Use the Zend Framework to remember the last clicked position - php

Question

I want to add a feature to an existing website thats built using the Zend Framework. One of the problems with this website is that it refreshes the page often at different positions on the web page. What I would like to do is use a built-in Zend framework function to keep the same position in a web page after it has been refreshed.
An example would be: A user clicks at the bottom of the page, the same page is reloaded but it does not reload at the top of the page, it stays where the user last clicked.
Is there such a thing?
Thank you

Answer 1

You will have to use a combination of Javascript (in the frontend) and Zend Framework (in the backend) to achieve this.
This is assuming you are using user cookies/sessions.
Create an event handler to detect mouse-clicks using Javascript anywhere on the page. In the event handler, use the event object to get the x and y-coordinates of the mouse position. (Mouse click event coordinates)
Set up an endpoint in your Zend Framework that will accept mouse coordinates for the user. For example: http://localhost/user/updateCoordinates?x=12&y=100
On mouse click, make your event handler perform an AJAX query sending the coordinates to the endpoint you set up in #2.
In Zend Framework, store these coordinates in the user session/cookie (so you can track it later)
On page load, get the value from the session and output Javascript code to automatically scroll to that coordinate. Also, remove the x and y-coordinate from the cookie since it has already been used.

Answer 2

You could use some javascript to record the scroll position of the window right before a refresh, and just save it to a cookie.
Then, when the next page loads, check for the cookie, scroll to its position, and delete it. This won't work well if the webpage has dynamically sized elements(example: an expanding accordion menu).
Personally though, I would try to avoid this. Every now and then I visit some website that likes to do stuff with my scroll bar and try to help me. Way too often they get it wrong and the webpage becomes unusable. Maybe you can just dynamically update the page(ajax?) instead of doing a real reload.

Answer 3

u can use existing components of ZF and combine them in some new plugin:
1) new ZF plugin saved in ZF structure in my case: /library/My/Controller/Plugin/ActionHistory.php
final class My_Controller_Plugin_ActionHistory extends Zend_Controller_Plugin_Abstract
{
/** #var bool flag indicating whether current action has been already logged */
private $dispatched = false;
/**
* #param Zend_Controller_Request_Abstract $request
* #return void
*/
public function pushStack(Zend_Controller_Request_Abstract $request) {
$storage = $this->getStorage();
$storage->stack[] = $request;
// limit the depth of the stack
if (count($storage->stack) > $this->getMaxDepth()) {
array_shift($storage->stack);
}
// mark current action as dispatched (influences getBacklink())
$this->dispatched = true;
}
public function popStack() {
$storage = $this->getStorage();
return array_pop($storage->stack);
}
/**
* Returns request to previous action (not current).
*
* #return Zend_Controller_Request_Abstract|null
*/
public function getBacklink() {
$storage = $this->getStorage();
$depth = count($storage->stack);
// points to top of the stack
$backlinkIndex = $depth - 1;
if ($this->dispatched) {
// current action has been already logged, "backlink" is second from the top
--$backlinkIndex;
}
return ($backlinkIndex >= 0 ? $storage->stack[$backlinkIndex] : null);
}
/**
* Returns stack with performed actions
* #return array
*/
public function getStack() {
return $this->getStorage()->stack;
}
/**
* #return Zend_Session_Namespace
*/
private function getStorage() {
static $storage = null;
if ($storage === null) {
$storage = new Zend_Session_Namespace(get_class($this), true);
if (!is_array($storage->stack)) {
// initialize stack if needed
$storage->stack = array();
}
}
return $storage;
}
/**
* Returns maximal depth of the action history
* #return int
*/
private function getMaxDepth() {
return 3;
}
}
2) Place somewhere this code to pushing history in stack. You can use history only e.g. with cooperation with logging to application or you can save all history. It depends on you:
// this code is example of usage in another ZF controller plugin class
$actionHistory = Zend_Controller_Action_HelperBroker::getStaticHelper("ActionHistory");
if ($actionHistory) {
// $this => instance of Zend_Controller_Plugin_Abstract
$actionHistory->pushStack($this->getRequest());
}
3) Then u can use this plugin in some controller where you want to handle action history like that:
// check if there is an backlink stored in actionStack, if yes than use it
if (($actionHistory = $this->getHelper('actionHistory'))) {
$request = $actionHistory->getBacklink();
if ($request) {
$actionHistory->popStack();
// use any of your redirect classes or simle redirector helper
// right path to previous site is accesible by $request->getUserParams()
$this->redirect($request->getUserParams());
}
}
Thats it:) Hope you can modify what you want but the theory and benefits of this solution are clear enought...