Support with rewrite URL in patterns - .htaccess

Question

I have this URL format:
https://www.example.com/shows/my_personal_show_2.0_34565.htm
Where the tailing number is the database reference, I need to rewrite it to:
https://www.example.com/shows/my-personal-show-2.0-my-personal-show.htm
We have thousands of indexed URLs by Google and need it to be rewritten via in .htaccess rules with 301 redirect to make it more SEO friendly without harming the SERP very much.
Thanks in advance.

Answer 1

Take SO as an example, the URL has this format:
https://stackoverflow.com/questions/48077576/support-with-rewrite-url-in-patterns
To make a SEO friendly URL, you can rewrite the URL to:
https://www.example.com/shows/34565/my-personal-show-2.0
To start, you can write your own router and map the above URL to the actual existing file:
.htacccess
RewriteRule ^shows/([0-9]+)/(.+)$ /router.php?id=$1&slug=$2 [QSA,L]
$1 is the back-reference to the regex part ([0-9]+) and $2 is the back-reference to the regex part (.+).
For the router.php, you can check if the given id and slug map to the existing htm file.
router.php
if (isset($_GET['id']) && isset($_GET['slug'])) {
$file_path = 'shows/' . str_replace('-', '_', $_GET['slug']) . '_' . $_GET['id'] . '.htm';
if (file_exists($file_path)) {
readfile($file_path);
}
else {
header("HTTP/1.0 404 Not Found");
}
exit;
}
The last thing is that you should make a permanently redirect of the SEO unfriendly URL to SEO friendly URL.
.htaccess
RewriteCond %{REQUEST_FILENAME} -f
RewriteCond %{REQUEST_URI} ^/shows/(.+)\_([0-9]+)\.htm$
RewriteRule ^ /redirect.php?id=%2&slug=%1 [QSA,L]
redirect.php
if (isset($_GET['id']) && isset($_GET['slug'])) {
$redirectURL = '/shows/' . intval($_GET['id']) . '/' . str_replace('_', '-', $_GET['slug']);
header('location: ' . $redirectURL, true, 301);
exit;
}