get & change URL variables

[mlewczuk]

Hello,
How to solve this problem: I have url with some variables, for example: www.someurl.com/index.php?var1=34&var2=OK&var3=Test. Now, I want to check if var2, and var3 are declered (becouse they can be not declered). If they are I want to change value of them and make new url with changed values of var2 and var3 (but var1 must be the same). If var2 and var3 aren't declered I want do declere them and make new url with specyfied values. Number of vars depends from some special factors (so in other words, I don't know how many variables will be declered and I don't know what will be order of them).

One more time:

url1: http://www.someurl.com/index.php?<b>var1=section1</b>&var2=87&var3=test&var4=phpbuilder

check variables, change values of specyfied vars (e.g. var1=section2) and make new url:

urlNEW: http://www.someurl.com/index.php?<B>var1=section2</B>&var2=87&var3=test&var4=phpbuilder

As you see all others vars are the same... only var1 was changed.

[Weedpacket]

Is the URL stored in a variable? Assuming it is, and the variable is called $url:

$url_parts = parse_url($url);
$querystring = $url_parts['query'];
parse_str($querystirng, $querystring_vars);

After that,

if(isset($querystring_vars['var2']))
{  // $querystring_vars['var2'] is set and has the value in $querystring_vars['var2']
}
else
{   // $querystring_vars['var2'] was not set
}

And after that it's just a matter of normal string operations to put together the new URL (and judicious application of urlencode() here and there to make sure the result is a properly-formatted URL).

[mlewczuk]

Url shoud be taken automatically from url of present page. Maybe I didn't describe this to good, becouse i meant that i wanted to to do something like this:

1. Take URL of present page (e.g. http://www.somepage.com/index.php?var1=se1&unknownvar=876 )

2. Check if var1 is declered

3. If declared then using <select> change value of var1 to se2 and redirect to http://www.somepage.com/index.php?var1=se2&unknownvar=876

4. If not declared, choose <select> value and then redirect to: http://www.somepage.com/index.php?unknownvar=876&var1=se2

As I said before, we don't know how many and what vars are declared -> I just want to change some var and change present url with new value of some var (but other declared vars of URL shoud be the same).

[Weedpacket]

All the variables listed in the URL of the present page are available in the $_GET array.

If $_GET['var2'] is set, then it's in the querystring.

Following that, the last sentence of my previous post applies.