Asked  7 Months ago    Answers:  5   Viewed   35 times

I've used mime_content_type() and File info but i never successed. i want to use now cURL with PHP and get the headers of the file which is hosted on another domain then extract & determine if the type is MP3 or not. ( i think the mime type of MP3 is audio/mpeg )

Briefly, i know that but i don't know how to apply it :)




PHP curl_getinfo()

  # the request
  $ch = curl_init('');
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

  # get the content type
  echo curl_getinfo($ch, CURLINFO_CONTENT_TYPE);

  # output
  text/html; charset=ISO-8859-1


curl -I


HTTP/1.1 301 Moved Permanently
Content-Type: text/html; charset=UTF-8
Date: Fri, 09 Apr 2010 20:35:12 GMT
Expires: Sun, 09 May 2010 20:35:12 GMT
Cache-Control: public, max-age=2592000
Server: gws
Content-Length: 219
Wednesday, March 31, 2021
answered 7 Months ago

You need to add the Curl libraries to the command line PHP.ini.

You can probably just copy the file C:wampbinapacheApache2.2.xbinphp.ini to c:wampbinphpphp5.3.10php.ini (adjust for the actual directories on your system).

Wednesday, March 31, 2021
answered 7 Months ago

Yes, you can get it like this.

$file_info = new finfo(FILEINFO_MIME_TYPE);
$mime_type = $file_info->buffer(file_get_contents($image_url));
echo $mime_type;
Saturday, May 29, 2021
answered 5 Months ago

Never trust the mime type, this can be easily spoofed by the client. They could submit an exe and give it a mime type of text/plain if they wanted to.

All zip files begin with a standard local file header signature (0x04034b50) so you could check that the first 4 bytes of the file match the zip signature bytes. See the PKZIP Appnote for more details.

If you have the zip extension enabled, you can go even further and attempt to open and read the zip to make sure it is a fully valid zip file.

Something like this works well:

$zip = zip_open('/path/to/');
if (is_int($zip)) {
    echo "Error $zip encountered reading the file, is it a valid zip?";
} else {
    echo "Thanks for uploading a valid zip file!";

zip_open returns a resource if opened successfully, otherwise an integer representing the error that occurred reading the file.

EDIT: To elaborate on some of your questions:

About application/octet-stream: This is as you said, a very generic type. This just means any file that contains 8-bit data which is basically everything and anything. application/zip is the de-facto standard mime-type, but some clients will use other values as you have discovered. Also given the fact that a client can easily spoof any file type to use application/zip I wouldn't rely on $_FILES['fileatt']['type'] since it can be anything.

AFIK, mime_content_type() simply looks at the file extension and maps it to a mime type from a mime.types file on the system or built into PHP. If someone put a .zip extension on an exe file it would still register as application/zip. I beleive certain extensions may examine the file header.

Zip::open() returns TRUE if the file was opened successfully, or an integer error code. Therefore, == will give you a false positive on an error because any non-zero integer will evaluate to true using == since it will cast a non-zero integer to TRUE. If you are going to check the return from Zip::open you should always use $res === true in order to check for success. You can find the meanings of the error codes here in the comment at the bottom of the page.

Bottom Line: Since you said you are already extracting the zip, it may be less of a bother to validate based on the mime type, but instead it would be easier to just attempt to open the file and go based on the return value of open. If it returns true, you can figure the file is a valid zip (there could of course be errors later in the file, but they at least uploaded something resembling a zip file).

Hope that helps you out.

Saturday, May 29, 2021
answered 5 Months ago

In Urlmon.dll, there's a function called FindMimeFromData.

From the documentation

MIME type detection, or "data sniffing," refers to the process of determining an appropriate MIME type from binary data. The final result depends on a combination of server-supplied MIME type headers, file extension, and/or the data itself. Usually, only the first 256 bytes of data are significant.

So, read the first (up to) 256 bytes from the file and pass it to FindMimeFromData.

Tuesday, June 1, 2021
answered 5 Months ago
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