在阅读了这个问题之后，我决定完全采用另一种方法，并挂接到过滤器中，而不是使用insert\\u with\\u markers（）

如果其他人想要的功能。htaccess代码插入，从核心WordPress文件复制WordPress功能：wp admin/includes/misc。php：

第109行：函数insert\\u with\\u markers（$filename，$marker，$insertion）{

以下功能仅供参考：

if ( ! function_exists( \'insert_with_markers\' ) ) {
    function insert_with_markers( $filename, $marker, $insertion ) {
    if ( ! file_exists( $filename ) ) {
        if ( ! is_writable( dirname( $filename ) ) ) {
            return false;
        }

        if ( ! touch( $filename ) ) {
            return false;
        }

        // Make sure the file is created with a minimum set of permissions.
        $perms = fileperms( $filename );
        if ( $perms ) {
            chmod( $filename, $perms | 0644 );
        }
    } elseif ( ! is_writeable( $filename ) ) {
        return false;
    }

    if ( ! is_array( $insertion ) ) {
        $insertion = explode( "\\n", $insertion );
    }

    $switched_locale = switch_to_locale( get_locale() );

    $instructions = sprintf(
        /* translators: 1: Marker. */
        __(
            \'The directives (lines) between `BEGIN %1$s` and `END %1$s` are
dynamically generated, and should only be modified via WordPress filters.
Any changes to the directives between these markers will be overwritten.\'
        ),
        $marker
    );

    $instructions = explode( "\\n", $instructions );
    foreach ( $instructions as $line => $text ) {
        $instructions[ $line ] = \'# \' . $text;
    }

    /**
     * Filters the inline instructions inserted before the dynamically generated content.
     *
     * @since 5.3.0
     *
     * @param string[] $instructions Array of lines with inline instructions.
     * @param string   $marker       The marker being inserted.
     */
    $instructions = apply_filters( \'insert_with_markers_inline_instructions\', $instructions, $marker );

    if ( $switched_locale ) {
        restore_previous_locale();
    }

    $insertion = array_merge( $instructions, $insertion );

    $start_marker = "# BEGIN {$marker}";
    $end_marker   = "# END {$marker}";

    $fp = fopen( $filename, \'r+\' );
    if ( ! $fp ) {
        return false;
    }

    // Attempt to get a lock. If the filesystem supports locking, this will block until the lock is acquired.
    flock( $fp, LOCK_EX );

    $lines = array();
    while ( ! feof( $fp ) ) {
        $lines[] = rtrim( fgets( $fp ), "\\r\\n" );
    }

    // Split out the existing file into the preceding lines, and those that appear after the marker.
    $pre_lines        = array();
    $post_lines       = array();
    $existing_lines   = array();
    $found_marker     = false;
    $found_end_marker = false;
    foreach ( $lines as $line ) {
        if ( ! $found_marker && false !== strpos( $line, $start_marker ) ) {
            $found_marker = true;
            continue;
        } elseif ( ! $found_end_marker && false !== strpos( $line, $end_marker ) ) {
            $found_end_marker = true;
            continue;
        }
        if ( ! $found_marker ) {
            $pre_lines[] = $line;
        } elseif ( $found_marker && $found_end_marker ) {
            $post_lines[] = $line;
        } else {
            $existing_lines[] = $line;
        }
    }

    // Check to see if there was a change.
    if ( $existing_lines === $insertion ) {
        flock( $fp, LOCK_UN );
        fclose( $fp );

        return true;
    }

    // Generate the new file data.
    $new_file_data = implode(
        "\\n",
        array_merge(
            $pre_lines,
            array( $start_marker ),
            $insertion,
            array( $end_marker ),
            $post_lines
        )
    );

    // Write to the start of the file, and truncate it to that length.
    fseek( $fp, 0 );
    $bytes = fwrite( $fp, $new_file_data );
    if ( $bytes ) {
        ftruncate( $fp, ftell( $fp ) );
    }
    fflush( $fp );
    flock( $fp, LOCK_UN );
    fclose( $fp );

    return (bool) $bytes;
}
}

      if (is_file(ABSPATH . \'.htaccess\')) {
                $htaccess = ABSPATH . \'.htaccess\';
                $lines = array();


                $Rulesstring = \'
                <filesMatch ".(ico|pdf|flv|jpg|jpeg|png|gif|svg|js|css|swf)$">
                Header set Cache-Control "max-age=31536000, public"
                </filesMatch>
                \';

                $lines = explode( "\\n", $Rulesstring );

                insert_with_markers($htaccess, "HelloFood", $lines);
      }