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C#: use "Class Library" Project for plugins

this question follows my previous question.
I have a c# ASP.NET application and i want to provide support for plugins. Plugins can be custom c# classes, javascript, html, css, images, etc.
I see no problem as long as my application is extended with c# classes because all the user has to do is create a new "class library" project in visual studio and implement the interfaces, i provide. Then build a dll out of it and upload it to my server. The plugin-developer can add static files (html, js, css, etc.) into this project as well but i found some problems with that:
Every static file i add to the plugin project gets the build action "content" and it seems i cannot read those files from my server. (see my previously answered question). I have to manually select "Embedded Resource" on each file, so it is packed with the plugin dll.
I want to support Typescript for the plugins. The Typescript compiler generates javascript files in the same directory as the typescript-files. But the javascript files are not included in the project and therefore i have to include these in the plugin project and then set the correct build action. I don't want the plugin developers to do that all the time.
If the static files have the build action "enbedded resources", then the server can pickup these files by using the assembly.GetManifestResourceNames() method. This method returns the resources as a string. The path is not separated by \ or / but with a dot instead. So i am not able to distinguish between file path (this is relevant) or filename (also relevant to pickup the correct files), because the original filename can also have dots.
So i am starting to question the "class library" project type is right for my needs. Is there a way to get around of my issues or do i have to use another project type?
Thank you for any help!
Edit: Changed the question a little bit so it is better to understand.

You could make a zip package with the plugin dll and files. NuGet also uses this mechanism. A .nupkg is also just a zip file.

I would start by looking at MEF (Managed Extensibility Framework).
MSDN information can be found here: https://msdn.microsoft.com/en-us/library/dd460648(v=vs.110).aspx
From that link you can get more information and I believe there is a tutorial as well.

Oh, for me it seems very simple.
Let the developer create the plugin freestyle and put all the additional files in a directory, let's call it extras
To implement the your interface they will need your assembly so I guess you will ship it via nuget, or just some link. No matter what the case, provide them with some powershell script what will be required to run before the final build
The script would create zip archive from the extras directory and add it to the ClassLibrary project as EmbeddedResource.
As you mentioned earlier, you can access EmbeddedResource. So all you would do is to unpack it and you would have the exact directory tree.
The best idea would be to provide project template with script included, and also the empty zip archive added as embedded resource (it will be easier to just pack the files in the script and replace the file), and pre-build action set to run the script.
Am I missing something?

What about this.
In your web application, you could add a function that loop into your plugin directory and find DLL implementing an Iplugin (name is up to you) interface.
The interface is defined in a class library that both your web application and plugins have to implement.
You can use the Httpcontext Server mappath to read javascript and other files.
Here is a very basic implementation
First, you have the plugin interface (a class library implemented both by the web application and the individual plugins) I implemented sample properties and methods...
using System.Web;
public interface IPlugin
{
string Name { get; set; }
string Output { get; set; }
void Load(ref httpcontext Context);
void Dispose();
void Display();
}
Next, you have the Actual plugin class library we want to implement.
using System.Web;
using IPlugins;
public class AwesomePlugin : IPlugins.IPlugin
{
private string _Name = "AwesomePlugin";
private HttpContext _Context;
public string Name {
get { return _Name; }
set { _Name = value; }
}
public string Output {
get { return "Yay !!!"; }
set {
throw new NotImplementedException();
}
}
public void Display()
{
throw new NotImplementedException();
}
public void Dispose()
{
throw new NotImplementedException();
}
public void Load(ref Web.HttpContext Context)
{
}
}
Finally, you dynamically load your plugins so you can use them in your application.
private Dictionary<string, IPlugins.IPlugin> _Plugins = new Dictionary<string, IPlugins.IPlugin>();
public void LoadPlugins()
{
lock (static_LoadPlugins_IpluginType_Init) {
try {
if (InitStaticVariableHelper(static_LoadPlugins_IpluginType_Init)) {
static_LoadPlugins_IpluginType = typeof(IPlugins.IPlugin);
}
} finally {
static_LoadPlugins_IpluginType_Init.State = 1;
}
}
string ServerPath = HttpContext.Current.Server.MapPath("~") + "Plugins";
dynamic Plugins = io.Directory.GetFiles(ServerPath);
foreach (string PluginPath in Plugins) {
dynamic Assembly = system.Reflection.Assembly.LoadFile(PluginPath);
Type PluginClass = Assembly.GetTypes.Where(T => T.GetInterface("IPlugin") != null).First;
IPlugins.IPlugin MyPlugin = Activator.CreateInstance(PluginClass);
MyPlugin.Load(httpcontext.Current);
_Plugins.#add(PluginClass.ToString, MyPlugin);
}
}
static bool InitStaticVariableHelper(Microsoft.VisualBasic.CompilerServices.StaticLocalInitFlag flag)
{
if (flag.State == 0) {
flag.State = 2;
return true;
} else if (flag.State == 2) {
throw new Microsoft.VisualBasic.CompilerServices.IncompleteInitialization();
} else {
return false;
}
}
That way, you can implement whatever you want in your plugin.
I believe you could load your plugins in a separate appdomain with restricted permissions to everything.
The files (Javascript / CSS / Html) should be available by accessing the full path of the file.
string ServerPath = HttpContext.Current.Server.MapPath("~") + "Plugins";
If the resources is embedded into the plugin DLL, you could read the stream from the loaded assembly or let the plugin manage its own embedded files.

For question Number 2, you can use
MS Build
to change the contenttype during build process.
You have to make yourself confident with MS Build

Class Library Localization in Windows Universal / Store App

I have a solution with a Windows Store app project and a Class Library project and I want to add Localization support.
How can I add the all the Resource files to my Class Library and use them in both my App and Class Library?

In order to avoid writing a lot of boilerplate and error prone code when you add a new resource string like:
Add it to .resw file
Add it to your Static class that provides access to the resource
Add it to each language specific .resw file (ex: en, fr, pt, etc)
You can use the following approach:
Create "Strings" folder and add there just one folder for default language (for example "en-US") in your Class Library
Add Resources.resw file to "en-US" folder with required keys/values
Install Multilingual App Toolkit
Enable MAT in VS for your Class Library (VS->Tools->Enable Multilingual App Toolkit)
Add required languages to your Class Library (VS->Project->Add Translation languages...)
Install ResW File Code Generator VS extension
Go to Resources.resw file properties and set Custom Tool to "ReswFileCodeGenerator" (you can also specify namespace in Custom Tool Namespace)
To solve issue with supported languages detection(currently generated manifest contains supported languages according to folder structure "Strings/en-US") you need to add folders for all required languages in your App library ("fr-FR", "bg-BG", etc) and put Resources.resw file with only one fake key.
Build your solution and enjoy!
With this approach all your resources are available via static class generated by ReswFileCodeGenerator and all of them work with x:uid in XAML. You don't need to care about keys synchronization between different languages. Also MAT can translate your resources for you.

Ok, I found how to do this and with a sample project found here
Basically the implementation is the following:
In the ClassLibrary create a folder named "Strings"
Inside the Strings folder create one for each language (ex: en, fr, pt, etc)
And add a Resources.resw in each of those folders with your keys/values
Now add a new Class in your ClassLibrary that has the following code(adapted to your project):
using System;
using Windows.ApplicationModel.Resources;
namespace MyClassLibraryName.Tools {
public static class LocalizationTool {
static ResourceLoader resourceLoader = null;
public static string MyStringOne {
get {
String name;
GetLibraryName("MyStringOne", out name);
return name;
}
}
private static void GetLibraryName(string resourceName, out string resourceValue) {
if(resourceLoader == null) {
resourceLoader = ResourceLoader.GetForCurrentView("MyClassLibraryName/Resources");
}
resourceValue = resourceLoader.GetString(resourceName);
}
}
}
And in your ClassLibrary or MainApp just call the following:
string text = LocalizationTool.MyStringOne;

Get relative file path in a class library project that is being referenced by a web project

I have an ASP.Net website that references a class library. In the class library I need to read a file into memory.
At the top level of my class library there is a folder called EmailTemplateHtml containing the file MailTemplate.html that I want to read in.
How can I do this?

In Visual Studio, you can configure your library such that the file is copied into the build directory of any project that depends upon it. Then you can get the path to the build directory at runtime in order to read your file.
Step by step instructions, starting from a fresh solution:
Create your application project and your class library project.
Add a reference to the class library project from the application project via Properties->Add->Reference from the application's context menu in Solution Explorer:
Create the file in your class library project that you need to read, then set its Copy to Output Directory property to either Copy always or Copy if newer via the Properties pane in Solution Explorer:
From within either the class library project or your application (either will work with exactly the same code), reference your file relative to Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location). For example:
using System.Reflection;
using System.IO;
namespace MyLibrary
{
public class MyClass
{
public static string ReadFoo()
{
var buildDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
var filePath = buildDir + #"\foo.txt";
return File.ReadAllText(filePath);
}
}
}
(Note that back before .NET Core, you could use a file path relative to System.IO.Directory.GetCurrentDirectory() instead, but this doesn't work in a .NET Core application because the initial working directory for .NET Core apps is the source directory instead of the build directory, apparently because this was needed by ASP.NET Core.)
Go ahead and call your library code from your application code, and everything will work fine. e.g.:
using Microsoft.AspNetCore.Mvc;
using MyLibrary;
namespace AspCoreAppWithLib.Controllers
{
public class HelloWorldController : Controller
{
[HttpGet("/read-file")]
public string ReadFileFromLibrary()
{
return MyClass.ReadFoo();
}
}
}

using System.IO;
using System.Reflection;
public static string ExecutionDirectoryPathName()
{
var dirPath = Assembly.GetExecutingAssembly().Location;
dirPath = Path.GetDirectoryName(dirPath);
return Path.GetFullPath(Path.Combine(dirPath, "\EmailTemplateHtml\MailTemplate.html"));
}

If you want to find the path where the assembly is located; from within the assembly then use the following code:
public static string ExecutionDirectoryPathName
{
get
{
var dirPath = Assembly.GetExecutingAssembly().Location;
dirPath = Path.GetDirectoryName(dirPath);
return dirPath + #"\";
}
}

I am not sure what you mean by a folder in the class library but you can use the current working directory if you wish to build a path as follows:
System.IO.Directory.GetCurrentDirectory()
You can then use the Path.Combine() method to build file paths.

You can add a Static class in your class library with some static methods/properties to set. Set the values from Global.ascx.cs on start app method. Now you can get the values of class library.
Hope this makes clear.
Happy coding

c# Class Library Project - Load DLL from same folder?

I'm working on a plugin for a existing C# .NET Program. It's structured in a manner where you put your custom .dll file in Program Root/Plugins/your plugin name/your plugin name.dll
This is all working well, but now I'm trying to use NAudio in my project.
I've downloaded NAudio via Nuget, and that part works fine, but the problem is that it looks for the NAudio.dll in Program Root, and not in the folder of my plugin.
This makes it hard to distribute my plugin, because it would rely on users dropping the NAudio.dll in their Program Root in addition to putting the plugin into the "Plugins" folder.
Source:
SettingsView.xaml:
<Button HorizontalAlignment="Center"
Margin="0 5"
Width="120"
Command="{Binding SoundTestCommand,
Source={StaticResource SettingsViewModel}}"
Content="Sound Test" />
SettingsViewModel.cs:
using NAudio.Wave;
.
.
.
public void SoundTest()
{
IWavePlayer waveOutDevice;
WaveStream mainOutputStream;
WaveChannel32 inputStream;
waveOutDevice = new WaveOut();
mainOutputStream = new Mp3FileReader(#"E:\1.mp3");
inputStream = new WaveChannel32(mainOutputStream);
inputStream.Volume = 0.2F;
waveOutDevice.Init(mainOutputStream);
waveOutDevice.Play();
}
How can I get C# to look for NAudio in Program Root/Plugins/my plugin name/NAudio.dll instead of looking for it in Program Root/NAudio.dll ?
I'm using VS Express 2013, Target Framework is 4.5 and Output type is Class Library.
Edit:
I found 2 ways to make this work ( I'm not sure what the pros and cons of both methods are - if anyone knows I would appreciate additional information ).
Using the NuGet Package Costura.Fody.
After installing the NuGet package, I simply had to set all other References "Copy Local" to "False" and then set "Copy Local" for NAudio to "True".
Now when I build, the NAudio.dll is compressed and added to my own DLL.
Using the AssemblyResolver outlined below.
It didn't work right away though, so here is some additional information that may help anyone facing the same issue:
I put Corey's code as he posted it into the Helpers folder.
My entry point is Plugin.cs, the class is public class Plugin : IPlugin, INotifyPropertyChanged
In there, the entry method is public void Initialize(IPluginHost pluginHost), but simply putting PluginResolver.Init(path) did not work.
The host program uses WPF and is threaded and I had to use a dispatcher helper function of the host program to get it to work: DispatcherHelper.Invoke(() => Resolver.Init(path));
As mentioned, I'm currently unsure which method to use, but I'm glad I got it to work. Thanks Corey!

You can use the PATH environment variable to add additional folders to the search path. This works for native DLLs, but I haven't tried to use it for .NET assemblies.
Another option is to add a hook to the AssemblyResolve event on the current application domain and use a custom resolver to load the appropriate assembly from wherever you find it. This can be done at the assembly level - I use it in NAudio.Lame to load an assembly from a resource.
Something along these lines:
public static class PluginResolver
{
private static bool hooked = false;
public static string PluginBasePath { get; private set; }
public static void Init(string BasePath)
{
PluginBasePath = BasePath;
if (!hooked)
{
AppDomain.CurrentDomain.AssemblyResolve += ResolvePluginAssembly;
hooked = true;
}
}
static Assembly ResolvePluginAssembly(object sender, ResolveEventArgs args)
{
var asmName = new AssemblyName(args.Name).Name + ".dll";
var assemblyFiles = Directory.EnumerateFiles(PluginBasePath, "*.dll", SearchOption.AllDirectories);
var asmFile = assemblyFiles.FirstOrDefault(fn => string.Compare(Path.GetFileName(fn), asmName, true) == 0);
if (string.IsNullOrEmpty(asmFile))
return null;
return Assembly.LoadFile(asmFile);
}
}
(Usings for the above: System.IO, System.Reflection, System.Linq)
Call Init with the base path to your plugins folder. When you try to reference an assembly that isn't loaded yet it will search for the first file that matches the base name of the assembly with dll appended. For instance, the NAudio assembly will match the first file named NAudio.dll. It will then load and return the assembly.
No checking is done in the above code on the version, etc. and no preference is given to the current plugin's folder.

How to make designer generated .Net application settings portable

I've been looking at modifying the source of the Doppler podcast aggregator with the goal of being able to run the program directly from my mp3 player.
Doppler stores application settings using a Visual Studio designer generated Settings class, which by default serializes user settings to the user's home directory. I'd like to change this so that all settings would be stored in the same directory as the exe.
It seems that this would be possible by creating a custom provider class which inherits the SettingsProvider class. Has anyone created such a provider and would like to share code?
Update: I was able to get a custom settings provider nearly working by using this MSDN sample, i.e. with simple inheritance. I was initially confused as Windows Forms designer stopped working until I did this trick suggested at Codeproject:
internal sealed partial class Settings
{
private MySettingsProvider settingsprovider = new MySettingsProvider();
public Settings()
{
foreach (SettingsProperty property in this.Properties)
{
property.Provider = settingsprovider;
}
...
The program still starts with window size 0;0 though.
Anyone with any insight to this?
Why the need to assing the provider in runtime---instead of using attributes as suggested by MSDN?
Why the changes in how the default settings are passed to the application with the default settings provider vs. the custom one?

Why not use the CodeProject PortableSettingsProvider solution as is (with a few minor changes) ?
I have done so in my project (StreamRecorder.NET) with success.
Some comments on the project's page were useful:
http://www.codeproject.com/Messages/2934144/Fixed-csharp-version.aspx
http://www.codeproject.com/Messages/3285411/Re-Win-Form-Designer-breaking-with-custom-Settings.aspx
And the code I ended up with:
static void Main(string[] args)
{
if (args.Contains("-p") || args.Contains("--portable"))
{
MakePortable(Properties.Settings.Default);
MakePortable(Properties.LastUsedSettings.Default);
MakePortable(Properties.DefaultSettings.Default);
}
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MainForm(args));
}
private static void MakePortable(ApplicationSettingsBase settings)
{
var portableSettingsProvider =
new PortableSettingsProvider(settings.GetType().Name + ".settings");
settings.Providers.Add(portableSettingsProvider);
foreach (System.Configuration.SettingsProperty prop in settings.Properties)
prop.Provider = portableSettingsProvider;
settings.Reload();
}
Lastly I made these changes to the CP project:
string _fileName;
public PortableSettingsProvider(string fileName)
{
_fileName = fileName;
}
public virtual string GetAppSettingsFilename()
{
//Used to determine the filename to store the settings
//return ApplicationName + ".settings";
return _fileName;
}

I know this question is quite old already. I just want to share my own version of a portable settings provider which I published as nuget package here.
The usage is pretty simple:
// make the default settings class portable
PortableSettingsProvider.ApplyProvider(Properties.Settings.Default);
I also explained the basic strategy of this implementation at https://www.codeproject.com/Articles/1238550/Making-Application-Settings-Portable.

Just to 'close' the question: The somewhat unsatisfactory solution I ended up with was
Create a custom settings provider, which inherits from SettingsProvider and stores the settings in a XML file
Set the Provider property of each of the setting (by selecting the entire grid in the designer) to the custom settings provider using the designer
Drawbacks: The forms designer breaks and gives an exception which basically says that the custom provider class cannot be found. The built exe however works OK. Setting the provider in the code as described in the question makes the designer work, but then for some reason, which I haven't looked closely at, the settings won't serialize.
It seems that making settings portable was all that was needed to make Doppler portable. Whether I'll start using Doppler as my main podcast aggregator or stick with my homebrew command line aggregator, I'll see.