tracking refering url by query string

generic

I want to track the referring url, only when it doesn't contain certain variables. So when I go from page.php?category=100 (viewing, say, Apples) to page.php?id=5 (viewing, say, Golden Delicious Apples), and if I click on add to basket (making the url page.php?id=5&action=add), I want to not track the $action so when I click 'back', it takes me back to the category page instead of the id page. Does that makes sense? I'm sure it's feasible I just can't wrap my head around the syntax.

So something kinda like:

session_start();

$queryString = $_SERVER['QUERY_STRING']; 
parse_str($queryString, $params);

if ($params !contain $action || $liked) {
     $referrer = 'page.php?' . $_SESSION['referrer_querystring'];
}

echo '<a href="' . $referrer . '">BACK</a>';

Saying if the referrer_querystring session doesn't contain an action or liked variable, then save the referrer, otherwise, don't save it. It's boggling my mind and I'm about to go on a rampage through the office. Can anyone help me break that down?

bradgrafelman

EDIT: On second thought, using [man]stripos/man isn't a very robust method since it could result in false positives. See NogDog's suggestion below.

NogDog

Something like this?

$params = parse_url($_SERVER['QUERY_STRING'], PHP_URL_QUERY);
if( ! isset($params['action']) or ! isset($params['liked'])) {

bradgrafelman

@: I believe your 'or' should be an 'and' to achieve the desired logic.

NogDog

bradgrafelman;11022769 wrote:
@: I believe your 'or' should be an 'and' to achieve the desired logic.

I could not determine for sure from the OP which logic was desired: do it if at least one of those is not set, or only if neither is set.

NogDog

Actually, I just realized I'm needlessly complicating things:

if( ! isset($_GET['action']) or ! isset($_GET['liked'])) {

...or am I missing something?

generic

NogDog;11022773 wrote:
Actually, I just realized I'm needlessly complicating things:
if( ! isset($_GET['action']) or ! isset($_GET['liked'])) {
...or am I missing something?

This is right, I'm more having issues with how to store it so I can put it into a back button format. Like, how do I get the last url and store it without overwriting it every time the page is loaded?

bradgrafelman

generic;11022775 wrote:
how do I get the last url

One simplified way:

$currentURL = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

EDIT: Just for clarity, that 'simplified' approach makes the following assumptions: HTTP protocol (version 1.1 OR version 1.0 with the 'Host' header properly specified), port 80.

generic

The problem is that the ?category variable I mentioned could be ?style, or ?id, or ?age, or ?gender, or ?q, or ?size. Those I want to track and be able to refer back to, just not action or liked. Those two are always appended after as a second parameter, so when I click back, it only goes back one parameter thereby making going back a two click (or more) action.

bradgrafelman

So... do you want to specifically save a given list of parameters, or do you simply want to save all except a given list of parameters?

generic

Either way would work. I know all the parameters being used, I'm just not sure what would be the best way to go about it.

The flow is something like: From the front page, you can search by category, gender, age, style, size or search_query. This displays an output from the database. When a specific item is selected, it calls up ?id=[product_id]. All is well, I can still go back no problem. Once in the product detail, they can add it (?id=[product_id]&action=add) or like it (?id=[product_id]&liked=1). This makes the back button require two clicks, one to get past the "like" and the other to get past the "id", back into the original output. OR if they're feeling sassy, they can like it AND add it, requiring three clicks. Hopefully that clarifies it a bit. The whole thing is confusing the hell out of me as it is haha

bradgrafelman

One way to do the latter approach I mentioned above might be:

$unwanted_params = [ 'param1', 'param2', 'param3' ];
$filtered_params = array_diff_key( $_GET, array_flip( $unwanted_params ) );
$query_string = "?" . http_build_query( $filtered_params );

generic

I gave it a try and it didn't like the square brackets. (unexpected "["...)

bradgrafelman

Guess I'm too used to using PHP 5.3 that I forget when those were introduced (or that not everyone has upgraded to the current branch of PHP, I suppose :p). Trade the square brackets for 'array(' and ')', respectively.

generic

Thanks so much for all the help so far, I really do appreciate your time! I'm still confused about how to store the last visited url and compare it against page.php'.$querystring.' to get back to the appropriate page in one mouse click. That's the part that's blowing my mind.