1<?php
2/**
3 * CSort class file.
4 *
5 * @author Qiang Xue <qiang.xue@gmail.com>
6 * @link http://www.yiiframework.com/
7 * @copyright Copyright &copy; 2008-2010 Yii Software LLC
8 * @license http://www.yiiframework.com/license/
9 */
10
11/**
12 * CSort represents information relevant to sorting.
13 *
14 * When data needs to be sorted according to one or several attributes,
15 * we can use CSort to represent the sorting information and generate
16 * appropriate hyperlinks that can lead to sort actions.
17 *
18 * CSort is designed to be used together with {@link CActiveRecord}.
19 * When creating a CSort instance, you need to specify {@link modelClass}.
20 * You can use CSort to generate hyperlinks by calling {@link link}.
21 * You can also use CSort to modify a {@link CDbCriteria} instance by calling {@link applyOrder} so that
22 * it can cause the query results to be sorted according to the specified
23 * attributes.
24 *
25 * In order to prevent SQL injection attacks, CSort ensures that only valid model attributes
26 * can be sorted. This is determined based on {@link modelClass} and {@link attributes}.
27 * When {@link attributes} is not set, all attributes belonging to {@link modelClass}
28 * can be sorted. When {@link attributes} is set, only those attributes declared in the property
29 * can be sorted.
30 *
31 * By configuring {@link attributes}, one can perform more complex sorts that may
32 * consist of things like compound attributes (e.g. sort based on the combination of
33 * first name and last name of users).
34 *
35 * The property {@link attributes} should be an array of key-value pairs, where the keys
36 * represent the attribute names, while the values represent the virtual attribute definitions.
37 * For more details, please check the documentation about {@link attributes}.
38 *
39 * @author Qiang Xue <qiang.xue@gmail.com>
40 * @version $Id: CSort.php 2156 2010-05-30 15:05:44Z qiang.xue $
41 * @package system.web
42 * @since 1.0.1
43 */
44class CSort extends CComponent
45{
46	/**
47	 * @var boolean whether the sorting can be applied to multiple attributes simultaneously.
48	 * Defaults to false, which means each time the data can only be sorted by one attribute.
49	 */
50	public $multiSort=false;
51	/**
52	 * @var string the name of the model class whose attributes can be sorted.
53	 * The model class must be a child class of {@link CActiveRecord}.
54	 */
55	public $modelClass;
56	/**
57	 * @var array list of attributes that are allowed to be sorted.
58	 * For example, array('user_id','create_time') would specify that only 'user_id'
59	 * and 'create_time' of the model {@link modelClass} can be sorted.
60	 * By default, this property is an empty array, which means all attributes in
61	 * {@link modelClass} are allowed to be sorted.
62	 *
63	 * This property can also be used to specify complex sorting. To do so,
64	 * a virtual attribute can be declared in terms of a key-value pair in the array.
65	 * The key refers to the name of the virtual attribute that may appear in the sort request,
66	 * while the value specifies the definition of the virtual attribute.
67	 *
68	 * In the simple case, a key-value pair can be like <code>'user'=>'user_id'</code>
69	 * where 'user' is the name of the virtual attribute while 'user_id' means the virtual
70	 * attribute is the 'user_id' attribute in the {@link modelClass}.
71	 *
72	 * A more flexible way is to specify the key-value pair as
73	 * <pre>
74	 * 'user'=>array(
75	 *     'asc'=>'first_name, last_name',
76	 *     'desc'=>'first_name DESC, last_name DESC',
77	 *     'label'=>'Name'
78	 * )
79	 * </pre>
80	 * where 'user' is the name of the virtual attribute that specifies the full name of user
81	 * (a compound attribute consisting of first name and last name of user). In this case,
82	 * we have to use an array to define the virtual attribute with three elements: 'asc',
83	 * 'desc' and 'label'.
84	 *
85	 * The above approach can also be used to declare virtual attributes that consist of relational
86	 * attributes. For example,
87	 * <pre>
88	 * 'price'=>array(
89	 *     'asc'=>'item.price',
90	 *     'desc'=>'item.price DESC',
91	 *     'label'=>'Item Price'
92	 * )
93	 * </pre>
94	 *
95	 * Note, the attribute name should not contain '-' or '.' characters because
96	 * they are used as {@link separators}.
97	 *
98	 * Starting from version 1.1.3, an additional option named 'default' can be used in the virtual attribute
99	 * declaration. This option specifies whether an attribute should be sorted in ascending or descending
100	 * order upon user clicking the corresponding sort hyperlink if it is not currently sorted. The valid
101	 * option values include 'asc' (default) and 'desc'. For example,
102	 * <pre>
103	 * 'price'=>array(
104	 *     'asc'=>'item.price',
105	 *     'desc'=>'item.price DESC',
106	 *     'label'=>'Item Price',
107	 *     'default'=>'desc',
108	 * )
109	 * </pre>
110	 *
111	 * Also starting from version 1.1.3, you can include a star ('*') element in this property so that
112	 * all model attributes are available for sorting, in addition to those virtual attributes. For example,
113	 * <pre>
114	 * 'attributes'=>array(
115	 *     'price'=>array(
116	 *         'asc'=>'item.price',
117	 *         'desc'=>'item.price DESC',
118	 *         'label'=>'Item Price',
119	 *         'default'=>'desc',
120	 *     ),
121	 *     '*',
122	 * )
123	 * </pre>
124	 * Note that when a name appears as both a model attribute and a virtual attribute, the position of
125	 * the star element in the array determines which one takes precedence. In particular, if the star
126	 * element is the first element in the array, the model attribute takes precedence; and if the star
127	 * element is the last one, the virtual attribute takes precedence.
128	 */
129	public $attributes=array();
130	/**
131	 * @var string the name of the GET parameter that specifies which attributes to be sorted
132	 * in which direction. Defaults to 'sort'.
133	 */
134	public $sortVar='sort';
135	/**
136	 * @var string the tag appeared in the GET parameter that indicates the attribute should be sorted
137	 * in descending order. Defaults to 'desc'.
138	 */
139	public $descTag='desc';
140	/**
141	 * @var string the default order that should be applied to the query criteria when
142	 * the current request does not specify any sort. For example, 'create_time DESC', or
143	 * 'name, create_time DESC'.
144	 *
145	 * Starting from version 1.1.3, you can also specify the default order using an array,
146	 * where the array keys are virtual attribute names as declared in {@link attributes},
147	 * and the array values indicate whether the sorting of the corresponding attributes should
148	 * be in descending order. For example,
149	 * <pre>
150	 * 'defaultOrder'=>array(
151	 *     'price'=>true,
152	 * )
153	 * </pre>
154	 */
155	public $defaultOrder;
156	/**
157	 * @var string the route (controller ID and action ID) for generating the sorted contents.
158	 * Defaults to empty string, meaning using the currently requested route.
159	 */
160	public $route='';
161	/**
162	 * @var array separators used in the generated URL. This must be an array consisting of
163	 * two elements. The first element specifies the character separating different
164	 * attributes, while the second element specifies the character separating attribute name
165	 * and the corresponding sort direction. Defaults to array('-','.').
166	 */
167	public $separators=array('-','.');
168	/**
169	 * @var array the additional GET parameters (name=>value) that should be used when generating sort URLs.
170	 * Defaults to null, meaning using the currently available GET parameters.
171	 * @since 1.0.9
172	 */
173	public $params;
174
175	private $_directions;
176
177	/**
178	 * Constructor.
179	 * @param string the class name of data models that need to be sorted.
180	 * This should be a child class of {@link CActiveRecord}.
181	 */
182	public function __construct($modelClass=null)
183	{
184		$this->modelClass=$modelClass;
185	}
186
187	/**
188	 * Modifies the query criteria by changing its {@link CDbCriteria::order} property.
189	 * This method will use {@link directions} to determine which columns need to be sorted.
190	 * They will be put in the ORDER BY clause. If the criteria already has non-empty {@link CDbCriteria::order} value,
191	 * the new value will be appended to it.
192	 * @param CDbCriteria the query criteria
193	 */
194	public function applyOrder($criteria)
195	{
196		$order=$this->getOrderBy();
197		if(!empty($order))
198		{
199			if(!empty($criteria->order))
200				$criteria->order.=', ';
201			$criteria->order.=$order;
202		}
203	}
204
205	/**
206	 * @return string the order-by columns represented by this sort object.
207	 * This can be put in the ORDER BY clause of a SQL statement.
208	 * @since 1.1.0
209	 */
210	public function getOrderBy()
211	{
212		$directions=$this->getDirections();
213		if(empty($directions))
214			return is_string($this->defaultOrder) ? $this->defaultOrder : '';
215		else
216		{
217			if($this->modelClass!==null)
218				$schema=CActiveRecord::model($this->modelClass)->getDbConnection()->getSchema();
219			$orders=array();
220			foreach($directions as $attribute=>$descending)
221			{
222				$definition=$this->resolveAttribute($attribute);
223				if(is_array($definition))
224				{
225					if($descending)
226						$orders[]=isset($definition['desc']) ? $definition['desc'] : $attribute.' DESC';
227					else
228						$orders[]=isset($definition['asc']) ? $definition['asc'] : $attribute;
229				}
230				else if($definition!==false)
231				{
232					$attribute=$definition;
233					if(isset($schema))
234					{
235						if(($pos=strpos($attribute,'.'))!==false)
236							$attribute=$schema->quoteTableName(substr($attribute,0,$pos)).'.'.$schema->quoteColumnName(substr($attribute,$pos+1));
237						else
238							$attribute=CActiveRecord::model($this->modelClass)->getTableAlias(true).'.'.$schema->quoteColumnName($attribute);
239					}
240					$orders[]=$descending?$attribute.' DESC':$attribute;
241				}
242			}
243			return implode(', ',$orders);
244		}
245	}
246
247	/**
248	 * Generates a hyperlink that can be clicked to cause sorting.
249	 * @param string the attribute name. This must be the actual attribute name, not alias.
250	 * If it is an attribute of a related AR object, the name should be prefixed with
251	 * the relation name (e.g. 'author.name', where 'author' is the relation name).
252	 * @param string the link label. If null, the label will be determined according
253	 * to the attribute (see {@link resolveLabel}).
254	 * @param array additional HTML attributes for the hyperlink tag
255	 * @return string the generated hyperlink
256	 */
257	public function link($attribute,$label=null,$htmlOptions=array())
258	{
259		if($label===null)
260			$label=$this->resolveLabel($attribute);
261		if(($definition=$this->resolveAttribute($attribute))===false)
262			return $label;
263		$directions=$this->getDirections();
264		if(isset($directions[$attribute]))
265		{
266			$class=$directions[$attribute] ? 'desc' : 'asc';
267			if(isset($htmlOptions['class']))
268				$htmlOptions['class'].=' '.$class;
269			else
270				$htmlOptions['class']=$class;
271			$descending=!$directions[$attribute];
272			unset($directions[$attribute]);
273		}
274		else if(is_array($definition) && isset($definition['default']))
275			$descending=$definition['default']==='desc';
276		else
277			$descending=false;
278
279		if($this->multiSort)
280			$directions=array_merge(array($attribute=>$descending),$directions);
281		else
282			$directions=array($attribute=>$descending);
283
284		$url=$this->createUrl(Yii::app()->getController(),$directions);
285
286		return $this->createLink($attribute,$label,$url,$htmlOptions);
287	}
288
289	/**
290	 * Resolves the attribute label for the specified attribute.
291	 * This will invoke {@link CActiveRecord::getAttributeLabel} to determine what label to use.
292	 * If the attribute refers to a virtual attribute declared in {@link attributes},
293	 * then the label given in the {@link attributes} will be returned instead.
294	 * @param string the attribute name.
295	 * @return string the attribute label
296	 */
297	public function resolveLabel($attribute)
298	{
299		$definition=$this->resolveAttribute($attribute);
300		if(is_array($definition))
301		{
302			if(isset($definition['label']))
303				return $definition['label'];
304		}
305		else if(is_string($definition))
306			$attribute=$definition;
307		if($this->modelClass!==null)
308			return CActiveRecord::model($this->modelClass)->getAttributeLabel($attribute);
309		else
310			return $attribute;
311	}
312
313	/**
314	 * Returns the currently requested sort information.
315	 * @return array sort directions indexed by attribute names.
316	 * The sort direction is true if the corresponding attribute should be
317	 * sorted in descending order.
318	 */
319	public function getDirections()
320	{
321		if($this->_directions===null)
322		{
323			$this->_directions=array();
324			if(isset($_GET[$this->sortVar]))
325			{
326				$attributes=explode($this->separators[0],$_GET[$this->sortVar]);
327				foreach($attributes as $attribute)
328				{
329					if(($pos=strpos($attribute,$this->separators[1]))!==false)
330					{
331						$descending=substr($attribute,$pos+1)===$this->descTag;
332						$attribute=substr($attribute,0,$pos);
333					}
334					else
335						$descending=false;
336
337					if(($this->resolveAttribute($attribute))!==false)
338					{
339						$this->_directions[$attribute]=$descending;
340						if(!$this->multiSort)
341							return $this->_directions;
342					}
343				}
344			}
345			if($this->_directions===array() && is_array($this->defaultOrder))
346				$this->_directions=$this->defaultOrder;
347		}
348		return $this->_directions;
349	}
350
351	/**
352	 * Returns the sort direction of the specified attribute in the current request.
353	 * @param string the attribute name
354	 * @return mixed the sort direction of the attribut. True if the attribute should be sorted in descending order,
355	 * false if in ascending order, and null if the attribute doesn't need to be sorted.
356	 */
357	public function getDirection($attribute)
358	{
359		$this->getDirections();
360		return isset($this->_directions[$attribute]) ? $this->_directions[$attribute] : null;
361	}
362
363	/**
364	 * Creates a URL that can lead to generating sorted data.
365	 * @param CController the controller that will be used to create the URL.
366	 * @param array the sort directions indexed by attribute names.
367	 * The sort direction is true if the corresponding attribute should be
368	 * sorted in descending order.
369	 * @return string the URL for sorting
370	 */
371	public function createUrl($controller,$directions)
372	{
373		$sorts=array();
374		foreach($directions as $attribute=>$descending)
375			$sorts[]=$descending ? $attribute.$this->separators[1].$this->descTag : $attribute;
376		$params=$this->params===null ? $_GET : $this->params;
377		$params[$this->sortVar]=implode($this->separators[0],$sorts);
378		return $controller->createUrl($this->route,$params);
379	}
380
381	/**
382	 * Returns the real definition of an attribute given its name.
383	 *
384	 * The resolution is based on {@link attributes} and {@link CActiveRecord::attributeNames}.
385	 * <ul>
386	 * <li>When {@link attributes} is an empty array, if the name refers to an attribute of {@link modelClass},
387	 * then the name is returned back.</li>
388	 * <li>When {@link attributes} is not empty, if the name refers to an attribute declared in {@link attributes},
389	 * then the corresponding virtual attribute definition is returned. Starting from version 1.1.3, if {@link attributes}
390	 * contains a star ('*') element, the name will also be used to match against all model attributes.</li>
391	 * <li>In all other cases, false is returned, meaning the name does not refer to a valid attribute.</li>
392	 * </ul>
393	 * @param string the attribute name that the user requests to sort on
394	 * @return mixed the attribute name or the virtual attribute definition. False if the attribute cannot be sorted.
395	 */
396	public function resolveAttribute($attribute)
397	{
398		if($this->attributes!==array())
399			$attributes=$this->attributes;
400		else if($this->modelClass!==null)
401			$attributes=CActiveRecord::model($this->modelClass)->attributeNames();
402		else
403			return false;
404		foreach($attributes as $name=>$definition)
405		{
406			if(is_string($name))
407			{
408				if($name===$attribute)
409					return $definition;
410			}
411			else if($definition==='*')
412			{
413				if($this->modelClass!==null && CActiveRecord::model($this->modelClass)->hasAttribute($attribute))
414					return $attribute;
415			}
416			else if($definition===$attribute)
417				return $attribute;
418		}
419		return false;
420	}
421
422	/**
423	 * Creates a hyperlink based on the given label and URL.
424	 * You may override this method to customize the link generation.
425	 * @param string the name of the attribute that this link is for
426	 * @param string the label of the hyperlink
427	 * @param string the URL
428	 * @param array additional HTML options
429	 * @return string the generated hyperlink
430	 */
431	protected function createLink($attribute,$label,$url,$htmlOptions)
432	{
433		return CHtml::link($label,$url,$htmlOptions);
434	}
435}