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<?php
// $Id$
/**
* @file
* Far Future expiration setting for basic mode.
*/
//----------------------------------------------------------------------------
// Menu system callbacks.
function cdn_basic_farfuture_download() {
$args = func_get_args();
// The first argument is the file's mtime. We don't need this anymore.
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// Reconstruct the path of the requested file.
$path = implode('/', $args);
// Disallow downloading of files that are also not allowed to be downloaded
// by Drupal's .htaccess file.
if (preg_match("/\.(engine|inc|info|install|make|module|profile|test|po|sh|.*sql|theme|tpl(\.php)?|xtmpl)$|^(\..*|Entries.*|Repository|Root|Tag|Template)$/", $path)) {
drupal_access_denied();
exit();
}
if (!file_exists($path)) {
/*
// If the file does not yet exist, try if it should be generated first.
if ($router_item = menu_get_item($path)) {
if ($router_item['access']) {
if ($router_item['file']) {
require_once($router_item['file']);
}
call_user_func_array($router_item['page_callback'], $router_item['page_arguments']);
}
}
*/
if (!file_exists($path)) {
drupal_not_found();
exit();
}
}
// Remove some useless/unwanted headers.
$remove_headers = explode("\n", CDN_BASIC_FARFUTURE_REMOVE_HEADERS);
$current_headers = array();
foreach (headers_list() as $header) {
$parts = explode(':', $header);
$current_headers[] = $parts[0];
}
foreach ($remove_headers as $header) {
if (in_array($header, $current_headers)) {
// header_remove() only exists in PHP >=5.3
if (function_exists('header_remove')) {
header_remove($header);
}
else {
// In PHP <5.3, we cannot remove headers. At least shorten them to save
// every byte possible and to stop leaking information needlessly.
drupal_set_header($header . ':');
}
}
}
// Remove all previously set Cache-Control headers, because we're going to
// override it. Since multiple Cache-Control headers might have been set,
// simply setting a new, overriding header isn't enough: that would only
// override the *last* Cache-Control header. Yay for PHP!
if (function_exists('header_remove')) {
header_remove('Cache-Control');
}
else {
drupal_set_header("Cache-Control:");
drupal_set_header("Cache-Control:");
}
// Default caching rules: no caching/immediate expiration.
drupal_set_header("Cache-Control: private, must-revalidate, proxy-revalidate");
drupal_set_header("Expires: " . gmdate("D, d M Y H:i:s", time() - 86400) . "GMT");
// Instead of being powered by PHP, tell the world this resource was powered
// by the CDN module!
drupal_set_header("X-Powered-By: Drupal CDN module");
// Instruct intermediate HTTP caches to store both a compressed (gzipped)
// and uncompressed version of the resource.
drupal_set_header("Vary: Accept-Encoding");
// Determine the content type.
drupal_set_header("Content-Type: " . _cdn_basic_farfuture_get_mimetype(basename($path)));
// Support partial content requests.
drupal_set_header("Accept-Ranges: bytes");
Ivo Van Geertruyen
committed
// Browsers that implement the W3C Access Control specification might refuse
// to use certain resources such as fonts if those resources violate the
// same-origin policy. Send a header to explicitly allow cross-domain use of
// those resources. (This is called Cross-Origin Resource Sharing, or CORS.)
drupal_set_header("Access-Control-Allow-Origin: *");
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// If the extension of the file that's being served is one of the far future
// extensions (by default: images, fonts and flash content), then cache it
// in the far future.
$farfuture_extensions = variable_get(CDN_BASIC_FARFUTURE_EXTENSIONS_VARIABLE, CDN_BASIC_FARFUTURE_EXTENSIONS_DEFAULT);
$extension = strtolower(pathinfo($path, PATHINFO_EXTENSION));
if (in_array($extension, explode("\n", $farfuture_extensions))) {
// Remove all previously set Cache-Control headers, because we're going to
// override it. Since multiple Cache-Control headers might have been set,
// simply setting a new, overriding header isn't enough: that would only
// override the *last* Cache-Control header. Yay for PHP!
if (function_exists('header_remove')) {
header_remove('Cache-Control');
}
else {
drupal_set_header("Cache-Control:");
drupal_set_header("Cache-Control:");
}
// Set a far future Cache-Control header (480 weeks), which prevents
// intermediate caches from transforming the data and allows any
// intermediate cache to cache it, since it's marked as a public resource.
drupal_set_header("Cache-Control: max-age=290304000, no-transform, public");
// Set a far future Expires header. The maximum UNIX timestamp is somewhere
// in 2038. Set it to a date in 2037, just to be safe.
drupal_set_header("Expires: Tue, 20 Jan 2037 04:20:42 GMT");
// Pretend the file was last modified a long time ago in the past, this will
// prevent browsers that don't support Cache-Control nor Expires headers to
// still request a new version too soon (these browsers calculate a
// heuristic to determine when to request a new version, based on the last
// time the resource has been modified).
// Also see http://code.google.com/speed/page-speed/docs/caching.html.
drupal_set_header("Last-Modified: Wed, 20 Jan 1988 04:20:42 GMT");
}
// GET requests with an "Accept-Encoding" header that lists "gzip".
if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE) {
// Only send gzipped files for some file extensions (it doesn't make sense
// to gzip images, for example).
if (in_array($extension, explode("\n", CDN_BASIC_FARFUTURE_GZIP_EXTENSIONS))) {
// Ensure a gzipped version of the file is stored on disk, instead of
// gzipping the file on every request.
$gzip_path = file_directory_path() . '/' . CDN_BASIC_FARFUTURE_GZIP_DIRECTORY . "/$path.$ufi.gz";
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if (!file_exists($gzip_path)) {
_cdn_basic_farfuture_create_directory_structure(dirname($gzip_path));
file_put_contents($gzip_path, gzencode(file_get_contents($path), 9));
}
// Make sure zlib.output_compression does not gzip our gzipped output.
ini_set('zlib.output_compression', '0');
// Prepare for gzipped output.
drupal_set_header("Content-Encoding: gzip");
$path = $gzip_path;
}
}
// Conditional GET requests (i.e. with If-Modified-Since header).
if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
// All files served by this function are designed to expire in the far
// future. Hence we can simply always tell the client the requested file
// was not modified.
drupal_set_header("HTTP/1.1 304 Not Modified");
}
// "Normal" GET requests.
else {
_cdn_transfer_file($path);
}
exit();
}
//----------------------------------------------------------------------------
// Public functions.
/**
* Gets the servers on which a file is available when basic mode is enabled.
*
* @param $path
* The path to get the servers for.
*/
function cdn_basic_farfuture_get_identifier($path) {
static $mapping;
static $ufi_info;
$servers = array();
// Gather all unique file identifier info.
if (!isset($ufi_info)) {
$ufi_info = module_invoke_all('cdn_unique_file_identifier_info');
}
// We only need to parse the textual CDN mapping once into a lookup table.
if (!isset($mapping)) {
$mapping = _cdn_basic_farfuture_parse_raw_mapping(variable_get(CDN_BASIC_FARFUTURE_UNIQUE_IDENTIFIER_MAPPING_VARIABLE, CDN_BASIC_FARFUTURE_UNIQUE_IDENTIFIER_MAPPING_DEFAULT));
}
// Determine which UFI method should be used. Note that we keep on trying to
// find another method until the end: the order of rules matters!
// However, specificity also matters. The directory pattern "foo/bar/*"
// should *always* override the less specific pattern "foo/*".
$ufi_method = FALSE;
$current_specificity = 0;
foreach (array_keys($mapping) as $directory) {
if (drupal_match_path($path, $directory)) {
// Parse the file extension from the given path; convert it to lower case.
$file_extension = strtolower(pathinfo($path, PATHINFO_EXTENSION));
// Based on the file extension, determine which key should be used to find
// the CDN URLs in the mapping lookup table, if any.
$extension = NULL;
if (array_key_exists($file_extension, $mapping[$directory])) {
$key = $file_extension;
}
elseif (array_key_exists('*', $mapping[$directory])) {
$extension = '*';
}
// If a matching extension was found, assign the corresponding UFI method.
if (isset($extension)) {
$specificity = $mapping[$directory][$extension]['specificity'];
if ($specificity > $current_specificity) {
$ufi_method = $mapping[$directory][$extension]['ufi method'];
$current_specificity = $specificity;
}
}
}
}
// Fall back to the default UFI method in case no UFI method is defined by
// the user.
if ($ufi_method === FALSE) {
$ufi_method = CDN_BASIC_FARFUTURE_UNIQUE_IDENTIFIER_DEFAULT;
}
$prefix = $ufi_info[$ufi_method]['prefix'];
if (isset($ufi_info[$ufi_method]['value'])) {
$value = $ufi_info[$ufi_method]['value'];
}
else {
$callback = $ufi_info[$ufi_method]['callback'];
$value = call_user_func_array($callback, array($path));
}
return "$prefix:$value";
}
//----------------------------------------------------------------------------
// Private functions.
/**
* Parse the raw (textual) mapping into a lookup table, where the key is the
* file extension and the value is a list of CDN URLs that serve the file.
*
* @param $mapping_raw
* A raw (textual) mapping.
* @return
* The corresponding mapping lookup table.
*/
function _cdn_basic_farfuture_parse_raw_mapping($mapping_raw) {
$mapping = array();
if (!empty($mapping_raw)) {
$lines = preg_split("/[\n\r]+/", $mapping_raw, -1, PREG_SPLIT_NO_EMPTY);
foreach ($lines as $line) {
// Parse this line. It may or may not limit the CDN URL to a list of
// file extensions.
$parts = explode('|', $line);
$directories = explode(':', $parts[0]);
$specificity = 0;
// There may be 2 or 3 parts:
// - part 1: directories
// - part 2: file extensions (optional)
// - part 3: unique file identifier method
if (count($parts) == 2) {
$extensions = array('*'); // Use the asterisk as a wildcard.
$ufi_method = strtolower(trim($parts[1]));
}
else if (count($parts) == 3) {
// Convert to lower case, remove periods, whitespace and split on ' '.
$extensions = explode(' ', trim(str_replace('.', '', strtolower($parts[1]))));
$ufi_method = strtolower(trim($parts[2]));
}
// Create the mapping lookup table.
foreach ($directories as $directory) {
$directory_specificity = 10 * count(explode('/', $directory));
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foreach ($extensions as $extension) {
$extension_specificity = ($extension == '*') ? 0 : 1;
$mapping[$directory][$extension] = array(
'ufi method' => $ufi_method,
'specificity' => $directory_specificity + $extension_specificity,
);
}
}
}
}
return $mapping;
}
/**
* Variant of Drupal's file_transfer(), based on
* http://www.thomthom.net/blog/2007/09/php-resumable-download-server/
* to support ranged requests as well.
*
* Note: ranged requests that request multiple ranges are not supported. They
* are responded to with a 416. See
* http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html
*/
function _cdn_transfer_file($path) {
$fp = @fopen($path, 'rb');
$size = filesize($path); // File size
$length = $size; // Content length
$start = 0; // Start byte
$end = $size - 1; // End byte
// In case of a range request, seek within the file to the correct location.
if (isset($_SERVER['HTTP_RANGE'])) {
$c_start = $start;
$c_end = $end;
// Extract the string containing the requested range.
list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
// If the client requested multiple ranges, repond with a 416.
if (strpos($range, ',') !== FALSE) {
header('HTTP/1.1 416 Requested Range Not Satisfiable');
header("Content-Range: bytes $start-$end/$size");
exit();
}
// Case "Range: -n": final n bytes are requested.
if ($range[0] == '-') {
$c_start = $size - substr($range, 1);
}
// Case "Range: m-n": bytes m through n are requested. When n is empty or
// non-numeric, n is the last byte.
else {
$range = explode('-', $range);
$c_start = intval($range[0]);
$c_end = (isset($range[1]) && is_numeric($range[1])) ? intval($range[1]) : $size;
}
// Minor normalization: end bytes can not be larger than $end.
$c_end = ($c_end > $end) ? $end : $c_end;
// If the requested range is not valid, respond with a 416.
if ($c_start > $c_end || $c_start > $end || $c_end > $end) {
header('HTTP/1.1 416 Requested Range Not Satisfiable');
header("Content-Range: bytes $start-$end/$size");
exit();
}
$start = $c_start;
$end = $c_end;
$length = $end - $start + 1;
fseek($fp, $start);
// The ranged request is valid and will be performed, respond with a 206.
header('HTTP/1.1 206 Partial Content');
header("Content-Range: bytes $start-$end/$size");
}
header("Content-Length: $length");
// Start buffered download. Prevent reading too far for a ranged request.
$buffer = 1024 * 8;
while (!feof($fp) && ($p = ftell($fp)) <= $end) {
if ($p + $buffer > $end) {
$buffer = $end - $p + 1;
}
set_time_limit(0); // Reset time limit for big files.
echo fread($fp, $buffer);
flush(); // Free up memory, to prevent triggering PHP's memory limit.
}
fclose($fp);
}
/**
* Determine an Internet Media Type, or MIME type from a filename.
* Borrowed from Drupal 7.
*
* @param $path
* A string containing the file path.
* @return
* The internet media type registered for the extension or
* application/octet-stream for unknown extensions.
*/
function _cdn_basic_farfuture_get_mimetype($path) {
cdn_load_include('mimetypes');
$mapping = cdn_mimetype_mapping();
$extension = '';
$file_parts = explode('.', basename($path));
// Remove the first part: a full filename should not match an extension.
array_shift($file_parts);
// Iterate over the file parts, trying to find a match.
// For my.awesome.image.jpeg, we try:
// - jpeg
// - image.jpeg, and
// - awesome.image.jpeg
while ($additional_part = array_pop($file_parts)) {
$extension = strtolower($additional_part . ($extension ? '.' . $extension : ''));
if (isset($mapping['extensions'][$extension])) {
return $mapping['mimetypes'][$mapping['extensions'][$extension]];
}
}
return 'application/octet-stream';
}
/**
* file_check_directory() doesn't support creating directory trees.
*/
function _cdn_basic_farfuture_create_directory_structure($path) {
// Create the directory structure in which the file will be stored. Because
// it's nested, file_check_directory() can't do this in one run.
$parts = explode('/', $path);
for ($i = 0; $i < count($parts); $i++) {
$directory = implode('/', array_slice($parts, 0, $i + 1));
file_check_directory(file_create_path($directory), FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);
}
}