Xamarin File Mime Type

Question

I'll currently develop an Xamarin app cross platform (iOS/Android) that download a file via CrossDownloadManager and decompress the zip with SharpZipLib.Portable.

All works fine, but I want to check the download file mime type before send it to the unzip library to avoid any problem. I cannot use the extension of file because is not required.

What are you going to do if the mime type is incorrect? Just pass the file to the unzip library and let it make sure it's correct. — Neil, Sep 25 '18 at 07:57

score 1 · Answer 1 · answered Nov 16 '18 at 13:48

According to Curiousity's answer, this is how you do it:

public String getMimeType(Uri uri) {
    String mimeType = null;
    if (uri.Scheme.Equals(ContentResolver.SchemeContent))
    {
        ContentResolver cr = Application.Context.ContentResolver;
        mimeType = cr.GetType(uri);
    }
    else
    {
        String fileExtension = MimeTypeMap.GetFileExtensionFromUrl(uri.ToString());
        mimeType = MimeTypeMap.Singleton.GetMimeTypeFromExtension(
        fileExtension.ToLower());
    }
    return mimeType;
}

Divyesh_08 · Answer 2 · 2019-07-08T09:09:11.940

*Use MimeTypes Nuget Package: https://www.nuget.org/packages/MimeTypes/

You just have to pass file name to get its content-type:

var mimeType = MimeTypes.GetMimeType(fileName);

This is how I get the mime type of image picked using Image picker's FinishedPickingMedia method in Xamarin.iOS [C#]

NSUrl referenceURL = e.Info[new NSString("UIImagePickerControllerReferenceURL")] as NSUrl;
if (referenceURL != null)
{
    var fileName = referenceURL.Path.ToString();
    var url = referenceURL.ToString();
    Console.WriteLine(referenceURL.ToString());
}


ALAssetsLibrary assetsLibrary = new ALAssetsLibrary();
assetsLibrary.AssetForUrl(referenceURL, delegate (ALAsset asset)
{
    ALAssetRepresentation representation = asset.DefaultRepresentation;
    if (representation!= null)
    {
        string fileName = representation.Filename;
        var mimeType = MimeTypes.GetMimeType(fileName);

    }

}, delegate (NSError error) {
    Console.WriteLine("User denied access to photo Library... {0}", error);
});

Xamarin File Mime Type

2 Answers2