如题，PHP如何自动识别第三方Restful API的内容，自动渲染成 json、xml、html、serialize、csv、php等数据？

其实这也不难，因为Rest API也是基于http协议的，只要我们按照协议走，就能做到自动化识别 API 的内容，方法如下：

1、API服务端要返回明确的 http Content-Type头信息，如：

Content-Type: application/json; charset=utf-8Content-Type: application/xml; charset=utf-8Content-Type: text/html; charset=utf-8

2、PHP端（客户端）接收到上述头信息后，再酌情自动化处理，参考代码如下：

<?php// 请求初始化$url = "//www.yinxi.net";$ch = curl_init();curl_setopt($ch, CURLOPT_URL, $url);curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);// 返回的 http body 内容$response = curl_exec($ch);// 返回的 http header 的 Content-Type 的内容$contentType = curl_getinfo($ch, "content_type");// 关闭请求资源curl_close($ch);// 结果自动格式输出$autoDetectFormats = array( "application/xml" => "xml", "text/xml"  => "xml", "application/json" => "json", "text/json"  => "json", "text/csv"  => "csv", "application/csv" => "csv", "application/vnd.php.serialized" => "serialize");if (strpos($contentType, ";")){ list($contentType) = explode(";", $contentType);}$contentType = trim($contentType);if (array_key_exists($contentType, $autoDetectFormats)){ echo "_" . $autoDetectFormats[$contentType]($response);}//+++++++++++++++++++++++++++++++++++++++++++++++++++++++// 常用 格式化 方法//+++++++++++++++++++++++++++++++++++++++++++++++++++++++/** * 格式化xml输出 */function _xml($string){ return $string ? (array)simplexml_load_string($string, "SimpleXMLElement", LIBXML_NOCDATA) : array();}/** * 格式化csv输出 */function _csv($string){ $data = array(); $rows = explode("", trim($string)); $headings = explode(",", array_shift($rows)); foreach( $rows as $row ) { // 利用 substr 去掉 开始 与 结尾 的 " $data_fields = explode("","", trim(substr($row, 1, -1))); if (count($data_fields) === count($headings)) {  $data[] = array_combine($headings, $data_fields); } } return $data;}/** * 格式化json输出 */function _json($string){ return json_decode(trim($string), true);}/** * 反序列化输出 */function _serialize($string){ return unserialize(trim($string));}/** * 执行PHP脚本输出 */function _php($string){ $string = trim($string); $populated = array(); eval("$populated = "$string";"); return $populated;}