source: trunk/include/functions_rate.inc.php @ 12412

Revision 12412, 5.8 KB checked in by rvelices, 8 years ago (diff)

avoid division by 0 warning when there are no rates in the database

  • Property svn:eol-style set to LF
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1<?php
2// +-----------------------------------------------------------------------+
3// | Piwigo - a PHP based photo gallery                                    |
4// +-----------------------------------------------------------------------+
5// | Copyright(C) 2008-2011 Piwigo Team                  http://piwigo.org |
6// | Copyright(C) 2003-2008 PhpWebGallery Team    http://phpwebgallery.net |
7// | Copyright(C) 2002-2003 Pierrick LE GALL   http://le-gall.net/pierrick |
8// +-----------------------------------------------------------------------+
9// | This program is free software; you can redistribute it and/or modify  |
10// | it under the terms of the GNU General Public License as published by  |
11// | the Free Software Foundation                                          |
12// |                                                                       |
13// | This program is distributed in the hope that it will be useful, but   |
14// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
15// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
16// | General Public License for more details.                              |
17// |                                                                       |
18// | You should have received a copy of the GNU General Public License     |
19// | along with this program; if not, write to the Free Software           |
20// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
21// | USA.                                                                  |
22// +-----------------------------------------------------------------------+
23
24/**
25 * rate a picture by a user
26 *
27 * @param int image identifier
28 * @param int rate
29 * @return void
30 */
31function rate_picture($image_id, $rate)
32{
33  global $conf, $user;
34
35  if (!isset($rate)
36      or !$conf['rate']
37      or !in_array($rate, $conf['rate_items']))
38  {
39    return false;
40  }
41
42  $user_anonymous = is_autorize_status(ACCESS_CLASSIC) ? false : true;
43
44  if ($user_anonymous and !$conf['rate_anonymous'])
45  {
46    return false;
47  }
48
49  $ip_components = explode('.', $_SERVER["REMOTE_ADDR"]);
50  if (count($ip_components) > 3)
51  {
52    array_pop($ip_components);
53  }
54  $anonymous_id = implode ('.', $ip_components);
55
56  if ($user_anonymous)
57  {
58    $save_anonymous_id = pwg_get_cookie_var('anonymous_rater', $anonymous_id);
59
60    if ($anonymous_id != $save_anonymous_id)
61    { // client has changed his IP adress or he's trying to fool us
62      $query = '
63SELECT element_id
64  FROM '.RATE_TABLE.'
65  WHERE user_id = '.$user['id'].'
66    AND anonymous_id = \''.$anonymous_id.'\'
67;';
68      $already_there = array_from_query($query, 'element_id');
69
70      if (count($already_there) > 0)
71      {
72        $query = '
73DELETE
74  FROM '.RATE_TABLE.'
75  WHERE user_id = '.$user['id'].'
76    AND anonymous_id = \''.$save_anonymous_id.'\'
77    AND element_id IN ('.implode(',', $already_there).')
78;';
79         pwg_query($query);
80       }
81
82       $query = '
83UPDATE '.RATE_TABLE.'
84  SET anonymous_id = \'' .$anonymous_id.'\'
85  WHERE user_id = '.$user['id'].'
86    AND anonymous_id = \'' . $save_anonymous_id.'\'
87;';
88       pwg_query($query);
89    } // end client changed ip
90
91    pwg_set_cookie_var('anonymous_rater', $anonymous_id);
92  } // end anonymous user
93
94  $query = '
95DELETE
96  FROM '.RATE_TABLE.'
97  WHERE element_id = '.$image_id.'
98    AND user_id = '.$user['id'].'
99';
100  if ($user_anonymous)
101  {
102    $query.= ' AND anonymous_id = \''.$anonymous_id.'\'';
103  }
104  pwg_query($query);
105  $query = '
106INSERT
107  INTO '.RATE_TABLE.'
108  (user_id,anonymous_id,element_id,rate,date)
109  VALUES
110  ('
111    .$user['id'].','
112    .'\''.$anonymous_id.'\','
113    .$image_id.','
114    .$rate
115    .',NOW())
116;';
117  pwg_query($query);
118
119  return update_rating_score($image_id);
120}
121
122
123/* update images.rating_score field
124  * we use a bayesian average (http://en.wikipedia.org/wiki/Bayesian_average) with
125C = average number of rates per item
126m = global average rate (all rates)
127
128 * param int $element_id optional, otherwise applies to all
129 * @return array(rating_score, count) if element_id is specified
130*/
131function update_rating_score($element_id = false)
132{
133  $query = '
134SELECT element_id,
135    COUNT(rate) AS rcount,
136    SUM(rate) AS rsum
137  FROM '.RATE_TABLE.'
138  GROUP by element_id';
139
140  $all_rates_count = 0;
141  $all_rates_avg = 0;
142  $item_ratecount_avg = 0;
143  $by_item = array();
144
145  $result = pwg_query($query);
146  while ($row = pwg_db_fetch_assoc($result))
147  {
148    $all_rates_count += $row['rcount'];
149    $all_rates_avg += $row['rsum'];
150    $by_item[$row['element_id']] = $row;
151  }
152
153  if ($all_rates_count>0)
154  {
155    $all_rates_avg /= $all_rates_count;
156    $item_ratecount_avg = $all_rates_count / count($by_item);
157  }
158
159  $updates = array();
160  foreach ($by_item as $id => $rate_summary )
161  {
162    $score = ( $item_ratecount_avg * $all_rates_avg + $rate_summary['rsum'] ) / ($item_ratecount_avg + $rate_summary['rcount']);
163    $score = round($score,2);
164    if ($id==$element_id)
165    {
166      $return = array(
167        'score' => $score,
168        'average' => round($rate_summary['rsum'] / $rate_summary['rcount'], 2),
169        'count' => $rate_summary['rcount'],
170        );
171    }
172    $updates[] = array( 'id'=>$id, 'rating_score'=>$score );
173  }
174  mass_updates(
175    IMAGES_TABLE,
176    array(
177      'primary' => array('id'),
178      'update' => array('rating_score')
179      ),
180    $updates
181    );
182
183  //set to null all items with no rate
184  if ( !isset($by_item[$element_id]) )
185  {
186    $query='
187SELECT id FROM '.IMAGES_TABLE .'
188  LEFT JOIN '.RATE_TABLE.' ON id=element_id
189  WHERE element_id IS NULL AND rating_score IS NOT NULL';
190
191    $to_update = array_from_query( $query, 'id');
192
193    if ( !empty($to_update) )
194    {
195      $query='
196UPDATE '.IMAGES_TABLE .'
197  SET rating_score=NULL
198  WHERE id IN (' . implode(',',$to_update) . ')';
199    pwg_query($query);
200    }
201  }
202
203  return isset($return) ? $return : array('score'=>null, 'average'=>null, 'count'=>0 );
204}
205
206?>
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