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<?php
/**
* WPSEO plugin file.
*
* @package WPSEO\Admin
*/
/**
* @class WPSEO_MyYoast_Proxy Loads the MyYoast proxy.
*
* This class registers a proxy page on `admin.php`. Which is reached with the `page=PAGE_IDENTIFIER` parameter.
* It will read external files and serves them like they are located locally.
*/
class WPSEO_MyYoast_Proxy implements WPSEO_WordPress_Integration {
/**
* The page identifier used in WordPress to register the MyYoast proxy page.
*
* @var string
*/
const PAGE_IDENTIFIER = 'wpseo_myyoast_proxy';
/**
* The cache control's max age. Used in the header of a successful proxy response.
*
* @var int
*/
const CACHE_CONTROL_MAX_AGE = DAY_IN_SECONDS;
/**
* Registers the hooks when the user is on the right page.
*
* @codeCoverageIgnore
*
* @return void
*/
public function register_hooks() {
if ( ! $this->is_proxy_page() ) {
return;
}
// Register the page for the proxy.
add_action( 'admin_menu', array( $this, 'add_proxy_page' ) );
add_action( 'admin_init', array( $this, 'handle_proxy_page' ) );
}
/**
* Registers the proxy page. It does not actually add a link to the dashboard.
*
* @codeCoverageIgnore
*
* @return void
*/
public function add_proxy_page() {
add_dashboard_page( '', '', 'read', self::PAGE_IDENTIFIER, '' );
}
/**
* Renders the requested proxy page and exits to prevent the WordPress UI from loading.
*
* @codeCoverageIgnore
*
* @return void
*/
public function handle_proxy_page() {
$this->render_proxy_page();
// Prevent the WordPress UI from loading.
exit;
}
/**
* Renders the requested proxy page.
*
* This is separated from the exits to be able to test it.
*
* @return void
*/
public function render_proxy_page() {
$proxy_options = $this->determine_proxy_options();
if ( $proxy_options === array() ) {
// Do not accept any other file than implemented.
$this->set_header( 'HTTP/1.0 501 Requested file not implemented' );
return;
}
// Set the headers before serving the remote file.
$this->set_header( 'Content-Type: ' . $proxy_options['content_type'] );
$this->set_header( 'Cache-Control: max-age=' . self::CACHE_CONTROL_MAX_AGE );
if ( $this->should_load_url_directly() ) {
/*
* If an error occurred, fallback to the next proxy method (`wp_remote_get`).
* Otherwise, we are done here.
*/
if ( $this->load_url( $proxy_options['url'] ) ) {
return;
}
}
try {
echo $this->get_remote_url_body( $proxy_options['url'] );
}
catch ( Exception $e ) {
/*
* Reset the file headers because the loading failed.
*
* Note: Due to supporting PHP 5.2 `header_remove` can not be used here.
* Overwrite the headers instead.
*/
$this->set_header( 'Content-Type: text/plain' );
$this->set_header( 'Cache-Control: max-age=0' );
$this->set_header( 'HTTP/1.0 500 ' . $e->getMessage() );
}
}
/**
* Tries to load the given url via `wp_remote_get`.
*
* @codeCoverageIgnore
*
* @param string $url The url to load.
*
* @throws Exception When `wp_remote_get` returned an error.
* @throws Exception When the response code is not 200.
*
* @return string The body of the response.
*/
protected function get_remote_url_body( $url ) {
$response = wp_remote_get( $url );
if ( $response instanceof WP_Error ) {
throw new Exception( 'Unable to retrieve file from MyYoast' );
}
if ( wp_remote_retrieve_response_code( $response ) !== 200 ) {
throw new Exception( 'Received unexpected response from MyYoast' );
}
return wp_remote_retrieve_body( $response );
}
/**
* Tries to load the given url.
*
* @link https://php.net/manual/en/function.readfile.php
*
* @codeCoverageIgnore
*
* @param string $url The url to load.
*
* @return bool False if an error occurred.
*/
protected function load_url( $url ) {
return readfile( $url ) !== false;
}
/**
* Determines the proxy options based on the file and plugin version arguments.
*
* When the file is known it returns an array like this:
* <code>
* $array = array(
* 'content_type' => 'the content type'
* 'url' => 'the url, possibly with the plugin version'
* )
* </code>
*
* @return array Empty for an unknown file. See format above for known files.
*/
protected function determine_proxy_options() {
if ( $this->get_proxy_file() === 'research-webworker' ) {
return array(
'content_type' => 'text/javascript; charset=UTF-8',
'url' => 'https://my.yoast.com/api/downloads/file/analysis-worker?plugin_version=' . $this->get_plugin_version(),
);
}
return array();
}
/**
* Checks the PHP configuration of allow_url_fopen.
*
* @codeCoverageIgnore
*
* @link https://php.net/manual/en/filesystem.configuration.php#ini.allow-url-fopen
*
* @return bool True when the PHP configuration allows for url loading via readfile.
*/
protected function should_load_url_directly() {
return ! ! ini_get( 'allow_url_fopen' );
}
/**
* Checks if the current page is the MyYoast proxy page.
*
* @codeCoverageIgnore
*
* @return bool True when the page request parameter equals the proxy page.
*/
protected function is_proxy_page() {
return filter_input( INPUT_GET, 'page' ) === self::PAGE_IDENTIFIER;
}
/**
* Returns the proxy file from the HTTP request parameters.
*
* @codeCoverageIgnore
*
* @return string The sanitized file request parameter.
*/
protected function get_proxy_file() {
return filter_input( INPUT_GET, 'file', FILTER_SANITIZE_STRING );
}
/**
* Returns the plugin version from the HTTP request parameters.
*
* @codeCoverageIgnore
*
* @return string The sanitized plugin_version request parameter.
*/
protected function get_plugin_version() {
$plugin_version = filter_input( INPUT_GET, 'plugin_version', FILTER_SANITIZE_STRING );
// Replace slashes to secure against requiring a file from another path.
$plugin_version = str_replace( array( '/', '\\' ), '_', $plugin_version );
return $plugin_version;
}
/**
* Sets the HTTP header.
*
* This is a tiny helper function to enable better testing.
*
* @codeCoverageIgnore
*
* @param string $header The header to set.
*
* @return void
*/
protected function set_header( $header ) {
header( $header );
}
}
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