I need to read some meta information from the downloaded file. But I do not know how to do it.

Here is my code:

```
// Path form field_file
$file = 'public://directory/filename.txt';
file_get_contents($file);

```

This code causes this warning:

> 
> Warning: file\_get\_contents(): Unable to find the wrapper "public" - did you forget to enable it when you configured PHP?
> 
> 
> 

Any idea of what I am doing wrong, please?