检查文件时的语法问题

Question

This piece of code has previously worked but I have C&P it to a new place and for some reason, it now won't work!

        <?
        $user_image = '/images/users/' . $_SESSION['id'] . 'a.jpg';
        if (file_exists(realpath(dirname(__FILE__) . $user_image))) 
        {
            echo '<img src="'.$user_image.'" alt="" />';
        } 
        else 
        {
            echo '<img src="/images/users/small.jpg" alt="" />';
        }
        ?>

As you can see, I am checking for a file, if exists, showing it, if not, showing a placeholder.

The $_SESSION['id'] variable does exist and is being used elsewhere within the script.

Any ideas what the problem is?

Thanks

Answer 1

Ok lets put it simple:

You have your images at

/foo/bar/images/users/*.jpg

and your script was at

/foo/bar/script.php

before, which worked, because realpath(dirname(__FILE__) . $user_image) creates

/foo/bar/image/users/*.jpg

But now, when you eg moved your script to another directory on the same level ( /foo/baz/script.php ), the output of the previous command will be

 /foo/baz/image/users/*.jpg

and this path does not exist.

You said in your comment you moved the script to another directory. If you didn't move the images too, your script definitely fails.

---

Also note there is a difference in accessing the images via a URL (ie from the outside) or via a file path (ie from the inside). Your images will always be available via www.yourdomain.com/images/users , but if you move your PHP script into another directory, dirname(__FILE__) has to give you another value and thus the test will fail :

foo/
|
- baz/
| |
| - script.php <-absolut path: /foo/baz/images/users/...
|
- bar/ <- entry point of URL is always here
  |
  - script.php <- absolut path: /foo/bar/images/users/...
  - images/    
    |
    - users/
      |
      - *.jpg

Update:

If your script is one level below the images, a fix could be:

file_exists(realpath(dirname(__FILE__) . '/../' . $_SESSION['id'] . 'a.jpg'))

This will generate something like /foo/images/users/v3/../12a.jpg . .. means going up a level.

Or going up several levels and using $user_image :

realpath(dirname(__FILE__) . '/../../..' . $user_image)