Merge pull request #3391 from gterdem/gterdem/blogs/custom_signinmanager

Add Blog Post: Customizing SignInManager

docs/en/Blog-Posts/2020-04-02/Post.md

@@ -0,0 +1,88 @@
+# Custom SignIn Manager
+
+## Introduction
+
+ABP Framework uses Microsoft Identity underneath hence supports customization as much as Microsoft Identity does.
+
+
+
+## Sample Code
+
+https://github.com/abpframework/abp-samples/blob/master/aspnet-core/BookStore-AzureAD/src/Acme.BookStore.Web/CustomSignInManager.cs
+
+
+
+## Creating CustomSignInManager
+
+To create your own custom SignIn Manager, you need to inherit `SignInManager<Volo.Abp.Identity.IdentityUser>`.
+
+````xml
+public class CustomSignInManager : SignInManager<Volo.Abp.Identity.IdentityUser>
+{
+    public CustomSigninManager(
+    UserManager<Volo.Abp.Identity.IdentityUser> userManager,
+    IHttpContextAccessor contextAccessor,
+    IUserClaimsPrincipalFactory<Volo.Abp.Identity.IdentityUser> claimsFactory,
+    IOptions<IdentityOptions> optionsAccessor,
+    ILogger<SignInManager<Volo.Abp.Identity.IdentityUser>> logger,
+    IAuthenticationSchemeProvider schemes,
+    IUserConfirmation<Volo.Abp.Identity.IdentityUser> confirmation) 
+    : base(userManager, contextAccessor, claimsFactory, optionsAccessor, logger, schemes, confirmation)
+    {
+    }
+}
+````
+
+
+
+## Overriding Methods
+
+Afterwards you can override a method like `GetExternalLoginInfoAsync`:
+
+````xml
+public override async Task<ExternalLoginInfo> GetExternalLoginInfoAsync(string expectedXsrf = null)
+{
+    var auth = await Context.AuthenticateAsync(IdentityConstants.ExternalScheme);
+    var items = auth?.Properties?.Items;
+    if (auth?.Principal == null || items == null || !items.ContainsKey("LoginProvider"))
+    {
+    	return null;
+    }
+
+    if (expectedXsrf != null)
+    {
+        if (!items.ContainsKey("XsrfId"))
+        {
+        	return null;
+        }
+        var userId = items[XsrfKey] as string;
+        if (userId != expectedXsrf)
+        {
+        return null;
+    }
+    var providerKey = auth.Principal.FindFirstValue(ClaimTypes.NameIdentifier);
+    var provider = items[LoginProviderKey] as string;
+    if (providerKey == null || provider == null)
+    {
+    	return null;
+    }
+
+    var providerDisplayName = (await GetExternalAuthenticationSchemesAsync()).FirstOrDefault(p => p.Name == provider)?.DisplayName ?? provider;
+    return new ExternalLoginInfo(auth.Principal, provider, providerKey, providerDisplayName)
+    {
+    	AuthenticationTokens = auth.Properties.GetTokens()
+    };
+}
+````
+
+
+
+## Registering to DI
+
+You need to register your Custom SignIn Manager to DI to activate it. Inside the `.Web` project, locate the `ApplicationNameWebModule` and add the following under `ConfigureServices` method:
+
+````xml
+context.Services
+.GetObject<IdentityBuilder>()
+    .AddSignInManager<CustomSigninManager>();
+````