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There is no tutorial on that and the pager is quite complex, thow you do not need to do much to get it going. After you have set up a working pager, I recommend taking a closer look at the class.pagermodule.php to find out more about its possibilities.

The best way to get going is to look at a page where you can find a pager, e.g. one of the discussions lists (recent discussions, bookmarked, mine etc.) You can find that code in /applications/vanilla/controllers/class.discussionscontroller.php

Let's look at the mine() method, which is quite short, but I stripped out what is not necessary to get a working example:

   public function mine($page = 'p1') {
...
       // Set criteria & get discussions data
       list($offset, $limit) = offsetLimit($page, c('Vanilla.Discussions.PerPage', 30));
...
       $countDiscussions = $this->setData('CountDiscussions', $discussionModel->getCount($wheres));
...
       // Build a pager
       $pagerFactory = new Gdn_PagerFactory();
       $this->EventArguments['PagerType'] = 'MorePager';
...
       $this->Pager = $pagerFactory->getPager($this->EventArguments['PagerType'], $this);
       $this->Pager->MoreCode = 'More Discussions';
       $this->Pager->LessCode = 'Newer Discussions';
       $this->Pager->ClientID = 'Pager';
       $this->Pager->configure(
           $offset,
           $limit,
           $countDiscussions,
           'discussions/mine/%1$s'
       );

       $this->setData('_PagerUrl', 'discussions/mine/{Page}');
       $this->setData('_Page', $page);
       $this->setData('_Limit', $limit);
...
       // Deliver JSON data if necessary
       if ($this->_DeliveryType != DELIVERY_TYPE_ALL) {
           $this->setJson('LessRow', $this->Pager->toString('less'));
           $this->setJson('MoreRow', $this->Pager->toString('more'));
           $this->View = 'discussions';
       }
...
   }

The main element in there is the following block:

       $this->Pager->configure(
           $offset,
           $limit,
           $countDiscussions,
           'discussions/mine/%1$s'
       );

The pager module needs to be configured with those information: where does the current page starts (offset), how much elements does it show (limit), how much elements are there in total (countDiscussions) and where should the previous and next page links should point to.

But look at method code step by step:

   public function mine($page = 'p1') {

In your plugin this will most probably be

   public function pluginController_foo_create($sender, $args) {

The $args array will contain everything that comes after yourforum.com/plugin/foo/...

Therefore, if your url scheme for e.g. the third page should be /plugin/foo/p3, you should have the following code for getting the page for building the pager: $page = $args[0] ?? 'p1';

If your url scheme is /plugin/foo/bar/baz/p3, the required code would be $page = $args[2] ?? 'p1';

       list($offset, $limit) = offsetLimit($page, c('Vanilla.Discussions.PerPage', 30));

This line does a lot! You should look up the function offsetLimit in functions.general.php. What's happening here is that the variables $offset and $limit are filled based on the $page variable and the config value for Vanilla.Discussions.PerPage. I would encoure to make your view configurable in the same way.

       list($offset, $limit) = offsetLimit($page, Gdn::config('Plugins.FooBar.PerPage', 30));

And if it makes sense, you can directly use a Vanilla PerPage setting as default!

        list($offset, $limit) = offsetLimit(
           $page,
           Gdn::config(
               'Plugins.FooBar.PerPage',
                Gdn::config(
                    'Vanilla.Discussions.PerPage',
                    30
                )
            )
        );

The following lines in the snippet are split because that way a plugin author can influence the look and feel of the pager of the mine() method.

       $this->EventArguments['PagerType'] = 'MorePager';
...
       $this->Pager = $pagerFactory->getPager($this->EventArguments['PagerType'], $this);

You can condense it to this line

       $this->Pager = $pagerFactory->getPager('MorePager', $this);

By the way: in most cases when you look at Vanilla code and see $this, you will have to replace that with $sender (if you stick to Vanillas conventions)

Frankly spoken, I'm not sure if you need this block:

       $this->setData('_PagerUrl', 'discussions/mine/{Page}');
       $this->setData('_Page', $page);
       $this->setData('_Limit', $limit);

ANd you have to decide by yourself if that makes sense for you:

       // Deliver JSON data if necessary
       if ($this->_DeliveryType != DELIVERY_TYPE_ALL) {
           $this->setJson('LessRow', $this->Pager->toString('less'));
           $this->setJson('MoreRow', $this->Pager->toString('more'));
           $this->View = 'discussions';
       }

In your view, a simple PagerModule::write() should be sufficient.

I would advice against using installation scripts for following reasons:

1. Vanilla is easy to install, they bring not much use.
2. It will always take some time between an officially available Vanilla version and a softaculous update. In the meantime your forum might be open for known security issues.
3. In order to work, they need to alter the Vanilla source code slightly. When any error occurs, it might be hard to give support because it might not be easy to tell if the installer/the hoster is causing the issue or Vanilla.

If you are searching for a forum solution and your provider offers a one click installer for Vanilla, then use it to try if Vanilla is the forum solution you are looking for. But after you've made your decision, free yourself from that bounds of the installer version and set up Vanilla by yourself. It's really easy.

Tell your provider that Php 7.0 is out of support: https://www.php.net/supported-versions.php