php 判断远程图片是否有效

13544870125

$url = "http://www.iteye.com/upload/logo/user/275746/46a4c886-427e-3554-b195-083430beb92a.jpg";
echo "<a href='$url'>$url</a><br/>";
$arr = get_headers($url,1);
echo $arr["Content-Type"]; //image/jpeg
　　以下是手册上的:
　　get_headers() 返回一个数组，包含有服务器响应一个 HTTP 请求所发送的标头。如果失败则返回
FALSE 并发出一条 E_WARNING 级别的错误信息。
　　如果将可选的 format 参数设为 1，则 get_headers() 会解析相应的信息并设定数组的键名。
　　<?php

$url = 'http://www.example.com';
print_r(get_headers($url));
print_r(get_headers($url, 1));
?>
上例的输出类似于：

Array
(
[0] => HTTP/1.1 200 OK
[1] => Date: Sat, 29 May 2004 12:28:13 GMT
[2] => Server: Apache/1.3.27 (Unix)  (Red-Hat/Linux)
[3] => Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT
[4] => ETag: "3f80f-1b6-3e1cb03b"
[5] => Accept-Ranges: bytes
[6] => Content-Length: 438
[7] => Connection: close
[8] => Content-Type: text/html
)
Array
(
[0] => HTTP/1.1 200 OK
[Date] => Sat, 29 May 2004 12:28:14 GMT
[Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
[Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
[ETag] => "3f80f-1b6-3e1cb03b"
[Accept-Ranges] => bytes
[Content-Length] => 438
[Connection] => close
[Content-Type] => text/html
)