind is that the HTTP_USER_AGENT var can be spoofed to be anything the user wants, which means you don't want to rely on its value. I could access your site and set my HTTP_USER_AGENT to Fishmonger.

http://search.cpan.org/~gaas/libwww-perl-5.808/lib/LWP/UserAgent.pm
$ua->agent( $product_id )

Get/set the product token that is used to identify the user agent on the network. The agent value is sent as the "User-Agent" header in the requests. The default is the string returned by the _agent() method (see below).

If the $product_id ends with space then the _agent() string is appended to it.

The user agent string should be one or more simple product identifiers with an optional version number separated by the "/" character. Examples are:

$ua->agent('Checkbot/0.4 ' . $ua->_agent);
$ua->agent('Checkbot/0.4 '); # same as above
$ua->agent('Mozilla/5.0');
$ua->agent(""); # don't identify

[wkdown]

Thats true but I'm guessing in most applications that doesn't matter. In my case, I am presenting a table of data pulled from a database and said data is editable. Now a 12 column table is fine on a PC but horrendous on a BlackBerry. So I weed out if they are on a handheld and, if so, simplify the table. If someone wants their Blackberry to feign being Firefox, be my guest and enjoy the horizontal scrolling! haha

[crmpicco]

it's $ENV{REMOTE_ADDR}, don't think it would work with $ENV[REMOTE_ADDR]. No need for quotes either.