PHP's file_exists() will not work for me?

问题

For some reason this PHP code below will not work, I can not figure it out.

It is very strange, file_exists does not seem to see that the image does exist, I have checked to make sure a good file path is being inserted into the file_exists function and it is still acting up

If I change file_exists to !file_exists it will return an images that exist and ones that do not exist

define('SITE_PATH2', 'http://localhost/');

$noimg = SITE_PATH2. 'images/userphoto/noimagesmall.jpg';
$thumb_name = 'http://localhost/images/userphoto/1/2/2/59874a886a0356abc1_thumb9.jpg';
if (file_exists($thumb_name)) {
    $img_name = $thumb_name;
}else{
    $img_name = $noimg;
}
echo $img_name;

回答1:

file_exists() needs to use a file path on the hard drive, not a URL. So you should have something more like:

$thumb_name = $_SERVER['DOCUMENT_ROOT'] . 'images/userphoto/1/2/2/59874a886a0356abc1_thumb9.jpg';
if(file_exists($thumb_name)) {
    some_code
}

http://us2.php.net/file_exists

回答2:

docs say:

As of PHP 5.0.0, this function can also be used with some URL wrappers. Refer to List of Supported Protocols/Wrappers for a listing of which wrappers support stat() family of functionality.

回答3:

file_exists does only work on the local file system.

So try this if you’re using localhost:

$thumb_name = 'images/userphoto/1/2/2/59874a886a0356abc1_thumb9.jpg';
if (file_exists($_SERVER['DOCUMENT_ROOT'].$thumb_name)) {
    $img_name = SITE_PATH2.$thumb_name;
} else {
    $img_name = $noimg;
}

回答4:

Have you enabled the option which allows you to use external URLs? You can set it in php.ini:

allow_url_fopen = 1

回答5:

http://php.net/manual/en/function.file-exists.php

did you check the comments below?

Just reading parts of it, but there seem to be several issues.

Caching may be a problem. When opening FTP urls it always returns true (they say in the comments) ...

回答6:

You have to write the file path like "file:///C:/Documents%20and%20Settings/xyz/Desktop/clip_image001.jpg".

回答7:

Try Below one. Its working for me

define('SITE_PATH2', 'http://localhost/');
$noimg = SITE_PATH2. 'images/userphoto/noimagesmall.jpg';
$thumb_name = 'http://localhost/images/userphoto/1/2/2/59874a886a0356abc1_thumb9.jpg';

if ($fileopen = @fopen($thumb_name)) {
    $img_name = $thumb_name;
    fclose($fileopen);
}else{
    $img_name = $noimg;
}
echo $img_name;

来源：https://stackoverflow.com/questions/1287837/phps-file-exists-will-not-work-for-me

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php

file-exists