C#•2y ago

Plugin system not casting properly

I'm trying to make a plugin system for my app, which does this:

public void LoadAndRunPlugins()
{
    foreach (string dllFile in Directory.GetFiles(pluginDirectory, "*.dll"))
    {
        try
        {
            Assembly assembly = pluginLoadContext.LoadFromAssemblyPath(Path.GetFullPath(dllFile));

            foreach (Type type in assembly.GetTypes().Where(asm => !asm.FullName.Contains("GyroShell.Library")))
            {
                if (type.GetInterface("IPlugin") != null)
                {
                    IPlugin plugin = Activator.CreateInstance(type) as IPlugin;
                    plugin.Initialize();
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"[-] PluginManager: Error loading and running plugin from {dllFile}: {ex.Message}");
        }
    }
}

public void LoadAndRunPlugins()
{
    foreach (string dllFile in Directory.GetFiles(pluginDirectory, "*.dll"))
    {
        try
        {
            Assembly assembly = pluginLoadContext.LoadFromAssemblyPath(Path.GetFullPath(dllFile));

            foreach (Type type in assembly.GetTypes().Where(asm => !asm.FullName.Contains("GyroShell.Library")))
            {
                if (type.GetInterface("IPlugin") != null)
                {
                    IPlugin plugin = Activator.CreateInstance(type) as IPlugin;
                    plugin.Initialize();
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"[-] PluginManager: Error loading and running plugin from {dllFile}: {ex.Message}");
        }
    }
}

public void LoadAndRunPlugins()
{
    foreach (string dllFile in Directory.GetFiles(pluginDirectory, "*.dll"))
    {
        try
        {
            Assembly assembly = pluginLoadContext.LoadFromAssemblyPath(Path.GetFullPath(dllFile));

            foreach (Type type in assembly.GetTypes().Where(asm => !asm.FullName.Contains("GyroShell.Library")))
            {
                if (type.GetInterface("IPlugin") != null)
                {
                    IPlugin plugin = Activator.CreateInstance(type) as IPlugin;
                    plugin.Initialize();
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"[-] PluginManager: Error loading and running plugin from {dllFile}: {ex.Message}");
        }
    }
}

public void LoadAndRunPlugins()
{
    foreach (string dllFile in Directory.GetFiles(pluginDirectory, "*.dll"))
    {
        try
        {
            Assembly assembly = pluginLoadContext.LoadFromAssemblyPath(Path.GetFullPath(dllFile));

            foreach (Type type in assembly.GetTypes().Where(asm => !asm.FullName.Contains("GyroShell.Library")))
            {
                if (type.GetInterface("IPlugin") != null)
                {
                    IPlugin plugin = Activator.CreateInstance(type) as IPlugin;
                    plugin.Initialize();
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"[-] PluginManager: Error loading and running plugin from {dllFile}: {ex.Message}");
        }
    }
}

The

IPlugin

IPlugin

IPlugin

IPlugin instance is null, so calling

plugin.Initialize()

plugin.Initialize()

plugin.Initialize()

plugin.Initialize() throws an NRE. The thing is, it should work just fine, given my plugin code:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GyroShell.Library.Interfaces;

namespace TestGyroShellModule
{
    public class PluginRoot : IPlugin
    {
        //public IPluginInfo PluginInformation => new PluginInfo();

        public void Initialize()
        {
            Debug.WriteLine("We're alive from test plugin!");
        }

        public void Shutdown()
        {
            // Shutdown logic
        }

        /*private class PluginInfo : IPluginInfo
        {
            public string Name => "Test GyroShell Plugin";
        }*/
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GyroShell.Library.Interfaces;

namespace TestGyroShellModule
{
    public class PluginRoot : IPlugin
    {
        //public IPluginInfo PluginInformation => new PluginInfo();

        public void Initialize()
        {
            Debug.WriteLine("We're alive from test plugin!");
        }

        public void Shutdown()
        {
            // Shutdown logic
        }

        /*private class PluginInfo : IPluginInfo
        {
            public string Name => "Test GyroShell Plugin";
        }*/
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GyroShell.Library.Interfaces;

namespace TestGyroShellModule
{
    public class PluginRoot : IPlugin
    {
        //public IPluginInfo PluginInformation => new PluginInfo();

        public void Initialize()
        {
            Debug.WriteLine("We're alive from test plugin!");
        }

        public void Shutdown()
        {
            // Shutdown logic
        }

        /*private class PluginInfo : IPluginInfo
        {
            public string Name => "Test GyroShell Plugin";
        }*/
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GyroShell.Library.Interfaces;

namespace TestGyroShellModule
{
    public class PluginRoot : IPlugin
    {
        //public IPluginInfo PluginInformation => new PluginInfo();

        public void Initialize()
        {
            Debug.WriteLine("We're alive from test plugin!");
        }

        public void Shutdown()
        {
            // Shutdown logic
        }

        /*private class PluginInfo : IPluginInfo
        {
            public string Name => "Test GyroShell Plugin";
        }*/
    }
}

And yes, they both reference the same exact interface, defined in

GyroShell.Library.Interfaces

GyroShell.Library.Interfaces

GyroShell.Library.Interfaces

GyroShell.Library.Interfaces.

Lastly, I've tried debugging this and nothing should go wrong. It tries to cast the

PluginRoot

PluginRoot

PluginRoot

PluginRoot class to an

IPlugin

IPlugin

IPlugin

IPlugin, which should work since it properly implements the interface, but it just fails. No exceptions are thrown.

hugeman•2/13/24, 10:02 PM

I'd do if (typeof(IPlugin).IsAssignableFrom(type))if (typeof(IPlugin).IsAssignableFrom(type))

Hhugeman I'd do `if (typeof(IPlugin).IsAssignableFrom(type))`

PdawgOP•2/13/24, 10:02 PM

Okay, I'll try this

PdawgOP•2/13/24, 10:03 PM

There's not an NRE anymore, but now it just fails to cast. Once again, no exceptions are thrown, and it should work just fine

PdawgOP•2/13/24, 10:03 PM

The test plugin references GyroShell.Library, so it's definitely implementing the correct interface

Jimmacle•2/13/24, 10:04 PM

if you expect the cast to succeed, use a C style cast instead of asas so you get an invalid cast exception if something unexpected happens

PdawgOP•2/13/24, 10:04 PM

Okay

PdawgOP•2/13/24, 10:04 PM

Well

Jimmacle•2/13/24, 10:04 PM

that will give you more info than it just returning null

PdawgOP•2/13/24, 10:04 PM

if (typeof(IPlugin).IsAssignableFrom(type))if (typeof(IPlugin).IsAssignableFrom(type)) it never gets past here though

PdawgOP•2/13/24, 10:04 PM

This is before the cast can be done

Jimmacle•2/13/24, 10:05 PM

then the cast isn't failing

PdawgOP•2/13/24, 10:05 PM

It thinks that you can't cast

PluginRoot

PluginRoot

even though it implements the interface properly

hugeman•2/13/24, 10:05 PM

Are you sure it's even processing your plugin's dll?

Hhugeman Are you sure it's even processing your plugin's dll?

PdawgOP•2/13/24, 10:06 PM

I believe so, when I tried debugging, the module showed up along with its respective Types

hugeman•2/13/24, 10:06 PM

Set a breakpoint on the LoadFromAssemblyPath line, and set a breakpoint on the typeof(IPlugin).IsAssignable...typeof(IPlugin).IsAssignable... line with a condition of type.Name == "PluginRoot"type.Name == "PluginRoot"

hugeman•2/13/24, 10:07 PM

And then check the debugger local variables for the type and see if it's correct

PdawgOP•2/13/24, 10:07 PM

Okay. Also, I tried the C Style cast and got a generic exception out of it:

hugeman•2/13/24, 10:08 PM

Maybe there's a version difference since you compiled the PluginRoot and the CLR doesn't like it

Jimmacle•2/13/24, 10:08 PM

do you have multiple types called

IPlugin

IPlugin

JJimmacle do you have multiple types called `IPlugin`?

PdawgOP•2/13/24, 10:08 PM

nope, just one

Hhugeman Set a breakpoint on the LoadFromAssemblyPath line, and set a breakpoint on the `...

PdawgOP•2/13/24, 10:09 PM

trying this rn

PdawgOP•2/13/24, 10:10 PM

@br4kejet

PdawgOP•2/13/24, 10:10 PM

This next breakpoint is never hit

hugeman•2/13/24, 10:10 PM

If you move next then it should try to run CreateInstance

hugeman•2/13/24, 10:11 PM

or you could do that

Hhugeman If you move next then it should try to run CreateInstance

PdawgOP•2/13/24, 10:11 PM

It just fails at the if statement, it thinks that the PluginRoot isn't assignable to IPlugin

PdawgOP•2/13/24, 10:11 PM

It won't run the CreateInstance

hugeman•2/13/24, 10:12 PM

Click the little arrow thing on type

Jimmacle•2/13/24, 10:12 PM

are you absolutely 100% sure there aren't multiple types in your project called

IPlugin

IPlugin

hugeman•2/13/24, 10:12 PM

Explore the interfaces

Jimmacle•2/13/24, 10:12 PM

because what this is indicating is the IPlugin you're testing against and the IPlugin the type implements are different types

Hhugeman Explore the interfaces

PdawgOP•2/13/24, 10:13 PM

JJimmacle because what this is indicating is the IPlugin you're testing against and the IP...

PdawgOP•2/13/24, 10:13 PM

I'm certain that they're implementing the same interface

PdawgOP•2/13/24, 10:14 PM

PdawgOP•2/13/24, 10:14 PM

PluginRoot implements GyroShell.Library.Interfaces.IPlugin

hugeman•2/13/24, 10:15 PM

I dunno then, the code I gave worked for me

hugeman•2/13/24, 10:15 PM

Though I use an abstract class instead of an interface

Hhugeman Though I use an abstract class instead of an interface

PdawgOP•2/13/24, 10:16 PM

should I do that instead?

hugeman•2/13/24, 10:17 PM

Could try it

PdawgOP•2/13/24, 10:17 PM

It doesn’t really matter which method I use, as long as it’s not some crude manual reflection thing

hugeman•2/13/24, 10:17 PM

Then if that works try using an interface again

PdawgOP•2/13/24, 10:17 PM

I’ll try an abstract later, I gotta go eat dinner

PdawgOP•2/13/24, 10:17 PM

Thanks for the help though

Jimmacle•2/13/24, 10:20 PM

dunno if it'll help but here's relevant code from the last plugin loader i was involved with https://github.com/TorchAPI/Torch/blob/master/Torch/Plugins/PluginManager.cs#L506-L573

PdawgOP•2/13/24, 10:26 PM

Cool, I’ll look into it later. Thanks!

PdawgOP•2/14/24, 2:11 AM

@br4kejet Hey, I'm back, and I tried an abstract class

PdawgOP•2/14/24, 2:11 AM

same problem as before

PdawgOP•2/14/24, 2:12 AM

I'll check the version of .NET and WASDK

PdawgOP•2/14/24, 2:17 AM

Nope, they're on the same version of WASDK and .NET

Plugin system not casting properly

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