/// <summary>
/// Loads plugins with the specified plugin interface type.
/// </summary>
/// <param name="path">
/// The path to look for plugins to load.
/// </param>
/// <param name="domains">The <see cref="AppDomain"/>s created by the loader.</param>
/// <param name="saveToZip">
/// Tells this function to see if the plugin was saved to a zip file and it's pdb file as well.
/// </param>
/// <returns>
/// A list of plugins loaded that derive from the specified type.
/// </returns>
public ICollection <T> LoadPlugins(string path, out List <AppDomain> domains, bool saveToZip = false)
#endif
{
string[] dllFileNames = null;
if (Directory.Exists(path))
{
dllFileNames = Directory.GetFiles(path, "*.dll");
}
// try to load from a zip as well if plugins are installed in both places.
var zippath = $"{path}.zip";
ICollection <T> plugins = new List <T>();
#if NET5_0_OR_GREATER
contexts = new List <PluginLoadContext>();
#elif NET45
domains = new List <AppDomain>();
#endif
// handle when path points to a zip file.
if (Directory.Exists(path) || File.Exists(zippath))
{
ICollection <Assembly> assemblies = new List <Assembly>();
if (dllFileNames != null)
{
foreach (var dllFile in dllFileNames)
{
#if NET5_0_OR_GREATER
var context = new PluginLoadContext($"Plugin#{dllFileNames.ToList().IndexOf(dllFile)}", path);
#else
var domain = AppDomain.CreateDomain($"Plugin#{dllFileNames.ToList().IndexOf(dllFile)}");
#endif
try
{
var asmFile = File.ReadAllBytes(dllFile);
// We need to handle the case where the pdb does not exist and where the
// symbols might actually be embedded inside the dll instead or simply does
// not exist yet.
#if NET5_0_OR_GREATER
var pdbFile = Debugger.IsAttached && File.Exists(dllFile.Replace("dll", "pdb", StringComparison.Ordinal))
? File.ReadAllBytes(
dllFile.Replace("dll", "pdb", StringComparison.Ordinal)) : null;
using var ms1 = new MemoryStream(asmFile);
using var ms2 = new MemoryStream(pdbFile);
var assembly = Debugger.IsAttached && pdbFile != null?
context.LoadFromStream(ms1, ms2) :
context.LoadFromStream(ms1);
contexts.Add(context);
#else
var pdbFile = Debugger.IsAttached && File.Exists(dllFile.Replace("dll", "pdb"))
? File.ReadAllBytes(dllFile.Replace("dll", "pdb")) : null;
var assembly = Debugger.IsAttached && pdbFile != null?
domain.Load(asmFile, pdbFile) :
domain.Load(asmFile);
domains.Add(domain);
#endif
assemblies.Add(assembly);
}
catch (BadImageFormatException)
{
// ignore the error and load the other files.
#if NET5_0_OR_GREATER
context.Unload();
#else
AppDomain.Unload(domain);
#endif
}
catch (FileLoadException)
{
#if NET5_0_OR_GREATER
var assembly = context.LoadFromAssemblyPath(dllFile);
contexts.Add(context);
assemblies.Add(assembly);
#elif NET45
try
{
var assembly = domain.Load(AssemblyName.GetAssemblyName(dllFile));
domains.Add(domain);
assemblies.Add(assembly);
}
catch (Exception)
{
// ignore the error and load the other files.
AppDomain.Unload(domain);
}
#elif !NET45
var assembly = Assembly.LoadFrom(dllFile);
domains.Add(domain);
assemblies.Add(assembly);
#endif
}
catch (FileNotFoundException)
{
// ignore the error and load other files.
#if NET5_0_OR_GREATER
context.Unload();
#else
AppDomain.Unload(domain);
#endif
}
}
}
if (saveToZip && File.Exists(zippath))
{
var filesInZip = new Dictionary <string, int>();
using (var zipFile = ZipFile.OpenRead(zippath))
{
foreach (var entry in zipFile.Entries)
{
filesInZip.Add(entry.FullName, zipFile.Entries.IndexOf(entry));
}
}
foreach (var entry in filesInZip.Keys)
{
// just lookup the dlls here. The LoadFromZip method will load the pdb’s if they are deemed needed.
if (entry.EndsWith(".dll", StringComparison.Ordinal))
{
#if NET5_0_OR_GREATER
var context = new PluginLoadContext($"ZipPlugin#{filesInZip[entry]}", path);
var assembly = ZipAssembly.LoadFromZip(zippath, entry, context);
contexts.Add(context);
#else
var domain = AppDomain.CreateDomain($"ZipPlugin#{filesInZip[entry]}");
var assembly = ZipAssembly.LoadFromZip(zippath, entry, domain);
domains.Add(domain);
#endif
if (assembly != null)
{
assemblies.Add(assembly);
}
}
}
}
var pluginType = typeof(T);
var pluginTypes = new List <Type>();
foreach (var assembly in assemblies)
{
if (assembly != null)
{
try
{
var types = assembly.GetTypes();
foreach (var type in types)
{
if (!type.IsInterface && !type.IsAbstract && type.GetInterface(pluginType.FullName) != null)
{
pluginTypes.Add(type);
}
}
}
catch (ReflectionTypeLoadException ex)
{
var exMsg = new StringBuilder();
foreach (var exceptions in ex.LoaderExceptions)
{
exMsg.Append($"{exceptions.Message}{Environment.NewLine}{exceptions.StackTrace}{Environment.NewLine}");
}
PluginLoaderMessage?.Invoke(null, new MessageEventArgs(exMsg.ToString(), "Error!", ErrorLevel.Error));
}
catch (ArgumentNullException ex)
{
var exMsg = string.Empty;
LogException(ex, ref exMsg);
PluginLoaderMessage?.Invoke(null, new MessageEventArgs(exMsg, "Error!", ErrorLevel.Error));
}
}
}
ICollection <int> toRemove = new List <int>();
foreach (var type in pluginTypes)
{
try
{
var plugin = (T)Activator.CreateInstance(type);
plugins.Add(plugin);
}
catch (MissingMethodException)
{
toRemove.Add(pluginTypes.IndexOf(type));
var index = 0;
#if NET5_0_OR_GREATER
foreach (var context in contexts)
{
if (context.Assemblies.Contains(type.Assembly) && context.IsCollectible)
{
index = contexts.IndexOf(context);
context.Unload();
}
}
#else
foreach (var domain in domains)
{
if (domain.GetAssemblies().ToList().Contains(type.Assembly))
{
index = domains.IndexOf(domain);
AppDomain.Unload(domain);
}
}
#endif
if (index > -1)
{
#if NET5_0_OR_GREATER
contexts.RemoveAt(index);
#else
domains.RemoveAt(index);
#endif
}
}
}
foreach (var indexToRemove in toRemove)
{
if (indexToRemove > -1)
{
pluginTypes.RemoveAt(indexToRemove);
}
}
toRemove.Clear();
return(plugins);
}
return(plugins);
}
/// <summary>
/// Loads plugins with the specified plugin interface type.
/// </summary>
/// <param name="path">The path to look for plugins to load.</param>
/// <param name="saveToZip">Tells this function to see if the plugin was saved to a zip file and it's pdb file as well.</param>
/// <param name="loadPDBFile">Tells the method to load the plugins pdb file or not. Ignored and loaded anyway when a debugger is attached.</param>
/// <returns>A list of plugins loaded that derive from the specified type.</returns>
public ICollection <T> LoadPlugins(string path, bool saveToZip = false, bool loadPDBFile = false)
{
string[] dllFileNames = null;
if (Directory.Exists(path))
{
dllFileNames = Directory.GetFiles(path, "*.dll");
}
// try to load from a zip as well if plugins are installed in both places.
var zippath = $"{path}.zip";
ICollection <T> plugins = new List <T>();
// handle when path points to a zip file.
if (Directory.Exists(path) || File.Exists(zippath))
{
ICollection <Assembly> assemblies = new List <Assembly>();
if (dllFileNames != null)
{
foreach (var dllFile in dllFileNames)
{
var loadPDB = loadPDBFile ? loadPDBFile : Debugger.IsAttached;
try
{
var asmFile = File.ReadAllBytes(dllFile);
try
{
#if NETSTANDARD2_1 || NETCOREAPP2_1 || NETCOREAPP2_2 || NETCOREAPP3_0 || NETCOREAPP3_1 || NET5_0
var pdbFile = loadPDB ? File.ReadAllBytes(dllFile.Replace("dll", "pdb", StringComparison.Ordinal)) : null;
#else
var pdbFile = loadPDB ? File.ReadAllBytes(dllFile.Replace("dll", "pdb")) : null;
#endif
var assembly = loadPDB ?
Assembly.Load(asmFile, pdbFile) :
Assembly.Load(asmFile);
assemblies.Add(assembly);
}
catch (FileNotFoundException)
{
var assembly = Assembly.Load(asmFile);
assemblies.Add(assembly);
}
}
catch (BadImageFormatException)
{
// ignore the error and load the other files.
}
catch (FileLoadException)
{
var assembly = Assembly.LoadFrom(dllFile);
assemblies.Add(assembly);
}
catch (FileNotFoundException)
{
// ignore the error and load other files.
}
}
}
if (saveToZip && File.Exists(zippath))
{
using (var zipFile = ZipFile.OpenRead(zippath))
{
foreach (var entry in zipFile.Entries)
{
// just lookup the dlls here. The LoadFromZip method will load the pdb’s if they are deemed needed.
if (entry.FullName.EndsWith(".dll", StringComparison.Ordinal))
{
var assembly = ZipAssembly.LoadFromZip(zippath, entry.FullName, loadPDBFile);
if (assembly != null)
{
assemblies.Add(assembly);
}
}
}
}
}
var pluginType = typeof(T);
ICollection <Type> pluginTypes = new List <Type>();
foreach (var assembly in assemblies)
{
if (assembly != null)
{
try
{
var types = assembly.GetTypes();
foreach (var type in types)
{
if (!type.IsInterface && !type.IsAbstract && type.GetInterface(pluginType.FullName) != null)
{
pluginTypes.Add(type);
}
}
}
catch (ReflectionTypeLoadException ex)
{
var exMsg = new StringBuilder();
foreach (var exceptions in ex.LoaderExceptions)
{
exMsg.Append($"{exceptions.Message}{Environment.NewLine}{exceptions.StackTrace}{Environment.NewLine}");
}
PluginLoaderMessage?.Invoke(null, new MessageEventArgs(exMsg.ToString(), "Error!", ErrorLevel.Error));
}
catch (ArgumentNullException ex)
{
var exMsg = string.Empty;
LogException(ex, ref exMsg);
PluginLoaderMessage?.Invoke(null, new MessageEventArgs(exMsg, "Error!", ErrorLevel.Error));
}
}
}
foreach (var type in pluginTypes)
{
var plugin = (T)Activator.CreateInstance(type);
plugins.Add(plugin);
}
return(plugins);
}
return(plugins);
}