# Symfony 1.4 Drag&Drop Nested Set Editor for Admin Generator

Most of my web application have some kind of hierarchical structure in their models. It gives my users the ability to categorize their data in a pleasant way. The only problem is that its hard to create a user interface for editing these hierarchies. I made a prototype which adds nested set support to the symfony (1.2) generator. This extension allows for full drag&drop nested set support! See for yourself by clicking the image:

click for a real demo of the nested set editor

The editor uses the treeTable jQuery plugin with added D&D support.

## Full source is available

Today I created the redotheoffice github repository. Right there you can find the full source of the project.

## Explanation

As I’m quite short on time right now, so I’ll only do a brief explanation and give you hints where to look in the source.

One first note is that the current implementation of NestedSet has a bug. Moving a deep branch to the root may corrupt the tree. I made a ticket and patch, but it’s not yet patched in the repositories. So manually update your Doctrine library, or only use this code for testing purposes…

The editor is based on a really simple model, using Doctrine’s actAs NestedSet (see config/doctrine/nested.yml):

 --- Tree: actAs: NestedSet: hasManyRoots: true rootColumnName: root_id columns: name: type: string(255) 

Next step is creating a default admin generator for the ‘Tree’ model. How to do this is clearly explained in Jobeet day 12: the Admin Generator. I think I did something like:

./symfony generate:app backend


### jQuery treeTable plugin

First enhancement is to implement the treeTable plugin. This turns the normal generated table into a collapsible tree.

Download the treeTable code, I copied the .js and .css to theweb/js and web/css and added them to theapps/backend/config/view.yml. Also make sure to load jQuery:

 default: http_metas: content-type: text/html   metas: ~   stylesheets: - jQuery.treeTable.css - main.css   javascripts: - http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js - http://ajax.googleapis.com/ajax/libs/jqueryui/1.5.3/jquery-ui.min.js - jquery.treeTable.js 

I happen to like the way jQuery can be loaded through the googleapi system. Symfony can handle the full URL’s by default, this style is easy to maintain and upgrade. Google also makes sure the headers of the js library are set correctly, which minimizes reloads of the files.

TreeTable is then enabled by overwriting theapps/backend/modules/tree/templates/_list.php template with some code that writes the correct classes to the individual rows. Also the table needs an id for easy finding the object:

 ... <table id="main_list" cellspacing="0"> ... <tbody> <?php foreach ($pager->getResults() as$i => $tree):$odd = fmod(++$i, 2) ? 'odd' : 'even' ?> <tr id="node-<?php echo$tree['id'] ?>" class="sf_admin_row <?php echo $odd ?><?php // insert hierarchical info$node = $tree->getNode(); if ($node->isValidNode() && $node->hasParent()) { echo " child-of-node-".$node->getParent()->getId(); } ?>"> <?php include_partial('tree/list_td_batch_actions', array('tree' => $tree, 'helper' =>$helper)) ?> <?php include_partial('tree/list_td_tabular', array('tree' => $tree)) ?> <?php include_partial('tree/list_td_actions', array('tree' =>$tree, 'helper' => $helper)) ?> </tr> <?php endforeach; ?> </tbody> ... <script type="text/javascript"> function checkAll() { var boxes = document.getElementsByTagName('input'); for(index in boxes) { box = boxes[index]; if (box.type == 'checkbox' && box.className == 'sf_admin_batch_checkbox') box.checked = document.getElementById('sf_admin_list_batch_checkbox').checked } return true; }$(document).ready(function() { $("#main_list").treeTable({ treeColumn: 2, initialState: 'expanded' }); } </script>  Doing this should give you a collapsible tree right inside your Admin Generator table. ### Adding Drag&Drop support Adding drag & drop on the client side is done by adding some javascript to the end of the _list.php template, see github. After dropping the item on a new parent the treeTable plugin takes care of updating the client visual interface. It’s up to us to send the data back to the server. For this I added a hidden select on each row of the table:  <td> <input type="checkbox" name="ids[]" value="<?php echo$tree->getPrimaryKey() ?>" class="sf_admin_batch_checkbox" /> <input type="hidden" id="select_node-<?php echo $tree->getPrimaryKey() ?>" name="newparent[<?php echo$tree->getPrimaryKey() ?>]" /> </td> 

To clarify a little I added the screenshot below, in which the input element is still shown. After dropping the javascript seeks the id of the parent dropped on and types it into the input of the dragged item. Sending this to the server will enable the server to update the parent of the item. The code resides in the ‘executeBatchOrder’ function inapps/backen/modules/tree/actions/actions.class.php.

### TreeForm implementation

The implementation of the TreeForm is also noteworthy. It removes all nested set columns (root_idlftrgt and level) and adds a fully functional dropdown for selecting the parent. This code can easily be dropped into your project and doesn’t depend on jQuery or any other external library. After submitting the form makes sure all columns for the nested set are properly updated to the new parent. See the image below, and the TreeForm.class.php file at github.

## Further enhancements

Things can always become better:

• Add a serialize function to treeTable which enables the possibility to get rid of the hidden input element on each row.
• Make it possible to edit the order of children from the same parent (now it always inserts asFirstChild). Possible solution could be an interface like nestedSortable
• Move the Update tree order batch action from the dropdown to the table footer (next to the New link)
• Change this prototype into a Plugin