<?php
/**
 *  Base include file for SimpleTest
 *  @package    SimpleTest
 *  @subpackage WebTester
 *  @version    $Id: user_agent.php,v 1.5 2010/12/14 17:35:45 moodlerobot Exp $
 */

/**#@+
 *  include other SimpleTest class files
 */
require_once(dirname(__FILE__) . '/cookies.php');
require_once(dirname(__FILE__) . '/http.php');
require_once(dirname(__FILE__) . '/encoding.php');
require_once(dirname(__FILE__) . '/authentication.php');
/**#@-*/

if (! defined('DEFAULT_MAX_REDIRECTS')) {
    define('DEFAULT_MAX_REDIRECTS', 3);
}
if (! defined('DEFAULT_CONNECTION_TIMEOUT')) {
    define('DEFAULT_CONNECTION_TIMEOUT', 15);
}

/**
 *    Fetches web pages whilst keeping track of
 *    cookies and authentication.
 *    @package SimpleTest
 *    @subpackage WebTester
 */
class SimpleUserAgent {
    var $_cookie_jar;
    var $_cookies_enabled = true;
    var $_authenticator;
    var $_max_redirects = DEFAULT_MAX_REDIRECTS;
    var $_proxy = false;
    var $_proxy_username = false;
    var $_proxy_password = false;
    var $_connection_timeout = DEFAULT_CONNECTION_TIMEOUT;
    var $_additional_headers = array();
    
    /**
     *    Starts with no cookies, realms or proxies.
     *    @access public
     */
    function SimpleUserAgent() {
        $this->_cookie_jar = new SimpleCookieJar();
        $this->_authenticator = new SimpleAuthenticator();
    }
    
    /**
     *    Removes expired and temporary cookies as if
     *    the browser was closed and re-opened. Authorisation
     *    has to be obtained again as well.
     *    @param string/integer $date   Time when session restarted.
     *                                  If omitted then all persistent
     *                                  cookies are kept.
     *    @access public
     */
    function restart($date = false) {
        $this->_cookie_jar->restartSession($date);
        $this->_authenticator->restartSession();
    }
    
    /**
     *    Adds a header to every fetch.
     *    @param string $header       Header line to add to every
     *                                request until cleared.
     *    @access public
     */
    function addHeader($header) {
        $this->_additional_headers[] = $header;
    }
    
    /**
     *    Ages the cookies by the specified time.
     *    @param integer $interval    Amount in seconds.
     *    @access public
     */
    function ageCookies($interval) {
        $this->_cookie_jar->agePrematurely($interval);
    }
    
    /**
     *    Sets an additional cookie. If a cookie has
     *    the same name and path it is replaced.
     *    @param string $name            Cookie key.
     *    @param string $value           Value of cookie.
     *    @param string $host            Host upon which the cookie is valid.
     *    @param string $path            Cookie path if not host wide.
     *    @param string $expiry          Expiry date.
     *    @access public
     */
    function setCookie($name, $value, $host = false, $path = '/', $expiry = false) {
        $this->_cookie_jar->setCookie($name, $value, $host, $path, $expiry);
    }
    
    /**
     *    Reads the most specific cookie value from the
     *    browser cookies.
     *    @param string $host        Host to search.
     *    @param string $path        Applicable path.
     *    @param string $name        Name of cookie to read.
     *    @return string             False if not present, else the
     *                               value as a string.
     *    @access public
     */
    function getCookieValue($host, $path, $name) {
        return $this->_cookie_jar->getCookieValue($host, $path, $name);
    }
    
    /**
     *    Reads the current cookies within the base URL.
     *    @param string $name     Key of cookie to find.
     *    @param SimpleUrl $base  Base URL to search from.
     *    @return string/boolean  Null if there is no base URL, false
     *                            if the cookie is not set.
     *    @access public
     */
    function getBaseCookieValue($name, $base) {
        if (! $base) {
            return null;
        }
        return $this->getCookieValue($base->getHost(), $base->getPath(), $name);
    }
    
    /**
     *    Switches off cookie sending and recieving.
     *    @access public
     */
    function ignoreCookies() {
        $this->_cookies_enabled = false;
    }
    
    /**
     *    Switches back on the cookie sending and recieving.
     *    @access public
     */
    function useCookies() {
        $this->_cookies_enabled = true;
    }
    
    /**
     *    Sets the socket timeout for opening a connection.
     *    @param integer $timeout      Maximum time in seconds.
     *    @access public
     */
    function setConnectionTimeout($timeout) {
        $this->_connection_timeout = $timeout;
    }
    
    /**
     *    Sets the maximum number of redirects before
     *    a page will be loaded anyway.
     *    @param integer $max        Most hops allowed.
     *    @access public
     */
    function setMaximumRedirects($max) {
        $this->_max_redirects = $max;
    }
    
    /**
     *    Sets proxy to use on all requests for when
     *    testing from behind a firewall. Set URL
     *    to false to disable.
     *    @param string $proxy        Proxy URL.
     *    @param string $username     Proxy username for authentication.
     *    @param string $password     Proxy password for authentication.
     *    @access public
     */
    function useProxy($proxy, $username, $password) {
        if (! $proxy) {
            $this->_proxy = false;
            return;
        }
        if ((strncmp($proxy, 'http://', 7) != 0) && (strncmp($proxy, 'https://', 8) != 0)) {
            $proxy = 'http://'. $proxy;
        }
        $this->_proxy = new SimpleUrl($proxy);
        $this->_proxy_username = $username;
        $this->_proxy_password = $password;
    }
    
    /**
     *    Test to see if the redirect limit is passed.
     *    @param integer $redirects        Count so far.
     *    @return boolean                  True if over.
     *    @access private
     */
    function _isTooManyRedirects($redirects) {
        return ($redirects > $this->_max_redirects);
    }
    
    /**
     *    Sets the identity for the current realm.
     *    @param string $host        Host to which realm applies.
     *    @param string $realm       Full name of realm.
     *    @param string $username    Username for realm.
     *    @param string $password    Password for realm.
     *    @access public
     */
    function setIdentity($host, $realm, $username, $password) {
        $this->_authenticator->setIdentityForRealm($host, $realm, $username, $password);
    }
    
    /**
     *    Fetches a URL as a response object. Will keep trying if redirected.
     *    It will also collect authentication realm information.
     *    @param string/SimpleUrl $url      Target to fetch.
     *    @param SimpleEncoding $encoding   Additional parameters for request.
     *    @return SimpleHttpResponse        Hopefully the target page.
     *    @access public
     */
    function &fetchResponse($url, $encoding) {
        if ($encoding->getMethod() != 'POST') {
            $url->addRequestParameters($encoding);
            $encoding->clear();
        }
        $response = &$this->_fetchWhileRedirected($url, $encoding);
        if ($headers = $response->getHeaders()) {
            if ($headers->isChallenge()) {
                $this->_authenticator->addRealm(
                        $url,
                        $headers->getAuthentication(),
                        $headers->getRealm());
            }
        }
        return $response;
    }
    
    /**
     *    Fetches the page until no longer redirected or
     *    until the redirect limit runs out.
     *    @param SimpleUrl $url                  Target to fetch.
     *    @param SimpelFormEncoding $encoding    Additional parameters for request.
     *    @return SimpleHttpResponse             Hopefully the target page.
     *    @access private
     */
    function &_fetchWhileRedirected($url, $encoding) {
        $redirects = 0;
        do {
            $response = &$this->_fetch($url, $encoding);
            if ($response->isError()) {
                return $response;
            }
            $headers = $response->getHeaders();
            $location = new SimpleUrl($headers->getLocation());
            $url = $location->makeAbsolute($url);
            if ($this->_cookies_enabled) {
                $headers->writeCookiesToJar($this->_cookie_jar, $url);
            }
            if (! $headers->isRedirect()) {
                break;
            }
            $encoding = new SimpleGetEncoding();
        } while (! $this->_isTooManyRedirects(++$redirects));
        return $response;
    }
    
    /**
     *    Actually make the web request.
     *    @param SimpleUrl $url                   Target to fetch.
     *    @param SimpleFormEncoding $encoding     Additional parameters for request.
     *    @return SimpleHttpResponse              Headers and hopefully content.
     *    @access protected
     */
    function &_fetch($url, $encoding) {
        $request = &$this->_createRequest($url, $encoding);
        $response = &$request->fetch($this->_connection_timeout);
        return $response;
    }
    
    /**
     *    Creates a full page request.
     *    @param SimpleUrl $url                 Target to fetch as url object.
     *    @param SimpleFormEncoding $encoding   POST/GET parameters.
     *    @return SimpleHttpRequest             New request.
     *    @access private
     */
    function &_createRequest($url, $encoding) {
        $request = &$this->_createHttpRequest($url, $encoding);
        $this->_addAdditionalHeaders($request);
        if ($this->_cookies_enabled) {
            $request->readCookiesFromJar($this->_cookie_jar, $url);
        }
        $this->_authenticator->addHeaders($request, $url);
        return $request;
    }
    
    /**
     *    Builds the appropriate HTTP request object.
     *    @param SimpleUrl $url                  Target to fetch as url object.
     *    @param SimpleFormEncoding $parameters  POST/GET parameters.
     *    @return SimpleHttpRequest              New request object.
     *    @access protected
     */
    function &_createHttpRequest($url, $encoding) {
        $request = new SimpleHttpRequest($this->_createRoute($url), $encoding);
        return $request;
    }
    
    /**
     *    Sets up either a direct route or via a proxy.
     *    @param SimpleUrl $url   Target to fetch as url object.
     *    @return SimpleRoute     Route to take to fetch URL.
     *    @access protected
     */
    function &_createRoute($url) {
        if ($this->_proxy) {
            $route = new SimpleProxyRoute(
                    $url,
                    $this->_proxy,
                    $this->_proxy_username,
                    $this->_proxy_password);
        } else {
            $route = new SimpleRoute($url);
        }
        return $route;
    }
    
    /**
     *    Adds additional manual headers.
     *    @param SimpleHttpRequest $request    Outgoing request.
     *    @access private
     */
    function _addAdditionalHeaders(&$request) {
        foreach ($this->_additional_headers as $header) {
            $request->addHeaderLine($header);
        }
    }
}
?>