如何安全地检查节点是否为空?(Symfony 2 爬虫) [英] How can I safely check is node empty or not? (Symfony 2 Crawler)

问题描述

当我尝试从页面中获取一些不存在的内容时，我发现了这个错误:

When I try to take some nonexistent content from page I catch this error:

The current node list is empty.
500 Internal Server Error - InvalidArgumentException 

如何安全地检查此内容是否存在?这里有一些不起作用的例子:

How can I safely check exists this content or not? Here some examples that does not work:

if($crawler->filter('.PropertyBody')->eq(2)->text()){
    // bla bla
}

if(!empty($crawler->filter('.PropertyBody')->eq(2)->text())){
    // bla bla
}
if(($crawler->filter('.PropertyBody')->eq(2)->text()) != null){
    // bla bla
}

谢谢，我帮助了自己:

$count = $crawler->filter('.PropertyBody')->count();
if($count > 2){
    $marks = $crawler->filter('.PropertyBody')->eq(2)->text();
}

推荐答案

你有没有尝试过这样的事情?

Have you tried something like this?

$text = null;
if (!empty($body = $crawler->filter('.PropertyBody'))) {
    if (!empty($node = $body->eq(2))) {
        $text = $node->text();
    }
}

$this->assertContains('yourText', $text);

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