WordPress PHP Redirect with Regex Wildcard

Question

This is for a project. I need to redirect certain incoming URL requests to files hosted on the same webserver. I cannot use .htaccess and I cannot rely on any plugins.

I managed to do this with a plugin but I am having a hard time extracting the necessary code in order to write my own plugin which does what I need to do hardcoded.

WordPress Multisite
All software up to date
"Redirection" WordPress Plugin (sucessfully)
writing custom WP functions to do this (semi-successfully)

I found some code in the Pantheon documentation:

$blog_id = get_current_blog_id();

// You can easily put a list of many 301 url redirects in this format
// Trailing slashes matters here so /old-url1 is different from /old-url1/
$redirect_targets = array(
  '/test/test.xml' => '/files/' . $blog_id . '/test.xml',
  '/regex/wildcard.xml(.*)' => '/files/' . $blog_id . '/regex.xml',     
);

if ( (isset($redirect_targets[ $_SERVER['REQUEST_URI'] ] ) ) && (php_sapi_name() != "cli") ) {
  echo 'https://'. $_SERVER['HTTP_HOST'] . $redirect_targets[ $_SERVER['REQUEST_URI'] ];
  header('HTTP/1.0 301 Moved Permanently');
  header('Location: https://'. $_SERVER['HTTP_HOST'] . $redirect_targets[ $_SERVER['REQUEST_URI'] ]);

  if (extension_loaded('newrelic')) {
    newrelic_name_transaction("redirect");
  } 
  exit();
}

https://example.com/test/test.xml sucessfully

redirects to

/files/5/text.xml

However, some incoming requests contain a query string, e.g.

https://example.com/regex/wildcard.xml?somequerystring

obviously, the redirect from

https://example.com/regex/wildcard.xml

to

/files/5/regex.xml

works fine.

However, as soon as there is a query string involved, the redirect does not work. Given that I need to do this with PHP, how can I achieve a wildcard redirect from either /regex/* or /regex/wildcard.xml* to /files/5/regex.xml?

Any help would be greatly appeciated.

Thanks, Daniel

Try this article once https://stackoverflow.com/questions/768431/how-to-make-a-redirect-in-php — Harsh Khare, Feb 08 '19 at 09:35
Thanks! Unfortunately I don't think it really applies to my problem. Essentially, all I need is to find out how to phrase the wildcard in php: '/regex/wildcard.xml(.*)' => '/files/' . $blog_id . '/regex.xml', — Daniel Slyman, Feb 08 '19 at 09:42
If it's any help, this is how I managed to do it with the plugin: https://howarddc.com/understanding-redirection-regular-expressions/ "Creating wildcard redirects" — Daniel Slyman, Feb 08 '19 at 09:43
I wrote to them, so far no reply and just from the code I can't figure it out. — Daniel Slyman, Feb 08 '19 at 10:46
Do you want to redirect https://example.com/regex/wildcard.xml?somequerystring to https://example.com/files/5/regex.xml skipping the query string? — Djanym, Feb 08 '19 at 10:58

Djanym · Answer 1 · 2019-02-08T22:31:42.100

If you prefer to retain your code logic and just make the code work, then try this:

$blog_id = get_current_blog_id();
$redirect_targets = array(
    '/wordpress\/test\/test\.xml/i' => 'files/'.$blog_id.'/test.xml',
    '/([^\/]+)\/([^\/]+)\.xml.*/i' => 'files/'.$blog_id.'/$1.xml',
);

// Get reuest uri without GET attributes.
$request_uri = get_request_uri();

// Loop through redirect rules.
foreach ($redirect_targets as $pattern => $redirect) {
    // If matched a rule, then create a new redirect URL
    if ( preg_match( $pattern, $request_uri ) ) {
        $new_request_uri = preg_replace( $pattern, $redirect, $request_uri );
        $new_url = 'https://'.$_SERVER['HTTP_HOST'].$new_request_uri;
        header( 'HTTP/1.0 301 Moved Permanently' );
        header( 'Location: '.$new_url );

        if ( extension_loaded( 'newrelic' ) ) {
            newrelic_name_transaction( "redirect" );
        }
        exit();
    }
}

// Returns REQUEST URI without 'get' arguments
// if example.com/test/test.php?some=arg it will return test/test.php
function get_request_uri () {
    return strtok( $_SERVER['REQUEST_URI'], '?' );
}

You can modify redirect rule as you want. It works as a normal Regex pattern.

WordPress PHP Redirect with Regex Wildcard

1 Answers1