Фремворк Limb

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====== Step5. Adding more functionality: news detail page, 5 latest news on the main page, sorting etc. ======

===== Sorting news =====

Let's suppose we need to sort news by "date" field. This can be accomplished in many different ways. One possible way is to set sorting properties by **order** attribute of <active_record:fetch> tag right in the template:

<code xml>
<active_record:fetch using='src/model/News' target='news' navigator='pager' order='date=DESC'/>
</code>

Another way is to call sort($params) method of newsline record set. You can use this method in case if you prefer using raw php-blocks in your templates:

<code php>
<?php 
   $news = lmbActiveRecord :: find('News')->sort('date' => 'DESC');
?>
 
<list:LIST from="$news">
[...]
</code>

One more way is to set default sorting parameters in News class:

<code php>
class News extends lmbActiveRecord
{
  protected $_default_sort_params = array('date' => 'DESC');
}
</code>


lmbActiveRecord :: $_default_sort_params allows you to set just default sorting params. If we passed any other sorting params using the first two methods - the default sorting params will be ignored.


===== The latest news on the main page =====

Now when we know how to sort news we can render some latest news on the main page of our application. To do so let's create (or modify) **crud/template/main_page/display.html** template:

<code xml>
<core:WRAP file="page.html" in="page_placeholder">

<h1>Main page</h1>

<active_record:fetch using='src/model/News' target="last_news" order='date=DESC' limit='3'/>

<list:LIST id="last_news">
  <list:ITEM>
  <table>
  <tr>
    <td>{$date}</td>
    <td>{$title}</td>
  </tr>
  <tr>
    <td colspan='2'>{$annotation}
    <route_url params='controller:news,action:detail,id:{$id}'>more...</route_url>
    </td>
  </tr>
  </table>
  <hr/>
  </list:ITEM>
  <route_url params='controller:news'>all news...</route_url>
</list:LIST>

</core:wrap>
</code>

Here we used **limit** attribute of <active_record:fetch> tag. We can always limit the size of any record set fetched by <active_record:fetch> tag with **limit** and **offset** attributes. 

There is an alternative way to apply limit and offset:

<code php>
<?php 
   $news = lmbActiveRecord :: find('News')->sort('date' => 'DESC')->paginate($offset = 0, $limit = 3);
?>
</code>

P.S. If you would like to see complete interface of news record set look at limb/core/src/lmbCollectionInterface.interface.php. lmbCollectionInterface is a common interface for all classes that implement collections (e.g. db record set or array holder lmbCollection).

The next line:
<code xml>
  <route_url params='controller:news,action:detail,id:{$id}'>more...</route_url>
</code>
is responsible for rendering links to pages with detail description of news.

If you started this tutorial with limb_app downloaded from SourseForge.net then you already have MainPageController. But if started this project from the scratch then you need to add a controller for the main page (**crud/src/controller/MainPageController.class.php**):
<code xml>
<?php
lmb_require('limb/web_app/src/controller/lmbController.class.php');
 
class MainPageController extends lmbController
{
}
?>
</code>

===== News detail page =====

Let's add new template **crud/template/news/detail.html** to render full information for some particular news:

<code xml>
<core:WRAP file="page.html" in="page_placeholder">

<active_record:fetch using='src/model/News' target="current_news" first="true">
  <fetch:params record_id='{$#request.id}'/>
</active_record:fetch>

<core:DATASOURCE id='current_news'>

<h1>{$title}</h1>

<b>Date</b> : {$date}<br/>

{$content|raw}

</core:DATASOURCE>

</core:wrap>
</code>

Please note **first** attribute of <active_record:fetch> tag that means what we don't need a complete record set but just a single (first) record. <core:datasource> tag accepts news object fetched by <active_record:fetch> tag. 

[[limb3:en:packages:wact:tags:fetch_tags:fetch_parameter_tag|<fetch:params>]] tag is used to pass some extra params to <active_record:fetch> tag. In our case we used this tag to pass news identifier we need to load. The value of news identifier (id) we take from "request" - the request object with POST and GET data is available in the global scope in WACT template(this is done for you by WEB_APP package). {$#request.id} expression means: "use request from global scope then take 'id' attribute from request".

We can always achieve the same result with raw php-block without using any WACT tag for fetching operations:

<code php>
<core:WRAP file="page.html" in="page_placeholder">

<?php $news = lmbActiveRecord :: findById('News', (int)$template->get('request')->get('id')); ?>

<core:DATASOURCE from='$news'>

<h1>{$title}</h1>

<b>Date</b> : {$date}<br/>

{$content|raw}

</core:DATASOURCE>

</core:wrap>
</code>

Or even without <core:datasource>:

<code php>
<core:WRAP file="page.html" in="page_placeholder">

<?php $news = lmbActiveRecord :: findById('News', (int)$template->get('request')->get('id')); ?>

<h1>{$$news.title}</h1>

<b>Date</b> : {$$news.date}<br/>

{$$news.content|raw}

</core:wrap>
</code>

The last point is to modify news/display.html a bit to render a link to news detail page as well as on the main page:
<code php>
  [...]
  <tr>
    <td colspan='4'>
      {$annotation}
      <route_url params='controller:news,action:detail,id:{$id}'>more...</route_url>
    </td>
  </tr>
  [...]
</code>

===== What's next? =====

  * [[.step6|Step6. Creating newsline RSS-feed]]