how to read the bytes that make up a file?

[jasongr]

Hello

I have a file which the user uploads
The file should be of type jpeg
I would like to ensure that the uploaded file has indeed the correct header format of jpeg: '\xFF\xD8\xFF\xE0\x00\x10\x4A\x46\x49\x46'

I need some way to read the first set of bytes that make up the file
and then to compare them to the correct header of
'\xFF\xD8\xFF\xE0\x00\x10\x4A\x46\x49\x46'

does anyone know how I can read these bytes and perform the comparison?

thanks in advance

[bokeh]

$mime_type = mime_content_type($uploaded_file);
print $mime_type; //should output image/jpeg for a .jpg file

[jasongr]

This only works on Windows
Also I am not sure how this function is implemented
I hope it doesn't base its returned value on the file extension.
My tests needs to be more intelligent than that
This is why I am trying to compare bytes from the file header

[bokeh]

To find out more look at this. http://www.php.net/mime_content_type

[jasongr]

here (http://forums.devnetwork.net/viewtopic.php?p=173387#173387) is a solution