fix(media): prevent getimagesize loopback deadlocks on missing images

[faisalahammad]

Summary

Fix getimagesize() LSAPI deadlocks on missing image URLs. When image URLs belong to internal site or CDN host but the file is missing locally, prevent getimagesize() from making self-referencing HTTP loopback requests back to OpenLiteSpeed web server.

Fixes #894

Changes

Media (src/media.cls.php)

Before:

private function _detect_dimensions( $src ) {
    $pathinfo = Utility::is_internal_file( $src );
    if ( $pathinfo ) {
        $src = $pathinfo[0];
    } elseif ( apply_filters( 'litespeed_media_ignore_remote_missing_sizes', false ) ) {
        return false;
    }
    // ...
    $sizes = getimagesize( $src );

After:

private function _detect_dimensions( $src ) {
    $pathinfo = Utility::is_internal_file( $src );
    if ( $pathinfo ) {
        $src = $pathinfo[0];
    } elseif ( Utility::is_internal_url( $src ) || apply_filters( 'litespeed_media_ignore_remote_missing_sizes', false ) ) {
        return false;
    }
    // ...
    $sizes = getimagesize( $src );

Why: If is_internal_file() returns false on an internal URL because the image is missing on disk, checking Utility::is_internal_url( $src ) returns false early. This skips getimagesize() so PHP workers do not make HTTP loopback GET calls to the same web server.

Utility (src/utility.cls.php)

Before:

// Only is_internal_file existed, which requires file to exist on local disk

After:

public static function is_internal_url( $url ) {
    if ( 'data:' === substr( $url, 0, 5 ) ) {
        return false;
    }

    $url_parsed = wp_parse_url( $url );
    if ( empty( $url_parsed['host'] ) ) {
        return true;
    }

    if ( self::internal( $url_parsed['host'] ) || CDN::internal( $url_parsed['host'] ) ) {
        return true;
    }

    return false;
}

Why: Checks if a URL host matches the internal site or internal CDN domain without checking file existence on disk.

Testing

Test 1: Missing Local Image URL

1. Enable Add Missing Sizes in Media optimization settings.
2. Load page containing an image tag with a missing local uploads URL.
   Result: Page loads immediately without delays or PHP getimagesize warnings in error log.

Test 2: Valid Local Image

1. Load page with an existing upload image without width/height attributes.
   Result: Width and height dimensions are calculated and injected from local filesystem path as expected.

[hi-hai]

Please use dev branch as base.

[timotei-litespeed]

@faisalahammad please make sure there is 1 bug fix per PR.
Thank you

[faisalahammad]

Rebased on dev branch with single commit for issue #894 fix. Thank you!

[timotei-litespeed]

@faisalahammad there are some conflicts to solve

[faisalahammad]

I have rebased the branch cleanly on dev branch with 1 commit. The merge conflicts are resolved.

[timotei-litespeed]

@faisalahammad thank you! :)
I will look over the change on Monday

[faisalahammad]

Addressed reviewer feedback in b80438c:\n\n- The deadlock fix is the internal site/CDN host check before getimagesize(); is_internal_file() alone returns false when the internal file is missing, which is the deadlock case.\n- Removed the new public Utility::is_internal_url() method. Host matching now reuses Utility::internal() and CDN::internal() through a private Media helper.\n- Retained the \Throwable catch because PHP 8 can raise ValueError for an empty filename.\n\nManual testing confirmed. No inline review threads were available through the GitHub API, so this is posted as the PR-level response.