Question

我正在尝试优化我为解析YouTube个人资料而编写的一个小PHP应用。输入YouTube用户名，该应用程序通过解析帐户配置文件的gdata查询返回的XML，返回上传的视频数量，收藏夹，订阅者等的简单列表。例如，这个XML：

<?xml version="1.0" encoding="UTF-8" ?> 
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:media="http://search.yahoo.com/mrss/" xmlns:gd="http://schemas.google.com/g/2005" xmlns:yt="http://gdata.youtube.com/schemas/2007" gd:etag="W/"C0EHSX47eCp7I2A9Wh5aEU4.""> 
<id>tag:youtube.com,2008:user:H5m_qmnr3dHOO8x7m7dtvw</id> 
<published>2006-06-15T22:59:11.000Z</published> 
<updated>2014-01-07T21:53:58.000Z</updated> 
<category scheme="http://schemas.google.com/g/2005#kind" term="http://gdata.youtube.com/schemas/2007#userProfile" /> 
<category scheme="http://gdata.youtube.com/schemas/2007/channeltypes.cat" term="DIRECTOR" /> 
<title>epontius</title> 
<summary>channel page of epontius</summary> 
<link rel="alternate" type="text/html" href="https://www.youtube.com/channel/UCH5m_qmnr3dHOO8x7m7dtvw" /> 
<link rel="self" type="application/atom+xml" href="https://gdata.youtube.com/feeds/api/users/H5m_qmnr3dHOO8x7m7dtvw?v=2" /> 
 <author> 
<name>epontius</name> 
<uri>https://gdata.youtube.com/feeds/api/users/epontius</uri> 
<yt:userId>H5m_qmnr3dHOO8x7m7dtvw</yt:userId> 
</author> 
<yt:channelId>UCH5m_qmnr3dHOO8x7m7dtvw</yt:channelId> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.subscriptions" href="https://gdata.youtube.com/feeds/api/users/epontius/subscriptions?v=2" countHint="161" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.liveevent" href="https://gdata.youtube.com/feeds/api/users/epontius/live/events?v=2" countHint="0" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.favorites" href="https://gdata.youtube.com/feeds/api/users/epontius/favorites?v=2" countHint="73" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.contacts" href="https://gdata.youtube.com/feeds/api/users/epontius/contacts?v=2" countHint="184" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.inbox" href="https://gdata.youtube.com/feeds/api/users/epontius/inbox?v=2" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.playlists" href="https://gdata.youtube.com/feeds/api/users/epontius/playlists?v=2" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.uploads" href="https://gdata.youtube.com/feeds/api/users/epontius/uploads?v=2" countHint="26" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.newsubscriptionvideos" href="https://gdata.youtube.com/feeds/api/users/epontius/newsubscriptionvideos?v=2" /> 
<gd:feedLink rel="http://gdata.youtube.com/schemas/2007#user.recentactivity" href="https://gdata.youtube.com/feeds/api/users/epontius/events?v=2" /> 
<yt:googlePlusUserId>105085469892080308187</yt:googlePlusUserId> 
<yt:location>US</yt:location> 
<yt:statistics lastWebAccess="1970-01-01T00:00:00.000Z" subscriberCount="245" videoWatchCount="0" viewCount="0" totalUploadViews="68815" /> 
<media:thumbnail url="https://yt3.ggpht.com/-N_Et9Qg1APc/AAAAAAAAAAI/AAAAAAAAAAA/VIuQ_GuzA0Q/s88-c-k-no/photo.jpg" /> 
<yt:userId>H5m_qmnr3dHOO8x7m7dtvw</yt:userId> 
<yt:username display="epontius">epontius</yt:username> 
</entry>

现有应用程序运行正常，但YouTube经常更改某些元素的顺序或添加/删除行中的项目，因此当我访问'countHint'属性时，应用程序返回不正确的数据。例如：

$uploadscount = $gd->feedLink[6]->attributes();
$uploads = $uploadscount['countHint'];
echo 'Number of uploads: ' . '<span class="datatext">' . $uploads . '</span>' . '<br />';

在这种情况下哪个会返回26。但是如果feedLink行的数量或顺序发生变化，我会得到错误的信息或错误，因为feedLink的索引号是硬编码的。每个feedLink似乎都有一个唯一的rel =属性，我希望能够使用xpath和某种类似于foreach的循环来搜索特定的rel值（即.rel =“http://gdata.youtube.com/schemas/2007#user.uploads”）然后能够获取其countHint属性值以将其分配给变量或至少获取其节点索引号（即在上载的情况下为6）然后访问相应的countHint属性。然后对每个我想要抓取的数据的feedLink行和属性重复此操作。这样，在修改这些feedLink行的情况下，它将更加准确和动态。我无法理解如何做到这一点。 feedLink元素是不同命名空间（gd）中的空元素，并且有多个使得使用xpath让我感到困惑。我一直在回归空值而迷路。任何建议将不胜感激。

确定。考虑到建议，我想我已经到了某个地方。

  foreach ($gd->feedLink as $feedLink) {
           $attributes = $feedLink->attributes();
            if (strpos($attributes['rel'], '#user.uploads')) {
             $uploads = $attributes['countHint'];
             }

            elseif (strpos($attributes['rel'], '#user.favorites')) {
             $favs = $attributes['countHint'];
              }

            elseif (strpos($attributes['rel'], '#user.subscriptions')) {
             $subscriptions = $attributes['countHint'];
              }

            elseif (strpos($attributes['rel'], '#user.liveevent')) {
             $liveevents = $attributes['countHint'];
             }

           elseif (strpos($attributes['rel'], '#user.contacts')) {
            $friends = $attributes['countHint'];
             }
          }

这将返回我正在寻找的正确值，但我现在担心我正在做循环中的额外处理，因为我会假设每个循环测试每一行，无论它是否已经找到该值在之前的循环？

Answer 1

使用foreach解析XML数据是正确的。我会在每个strpos()上执行feedlink，直到找到uploads元素。然后我会设置$uploadscount。

像这样的东西，也许：

foreach ($gd->feedLink as $feedLink) {
  $attributes = $feedlink->attributes();
  if (strpos($attributes['rel'], '#user.uploads')) {
    $uploadscount = $attributes;
    break;
  }
  continue; 
}

PHP和XML根据属性查找节点以查找另一个属性或节点的索引

1 个答案: