使用返回 null 的 curl 解析 XML

Question

我正在尝试解析 RSS 提要，但我得到的似乎是一个空的 DOM 文档对象。我当前的代码是：

$xml_url = "https://thehockeywriters.com/category/san-jose-sharks/feed/";

    $curl = curl_init();
    curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
    curl_setopt( $curl, CURLOPT_URL, $xml_url );

    $xml = curl_exec( $curl );
    curl_close( $curl );

    //$xml = iconv('UTF-8', 'UTF-8//IGNORE', $xml);
    //$xml = utf8_encode($xml);
    $document = new DOMDocument;
    $document->loadXML( $xml ); 
    if( ini_get('allow_url_fopen') ) {
      echo "allow url fopen? Yes";
    }
    echo "<br />";
    var_dump($document);

    $items = $document->getElementsByTagName("item");

    foreach ($items as $item) {
        $title = $item->getElementsByTagName('title');
        echo $title;
    }

    $url = 'https://thehockeywriters.com/category/san-jose-sharks/feed/';
    $xml = simplexml_load_file($url);
    foreach ($items as $item) {
        $title = $item->title;
        echo $title;
    }
    print_r($xml);
    echo "<br />";
    var_dump($xml);
    echo "<br />hello?";

此代码是根据在堆栈溢出时发现的以下示例中给出的答案和建议来解析相同 url 的两次单独尝试：
Example 1
Example 2

我尝试过或查找过的事情：
1. 检查以确保允许allow_url_fopen
2.确保有UTF编码
3. 验证 XML
4. 之前链接的 Stack Overflow 帖子中提供的代码示例

这是我当前的输出，var_dumps 和 echo's

allow url fopen? Yes
object(DOMDocument)#2 (34) { ["doctype"]=> NULL ["implementation"]=> string(22) "(object value omitted)" 
["documentElement"]=> NULL ["actualEncoding"]=> NULL ["encoding"]=> NULL 
["xmlEncoding"]=> NULL ["standalone"]=> bool(true) ["xmlStandalone"]=> bool(true) 
["version"]=> string(3) "1.0" ["xmlVersion"]=> string(3) "1.0" 
["strictErrorChecking"]=> bool(true) ["documentURI"]=> NULL ["config"]=> NULL 
["formatOutput"]=> bool(false) ["validateOnParse"]=> bool(false) ["resolveExternals"]=> bool(false) 
["preserveWhiteSpace"]=> bool(true) ["recover"]=> bool(false) ["substituteEntities"]=> bool(false) 
["nodeName"]=> string(9) "#document" ["nodeValue"]=> NULL ["nodeType"]=> int(9) ["parentNode"]=> NULL 
["childNodes"]=> string(22) "(object value omitted)" ["firstChild"]=> NULL ["lastChild"]=> NULL 
["previousSibling"]=> NULL ["attributes"]=> NULL ["ownerDocument"]=> NULL ["namespaceURI"]=> NULL 
["prefix"]=> string(0) "" ["localName"]=> NULL ["baseURI"]=> NULL ["textContent"]=> string(0) "" } 
bool(false) 
hello?

Answer 1

我对您的代码的唯一问题是不定义用户代理会给我错误 403 以访问提要。

将来，您可以使用curl_getinfo 提取请求的状态码，以确保它没有失败，并进一步将其与代码 200 进行匹配，即 OK。

$httpcode = curl_getinfo($curl, CURLINFO_HTTP_CODE);

除了循环中的一些错误。

使用 SimpleXML：

<?php
$url = "https://thehockeywriters.com/category/san-jose-sharks/feed/";

$curl = curl_init();
curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0");
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_URL, $url);
$data = curl_exec($curl);
$httpcode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
curl_close($curl);

if ($httpcode !== 200)
{
    echo "Failed to retrieve feed... Error code: $httpcode";
    die();
}

$feed = new SimpleXMLElement($data);
// list all titles...
foreach ($feed->channel->item as $item)
{
    echo $item->title, "<br>\n";
}

使用 DOMDocument：

<?php
$url = "https://thehockeywriters.com/category/san-jose-sharks/feed/";

$curl = curl_init();
curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0");
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_URL, $url);
$data = curl_exec($curl);
$httpcode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
curl_close($curl);

if ($httpcode !== 200)
{
    echo "Failed to retrieve feed... Error code: $httpcode";
    die();
}

$xml = new DOMDocument();
$xml->loadXML($data);
// list all titles...
foreach ($xml->getElementsByTagName("item") as $item)
{
    foreach ($item->getElementsByTagName("title") as $title)
    {
        echo $title->nodeValue, "<br>\n";
    }
}

如果您只想打印所有项目的标题/描述：

foreach ($feed->channel->item as $item)
{
    echo $item->title;
    echo $item->description;
    // uncomment the below line to print only the first entry.
    // break;
}

如果您只想要第一个条目，而不使用 foreach：

echo $feed->channel->item[0]->title;
echo $feed->channel->item[0]->description;

将标题和描述保存到数组中以供以后使用：

$result = [];
foreach ($feed->channel->item as $item)
{
    $result[] = 
    [
        'title' => (string)$item->title,
        'description' => (string)$item->description
    ];
    // could make a key => value alternatively from the above with 
    // title as key like this: 
    // $result[(string)$item->title] = (string)$item->description;
}

使用 MySQLi/PDO 准备好的 Foreach 语句：

foreach ($feed->channel->item as $item)
{
    // MySQLi
    $stmt->bind_param('ss', $item->title, $item->description);
    $stmt->execute();
    // PDO
    //$stmt->bindParam(':title', $item->title, PDO::PARAM_STR);
    //$stmt->bindParam(':description', $item->description, PDO::PARAM_STR);
    //$stmt->execute();
}

Answer 2

我选择了 Prix 的答案来指出用户代理定义，但我想出了另一种执行循环的方法，它可以避免嵌套循环并更容易访问其他节点。这是我正在使用的（DOM 文档解决方案）：

$xml_url = "https://thehockeywriters.com/category/san-jose-sharks/feed/";

$curl = curl_init();
curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt( $curl, CURLOPT_URL, $xml_url );
curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0");

$xml = curl_exec( $curl );
curl_close( $curl );

$document = new DOMDocument;
$document->loadXML( $xml ); 

$items = $document->getElementsByTagName("item");       
foreach ($items as $item) {     
    $title = $item->getElementsByTagName('title')->item(0)->nodeValue;
    echo $title;
    $desc = $item->getElementsByTagName('description')->item(0)->nodeValue;
    echo $desc;
}