How to open files from the user's local device?

[lilDuckuling]

I created a serverside Blazor App and "electronized" it by following the instructions in the read me. One of the requirements for this app is to read/write/open files on the user's local device. I tried doing this first by simply using the c# System.IO File and Directory classes. Then i tried using Electron.Shell API.

//using the system classes
public void openFile(Folder folder)
{ 
    isTextFileOpen = false;
    if (folder.IsPseudoFolder && File.Exists(folder.Path))
    {
        if (".txt" == new FileInfo(folder.Name).Extension)
        {
            isTextFileOpen = true;
            filePath = folder.Path;
            fileContent = FileSystemService.ReadFromFile(folder.Path);
        }
        else
        {
            using (System.Diagnostics.Process fileopener = new System.Diagnostics.Process())
            {
                fileopener.StartInfo.FileName = "explorer";
                fileopener.StartInfo.Arguments = "\"" + folder.Path + "\"";
                fileopener.Start();
            }
        }
    }
}

//using Electron.Shell API
public async Task openFileElectron()
{
    var error = await Electron.Shell.OpenPathAsync($@"{MyRootPath}\MyText.txt");
    if (string.IsNullOrEmpty(error))
    {
        Console.WriteLine("File opened successfully");
     }
 }

Since it's a blazor serverside app, the code is executed on the server/host, meaning, when i run either of these methods (on a client device), the file gets opened on the host's device, not on the client's device.

So is there a way to actually access the client's file system and read/write/open files on their local harddrive using electron? Also i know there are File System APIs for WebApps, but those are very restricted (due to security reasons) and don't work on every browser, so that's not an option for me.
Any help would be appreciated🙏

Additional Info:
packages installed: ElectronNET.Core (0.2.0) and ElectronNET.Core.AspNet (0.2.0)
I use a serverside Blazor app, NOT Blazor Webassembly

[FlorianRappl]

It sounds to me that you are using an obsolete version of ElectronNET. Please migrate to ElectronNET.Core. There is no support for the outdated packages.

[lilDuckuling]

I use the serverside Blazor not Webassembly, so (as far as i understand) there still has to be a host, where the blazor server is running and the client connects to via SignalR.

For reference, here's what i've tried:
I packaged and published the app using this publishing profile. On a different pc (client), i tried running that exe file (published earlier): The app started, but showed a blank page with the MenuBar visible. Then on my other pc (host), where i develop, i started the app in the browser (which VS Studio hosts on a kestrel server). Since both the host and client are in the same network and i configured the ipaddress + port in my Program.cs file, the blazor instance in the app (running on the client) was able to connect to the blazor server running on my host pc -> the app now loaded and was interactive. Considering this, i concluded, that eventhough the blazor instance is in a selfcontained electron app, it still needs the host-client signalR connection to work.

[FlorianRappl]

Yes, but see my comment. That "host" is within the same machine - so same directories etc. Therefore I do not understand the distinction.

Having the .NET BE (controlling Electron / the client application) somewhere else (in your network) is not supported. They are an application after all.

If that is what you want consider using a real backend somewhere else and still use the ElectronNET.Core attached backend on the same machine (logically its one unit - use it as designed). The attached backend can still make HTTP calls to the real backend then. But that real backend cannot (and should not) control the ElectronNET application.

Hope that helps.

[lilDuckuling]

So is the behavior i described earlier (that i had to start the app in a kestrel server manually for the app to work) not supposed to happen? Instead, when executing the exe file, should the "server" (for blazor to connect to) get started automatically? This is also what i see happening when i run the app using the asp.net (unpackaged) debug launch setting: it starts the electron app and in the console it shows the kestrel server running. So could it be, that my packaging/publishing configurations are wrong and therefore the app doesn't start the kestrel server when executing?
If not, I'm probably misunderstanding some concepts here

[FlorianRappl]

Yes, I don't know of this behavior and when I run the application (and it seems all the other users) then everything works as it should.

As mentioned its one package, and ships as one package (make sure to hit the publish as documented to produce a runnable application) - if that executable is run it will start both (Electron and the .NET application, which controls the electron part via RPC internally).

[lilDuckuling]

Thanks a lot! For whatever reason the publishing didn't work right with the 0.2.0. ElectronNET.Core package. After installing the current latest release (0.3.0-pre.331 the publishing worked and the exe file now behaves correctly.

[FlorianRappl]

Great, thanks for the feedback! Happy that it works now as expected.