symfony dynamic max_per_page

max_per_page

In this post I'll show a very easy and a really useful thing. It is dynamic max_per_page value of the list pager. Such feature gives you the possibility to change the number of elements displayed in a list just by one click. It can be used both in the frontend and backend (the pager is the same) - I'll use the doctrine generated admin module (and the interface will be placed inside the filters box):

templates

First, let's make it visible. Add the following entry to application config/app.yml file:

all:
  const:
    max_per_page: [ 10, 25, 50 ]

Now we may refer to app_const_max_per_page config value which holds few standard max_per_page values to be used (this can be used in many different admin modules). Let's say we've got an admin module for our custom MyModel model. Now, override the cached _filters.php template: fetch it from cache/admin/dev/modules/autoMyModel/templates and put it in apps/APP/modules/my_model/templates. Take a look at the following part of the code:

          </td>
        </tr>
      </tfoot>
      <tbody>
        <!-- insert here -->
        <tr>
          <td colspan="2">

and insert few lines of code (replace the comment) to get the following:

          </td>
        </tr>
      </tfoot>
      <tbody>
        <tr>
          <td colspan="2">
            set maximum elements per page:
            <?php foreach (sfConfig::get('app_const_max_per_page') as $value): ?>
              <span class="max_per_page_selector"><?php echo link_to($value, 'my_model/setMaxPerPage?max='.$value) ?></span>
            <?php endforeach; ?>
          </td>
        </tr>
        <tr>
          <td colspan="2">

controller/action

The interface to change max_per_page is ready, so we have to improve the controller now. Let's add an action which stores the number of elements to display per page in user session (symofny has nice set(get)Attributes methods). So here it comes:

  /**
   * Sets my_model list's max per page config value, using user session
   * attribute.
   *
   * @param sfWebRequest $request
   */
  public function executeSetMaxPerPage(sfWebRequest $request)
  {
    $this->getUser()->setAttribute('my_model.max_per_page', $max = $request->getParameter('max'));
    $this->getUser()->setFlash('notice', 'max_per_page has been set to: '.$max);
    $this->redirect('@my_model');
  }

configuration generator

And finally, tell the pager to look for the custom value each time the list is going to be rendered. We need to override the method in configuration generator of the admin module:

class my_modelGeneratorConfiguration extends BaseMy_modelGeneratorConfiguration
{
  /**
   * Returns max_per_page config value for my_model module. If it's not
   * defined manually by the user, default value is returned.
   *
   * @return Integer
   */
  public function getPagerMaxPerPage()
  {
    if ($max = sfContext::getInstance()->getUser()->getAttribute('my_model.max_per_page'))
      return $max;
    else
      return parent::getPagerMaxPerPage();
  }

It's all as easy as it could be. The controller searches the servers for the current user session data and returns either the custom data (if found) or the default value (which is taken from the generator.yml file).

Unfortunately, the sfContext::getInstance() is used here (this causes a lot of problems when the default context problem occurs). After a quick look I didn't find the better way to access the user from the configuration generator (but if you know how to - let me know ;).

(I'm wondering why it's not built in into symfony).