PHP - existing string value not found in $_SESSION array - php

Question

I asked this question before, but it got no responses, so I deleted the last question, and simplified/clarified the question, and am reposting
I have a comics site... I'm working on a SO-style tagging system. A user can select 1 or many tags which will display all associated comics.
To remember the user selections, I'm storing them in a $_SESSION array.
The issue I'm having is that one of the strings, 'business', being stored in the $_SESSION['tagnames'] array after it is chosen by the user is not being found in the array...
The way it's supposed to work is a user selects a tag, and to deselect it, they click it again... so I check if the string is in the $_SESSION... if it is, unset it... here is a snippet:
//var_dump shows these are both set fine when a user clicks on the tag they want
$tagid = (isset($_GET['tagid']) ? ($_GET['tagid']) : null);
$tagname = (isset($_GET['tagname']) ? ($_GET['tagname']) : null);
...
//Tag IDS are added and removed without issue:
//if tag id exists in $_SESSION['tags'] array, remove it
if ($key = array_search($tagid, $_SESSION['tagids'])) {
unset($_SESSION['tagids'][$key]);
}
else {
$_SESSION['tagids'][] = $tagid;
}
...
//but one of the tag names, 'business', is not being removed... and is actually added again even when I press F5 to refresh
if ($key = array_search($tagname, $_SESSION['tagname'])) {
unset($_SESSION['tagname'][$key]);
}
else {
$_SESSION['tagname'][] = $tagname;
}
This is a var_dump of the sql statement: It correctly shows the query being changed based on which tag id is selected.
Here's a var_dump of the $_SESSION['tagname']... you can see that it recognizes when tags 2 and 3 (differences and similarities) have already been added (I used array_search() to check), but it doesn't find tagid 1, 'business', even though it's clearly been added several times.
Here's the function that returns the selected tag names to the user:
function getSelectedTags() {
global $tagid, $tagname;
if ($key = array_search($tagname, $_SESSION['tagname'])) {
unset($_SESSION['tagname'][$key]);
}
else {
$_SESSION['tagname'][] = $tagname;
}
var_dump($_SESSION['tagname']);
foreach ($_SESSION['tagname'] as $tagname) {
echo '<span class="tags">' . $tagname . '</span>';
}
}
Any thoughts why tagname 'business' is the only thing causing an issue?
Even after I destroy the session, pressing F5 to refresh will automatically put tagname 'business' into the $_SESSION['tagname'] array.
EDIT: More comprehensive code:
Homepage.php: user clicks on returned tags from getDBTags() to add a tag to the $_SESSION array on imageDisplay.php
<h5>Tags</h5>
<?php echo getDBTags(); ?>
<br/>
<p>Your tags:</p>
<?php echo getSelectedTags(); ?>
imageDisplay.php: responsible for handling how images are filtered and displayed...
getDBTags() returns tag choices from the database so users can click on them:
function getDBTags() {
include 'dbconnect.php';
global $cat;
$sql = "SELECT tagid, tagname FROM tags";
$query = $mysqli->query($sql);
while ($row = $query->fetch_assoc()) {
echo '<span class="tags">'.$row['tagname'].'</span>';
}
mysqli_close($mysqli);
}
getFilters() decides how images should be filtered by having a dynamic query, then sends the query to pagination(), which displays filtered images on pages.
function getFilters() {
include 'dbconnect.php';
global $cat, $site, $table, $tagid;
$order = " ORDER BY date DESC";
//if tag id exists in $_SESSION['tags'] array, remove it
if ($key = array_search($tagid, $_SESSION['tagids'])) {
unset($_SESSION['tagids'][$key]);
}
//if it doesn't, add it
else {
$_SESSION['tagids'][] = $tagid;
}
//var_dump($_SESSION['tagids']);
if ($cat != null) $catquery = " AND catidFK = $cat";
else $catquery = null;
$sql =
"SELECT c.*, t.*
FROM comics c
INNER JOIN comictags ct ON (c.id = ct.comicID)
INNER JOIN tags t ON (t.tagid = ct.tagID)
WHERE ct.tagID IN ('" . implode(', ', $_SESSION['tagids']). "')
". $catquery ." " . $order;
if (!$mysqli->query($sql)) printf("<br /><b>Error:</b> %s\n", $mysqli->error);
$query = $mysqli->query($sql);
var_dump($sql);
mysqli_close($mysqli);
return $query;
}
getSelectedTags() returns the selected tag title back to the user so they can see what they've chosen. If they click on a tag again (returned from getDBTags() above), it will remove the tag from $_SESSION['tagname']. This is the problem area:
function getSelectedTags() {
global $tagid, $tagname;
if ($key = array_search($tagname, $_SESSION['tagname'])) {
unset($_SESSION['tagname'][$key]);
}
else {
$_SESSION['tagname'][] = $tagname;
}
//var_dump($key = array_search($tagname, $_SESSION['tagname']));
var_dump($_SESSION['tagname']);
foreach ($_SESSION['tagname'] as $tagname) {
echo '<span class="tags">' . $tagname . '</span>';
}
}

Answer 1

There are three issues which stand out (well two stand out, one is very subtle).
1. Open only one DB connection and leave it:
First, instead of opening and closing the connection in $mysqli in your functions, do it once at the start of the script and leave it open. You'll need to modify your functions to accept $mysqli as a parameter (preferred) or access it via global $mysqli; (not preferred). There is no need to call mysqli_close(), as that is done implicitly.
In your getFilters() function, you are actually closing the MySQLi resource $mysqli and then attempting to return $query; where $query is a result resource. Doing that will render the result resource useless.
// Pass $mysqli as a parameter
function getFilters($mysqli) {
//...
// Do alll your stuff...
// And do not call mysqli_close()!
return $query
}
2. Use strict comparison and test for FALSE with array_search():
When using array_search(), if your result is the first element in the array at key [0], that will be regarded by a surrounding if () condition as a falsy return rather than the positive result it should be. For that reason, a tag at position [0] will get repeatedly added rather than removed. This will need to be fixed in a couple of places...
// First get the key, which is an int or FALSE
$key = array_search($tagid, $_SESSION['tagids']);
// Unset if it is FALSE by strict comparison
if ($key !== FALSE) {
unset($_SESSION['tagids'][$key]);
}
else {
$_SESSION['tagids'][] = $tagid;
}
3. Global variable $tagname is ruined by a foreach:
You have accessed the global $tagname in getSelectedTags(). But in that function you have a foreach loop which does :
foreach ($_SESSION['tagname'] as $tagname)
When using $tagname as the loop's variable there, it is actually overwriting the global $tagname on each iteration. You need to change that to a different value, or whenever you call getSelectedTags(), $tagname the global will become whatever the last tag in $_SESSION['tagname'] had been, without exception.
// use a different varname in the loop
foreach ($_SESSION['tagname'] as $tn) {
// Also calling htmlspecialchars to escape here. Do this in any variable to HTML output...
echo '<span class="tags">' . htmlspecialchars($tn) . '</span>';
}