1001menus / baum
Baum is an implementation of the Nested Set pattern for Eloquent models.
Requires
- php: >=5.3.0
- illuminate/console: 4.*
- illuminate/database: 4.*
- illuminate/filesystem: 4.*
- illuminate/support: 4.*
Requires (Dev)
- mockery/mockery: 0.7.2
- phpunit/phpunit: 3.7.*
This package is auto-updated.
Last update: 2024-10-19 09:14:25 UTC
README
Baum is an implementation of the Nested Set pattern for Laravel 4's Eloquent ORM.
Documentation
About Nested Sets
A nested set is a smart way to implement an ordered tree that allows for fast, non-recursive queries. For example, you can fetch all descendants of a node in a single query, no matter how deep the tree. The drawback is that insertions/moves/deletes require complex SQL, but that is handled behind the curtains by this package!
Nested sets are appropriate for ordered trees (e.g. menus, commercial categories) and big trees that must be queried efficiently (e.g. threaded posts).
See the wikipedia entry for nested sets for more info. Also, this is a good introductory tutorial: http://www.evanpetersen.com/item/nested-sets.html
The theory behind, a TL;DR version
An easy way to visualize how a nested set works is to think of a parent entity surrounding all of its children, and its parent surrounding it, etc. So this tree:
root
|_ Child 1
|_ Child 1.1
|_ Child 1.2
|_ Child 2
|_ Child 2.1
|_ Child 2.2
Could be visualized like this:
___________________________________________________________________
| Root |
| ____________________________ ____________________________ |
| | Child 1 | | Child 2 | |
| | __________ _________ | | __________ _________ | |
| | | C 1.1 | | C 1.2 | | | | C 2.1 | | C 2.2 | | |
1 2 3_________4 5________6 7 8 9_________10 11_______12 13 14
| |___________________________| |___________________________| |
|___________________________________________________________________|
The numbers represent the left and right boundaries. The table then might look like this:
id | parent_id | lft | rgt | depth | data
1 | | 1 | 14 | 0 | root
2 | 1 | 2 | 7 | 1 | Child 1
3 | 2 | 3 | 4 | 2 | Child 1.1
4 | 2 | 5 | 6 | 2 | Child 1.2
5 | 1 | 8 | 13 | 1 | Child 2
6 | 5 | 9 | 10 | 2 | Child 2.1
7 | 5 | 11 | 12 | 2 | Child 2.2
To get all children of a parent node, you
SELECT * WHERE lft IS BETWEEN parent.lft AND parent.rgt
To get the number of children, it's
(right - left - 1)/2
To get a node and all its ancestors going back to the root, you
SELECT * WHERE node.lft IS BETWEEN lft AND rgt
As you can see, queries that would be recursive and prohibitively slow on ordinary trees are suddenly quite fast. Nifty, isn't it?
Installation
Baum works with Laravel 4 onwards. You can add it to your composer.json
file
with:
"baum/baum": "~1.0"
Run composer install
to install it.
As with most Laravel 4 packages you'll then need to register the Baum
service provider. To do that, head over your app/config/app.php
file and add
the following line into the providers
array:
'Baum\BaumServiceProvider',
Getting started
After the package is correctly installed the easiest way to get started is to run the provided generator:
php artisan baum:install MODEL
Replace model by the class name you plan to use for your Nested Set model.
The generator will install a migration and a model file into your application configured to work with the Nested Set behaviour provided by Baum. You SHOULD take a look at those files, as each of them describes how they can be customized.
Next, you would probably run artisan migrate
to apply the migration.
Model configuration
In order to work with Baum, you must ensure that your model class extends
Baum\Node
.
This is the easiest it can get:
class Category extends Baum\Node {
}
This is a slightly more complex example where we have the column names customized:
class Dictionary extends Baum\Node {
protected $table = 'dictionary';
// 'parent_id' column name
protected $parentColumn = 'parent_id';
// 'lft' column name
protected $leftColumn = 'lidx';
// 'rgt' column name
protected $rightColumn = 'ridx';
// 'depth' column name
protected $depthColumn = 'nesting';
// guard attributes from mass-assignment
protected $guarded = array('id', 'parent_id', 'lidx', 'ridx', 'nesting');
}
Remember that, obviously, the column names must match those in the database table.
Migration configuration
You must ensure that the database table that supports your Baum models has the following columns:
parent_id
: a reference to the parent (int)lft
: left index bound (int)rgt
: right index bound (int)depth
: depth or nesting level (int)
Here is a sample migration file:
class Category extends Migration {
public function up() {
Schema::create('categories', function(Blueprint $table) {
$table->increments('id');
$table->integer('parent_id')->nullable();
$table->integer('lft')->nullable();
$table->integer('rgt')->nullable();
$table->integer('depth')->nullable();
$table->string('name', 255);
$table->timestamps();
});
}
public function down() {
Schema::drop('categories');
}
}
You may freely modify the column names, provided you change them both in the migration and the model.
Usage
After you've configured your model and run the migration, you are now ready to use Baum with your model. Below are some examples.
- Creating a root node
- Inserting nodes
- Deleting nodes
- Getting the nesting level of a node
- Moving nodes around
- Asking questions to your nodes
- Relations
- Root and Leaf scopes
- Accessing the ancestry/descendancy chain
- Dumping the hierarchy tree
- Model events:
moving
andmoved
- Scope support
- Misc/Utility functions
Creating a root node
By default, all nodes are created as roots:
$root = Category::create(['name' => 'Root category']);
Alternatively, you may find yourself in the need of converting an existing node into a root node:
$node->makeRoot();
Inserting nodes
// Directly with a relation
$child1 = $root->children()->create(['name' => 'Child 1']);
// with the `makeChildOf` method
$child2 = Category::create(['name' => 'Child 2']);
$child2->makeChildOf($root);
Deleting nodes
$child1->delete();
Descendants of deleted nodes will also be deleted and all the lft
and rgt
bound will be recalculated. Pleases note that, for now, deleting
and deleted
model events for the descendants will not be fired.
Getting the nesting level of a node
The getLevel()
method will return current nesting level, or depth, of a node.
$node->getLevel() // 0 when root
Moving nodes around
Baum provides several methods for moving nodes around:
moveLeft()
: Find the left sibling and move to the left of it.moveRight()
: Find the right sibling and move to the right of it.moveToLeftOf($otherNode)
: Move to the node to the left of ...moveToRightOf($otherNode)
: Move to the node to the right of ...makeNextSiblingOf($otherNode)
: Alias formoveToRightOf
.makeSiblingOf($otherNode)
: Alias formakeNextSiblingOf
.makePreviousSiblingOf($otherNode)
: Alias formoveToLeftOf
.makeChildOf($otherNode)
: Make the node a child of ...makeRoot()
: Make current node a root node.
For example:
$root = Creatures::create(['name' => 'The Root of All Evil']);
$dragons = Creatures::create(['name' => 'Here Be Dragons']);
$dragons->makeChildOf($root);
$monsters = new Creatures(['name' => 'Horrible Monsters']);
$monsters->save();
$monsters->makeSiblingOf($dragons);
$demons = Creatures::where('name', '=', 'demons')->first();
$demons->moveToLeftOf($dragons);
Asking questions to your nodes
You can ask some questions to your Baum nodes:
isRoot()
: Returns true if this is a root node.isLeaf()
: Returns true if this is a leaf node (end of a branch).isChild()
: Returns true if this is a child node.isDescendantOf($other)
: Returns true if node is a descendant of the other.isSelfOrDescendantOf($other)
: Returns true if node is self or a descendant.isAncestorOf($other)
: Returns true if node is an ancestor of the other.isSelfOrAncestorOf($other)
: Returns true if node is self or an ancestor.equals($node)
: current node instance equals the other.insideSubtree($node)
: Checks wether the given node is inside the subtree defined by the left and right indices.inSameScope($node)
: Returns true if the given node is in the same scope as the current one. That is, if every column in thescoped
property has the same value in both nodes.
Using the nodes from the previous example:
$demons->isRoot(); // => false
$demons->isDescendantOf($root) // => true
Relations
Baum provides two self-referential Eloquent relations for your nodes: parent
and children
.
$parent = $node->parent()->get();
$children = $node->children()->get();
Root and Leaf scopes
Baum provides some very basic query scopes for accessing the root and leaf nodes:
// Query scope which targets all root nodes
Category::roots()
// All leaf nodes (nodes at the end of a branch)
Category:allLeaves()
You may also be interested in only the first root:
$firstRootNode = Category::root();
Accessing the ancestry/descendancy chain
There are several methods which Baum offers to access the ancestry/descendancy chain of a node in the Nested Set tree. The main thing to keep in mind is that they are provided in two ways:
First as query scopes, returning an Illuminate\Database\Eloquent\Builder
instance to continue to query further. To get actual results from these,
remember to call get()
or first()
.
ancestorsAndSelf()
: Targets all the ancestor chain nodes including the current one.ancestors()
: Query the ancestor chain nodes excluding the current one.siblingsAndSelf()
: Instance scope which targets all children of the parent, including self.siblings()
: Instance scope targeting all children of the parent, except self.leaves()
: Instance scope targeting all of its nested children which do not have children.descendantsAndSelf()
: Scope targeting itself and all of its nested children.descendants()
: Set of all children & nested children.immediateDescendants()
: Set of all children nodes (non-recursive).
Second, as methods which return actual Baum\Node
instances (inside a Collection
object where appropiate):
getRoot()
: Returns the root node starting at the current node.getAncestorsAndSelf()
: Retrieve all of the ancestor chain including the current node.getAncestorsAndSelfWithoutRoot()
: All ancestors (including the current node) except the root node.getAncestors()
: Get all of the ancestor chain from the database excluding the current node.getAncestorsWithoutRoot()
: All ancestors except the current node and the root node.getSiblingsAndSelf()
: Get all children of the parent, including self.getSiblings()
: Return all children of the parent, except self.getLeaves()
: Return all of its nested children which do not have children.getDescendantsAndSelf()
: Retrieve all nested children and self.getDescendants()
: Retrieve all of its children & nested children.getImmediateDescendants()
: Retrieve all of its children nodes (non-recursive).
Here's a simple example for iterating a node's descendants (provided a name attribute is available):
$node = Category::where('name', '=', 'Books')->first();
foreach($node->getDescendantsAndSelf() as $descendant) {
echo "{$descendant->name}";
}
Dumping the hierarchy tree
Baum extends the default Eloquent\Collection
class and provides the
toHierarchy
method to it which returns a nested collection representing the
queried tree.
Retrieving a complete tree hierarchy into a regular Collection
object with
its children properly nested is as simple as:
$tree = Category::where('name', '=', Books)->getDescendantsAndSelf()->toHierarchy();
Model events: moving
and moved
Baum models fire the following events: moving
and moved
every time a node
is moved around the Nested Set tree. This allows you to hook into those points
in the node movement process. As with normal Eloquent model events, if false
is returned from the moving
event, the movement operation will be cancelled.
The recommended way to hook into those events is by using the model's boot method:
class Category extends Baum\Node {
public static function boot() {
parent::boot();
static::moving(function($node) {
// Before moving the node this function will be called.
});
static::moved(function($node) {
// After the move operation is processed this function will be
// called.
});
}
}
Scope support
Baum provides a simple method to provide Nested Set "scoping" which restricts what we consider part of a nested set tree. This should allow for multiple nested set trees in the same database table.
To make use of the scoping funcionality you may override the scoped
model
attribute in your subclass. This attribute should contain an array of the column
names (database fields) which shall be used to restrict Nested Set queries:
class Category extends Baum\Node {
...
protected $scoped = array('company_id');
...
}
In the previous example, company_id
effectively restricts (or "scopes") a
Nested Set tree. So, for each value of that field we may be able to construct
a full different tree.
$root1 = Category::create(['name' => 'R1', 'company_id' => 1]);
$root2 = Category::create(['name' => 'R2', 'company_id' => 2]);
$child1 = Category::create(['name' => 'C1', 'company_id' => 1]);
$child2 = Category::create(['name' => 'C2', 'company_id' => 2]);
$child1->makeChildOf($root1);
$child2->makeChildOf($root2);
$root1->children()->get(); // <- returns $child1
$root2->children()->get(); // <- returns $child2
All methods which ask or traverse the Nested Set tree will use the scoped
attribute (if provided).
Misc/Utility functions
Node extraction query scopes
Baum provides some query scopes which may be used to extract (remove) selected nodes from the current results set.
withoutNode(node)
: Extracts the specified node from the current results set.withoutSelf()
: Extracts itself from the current results set.withoutRoot()
: Extracts the current root node from the results set.
$node = Category::where('name', '=', 'Some category I do not want to see.')->first();
$root = Category::where('name', '=', 'Old boooks')->first();
var_dump($root->descendantsAndSelf()->withoutNode($node)->get());
... // <- This result set will not contain $node
Contributing
Thinking of contributing? Maybe you've found some nasty bug? That's great news!
- Fork the project:.
- Create your bugfix/feature branch.
- Code away your changes and, if you can, provide some tests.
- Commit your changes & push to the branch.
- Create a new Pull Request
License
Baum is licensed under the terms of the MIT License (See LICENSE file for details).
Coded by Estanislau Trepat (etrepat). I'm also @etrepat on twitter.