Recursive array search - keep proper order and iterate down array - php

Question

When accessing the script I am writing, you pass the category path to it when accessing the page. The script then compares the data to an array of actual categories, or a branch, that should be associated with that category.
I am setting the parents and all of its children into a tree and then going down the branch and comparing the data to ensure the customer is using a correct url. Here's a quick example of how the code works:
// Customer is accessing from site.com/store/some-cat/some-othercat
// We pass those variables with the htaccess to script.php?var=$1,$2
// We then explode that to make an array on $var[0] and $var[1]
$categoryMap = explode(",", $_GET['var']);
$categoryID = array();
$categoryInfoMap = array();
foreach ($categoryMap as $a) {
$categoryIDs[] = trim($a);
}
$getCategoryInfo = $db->fn->query("SELECT * FROM store_category");
....
// Inside while loop...
$categoryInfoMap[] = $db->result[]; // stored whole results as array
// End of the while loop
$masterKey = $mainClass->findKeyInDbArray($categoryInfoMap, 'c.path', $categoryMap[0]);
if ((isset($masterKey) && $masterKey === "0") || !empty($masterKey)) {
$thisId = $categoryInfoMap[$masterKey]['c.id'];
$thisPath = $categoryInfoMap[$masterKey]['c.path'];
$thisName = $categoryInfoMap[$masterKey]['c.name'];
$tree = $mainClass->buildTree($categoryInfoMap);
$children = $tree['children'][$thisId];
$childrenItems = "";
foreach ($categoryIDs as $cid) {
// One of the categories entered doesnt exist at all so we redirect,
// else we will go through them and make sure theyre apart of the branch
if (!$mainClass->recursive_array_search($cid, $tree)) {
... redirect them somewhere and die()
} else {
if (!$mainClass->recursive_array_search($cid, $children)) {
... redirect them somewhere and die()
} else {
!!!!!!!!!!!!============!!!!!!!!!!!!!!
THIS IS THE IMPORTANT PART HERE
!!!!!!!!!!!!============!!!!!!!!!!!!!!
}
}
}
}
... Rest of the script which works for now
Here is the functions used in the code above
public function findKeyInDbArray($products, $field, $value) {
foreach($products as $key => $product) {
if ($product[$field] === $value) {
return "$key";
}
}
return NULL;
}
public function buildTree($arr) {
$tree = array(
'children' => array()
);
$index = array(0=>&$tree);
foreach ($arr as $key => $val) {
$parent = &$index[$val['c.parentcatid']];
$node = $val;
$parent['children'][$val['c.id']] = $node;
$index[$val['c.id']] = &$parent['children'][$val['c.id']];
}
return $tree;
}
public function recursive_array_search($needle,$haystack) {
foreach($haystack as $key=>$value) {
$current_key=$key;
if($needle===$value OR (is_array($value) && $this->recursive_array_search($needle,$value) !== false)) {
return $current_key;
}
}
return false;
}
And here's an example of the tree array, from the parent node down. Shorted for visibility reasons
Array(
[c.id] => 1
[c.name] => Radios
[c.path] => radios
[c.parentcatid] => 0
[children] => (
[2] => (
[0] => 2
....
[children] => (
[3] => (
[c.id] => 3
....
[c.parentcatid] => 2
),
[4] => (
[c.id] => 4
....
[c.parentcatid] => 2
)
)
)
......
[10] => (
[0] => 10
....
[c.parentcatid] => 1
)
)
SO onto the good bits
Right now the code is working to prove that the branches have matching variables from their tree. If the item path, which is the variable we are using to compare to the url $var matches, then it will continue and work. so if in the branch the following values exist:
array(c.path => 'foo'),
array(c.path => 'bar')
And I visit the script as site.com/store/foo/bar then everything works great. If i visit the site as site.com/store/foo/notBar then it will fail, as the notBar variable is not a member of this branch. That's perfect right? Everything should work! Except it doesn't and for a good reason.
The issue here
If the item matches in the branch then it has passed the check and it's the end of the check. Not if the item is passed in the wrong order, such as site.com/store/bar/foo, then it still technically has good variables in it, but it should NOT pass since the structure is not in the order its coming down the parent array. Likewise, if another branch farther up the tree, lets say barwithNoChildren exists, i can swap foo or bar out with it and still pass, even though nothing should be there.
Hopefully you guy understand what I am asking, and can help suggest ways around this. I've been wracking my brain on this system for the last couple of days and since they want fancy urls for seo and other reasons, it's been a lot more difficult than I planned. Thanks for any suggestions!

Answer 1

A tree structure is not really helpful for this purpose. You should be thinking about how to create a data structure that makes it easy for you to match the input. Since your category input describes a branch of the tree, the best thing to do is build an array that you can use to match those branch descriptions to your categories efficiently.
Let's build an array where the keys are the paths for each category as described by their slugs, and the values are the category IDs. We can then immediately identify the matching category, or fail if the path is not in the array.
This breadcrumb-like structure is another pattern that is commonly used with categories. Along with the tree and flat id map, you can do pretty much anything you need. The key takeaway is to think about creating different structures with your data to accomplish different tasks. It's usually more efficient and less error prone to create a new structure that's easy to work with than it is to create complex logic to try and work with an existing structure that doesn't lend itself to the task at hand.
<?php
//Mock category records, would come from the DB in the real world
$categoryRecords = [
['id' => 1, 'title' => 'Radios', 'slug' => 'radios', 'parent_id' => 0],
['id' => 2, 'title' => 'Accessories', 'slug' => 'misc', 'parent_id' => 1],
['id' => 3, 'title' => 'Motorola', 'slug' => 'motorola', 'parent_id' => 1],
['id' => 4, 'title' => 'Handheld', 'slug' => 'handheld', 'parent_id' => 3],
['id' => 5, 'title' => 'Mobile', 'slug' => 'mobile', 'parent_id' => 3]
];
//Create an array that maps parent IDs to primary keys
$idMap = [];
foreach ($categoryRecords as $currRecord)
{
$idMap[$currRecord['id']] = $currRecord;
}
//Traverse the flat array and build the path lines
$paths = [];
$categoryIds = array_keys($idMap);
foreach ($categoryIds as $currLeafId)
{
$currCategoryId = $currLeafId;
$currLine = [];
do
{
$currLine[] = $idMap[$currCategoryId]['slug'];
$currCategoryId = $idMap[$currCategoryId]['parent_id'];
} while ($currCategoryId != 0);
$currLine = array_reverse($currLine);
$currPath = implode('/', $currLine);
$paths[$currPath] = $currLeafId;
}
//Join your input - $_GET['var'] in your example
$inputPath = implode('/', ['radios', 'motorola', 'handheld']);
//Now you can see if the incoming path matched a category
if(array_key_exists($inputPath, $paths))
{
$category = $categoryRecords[$paths[$inputPath]];
echo 'Matched category: '.$category['title'].PHP_EOL;
}
else
{
echo 'Invalid category path';
}