Making a dynamic query based on a cookie change

Question

I have a PHP function which sets/unsets something (category and tags) in the cookie and then makes a dynamic query based on it:

public function tagged(){
 $this->specific_tag = true;
 function unset_cookie($cookie_name) {
 setcookie($cookie_name, "", time() - 3600, '/');
 unset($_COOKIE[$cookie_name]);
 }
 function set_cookie($cookie_name, $cookie_value) {
 setcookie($cookie_name, $cookie_value, 2147483647, '/');
 $_COOKIE[$cookie_name] = $cookie_value;
 }
 if ( isset($_GET['c']) ) {
 if ( empty($_GET['c']) ) {
 unset_cookie('qanda_questions_category');
 } else {
 set_cookie('qanda_questions_category', $_GET['c']);
 }
 }
 if ( isset($_GET['t']) ) {
 if ( empty($_GET['t']) ) {
 unset_cookie('qanda_questions_tag');
 } else {
 set_cookie('qanda_questions_tag', $_GET['t']);
 }
 }
 $this->consider_category_tag_cookies();
 if ( $this->category_cookie || $this->tag_cookie ) {
 $query_where = $query_join = '';
 if ( $this->category_cookie ) {
 $query_where .= "AND qa.category = :c";
 $this->parameters[":c"] = $_COOKIE['qanda_questions_category'];
 }
 if ( $this->tag_cookie ) {
 $query_join .= " INNER JOIN qanda_tags qt ON qt.qanda_id = qa.id
 INNER JOIN tags ON tags.id = qt.tag_id";
 $query_where .= " AND tags.name = :t";
 $this->parameters[":t"] = $_COOKIE['qanda_questions_tag'];
 }
 return $this->index($query_where, $query_join, __FUNCTION__);
 } else {
 return header("Location: /myweb/questions".make_url_query($_GET, [],['c','t']));
 }
}

I've tried so much to write it clean and functional, but it contains lots of if statements. It bothers me and I think it should be possible to reduce some of them. Do you have any idea?

Do I need to add more function to the code? Or should I chop the code into multiple separated functions? Anyway, how can I write it more cleanly?

Answer 1

First suggestion is that you shouldn't write the same code twice.

Your $_GET-if-conditions can be put into a separate function.

$this->handleCookieByGetParameter('c', 'qanda_questions_category');
$this->handleCookieByGetParameter('t', 'qanda_questions_tag');
public function handleCookieByGetParameter($parameter, $name)
{
 if ( isset($_GET[$parameter]) ) {
 if ( empty($_GET[$parameter]) ) {
 unset_cookie($name);
 } else {
 set_cookie($name, $_GET[$parameter]);
 }
 }
}

and then I recommend that you check your error before you handle your other stuff:

if ( !$this->category_cookie && !$this->tag_cookie ) {
 return header("Location: /myweb/questions".make_url_query($_GET, [],['c','t']));
 // better an RedirectException
}
$query_where = $query_join = '';
if ( $this->category_cookie ) {
 $query_where .= "AND qa.category = :c";
 $this->parameters[":c"] = $_COOKIE['qanda_questions_category'];
}
if ( $this->tag_cookie ) {
 $query_join .= " INNER JOIN qanda_tags qt ON qt.qanda_id = qa.id
 INNER JOIN tags ON tags.id = qt.tag_id";
 $query_where .= " AND tags.name = :t";
 $this->parameters[":t"] = $_COOKIE['qanda_questions_tag'];
}
return $this->index($query_where, $query_join, __FUNCTION__);

my next step would be to look to extract the query code into a separate function, so I could use it for other methods too.