feedのキャッシュ

feed_cache_test.php

<?php
$cache_dir  = dirname( __FILE__ ) . DIRECTORY_SEPARATOR . 'cache' ;
if( realpath( $cache_dir ) === false ) {
  if( ! mkdir( $cache_dir, 0777 ) ) {
    exit( 'Error!' ) ;
  }
}
$cache_dir  = realpath( $cache_dir ) ;


$now      = time() ;
$lifetime = 3600 ;
$feeds[ 'kachibito' ] = 'http://kachibito.net/feed' ;

foreach( $feeds as $name => $feed ) {
  $file = $cache_dir . DIRECTORY_SEPARATOR . md5( $feed ) ;
  if( file_exists( $file ) && ( $now - $lifetime ) < filemtime( $file ) ) {
    $output[ $name ]  = file_get_contents( $file ) ;
    continue ;
  }
  $output[ $name ]  = file_get_contents( $feed ) ;
  if( $output[ $name ] !== false ) {
    file_put_contents( $file, $output[ $name ], LOCK_EX ) ;
    touch( $file, $now ) ;
  } else {
    $output[ $name ]  = 'フィード [ ' . $feed . ' ] は読み込めませんでした。' ;
  }
}

echo  htmlentities( $output[ 'kachibito' ], ENT_QUOTES, 'UTF-8' ) ;