Compressing HTML in PHP (no comments or whitespace)

Note: if you’re a web developer you might be interested in registering to become a ProgClub member. ProgClub is a free international club for computer programmers and we run some mailing lists you might like to hang out on to chat about software development, life, etc.

In addition to compressing CSS in PHP I’ve been compressing HTML. My HTML compressor is a bit of a hack. It doesn’t handle CDATA sections for instance. But it should generally work OK. Here it is:

function slib_compress_html( $buffer ) {
  $replace = array(
    "#<!--.*?-->#s" => "",      // strip comments
    "#>\s+<#"       => ">\n<",  // strip excess whitespace
    "#\n\s+<#"      => "\n<"    // strip excess whitespace
  $search = array_keys( $replace );
  $html = preg_replace( $search, $replace, $buffer );
  return trim( $html );

I use this function to compress HTML generated by my PHP scripts by putting ob_start( ‘slib_compress_html’ ) at the beginning of my script (after the ob_gzhandler) and ob_end_flush() at the end. My HTML compression code looks like this:

    if ( extension_loaded( 'zlib' ) ) { ob_start( 'ob_gzhandler' ); }
    ob_start( 'slib_compress_html' );

    run_app( $app_factory );

    if ( extension_loaded( 'zlib' ) ) { ob_end_flush(); }

Leave a Reply