Skip to main content

Part-3 Steps To Implement Google Authentication Into Existing Blazor WebAssembly Standalone Application

In this article, we will understand steps to integrate google authentication from scratch manually into the Blazor WebAssembly standalone application. Part-1 google authentication steps by default bundled with blazor webassembly application on selecting the authentication checkbox while creating the project. But here we will inject the authentication into the project that is not previously enabled with authentication.

Create Blazor WebAssembly Project:

Let's create a Blazor WebAssembly project without checking the authentication.

Install Authentication NuGet:

Package Manager:
Install-Package Microsoft.AspNetCore.Components.WebAssembly.Authentication -Version 5.0.5
.Net CLI:
dotnet add package Microsoft.AspNetCore.Components.WebAssembly.Authentication --version 5.0.5

Register Blazor Application In Google API's Console:

Create an account in Google API's Console(

Select the 'Credentials' menu and then click on 'Create Credentials'options and then select 'OAuth Client ID'.

Register our application here:
  • Create a name for our application.
  • Then register our blazor web assembly application domain.
  • Then register login callback URL.(its path should be fixed like '/authentication/login-callback', so these URL's automatically defined by our blazor application).
Now download the JSON file for settings that we need to configure in our Blazor Web Assembly application.

Configure Settings In Blazor WebAssembly Application:

Now in the app settings file in 'wwwroot' folder need to configure the following settings:
  • Authority -  value should be a domain. So for google authentication, its value should be "".
  • ClientId - its value copy from the downloaded JSON file from google console.
  • PostLogoutRedirectUri - its default path should be '/authentication/logout-callback'. Application will be redirect to this path on clicking logout.
  • RedirectUri - its default path should be '/authentication/login-callback'. This path should match with the google registered path value. This path used to redirect applications on redirect.
  • ResponseType - its value should be 'id_token'.
  "Local": {
    "Authority": "",
    "ClientId": "your_google_console_clientId",
    "PostLogoutRedirectUri": "https://localhost:5001/authentication/logout-callback",
    "RedirectUri": "https://localhost:5001/authentication/login-callback",
    "ResponseType": "id_token"

Configure OIDC Service:

Now configure the OIDC service in the 'Program.cs' file
builder.Services.AddOidcAuthentication(options => {
	builder.Configuration.Bind("Local", options.ProviderOptions);
  • Here binding or loading the authentication settings from JSON into OIDC auth service.

Create Authentication Component:

If you recall in previous steps you can observe authentication ur's like 'authentication/logout-callback', 'authentication/login-callback', etc. These all paths related to 'authentication' need to be loads this newly creating authentication component. This component will contain blazor defined component like 'RemoteAuthenticatorView'. The 'RemoteAuthenticatorView' component will perform all auth workflow based on the URL path.
@page "/authentication/{action}"
@using Microsoft.AspNetCore.Components.WebAssembly.Authentication

<RemoteAuthenticatorView Action="@Action">


    [Parameter] public string Action { get; set; }
  • Here part of the URL is passed as input param to 'RemoteAuthenticatiorView' component. So based on the path login flow executes.

Add AuthenticationService.js:

On installing the blazor webassembly authentication library it also creates a js file like 'AthenticationService.js' file. This js file contains core logic for the authentication process. So we need to add the reference of this js file into our index.html file just above the closing body tag.
<script src="_content/Microsoft.AspNetCore.Components.WebAssembly.Authentication/AuthenticationService.js">

CascadingAuthenticationState Component:

To inject authentication state into our blazor webassembly application then the CascadingAuthenticationState component should be the parent component of the entire application. The CascadingAuthenticationState must be rendered in 'App.razor' component.
@using Microsoft.AspNetCore.Components.Authorization
    <Router AppAssembly="@typeof(Program).Assembly" PreferExactMatches="@true">
        <Found Context="routeData">
            <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
            <LayoutView Layout="@typeof(MainLayout)">
                <p>Sorry, there's nothing at this address.</p>
  • The 'CascadingAuthenticationState' component loads from the 'Microsoft.AspNetCore.Components.Authorization'.

Create Login And Logout Button:

Now in the 'Shared' folder let's create a new component like 'LoginDisplay.razor'
@using Microsoft.AspNetCore.Components.Authorization
@using Microsoft.AspNetCore.Components.WebAssembly.Authentication

@inject NavigationManager Navigation
@inject SignOutSessionStateManager SignOutManager

        Hello, @context.User.Identity.Name!
        <button class="nav-link btn btn-link" @onclick="BeginSignOut">Log out</button>
        <a href="authentication/login">Log in</a>

    private async Task BeginSignOut(MouseEventArgs args)
        await SignOutManager.SetSignOutState();
  • (Line: 13) The 'Login' button configured. It navigates our 'Authentication.razor' component. So in the URL 'login' keyword plays a crucial role based on this appropriate login functionality will be triggered by the 'RemoteAuthenticatorView' component.
  • (Line: 10) The logout button configured with the 'BeginSingOut' callback method.
  • (Line: 18-22) Before logging out we need to set an application state like 'SignOutManager.SetSignOutState' and navigated to the 'Authentication.razor' component. Based on 'logout' keyword logout functionality triggered.
Now we can run our app and test the google authentication.
So that all about the core steps to integrate google authentication from scratch into the Blazor WebAssembly application.

Video Session:

Support Me!
Buy Me A Coffee PayPal Me

Wrapping Up:

Hopefully, I think this article delivered some useful information about adding google users to the database and generating JWT Blazor Webassembly Standalone Application. I love to have your feedback, suggestions, and better techniques in the comment section below.

Follow Me:


  1. How do configure this If I have authentication using Identity framework?

    1. I am having problem as the Authorize works for the Identity, not the Google authentication. Is it possible to have two authentication providers? This is the error that I am getting:
      blazor.webassembly.js:1 crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
      Unhandled exception rendering component: Specified cast is not valid.
      System.InvalidCastException: Specified cast is not valid.
      at Microsoft.Extensions.DependencyInjection.WebAssemblyAuthenticationServiceCollectionExtensions.<>c__0`3[[Microsoft.AspNetCore.Components.WebAssembly.Authentication.RemoteAuthenticationState, Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=, Culture=neutral, PublicKeyToken=adb9793829ddae60],[Microsoft.AspNetCore.Components.WebAssembly.Authentication.RemoteUserAccount, Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=, Culture=neutral, PublicKeyToken=adb9793829ddae60],[Microsoft.AspNetCore.Components.WebAssembly.Authentication.OidcProviderOptions, Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=, Culture=neutral, PublicKeyToken=adb9793829ddae60]].b__0_0(IServiceProvider sp)
      at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
      at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSiteMain(ServiceCallSite callSite, RuntimeResolverContext argument)
      at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
      at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)

    2. Hi mns,
      if you want to use Microsoft Identity Authentication,
      Then you can't do it directly in blazor webassembly, you must depend on Web API . So in web API you have to implement the identity authentication. Then blazor webassembly side you need to use jwt token for authentication.

      I had another blog for jwt token authentication in blazor webassembly

    3. Thanks a lot for fast reply sir. Log in using Identity framework is working, however not with the Google authentication using oauth.

    4. And I do have a web api. To be specific, I am actually trying to receive google contacts using People API. I am able to do this via web api, however, I cannot retrieve the results from API on Blazor web assembly project. I am using HttpClient on Blazor. The error in console says "Response to preflight request doesn't pass access control check: Redirect is not allowed for a preflight request". But thank you, I will take a look at the article you posted.


Post a Comment

Popular posts from this blog

Endpoint Routing In Asp.Net Core

How Routing Works In  Core 2.1 And Below Versions?: In Asp.Net Core routing is configured using app.UseRouter() or app.UseMvc() middleware. app.UseMvc(routes => { routes.MapRoute( name: "default", template: "{controller=Home}/{action=Index}/{id?}"); }); Here in Dotnet Core version 2.1 or below versions on the execution of route middleware request will be navigated appropriate controller matched to the route. An operation or functionality which is dependent on route URL or route values and that need to be implemented before the execution of route middleware can be done by accessing the route path from the current request context as below app.Use(async (context, next) => { if(context.Request.Path.Value.IndexOf("oldvehicle") != -1) { context.Response.Redirect("vehicle"); } else { await next(); } }); app.UseMvc(routes => { routes.MapRoute( name: "vehicleRoute", template: "vehicle", defaul

Asp.Net Core MVC Form Validation Techniques

Introduction: Form validations in any applications are like assures that a valid data is storing on servers. All programing frameworks have their own individual implementations for form validations. In Dotnet Core MVC application server-side validations carried on by the models with the help of Data Annotations and the client-side validations carried by the plugin jQuery Unobtrusive Validation. jQuery Unobtrusive Validation is a custom library developed by Microsoft based on the popular library  jQuery Validate . In this article, we are going to learn how the model validation and client-side validation works in Asp.Net Core MVC Application with sample examples. Getting Started: Let's create an Asp.Net Core MVC application project using preferred editors like Microsoft Visual Studio or Microsoft Visual Studio Code. Here I'm using Visual Studio. Let's create an MVC controller and name it as 'PersonController.cs' and add an action method as bel

How Response Caching Works In Asp.Net Core

What Is Response Caching?: Response Caching means storing of response output and using stored response until it's under it's the expiration time. Response Caching approach cuts down some requests to the server and also reduces some workload on the server. Response Caching Headers: Response Caching carried out by the few Http based headers information between client and server. Main Response Caching Headers are like below Cache-Control Pragma Vary Cache-Control Header: Cache-Control header is the main header type for the response caching. Cache-Control will be decorated with the following directives. public - this directive indicates any cache may store the response. private - this directive allows to store response with respect to a single user and can't be stored with shared cache stores. max-age - this directive represents a time to hold a response in the cache. no-cache - this directive represents no storing of response and always fetch the fr

Blazor WebAssembly Custom Authentication From Scratch

In this article, we are going to explore and implement custom authentication from the scratch. In this sample, we will use JWT authentication for user authentication. Main Building Blocks Of Blazor WebAssembly Authentication: The core concepts of blazor webassembly authentication are: AuthenticationStateProvider Service AuthorizeView Component Task<AuthenticationState> Cascading Property CascadingAuthenticationState Component AuthorizeRouteView Component AuthenticationStateProvider Service - this provider holds the authentication information about the login user. The 'GetAuthenticationStateAsync()' method in the Authentication state provider returns user AuthenticationState. The 'NotifyAuthenticationStateChaged()' to notify the latest user information within the components which using this AuthenticationStateProvider. AuthorizeView Component - displays different content depending on the user authorization state. This component uses the AuthenticationStateProvider

.NET Core MVC Application File Upload To Physical Location With Buffered Technique

Buffering Technique In File Upload: The server will use its Memory(RAM) or Disk Storage to save the files on receiving a file upload request from the client.  Usage of Memory(RAM) or Disk depends on the number of file requests and the size of the file.  Any single buffered file exceeding 64KB is moved from Memory to a temp file on disk.  If an application receives heavy traffic of uploading files there might be a chance of out of Disk or RAM memory which leads to crash application. So this Buffer technique used for small files uploading. In the following article, we create a sample for the file uploading using .NET Core MVC application. Create The .NET Core MVC Project: Let's create a .NET Core MVC project, here for this sample I'm using Visual Studio Code as below.   Check the link to use the Visual Studio Code for .NET Core Application . IFormFile: Microsoft.AspNetCore.Http.IFormFile used for file upload with buffered technique. On uploading files f

Ionic Picker Sample Code In Angular

Introduction: Ionic Picker(ion-picker) is a popup slides up from the bottom of the device screen, which contains rows with selectable column separated items. The main building block of ion-picker as follows: PickerController PickerOptions PickerController: PickerController object helps in creating an ion-picker overlay. create(opts?: Opts): Promise<Overlay> PickerController create method helps in create the picker overlay with the picker options PickerOptions: PickerOptions is a configuration object used by PickerController to display ion-picker. Single Column Ionic Picker: single.item.picker.ts: import { Component } from "@angular/core"; import { PickerController } from "@ionic/angular"; import { PickerOptions } from "@ionic/core"; @Component({ selector: "single-column-picker", templateUrl:"single.item.picker.html" }) export class SingleItemPicker { animals: string[] = ["Tiger&quo

GraphQL API Integration In Asp.Net Core Application

Introduction: GraphQL is a query language for your API and a server-side runtime for executing queries by using a type system you define for your data. GraphQL can be integrated into any framework like ASP.NET, Java, NestJs, etc and it isn't tied to any specific database or storage engine and is instead backed by your existing code and data. How GraphQL API Different From Rest API: GraphQL exposes a single end-point or route for the entire application, regardless of its responses or actions. HTTP-POST is the only Http verb recommended by the GraphQL. The client applications (consumers of API) can give instructions to GraphQL API about what type of properties to be returned in the response. Building Blocks Of GraphQL API: The main building blocks of GraphQL API is Schemas and Types.  A 'Schema' in GrpahQL API describes the functionality available to the clients connect to API. Schema mostly consists of GraphQL Object Types, Queries, Mutations, etc. T

.Net Core HttpClient JSON Extension Methods Using System.Net.Http.Json Package

.Net Core 3.0 onwards Microsoft brought up a new package called System.Net.Http.Json. This new package provides JSON extension methods for HttpClient. These JSON extension methods will have a prebuild mechanism for serializing or deserializing response data or payload of HttpClient call. System.Net.Http.Json extension methods that are provided to HttpClient, few of them are mentioned below. GetFromJsonAsync PostAsJsonAsync PutAsJsonAsync ReadFromJsonAsync In this article, we understand System.Net.Http.Json package by implementing the HttpClient samples by with and without JSON extension methods and compare them. Create A .Net Core Web API Sample Application: Let's create a .Net Core sample Web API application, from this application we will consume another Web API by implementing HttpClient calls. We can create a Web API sample application using IDE like Visual Studio 2019(Supports .Net Core 3.0 plus) or  Visual Studio Code . Create A Typed Client: In .Net Core using the Http

ASP.NET Core Web API Versioning

Introduction: An iteration and evolutionary changes of an ASP.NET Core Web API is handled by Versioning. Versioning of an API gives confidence to the clients which consumes API for a long time. Any changes or development of an API will be accessible using the new version and it won't cause issues to the clients consuming the old version of API. When To Use Versioning: Any API response changes. Developing an API by implementing testing levels like 'Alpha', 'Beta', and 'RC' versions before releasing Production. Deprecating an API which means API going to be removed or upgraded by a version within a short period. Versioning Types: Query String Versioning Url Path Versioning Media Type Versioning API Version Nuget: To Configure versioning to AspNet Core Web API Microsoft provided a library(Microsoft.AspNetCore.Mvc.Versioning). So to use the versioning library please install NuGet below.              Install-Package Microsoft.A

Blazor Server CRUD Operations

Introduction: Blazor Server is a web framework to develop server-side single-page applications. Blazor is made up of components with the combinations on C#, Html, CSS.  Blazor Server is production-ready from the .Net Core 3.0.  Blazor Server Working Mechanism: Blazor Server is a very light-weight web development framework.  In Blazor Server, not all code gets downloaded to the client browsers. Blazor Server made of components these components can be a block of code or page with respective navigation.  Blazor server application communicates with the server with a SignalR background connection which is inbuilt functionality. Application click,  form submission, change events, application page navigation every operation is carried out by the SignalR connection by communicating with the server.  Blazor updates the Html DOM very gently on every data update without any overhead. Blazor Server application maintains a nice intelligent tree structure to update the required inform