PHP函数：CURL抓取网站内容的，支持301 302跳转

我们在抓取网站内容的时候，经常遇到稀奇古怪的防盗链，比如上次碰到一个站的图片地址是假的，访问后要301跳转一次才到真正的图片路径，这个真实的路径又做了防盗措施，判断referer是不是上个假的图片地址。用curl试了几次，终于整出一个函数，效果不错。

$curl_loops = 0;//避免死了循环必备
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$curl_max_loops = 3;
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function curl_get_file_contents($url, $referer='') {
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global $curl_loops, $curl_max_loops;
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$useragent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
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if ($curl_loops++ >= $curl_max_loops) {
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$curl_loops = 0;
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return false;
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}
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$ch = curl_init();
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curl_setopt($ch, CURLOPT_URL, $url);?curl_setopt($ch, CURLOPT_HEADER, true);
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curl_setopt($ch, CURLOPT_USERAGENT, $useragent);
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curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
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curl_setopt($ch, CURLOPT_REFERER, $referer);
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$data = curl_exec($ch);
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$ret = $data;
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list($header, $data) = explode("\r\n\r\n", $data, 2);
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$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
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$last_url = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
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curl_close($ch);
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if ($http_code == 301 || $http_code == 302) {
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$matches = array();
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preg_match('/Location:(.*?)\n/', $header, $matches);
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$url = @parse_url(trim(array_pop($matches)));
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if (!$url) {
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?$curl_loops = 0;
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?return $data;
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}
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$new_url = $url['scheme'] . '://' . $url['host'] . $url['path']
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. (isset($url['query']) ? '?' . $url['query'] : '');
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$new_url = stripslashes($new_url);
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return curl_get_file_contents($new_url, $last_url);
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} else {
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$curl_loops = 0;
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list($header, $data) = explode("\r\n\r\n", $ret, 2);
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return $data;
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}
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}