SilverStripe unique URL (debug) - php

Question

In this DataObject there is a user supplied field Title which has to be converted to a unique URL slug.
Desired Result: Duplicate URL's should get a suffix to its value. So saving 2 records with Title Foo should result in one record with foo as its value for column URL and the second record should have value foo-2 for the same column.
public function onBeforeWrite() {
parent::onBeforeWrite();
// Sanitize Title field to use for URL
$filter = URLSegmentFilter::create();
$this->URL = $filter->filter($this->Title);
// If URL is not unique, add suffix
$i = 1;
while($this->uniqueURL($this->URL)) {
$i++;
$this->URL = $this->URL . "-" . $i;
}
}
method: uniqueURL (within same class)
public function uniqueURL($URL) {
// Check if there is a record with the same URL
$existingURL = DataObject::get('NewsArticle', "URL = '$URL'");
if ($existingURL) {
// this is a duplicate URL
return false;
} else {
// this is a unique url
return true;
}
}
Saving Foo twice would result in foo and foo-2.
When saving two records with the same Title Foo results in two URL fields with foo

Answer 1

Why do you have two foo urls?
If you check your DB before inserting all records, this means that the check will not work on your record batch.
Don't use a loop to count unique urls
You don't need to loop and check every time and increment the count ($i). Performance wise youre far better off doing a COUNT() in a query and just use that value for your next insert.
// The following does exactly the same with just 1 query. No loop needed.
$count = DB::query("SELECT COUNT(*) FROM Table WHERE Title LIKE '{$filteredTitle}'")->value();
if ($count > 1) {
$filteredTitle .= "-" . $count;
}
$this->URL = $filteredTitle
Solutions
To do it onBeforeWrite() the only possibility is to Query your data AND check your records before they are saved.
Or a simpler solution with the same results is that you can change the url in an onAfterWrite() , and check use the amount of same titles as number.
public function onAfterWrite() {
parent::onAfterWrite();
// Sanitize Title field to use for URL
$filter = URLSegmentFilter::create();
$filteredTitle= $filter->filter($this->Title);
$count = DB::query("SELECT COUNT(*) FROM Table WHERE Title LIKE '{$filteredTitle}'")->value();
if ($count > 1) {
$filteredTitle .= "-" . $count;
}
$this->URL = $filteredTitle
}