/inc/simpletest/browser.php

<?php
    /**
     *	Base include file for SimpleTest
     *	@package	SimpleTest
     *	@subpackage	WebTester
     *	@version	$Id: browser.php,v 1.160 2005/09/09 01:27:37 lastcraft Exp $
     */

    /**#@+
     *	include other SimpleTest class files
     */
    require_once(dirname(__FILE__) . '/simpletest.php');
    require_once(dirname(__FILE__) . '/http.php');
    require_once(dirname(__FILE__) . '/encoding.php');
    require_once(dirname(__FILE__) . '/page.php');
    require_once(dirname(__FILE__) . '/selector.php');
    require_once(dirname(__FILE__) . '/frames.php');
    require_once(dirname(__FILE__) . '/user_agent.php');
    /**#@-*/

    if (!defined('DEFAULT_MAX_NESTED_FRAMES')) {
        define('DEFAULT_MAX_NESTED_FRAMES', 3);
    }

    /**
     *    Browser history list.
	 *    @package SimpleTest
	 *    @subpackage WebTester
     */
    class SimpleBrowserHistory {
        var $_sequence;
        var $_position;

        /**
         *    Starts empty.
         *    @access public
         */
        function SimpleBrowserHistory() {
            $this->_sequence = array();
            $this->_position = -1;
        }

        /**
         *    Test for no entries yet.
         *    @return boolean        True if empty.
         *    @access private
         */
        function _isEmpty() {
            return ($this->_position == -1);
        }

        /**
         *    Test for being at the beginning.
         *    @return boolean        True if first.
         *    @access private
         */
        function _atBeginning() {
            return ($this->_position == 0) && ! $this->_isEmpty();
        }

        /**
         *    Test for being at the last entry.
         *    @return boolean        True if last.
         *    @access private
         */
        function _atEnd() {
            return ($this->_position + 1 >= count($this->_sequence)) && ! $this->_isEmpty();
        }

        /**
         *    Adds a successfully fetched page to the history.
         *    @param SimpleUrl $url                 URL of fetch.
         *    @param SimpleEncoding $parameters     Any post data with the fetch.
         *    @access public
         */
        function recordEntry($url, $parameters) {
            $this->_dropFuture();
            array_push(
                    $this->_sequence,
                    array('url' => $url, 'parameters' => $parameters));
            $this->_position++;
        }

        /**
         *    Last fully qualified URL for current history
         *    position.
         *    @return SimpleUrl        URL for this position.
         *    @access public
         */
        function getUrl() {
            if ($this->_isEmpty()) {
                return false;
            }
            return $this->_sequence[$this->_position]['url'];
        }

        /**
         *    Parameters of last fetch from current history
         *    position.
         *    @return SimpleFormEncoding    Post parameters.
         *    @access public
         */
        function getParameters() {
            if ($this->_isEmpty()) {
                return false;
            }
            return $this->_sequence[$this->_position]['parameters'];
        }

        /**
         *    Step back one place in the history. Stops at
         *    the first page.
         *    @return boolean     True if any previous entries.
         *    @access public
         */
        function back() {
            if ($this->_isEmpty() || $this->_atBeginning()) {
                return false;
            }
            $this->_position--;
            return true;
        }

        /**
         *    Step forward one place. If already at the
         *    latest entry then nothing will happen.
         *    @return boolean     True if any future entries.
         *    @access public
         */
        function forward() {
            if ($this->_isEmpty() || $this->_atEnd()) {
                return false;
            }
            $this->_position++;
            return true;
        }

        /**
         *    Ditches all future entries beyond the current
         *    point.
         *    @access private
         */
        function _dropFuture() {
            if ($this->_isEmpty()) {
                return;
            }
            while (! $this->_atEnd()) {
                array_pop($this->_sequence);
            }
        }
    }

    /**
     *    Simulated web browser. This is an aggregate of
     *    the user agent, the HTML parsing, request history
     *    and the last header set.
	 *    @package SimpleTest
	 *    @subpackage WebTester
     */
    class SimpleBrowser {
        var $_user_agent;
        var $_page;
        var $_history;
        var $_ignore_frames;
        var $_maximum_nested_frames;

        /**
         *    Starts with a fresh browser with no
         *    cookie or any other state information. The
         *    exception is that a default proxy will be
         *    set up if specified in the options.
         *    @access public
         */
        function SimpleBrowser() {
            $this->_user_agent = &$this->_createUserAgent();
            $this->_user_agent->useProxy(
                    SimpleTest::getDefaultProxy(),
                    SimpleTest::getDefaultProxyUsername(),
                    SimpleTest::getDefaultProxyPassword());
            $this->_page = &new SimplePage();
            $this->_history = &$this->_createHistory();
            $this->_ignore_frames = false;
            $this->_maximum_nested_frames = DEFAULT_MAX_NESTED_FRAMES;
        }

        /**
         *    Creates the underlying user agent.
         *    @return SimpleFetcher    Content fetcher.
         *    @access protected
         */
        function &_createUserAgent() {
            $user_agent = &new SimpleUserAgent();
            return $user_agent;
        }

        /**
         *    Creates a new empty history list.
         *    @return SimpleBrowserHistory    New list.
         *    @access protected
         */
        function &_createHistory() {
            $history = &new SimpleBrowserHistory();
            return $history;
        }

        /**
         *    Disables frames support. Frames will not be fetched
         *    and the frameset page will be used instead.
         *    @access public
         */
        function ignoreFrames() {
            $this->_ignore_frames = true;
        }

        /**
         *    Enables frames support. Frames will be fetched from
         *    now on.
         *    @access public
         */
        function useFrames() {
            $this->_ignore_frames = false;
        }

        /**
         *    Parses the raw content into a page. Will load further
         *    frame pages unless frames are disabled.
         *    @param SimpleHttpResponse $response    Response from fetch.
         *    @param integer $depth                  Nested frameset depth.
         *    @return SimplePage                     Parsed HTML.
         *    @access protected
         */
        function &_parse($response, $depth = 0) {
            $builder = &new SimplePageBuilder();
            $page = &$builder->parse($response);
            if ($this->_ignore_frames || ! $page->hasFrames() || ($depth > $this->_maximum_nested_frames)) {
                return $page;
            }
            $frameset = &new SimpleFrameset($page);
            foreach ($page->getFrameset() as $key => $url) {
                $frame = &$this->_fetch($url, new SimpleGetEncoding(), $depth + 1);
                $frameset->addFrame($frame, $key);
            }
            return $frameset;
        }

        /**
         *    Fetches a page.
         *    @param string/SimpleUrl $url          Target to fetch.
         *    @param SimpleEncoding $encoding       GET/POST parameters.
         *    @param integer $depth                 Nested frameset depth protection.
         *    @return SimplePage                    Parsed page.
         *    @access private
         */
        function &_fetch($url, $encoding, $depth = 0) {
            $response = &$this->_user_agent->fetchResponse($url, $encoding);
            if ($response->isError()) {
                $page = &new SimplePage($response);
            } else {
                $page = &$this->_parse($response, $depth);
            }
            return $page;
        }

        /**
         *    Fetches a page or a single frame if that is the current
         *    focus.
         *    @param SimpleUrl $url                   Target to fetch.
         *    @param SimpleEncoding $parameters       GET/POST parameters.
         *    @return string                          Raw content of page.
         *    @access private
         */
        function _load($url, $parameters) {
            $frame = $url->getTarget();
            if (! $frame || ! $this->_page->hasFrames() || (strtolower($frame) == '_top')) {
                return $this->_loadPage($url, $parameters);
            }
            return $this->_loadFrame(array($frame), $url, $parameters);
        }

        /**
         *    Fetches a page and makes it the current page/frame.
         *    @param string/SimpleUrl $url            Target to fetch as string.
         *    @param SimplePostEncoding $parameters   POST parameters.
         *    @return string                          Raw content of page.
         *    @access private
         */
        function _loadPage($url, $parameters) {
            $this->_page = &$this->_fetch($url, $parameters);
            $this->_history->recordEntry(
                    $this->_page->getUrl(),
                    $this->_page->getRequestData());
            return $this->_page->getRaw();
        }

        /**
         *    Fetches a frame into the existing frameset replacing the
         *    original.
         *    @param array $frames                    List of names to drill down.
         *    @param string/SimpleUrl $url            Target to fetch as string.
         *    @param SimpleFormEncoding $parameters   POST parameters.
         *    @return string                          Raw content of page.
         *    @access private
         */
        function _loadFrame($frames, $url, $parameters) {
            $page = &$this->_fetch($url, $parameters);
            $this->_page->setFrame($frames, $page);
        }

        /**
         *    Removes expired and temporary cookies as if
         *    the browser was closed and re-opened.
         *    @param string/integer $date   Time when session restarted.
         *                                  If omitted then all persistent
         *                                  cookies are kept.
         *    @access public
         */
        function restart($date = false) {
            $this->_user_agent->restart($date);
        }

        /**
         *    Adds a header to every fetch.
         *    @param string $header       Header line to add to every
         *                                request until cleared.
         *    @access public
         */
        function addHeader($header) {
            $this->_user_agent->addHeader($header);
        }

        /**
         *    Ages the cookies by the specified time.
         *    @param integer $interval    Amount in seconds.
         *    @access public
         */
        function ageCookies($interval) {
            $this->_user_agent->ageCookies($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) {
            $this->_user_agent->setCookie($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 $this->_user_agent->getCookieValue($host, $path, $name);
        }

        /**
         *    Reads the current cookies for the current URL.
         *    @param string $name   Key of cookie to find.
         *    @return string        Null if there is no current URL, false
         *                          if the cookie is not set.
         *    @access public
         */
        function getCurrentCookieValue($name) {
            return $this->_user_agent->getBaseCookieValue($name, $this->_page->getUrl());
        }

        /**
         *    Sets the maximum number of redirects before
         *    a page will be loaded anyway.
         *    @param integer $max        Most hops allowed.
         *    @access public
         */
        function setMaximumRedirects($max) {
            $this->_user_agent->setMaximumRedirects($max);
        }

        /**
         *    Sets the maximum number of nesting of framed pages
         *    within a framed page to prevent loops.
         *    @param integer $max        Highest depth allowed.
         *    @access public
         */
        function setMaximumNestedFrames($max) {
            $this->_maximum_nested_frames = $max;
        }

        /**
         *    Sets the socket timeout for opening a connection.
         *    @param integer $timeout      Maximum time in seconds.
         *    @access public
         */
        function setConnectionTimeout($timeout) {
            $this->_user_agent->setConnectionTimeout($timeout);
        }

        /**
         *    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 = false, $password = false) {
            $this->_user_agent->useProxy($proxy, $username, $password);
        }

        /**
         *    Fetches the page content with a HEAD request.
         *    Will affect cookies, but will not change the base URL.
         *    @param string/SimpleUrl $url                Target to fetch as string.
         *    @param hash/SimpleHeadEncoding $parameters  Additional parameters for
         *                                                HEAD request.
         *    @return boolean                             True if successful.
         *    @access public
         */
        function head($url, $parameters = false) {
            if (! is_object($url)) {
                $url = new SimpleUrl($url);
            }
            if ($this->getUrl()) {
                $url = $url->makeAbsolute($this->getUrl());
            }
            $response = &$this->_user_agent->fetchResponse($url, new SimpleHeadEncoding($parameters));
            return ! $response->isError();
        }

        /**
         *    Fetches the page content with a simple GET request.
         *    @param string/SimpleUrl $url                Target to fetch.
         *    @param hash/SimpleFormEncoding $parameters  Additional parameters for
         *                                                GET request.
         *    @return string                              Content of page or false.
         *    @access public
         */
        function get($url, $parameters = false) {
            if (! is_object($url)) {
                $url = new SimpleUrl($url);
            }
            if ($this->getUrl()) {
                $url = $url->makeAbsolute($this->getUrl());
            }
            return $this->_load($url, new SimpleGetEncoding($parameters));
        }

        /**
         *    Fetches the page content with a POST request.
         *    @param string/SimpleUrl $url                Target to fetch as string.
         *    @param hash/SimpleFormEncoding $parameters  POST parameters.
         *    @return string                              Content of page.
         *    @access public
         */
        function post($url, $parameters = false) {
            if (! is_object($url)) {
                $url = new SimpleUrl($url);
            }
            if ($this->getUrl()) {
                $url = $url->makeAbsolute($this->getUrl());
            }
            return $this->_load($url, new SimplePostEncoding($parameters));
        }

        /**
         *    Equivalent to hitting the retry button on the
         *    browser. Will attempt to repeat the page fetch. If
         *    there is no history to repeat it will give false.
         *    @return string/boolean   Content if fetch succeeded
         *                             else false.
         *    @access public
         */
        function retry() {
            $frames = $this->_page->getFrameFocus();
            if (count($frames) > 0) {
                $this->_loadFrame(
                        $frames,
                        $this->_page->getUrl(),
                        $this->_page->getRequestData());
                return $this->_page->getRaw();
            }
            if ($url = $this->_history->getUrl()) {
                $this->_page = &$this->_fetch($url, $this->_history->getParameters());
                return $this->_page->getRaw();
            }
            return false;
        }

        /**
         *    Equivalent to hitting the back button on the
         *    browser. The browser history is unchanged on
         *    failure. The page content is refetched as there
         *    is no concept of content caching in SimpleTest.
         *    @return boolean     True if history entry and
         *                        fetch succeeded
         *    @access public
         */
        function back() {
            if (! $this->_history->back()) {
                return false;
            }
            $content = $this->retry();
            if (! $content) {
                $this->_history->forward();
            }
            return $content;
        }

        /**
         *    Equivalent to hitting the forward button on the
         *    browser. The browser history is unchanged on
         *    failure. The page content is refetched as there
         *    is no concept of content caching in SimpleTest.
         *    @return boolean     True if history entry and
         *                        fetch succeeded
         *    @access public
         */
        function forward() {
            if (! $this->_history->forward()) {
                return false;
            }
            $content = $this->retry();
            if (! $content) {
                $this->_history->back();
            }
            return $content;
        }

        /**
         *    Retries a request after setting the authentication
         *    for the current realm.
         *    @param string $username    Username for realm.
         *    @param string $password    Password for realm.
         *    @return boolean            True if successful fetch. Note
         *                               that authentication may still have
         *                               failed.
         *    @access public
         */
        function authenticate($username, $password) {
            if (! $this->_page->getRealm()) {
                return false;
            }
            $url = $this->_page->getUrl();
            if (! $url) {
                return false;
            }
            $this->_user_agent->setIdentity(
                    $url->getHost(),
                    $this->_page->getRealm(),
                    $username,
                    $password);
            return $this->retry();
        }

        /**
         *    Accessor for a breakdown of the frameset.
         *    @return array   Hash tree of frames by name
         *                    or index if no name.
         *    @access public
         */
        function getFrames() {
            return $this->_page->getFrames();
        }

        /**
         *    Accessor for current frame focus. Will be
         *    false if no frame has focus.
         *    @return integer/string/boolean    Label if any, otherwise
         *                                      the position in the frameset
         *                                      or false if none.
         *    @access public
         */
        function getFrameFocus() {
            return $this->_page->getFrameFocus();
        }

        /**
         *    Sets the focus by index. The integer index starts from 1.
         *    @param integer $choice    Chosen frame.
         *    @return boolean           True if frame exists.
         *    @access public
         */
        function setFrameFocusByIndex($choice) {
            return $this->_page->setFrameFocusByIndex($choice);
        }

        /**
         *    Sets the focus by name.
         *    @param string $name    Chosen frame.
         *    @return boolean        True if frame exists.
         *    @access public
         */
        function setFrameFocus($name) {
            return $this->_page->setFrameFocus($name);
        }

        /**
         *    Clears the frame focus. All frames will be searched
         *    for content.
         *    @access public
         */
        function clearFrameFocus() {
            return $this->_page->clearFrameFocus();
        }

        /**
         *    Accessor for last error.
         *    @return string        Error from last response.
         *    @access public
         */
        function getTransportError() {
            return $this->_page->getTransportError();
        }

        /**
         *    Accessor for current MIME type.
         *    @return string    MIME type as string; e.g. 'text/html'
         *    @access public
         */
        function getMimeType() {
            return $this->_page->getMimeType();
        }

        /**
         *    Accessor for last response code.
         *    @return integer    Last HTTP response code received.
         *    @access public
         */
        function getResponseCode() {
            return $this->_page->getResponseCode();
        }

        /**
         *    Accessor for last Authentication type. Only valid
         *    straight after a challenge (401).
         *    @return string    Description of challenge type.
         *    @access public
         */
        function getAuthentication() {
            return $this->_page->getAuthentication();
        }

        /**
         *    Accessor for last Authentication realm. Only valid
         *    straight after a challenge (401).
         *    @return string    Name of security realm.
         *    @access public
         */
        function getRealm() {
            return $this->_page->getRealm();
        }

        /**
         *    Accessor for current URL of page or frame if
         *    focused.
         *    @return string    Location of current page or frame as
         *                      a string.
         */
        function getUrl() {
            $url = $this->_page->getUrl();
            return $url ? $url->asString() : false;
        }

        /**
         *    Accessor for raw bytes sent down the wire.
         *    @return string      Original text sent.
         *    @access public
         */
        function getRequest() {
            return $this->_page->getRequest();
        }

        /**
         *    Accessor for raw header information.
         *    @return string      Header block.
         *    @access public
         */
        function getHeaders() {
            return $this->_page->getHeaders();
        }

        /**
         *    Accessor for raw page information.
         *    @return string      Original text content of web page.
         *    @access public
         */
        function getContent() {
            return $this->_page->getRaw();
        }

        /**
         *    Accessor for plain text version of the page.
         *    @return string      Normalised text representation.
         *    @access public
         */
        function getContentAsText() {
            return $this->_page->getText();
        }

        /**
         *    Accessor for parsed title.
         *    @return string     Title or false if no title is present.
         *    @access public
         */
        function getTitle() {
            return $this->_page->getTitle();
        }

        /**
         *    Accessor for a list of all fixed links in current page.
         *    @return array   List of urls with scheme of
         *                    http or https and hostname.
         *    @access public
         */
        function getAbsoluteUrls() {
            return $this->_page->getAbsoluteUrls();
        }

        /**
         *    Accessor for a list of all relative links.
         *    @return array      List of urls without hostname.
         *    @access public
         */
        function getRelativeUrls() {
            return $this->_page->getRelativeUrls();
        }

        /**
         *    Sets all form fields with that name.
         *    @param string $label   Name or label of field in forms.
         *    @param string $value   New value of field.
         *    @return boolean        True if field exists, otherwise false.
         *    @access public
         */
        function setField($label, $value) {
            return $this->_page->setField(new SimpleByLabelOrName($label), $value);
        }

        /**
         *    Sets all form fields with that name. Will use label if
         *    one is available (not yet implemented).
         *    @param string $name    Name of field in forms.
         *    @param string $value   New value of field.
         *    @return boolean        True if field exists, otherwise false.
         *    @access public
         */
        function setFieldByName($name, $value) {
            return $this->_page->setField(new SimpleByName($name), $value);
        }

        /**
         *    Sets all form fields with that id attribute.
         *    @param string/integer $id   Id of field in forms.
         *    @param string $value        New value of field.
         *    @return boolean             True if field exists, otherwise false.
         *    @access public
         */
        function setFieldById($id, $value) {
            return $this->_page->setField(new SimpleById($id), $value);
        }

        /**
         *    Accessor for a form element value within the page.
         *    Finds the first match.
         *    @param string $label       Field label.
         *    @return string/boolean     A value if the field is
         *                               present, false if unchecked
         *                               and null if missing.
         *    @access public
         */
        function getField($label) {
            return $this->_page->getField(new SimpleByLabelOrName($label));
        }

        /**
         *    Accessor for a form element value within the page.
         *    Finds the first match.
         *    @param string $name        Field name.
         *    @return string/boolean     A string if the field is
         *                               present, false if unchecked
         *                               and null if missing.
         *    @access public
         */
        function getFieldByName($name) {
            return $this->_page->getField(new SimpleByName($name));
        }

        /**
         *    Accessor for a form element value within the page.
         *    @param string/integer $id  Id of field in forms.
         *    @return string/boolean     A string if the field is
         *                               present, false if unchecked
         *                               and null if missing.
         *    @access public
         */
        function getFieldById($id) {
            return $this->_page->getField(new SimpleById($id));
        }

        /**
         *    Clicks the submit button by label. The owning
         *    form will be submitted by this.
         *    @param string $label    Button label. An unlabeled
         *                            button can be triggered by 'Submit'.
         *    @param hash $additional Additional form data.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function clickSubmit($label = 'Submit', $additional = false) {
            if (! ($form = &$this->_page->getFormBySubmit(new SimpleByLabel($label)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitButton(new SimpleByLabel($label), $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Clicks the submit button by name attribute. The owning
         *    form will be submitted by this.
         *    @param string $name     Button name.
         *    @param hash $additional Additional form data.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function clickSubmitByName($name, $additional = false) {
            if (! ($form = &$this->_page->getFormBySubmit(new SimpleByName($name)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitButton(new SimpleByName($name), $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Clicks the submit button by ID attribute of the button
         *    itself. The owning form will be submitted by this.
         *    @param string $id       Button ID.
         *    @param hash $additional Additional form data.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function clickSubmitById($id, $additional = false) {
            if (! ($form = &$this->_page->getFormBySubmit(new SimpleById($id)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitButton(new SimpleById($id), $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Clicks the submit image by some kind of label. Usually
         *    the alt tag or the nearest equivalent. The owning
         *    form will be submitted by this. Clicking outside of
         *    the boundary of the coordinates will result in
         *    a failure.
         *    @param string $label    ID attribute of button.
         *    @param integer $x       X-coordinate of imaginary click.
         *    @param integer $y       Y-coordinate of imaginary click.
         *    @param hash $additional Additional form data.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function clickImage($label, $x = 1, $y = 1, $additional = false) {
            if (! ($form = &$this->_page->getFormByImage(new SimpleByLabel($label)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitImage(new SimpleByLabel($label), $x, $y, $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Clicks the submit image by the name. Usually
         *    the alt tag or the nearest equivalent. The owning
         *    form will be submitted by this. Clicking outside of
         *    the boundary of the coordinates will result in
         *    a failure.
         *    @param string $name     Name attribute of button.
         *    @param integer $x       X-coordinate of imaginary click.
         *    @param integer $y       Y-coordinate of imaginary click.
         *    @param hash $additional Additional form data.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function clickImageByName($name, $x = 1, $y = 1, $additional = false) {
            if (! ($form = &$this->_page->getFormByImage(new SimpleByName($name)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitImage(new SimpleByName($name), $x, $y, $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Clicks the submit image by ID attribute. The owning
         *    form will be submitted by this. Clicking outside of
         *    the boundary of the coordinates will result in
         *    a failure.
         *    @param integer/string $id    ID attribute of button.
         *    @param integer $x            X-coordinate of imaginary click.
         *    @param integer $y            Y-coordinate of imaginary click.
         *    @param hash $additional      Additional form data.
         *    @return string/boolean       Page on success.
         *    @access public
         */
        function clickImageById($id, $x = 1, $y = 1, $additional = false) {
            if (! ($form = &$this->_page->getFormByImage(new SimpleById($id)))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submitImage(new SimpleById($id), $x, $y, $additional));
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Submits a form by the ID.
         *    @param string $id       The form ID. No submit button value
         *                            will be sent.
         *    @return string/boolean  Page on success.
         *    @access public
         */
        function submitFormById($id) {
            if (! ($form = &$this->_page->getFormById($id))) {
                return false;
            }
            $success = $this->_load(
                    $form->getAction(),
                    $form->submit());
            return ($success ? $this->getContent() : $success);
        }

        /**
         *    Follows a link by label. Will click the first link
         *    found with this link text by default, or a later
         *    one if an index is given. The match ignores case and
         *    white space issues.
         *    @param string $label     Text between the anchor tags.
         *    @param integer $index    Link position counting from zero.
         *    @return string/boolean   Page on success.
         *    @access public
         */
        function clickLink($label, $index = 0) {
            $urls = $this->_page->getUrlsByLabel($label);
            if (count($urls) == 0) {
                return false;
            }
            if (count($urls) < $index + 1) {
                return false;
            }
            $this->_load($urls[$index], new SimpleGetEncoding());
            return $this->getContent();
        }

        /**
         *    Tests to see if a link is present by label.
         *    @param string $label     Text of value attribute.
         *    @return boolean          True if link present.
         *    @access public
         */
        function isLink($label) {
            return (count($this->_page->getUrlsByLabel($label)) > 0);
        }

        /**
         *    Follows a link by id attribute.
         *    @param string $id        ID attribute value.
         *    @return string/boolean   Page on success.
         *    @access public
         */
        function clickLinkById($id) {
            if (! ($url = $this->_page->getUrlById($id))) {
                return false;
            }
            $this->_load($url, new SimpleGetEncoding());
            return $this->getContent();
        }

        /**
         *    Tests to see if a link is present by ID attribute.
         *    @param string $id     Text of id attribute.
         *    @return boolean       True if link present.
         *    @access public
         */
        function isLinkById($id) {
            return (boolean)$this->_page->getUrlById($id);
        }

        /**
         *    Clicks a visible text item. Will first try buttons,
         *    then links and then images.
         *    @param string $label        Visible text or alt text.
         *    @return string/boolean      Raw page or false.
         *    @access public
         */
        function click($label) {
            $raw = $this->clickSubmit($label);
            if (! $raw) {
                $raw = $this->clickLink($label);
            }
            if (! $raw) {
                $raw = $this->clickImage($label);
            }
            return $raw;
        }
    }
?>