This project is an attempt to fix mingyaulee/Blazor.BrowserExtension#43 where Blazor for Chrome Extension cannot use Razor Class Library (RCL) assets due to _content being prohibited in Chrome Extension folders. It's also unlikely that there would be an official fix per dotnet/aspnetcore#45531.

You can also use this library as a custom interceptor for IJsRuntime that perform custom logic before calling InvokeAsync. It's recommended for Blazor WebAssembly only.

See Demo folder for sample of a WebAssembly project as well as a Blazor Chrome Extension project using mingyaulee/Blazor.BrowserExtension and KristofferStrube/Blazor.FileSystemAccess RCL.

Installation & Setup

Nuget Package

Install this library through Nuget package Blazor.JsRuntimeRedirect:

dotnet add package Blazor.JsRuntimeRedirect

Setup Dependency Injection

Call AddJsRuntimeRedirect to replace current implementation of IJsRuntime to the library's wrapper:

builder.Services
    // Other services
    .AddJsRuntimeRedirect();

Warning
AddJsRuntimeRedirect searches the current IServiceCollection for IJsRuntime's ImplementationInstance. If there is none, exception would be thrown.

AddJsRuntimeRedirect wraps the current ImplementationInstance of IJsRuntime to perform additional logic before calling their original methods.

Options

By default, the library attempt to redirect all import calls with _content in the path to content. This would solve mingyaulee/Blazor.BrowserExtension#43. You can override the settings using Options pattern's Configure or simply configure it with AddJsRuntimeRedirect method:

builder.Services
    .AddJsRuntimeRedirect(options =>
    {
        options.RedirectAfter = "testcontent";
        options.RedirectIdentifiers = new(StringComparer.OrdinalIgnoreCase) { "import", };
    });

• ShouldRedirect (default true): Whether the Redirect logic should be executed. RedirectBefore, RedirectAfter, RedirectIdentifiers are ignored if this is set to false.

• RedirectBefore (default _content): the name of the path segment that should be replaced.

• RedirectAfter (default content): the name of the path segment that should be replaced with.

• RedirectIdentifiers (default { "import" }): if set (non-null), the redirect logic is only considered if the identifier (i.e. the calling method, for example import or alert) is a value in the list. If set to null, every path is considered and therefore is not recommended due to performance impact.

• BeginInvokeJsInterceptor (default null): A method that is called before any logic is executed. Here you can modify the values of identifier and args. If you set Canceled to true, the call would be terminated.

Note
BeginInvokeJsInterceptor is called before ShouldRedirect logic. It's executed even if ShouldRedirect is false. However if you set Canceled to true, ShouldRedirect logic is not executed as the call is cancelled anyway.

From the demo project, an example of using BeginInvokeJsInterceptor which replaces all prompt JS call into alert and cancel the call altogether if the first argument is CancelThis:

options.BeginInvokeJsInterceptor = values =>
{
    if (values.Identifier == "prompt")
    {
        if (values.Args?.FirstOrDefault() as string == "CancelThis")
        {
            values.Canceled = true;
        }
        else
        {
            values.Identifier = "alert";
        }
    }
};