下面是我的代码，它输出wiki页面上Plot选项卡下的内容，我使用的是getElementById，它抛出了一些我粘贴在下面的异常，有人能修改它吗。提前感谢。
<?php
/**
* Downloads a web page from $url, selects the the element by $id
* and returns it's xml string representation.
*/
//Taking input
if(isset($_POST['submit'])) /* i.e. the PHP code is executed only when someone presses Submit button in the below given HTML Form */
{
$var = $_POST['var']; // Here $var is the input taken from user.
}
function getElementByIdAsString($url, $id, $pretty = true) {
$doc = new DOMDocument();
@$doc->loadHTMLFile($url);
if(!$doc) {
throw new Exception("Failed to load $url");
}
// Obtain the element
$element = $doc->getElementById($id);
if(!$element) {
throw new Exception("An element with id $id was not found");
}
if($pretty) {
$doc->formatOutput = true;
}
// Return the string representation of the element
return $doc->saveXML($element);
}
// call it:
echo getElementByIdAsString('https://en.wikipedia.org/wiki/I_Too_Had_a_Love_Story', 'Plot');
?>
例外情况是：
Fatal error: Uncaught exception 'Exception' with message 'An element with id Plot was not found' in C:'xampp'htdocs'example2.php:23 Stack trace: #0 C:'xampp'htdocs'example2.php(35): getElementByIdAsString() #1 {main} thrown in C:'xampp'htdocs'example2.php on line 23
我尝试您的代码，它工作正常并返回<span class="mw-headline" id="Plot">Plot</span>。我认为你在使用DOMDocument::loadHTMLFile和@:时遇到的问题
@$doc->loadHTMLFile($url);
因为此方法返回
成功时bool true或失败时bool false
有时它会返回false（例如，对于许多请求，来自wikipedia的403），并且您的dom元素为空。在这种情况下，您的$element = $doc->getElementById($id);找不到此元素。
尝试将您的代码更改为：
<?php
/**
* Downloads a web page from $url, selects the the element by $id
* and returns it's xml string representation.
*/
//Taking input
if(isset($_POST['submit'])) /* i.e. the PHP code is executed only when someone presses Submit button in the below given HTML Form */
{
$var = $_POST['var']; // Here $var is the input taken from user.
}
function getElementByIdAsString($url, $id, $pretty = true) {
$doc = new DOMDocument();
$loadResult = @$doc->loadHTMLFile($url);
if(!$doc || !$loadResult) {
throw new Exception("Failed to load $url");
}
// Obtain the element
$element = $doc->getElementById($id);
if(!$element) {
throw new Exception("An element with id $id was not found");
}
if($pretty) {
$doc->formatOutput = true;
}
// Return the string representation of the element
return $doc->saveXML($element);
}
// call it:
echo getElementByIdAsString('https://en.wikipedia.org/wiki/I_Too_Had_a_Love_Story', 'Plot');
?>
Wkipedia可能不适用于您的脚本（一些站点会阻止解析器脚本）。尝试使用curl获取您的响应的状态代码
$url = 'en.wikipedia.org/wiki/I_Too_Had_a_Love_Story';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$html = curl_exec($ch);
$status_code = curl_getinfo($ch,CURLINFO_HTTP_CODE);