=====第十三天标签======= // 原文：http://www.symfony-project.com/askeet/13 // **回顾：**　目前的askeet程序已具有网页服务，RRS和发电子邮件等功能。使用者能提问题，其问题也能被其他用户回答。但目前的askeet仍缺乏分类的机制。就拿对问题分类来说，我们可用树状结构对问题分门别类，最终生成几百个类别。这样会对查询造成极度的不便。然而，web 2.0 引进了一种新的管理类别的方法：标签。与树状结构中的类别不同的是，标签不依赖等级来分类，而且一条目可拥有多标签。例如，猫，用树状结构分类可编排在条目动物/哺乳动物/四脚的/猫科。用标签就简单多了，例如用宠物+灵俐来描述猫。其好处是所有的用户能为自己的问题分类（加标签），更易于查询。这就是[[http://en.wikipedia.org/wiki/Folksonomy|大众分类法]] =====QuestionTag类===== {{symfony:13:mcd3.gif|}} ====Schema update====

...

$ symfony propel-build-model

====Custom class====


 $word)
    {
      if ($word == '"')
      {
        $delim++;
        continue;
      }
      if (($delim % 2 == 1) && $words[$key - 1] == '"')
      {
        $tags[] = trim($word);
      }
      else
      {
        $tags = array_merge($tags, preg_split('/\s+/', trim($word), -1, PREG_SPLIT_NO_EMPTY));
      }
    }
 
    return $tags;
  }
}
 
?>

====Extend the model====


public function setTag($v)
{
  parent::setTag($v);
 
  $this->setNormalizedTag(Tag::normalize($v));
}

====Add some test data====


QuestionTag:
  t1: { question_id: q1, user_id: fabien, tag: relatives }
  t2: { question_id: q1, user_id: fabien, tag: girl }
  t4: { question_id: q1, user_id: francois, tag: activities }
  t6: { question_id: q2, user_id: francois, tag: 'real life' }
  t5: { question_id: q2, user_id: fabien, tag: relatives }
  t5: { question_id: q2, user_id: fabien, tag: present }
  t6: { question_id: q2, user_id: francois, tag: 'real life' }
  t7: { question_id: q3, user_id: francois, tag: blog }
  t8: { question_id: q3, user_id: francois, tag: activities }

$ php batch/load_data.php

=====Display the tags of a question=====

$ symfony init-module frontend tag

====Extend model====


public function getTags()
{
  $c = new Criteria();
  $c->clearSelectColumns();
  $c->addSelectColumn(QuestionTagPeer::NORMALIZED_TAG);
  $c->add(QuestionTagPeer::QUESTION_ID, $this->getId());
  $c->setDistinct();
  $c->addAscendingOrderByColumn(QuestionTagPeer::NORMALIZED_TAG);
 
  $tags = array();
  $rs = QuestionTagPeer::doSelectRS($c);
  while ($rs->next())
  {
    $tags[] = $rs->getString(1);
  }
 
  return $tags;
}

====Modify the view====


showSuccess:
  components:
    sidebar: [sidebar, question]


public function executeQuestion()
{
  $this->question = QuestionPeer::getQuestionFromTitle($this->getRequestParameter('stripped_title'));
}



 
question tags
 

   $question, 'tags' => $question->getTags())) ?>


tag:
  url:   /tag/:tag
  param: { module: tag, action: show }

====Test it==== #hori_border[ http://askeet/question/what-can-i-offer-to-my-step-mother ]# {{symfony:askeet:13:tag_list_question.gif|}} =====Display a short list of popular tags for a question===== ====Extend the model====


SELECT normalized_tag AS tag, COUNT(normalized_tag) AS count
FROM question_tag
WHERE question_id = $id
GROUP BY normalized_tag
ORDER BY count DESC
LIMIT $max


public function getPopularTags($max = 5)
{
  $tags = array();
 
  $con = Propel::getConnection();
  $query = '
    SELECT %s AS tag, COUNT(%s) AS count
    FROM %s
    WHERE %s = ?
    GROUP BY %s
    ORDER BY count DESC
  ';
 
  $query = sprintf($query,
    QuestionTagPeer::NORMALIZED_TAG,
    QuestionTagPeer::NORMALIZED_TAG,
    QuestionTagPeer::TABLE_NAME,
    QuestionTagPeer::QUESTION_ID,
    QuestionTagPeer::NORMALIZED_TAG
  );
 
  $stmt = $con->prepareStatement($query);
  $stmt->setInt(1, $this->getId());
  $stmt->setLimit($max);
  $rs = $stmt->executeQuery();
  while ($rs->next())
  {
    $tags[$rs->getString('tag')] = $rs->getInt('count');
  }
 
  return $tags;
}

====Modify the view====



 
getResults() as $question): ?>
  
    
       $question)) ?>
    
 
    getTitle(), '@question?stripped_title='.$question->getStrippedTitle()) ?>
 
    
      asked by getUser(), '@user_profile?nickname='.$question->getUser()->getNickname()) ?> on getCreatedAt(), 'f') ?>
      getHtmlBody()), 200) ?>
    
 
    tags:


function tags_for_question($question, $max = 5)
{
  $tags = array();
 
  foreach ($question->getPopularTags($max) as $tag => $count)
  {
    $tags[] = link_to($tag, '@tag?tag='.$tag);
  }
 
  return implode(' + ', $tags);
}

====Test==== #hori_border[http://askeet/]# {{symfony:askeet:13:popular_tags_question_list.gif|}} =====Display the list of questions tagged with a word===== ====The tag/show action====


public function executeShow()
{
  $this->question_pager = QuestionPeer::getPopularByTag($this->getRequestParameter('tag'), $this->getRequestParameter('page'));
}

====Extend the model====


public static function getPopularByTag($tag, $page)
{
  $c = new Criteria();
  $c->add(QuestionTagPeer::NORMALIZED_TAG, $tag);
  $c->addDescendingOrderByColumn(QuestionPeer::INTERESTED_USERS);
  $c->addJoin(QuestionTagPeer::QUESTION_ID, QuestionPeer::ID, Criteria::LEFT_JOIN);
 
  $pager = new sfPropelPager('Question', sfConfig::get('app_pager_homepage_max'));
  $pager->setCriteria($c);
  $pager->setPage($page);
  $pager->init();
 
  return $pager;
}

====Create the template====


popular questions for tag "get('tag') ?>"
 
 $question_pager, 'rule' => '@tag?tag=.'$sf_params->get(tag))) ?>

====Add the page parameter in the routing rule====


tag:
  url:   /tag/:tag/:page
  param: { module: tag, action: show, page: 1 }

====Test it==== #hori_border[http://askeet/tag/activities]# {{symfony:askeet:13:tagged_question_list.gif|}} =====See you Tomorrow=====