Take a look at mime_content_type or Fileinfo. These are built-in PHP commands for determining the type of a file by looking at the contents of the file. Also check the comments on the above two pages, there are some other good suggestions. Personally I’ve had good luck using something that’s essentially system(“file -bi $uploadedfile”), but … Read more
The PHP Manual has this example: <?php // open the file in a binary mode $name=”./img/ok.png”; $fp = fopen($name, ‘rb’); // send the right headers header(“Content-Type: image/png”); header(“Content-Length: ” . filesize($name)); // dump the picture and stop the script fpassthru($fp); exit; ?> The important points is that you must send a Content-Type header. Also, you … Read more
First and foremost, you should consider calling MimeTypeMap#getMimeTypeFromExtension(), like this: // url = file path or whatever suitable URL you want. public static String getMimeType(String url) { String type = null; String extension = MimeTypeMap.getFileExtensionFromUrl(url); if (extension != null) { type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension); } return type; }
The header just denotes what the content is encoded in. It is not necessarily possible to deduce the type of the content from the content itself, i.e. you can’t necessarily just look at the content and know what to do with it. That’s what HTTP headers are for, they tell the recipient what kind of … Read more
For BIFF .xls files application/vnd.ms-excel For Excel2007 and above .xlsx files application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
It means that the server is sending a Javascript HTTP response with Content-Type: text/plain You need to configure the server to send a JavaScript response with Content-Type: application/javascript
For Node.js applications, check your configuration: app.use(express.static(__dirname + ‘/public’)); Notice that /public does not have a forward slash at the end, so you will need to include it in your href option of your HTML: href=”https://stackoverflow.com/css/style.css”> If you did include a forward slash (/public/) then you can just do href=”https://stackoverflow.com/questions/48248832/css/style.css”.
The accept attribute is incredibly useful. It is a hint to browsers to only show files that are allowed for the current input. While it can typically be overridden by users, it helps narrow down the results for users by default, so they can get exactly what they’re looking for without having to sift through … Read more
You can easily determine the file MIME type with JavaScript’s FileReader before uploading it to a server. I agree that we should prefer server-side checking over client-side, but client-side checking is still possible. I’ll show you how and provide a working demo at the bottom. Check that your browser supports both File and Blob. All … Read more
I did use urlmon.dll in the end. I thought there would be an easier way but this works. I include the code to help anyone else and allow me to find it again if I need it. using System.Runtime.InteropServices; … [DllImport(@”urlmon.dll”, CharSet = CharSet.Auto)] private extern static System.UInt32 FindMimeFromData( System.UInt32 pBC, [MarshalAs(UnmanagedType.LPStr)] System.String pwzUrl, [MarshalAs(UnmanagedType.LPArray)] … Read more