PHP to determine the existence of remote pictures of several methods _php skills

In doing a picture preview of the things, encountered a problem, is to determine whether the remote file exists (not the same server).
The code is as follows:

Copy Code code as follows:

Method One
function file_exists ($url)
{
$ch = Curl_init ();
curl_setopt ($ch, Curlopt_url, $url);
curl_setopt ($ch, curlopt_nobody, 1); Do not download
curl_setopt ($ch, Curlopt_failonerror, 1);
curl_setopt ($ch, Curlopt_returntransfer, 1);

if (curl_exec ($ch)!==false)
return true;
Else
return false;
}

Method Two
function File_exists2 ($url)
{
if (file_get_contents ($url, 0,null,0,1))
return 1;
Else
return 0;
}
Method Three
function File_exists ($url) {
$curl = Curl_init ($url);
Do not retrieve data
curl_setopt ($curl, Curlopt_nobody, true);
Send Request
$result = curl_exec ($curl);
$found = false;
If the request did not send a failure
if ($result!== false) {
and check to see if the HTTP response code is 200.
}

Method one returns false regardless of whether the picture is in or out;
Method Two windows is feasible under Linux, regardless of whether the picture is not in the return to true;
Method Three should be the most appropriate
In addition: there is an efficiency problem with the Get_headers () method, which is not recommended for use as this solution

Fsockopen version:

Copy Code code as follows:

$url = "Yun_qi_img/baidu_sylogo1.gif";

$info = Parse_url ($url);
$fp = Fsockopen ($info [' Host '], $errno, $ERRSTR, 30);
Fputs ($fp, "get {$info [' path ']} http/1.1\r\n");
Fputs ($FP, "host: {$info [' host ']}\r\n");
Fputs ($fp, "connection:close\r\n\r\n");
$headers = Array ();
while (!feof ($fp)) {
$line = fgets ($FP);
if ($line!= "\ r \ n") {
$headers [] = $line;
}else {
Break
}
}

echo "<pre>";
Print_r ($headers);

The HTTP status code is used to determine whether a file exists, for example, Response 302,301,404 is non-existent, if 200,304, etc. can be considered as a file existence.

fopen () Method:

Copy Code code as follows:

<?php
$url = ' yun_qi_img/test.jpg ';

if (@fopen ($url, ' R '))
{
Echo ' File Exits ';
}
Else
{
Echo ' File does not Exits ';
}
?>

Curl Method:

Copy Code code as follows:

<?php
$url 2 = ' yun_qi_img/test.jpg ';

$ch = Curl_init ();
$timeout = 10;
curl_setopt ($ch, Curlopt_url, $url 2);
curl_setopt ($ch, Curlopt_header, 1);
curl_setopt ($ch, Curlopt_returntransfer, 1);
curl_setopt ($ch, Curlopt_connecttimeout, $timeout);

$contents = curl_exec ($ch);
Echo $contents;
if (Preg_match ("/404/", $contents)) {
Echo ' file does not exist ';
}
?>