Culture env variables (#71)

* Fix AddHttpClient extension code being ignored on .net6

* Adds options for environment variables. Fixes #67

* Link to examples in error message.

* Some cleanup + docs

Author: Tewr

src/BlazorWorker.WorkerCore/BlazorWorker.WorkerCore.xml

@@ -74,9 +74,28 @@ public WorkerInitOptions()
         /// </summary>
         public string EndInvokeCallBackEndpoint { get; set; }
 
+        /// <summary>
+        /// Sets environment variables in the target worker. 
+        /// </summary>
+        /// <remarks>
+        /// Defaults to a single entry: DOTNET_SYSTEM_GLOBALIZATION_INVARIANT = '1'.
+        /// For more information see https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables
+        /// </remarks>
+        public Dictionary<string, string> EnvMap { get; set; } 
+            = new Dictionary<string, string>() { 
+                { "DOTNET_SYSTEM_GLOBALIZATION_INVARIANT", "1" },
+            };
+
         public WorkerInitOptions MergeWith(WorkerInitOptions initOptions)
         {
-
+            var newEnvMap = new Dictionary<string , string>(this.EnvMap);
+            if (initOptions.EnvMap != null)
+            {
+                foreach (var entry in initOptions.EnvMap)
+                {
+                    newEnvMap[entry.Key] = entry.Value;
+                }
+            }
             return new WorkerInitOptions
             {
                 CallbackMethod = initOptions.CallbackMethod ?? this.CallbackMethod,
@@ -87,7 +106,8 @@ public WorkerInitOptions MergeWith(WorkerInitOptions initOptions)
                 UseConventionalServiceAssembly = initOptions.UseConventionalServiceAssembly,
                 MessageEndPoint = initOptions.MessageEndPoint ?? this.MessageEndPoint,
                 InitEndPoint = initOptions.InitEndPoint ?? this.InitEndPoint,
-                EndInvokeCallBackEndpoint = initOptions.EndInvokeCallBackEndpoint ?? this.EndInvokeCallBackEndpoint
+                EndInvokeCallBackEndpoint = initOptions.EndInvokeCallBackEndpoint ?? this.EndInvokeCallBackEndpoint,
+                EnvMap = newEnvMap
             };
         }
     }
@@ -156,7 +176,7 @@ public static WorkerInitOptions AddHttpClient(this WorkerInitOptions source)
             source.AddAssemblies("System.Net.Http.dll", "System.Net.Http.WebAssemblyHttpHandler.dll");
 #endif
 
-#if NET5
+#if NET5_0_OR_GREATER
             source.AddAssemblies(
                 "System.Net.Http.dll", 
                 "System.Security.Cryptography.X509Certificates.dll",
@@ -169,5 +189,21 @@ public static WorkerInitOptions AddHttpClient(this WorkerInitOptions source)
 
             return source;
         }
+
+        /// <summary>
+        /// Set the specified <paramref name="environmentVariableName"/> to the specified <paramref name="value"/> when the worker runtime has been initialized
+        /// </summary>
+        /// <param name="source"></param>
+        /// <param name="environmentVariableName"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        /// <remarks>
+        /// For more information see https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables
+        /// </remarks>
+        public static WorkerInitOptions SetEnv(this WorkerInitOptions source, string environmentVariableName, string value)
+        {
+            source.EnvMap[environmentVariableName] = value;
+            return source;
+        }
     }
 }

src/BlazorWorker.WorkerCore/InitOptions.cs

@@ -231,7 +231,7 @@ private static InitInstanceResult InitInstance(long callId, string typeName, str
 
         private static Assembly LogFailedAssemblyResolve(object sender, ResolveEventArgs args)
         {
-            Console.Error.WriteLine($"{typeof(SimpleInstanceService).FullName}: '{args.RequestingAssembly}' is requesting missing assembly '{args.Name}')");
+            Console.Error.WriteLine($"{typeof(SimpleInstanceService).FullName}: '{args.RequestingAssembly}' is requesting missing assembly '{args.Name}'). See https://github.com/Tewr/BlazorWorker#setup-dependencies for common solutions to this problem.");
 
             //return null;
             // Nobody really cares about this exception for now, it can't be caught.

src/BlazorWorker.WorkerCore/SimpleInstanceService/SimpleInstanceService.cs

@@ -92,8 +92,15 @@ window.BlazorWorker = function () {
                 default: return fileName;
             }
         };
-        module.onRuntimeInitialized = () => 
-            MONO.mono_wasm_setenv('DOTNET_SYSTEM_GLOBALIZATION_INVARIANT', '1');
+        module.onRuntimeInitialized = () => {
+            const envMap = initConf.envMap;
+            for (const key in envMap) {
+                if (Object.prototype.hasOwnProperty.call(envMap, key)) {
+                    MONO.mono_wasm_setenv(key, envMap[key]);
+                }
+            }
+        }
+            
         module.preRun.push(() => {
             const mono_wasm_add_assembly = Module.cwrap('mono_wasm_add_assembly', null, [
                 'string',
@@ -269,6 +276,7 @@ window.BlazorWorker = function () {
             endInvokeCallBackEndpoint: initOptions.endInvokeCallBackEndpoint,
             wasmRoot: initOptions.wasmRoot,
             blazorBoot: "_framework/blazor.boot.json",
+            envMap: initOptions.envMap,
             debug: initOptions.debug
         };