Why Does My PHP Code Always Report an Image File Exists, Even When It Doesn\'t?

Using PHP to Verify the Existence of an Image File

Problem:

You intend to ascertain the existence of a specific image file hosted on your content delivery network (CDN). However, the code you've implemented appears to be ineffective.

Code Attempted:

<code class="php">if (file_exists(http://www.example.com/images/$filename)) {
    echo "The file exists";
} else {
    echo "The file does not exist";
}</code>

Observed Outcome:

Regardless of the image's actual existence, the code consistently reports "The file exists."

Solution:

The primary issue with the code is the absence of quotation marks around the filename variable ($filename). This variable must be enclosed in quotes to be interpreted as a string. Additionally, it is crucial to verify that $filename has undergone proper validation.

Updated Code:

<code class="php">if (file_exists('http://www.mydomain.com/images/'.$filename)) {
    …
}</code>

Caveat:

It is crucial to note that the code will only function correctly if the allow_url_fopen setting in your PHP configuration is enabled.

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