From 0c90e1989502c9a50c60e223984e9df6ab1d389f Mon Sep 17 00:00:00 2001
From: morbalint <balint@morasz.hu>
Date: Wed, 27 Dec 2023 16:30:16 +0100
Subject: [PATCH] add Google login

---
 .../Pages/Account/ExternalLogin.cshtml.cs     | 44 ++++++++++++++-----
 Kemkas.Web/Kemkas.Web.csproj                  |  1 +
 Kemkas.Web/Program.cs                         |  8 +++-
 Kemkas.Web/nginx.conf                         |  6 +++
 Kemkas.Web/packages.lock.json                 |  6 +++
 5 files changed, 53 insertions(+), 12 deletions(-)

diff --git a/Kemkas.Web/Areas/Identity/Pages/Account/ExternalLogin.cshtml.cs b/Kemkas.Web/Areas/Identity/Pages/Account/ExternalLogin.cshtml.cs
index 5b4931f..e312d95 100644
--- a/Kemkas.Web/Areas/Identity/Pages/Account/ExternalLogin.cshtml.cs
+++ b/Kemkas.Web/Areas/Identity/Pages/Account/ExternalLogin.cshtml.cs
@@ -123,20 +123,42 @@ namespace Kemkas.Web.Areas.Identity.Pages.Account
             {
                 return RedirectToPage("./Lockout");
             }
-            else
+
+            // If the user does not have an account, and no email claim, then ask the user to create an account.
+            ReturnUrl = returnUrl;
+            ProviderDisplayName = info.ProviderDisplayName;
+            if (!info.Principal.HasClaim(c => c.Type == ClaimTypes.Email))
             {
-                // If the user does not have an account, then ask the user to create an account.
-                ReturnUrl = returnUrl;
-                ProviderDisplayName = info.ProviderDisplayName;
-                if (info.Principal.HasClaim(c => c.Type == ClaimTypes.Email))
-                {
-                    Input = new InputModel
-                    {
-                        Email = info.Principal.FindFirstValue(ClaimTypes.Email)
-                    };
-                }
                 return Page();
             }
+                
+            // User doesn't have account but external provider has email claim. => Register with claimed email.
+            Input = new InputModel
+            {
+                Email = info.Principal.FindFirstValue(ClaimTypes.Email)
+            };
+            var user = CreateUser();
+            await _userStore.SetUserNameAsync(user, Input.Email, CancellationToken.None);
+            await _emailStore.SetEmailAsync(user, Input.Email, CancellationToken.None);
+            var registrationResult = await _userManager.CreateAsync(user);
+            if (registrationResult.Succeeded)
+            {
+                registrationResult = await _userManager.AddLoginAsync(user, info);
+                if (registrationResult.Succeeded)
+                {
+                    _logger.LogInformation("User created an account using {Name} provider.", info.LoginProvider);
+                    var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
+                    await _userManager.ConfirmEmailAsync(user, code);
+                    await _signInManager.SignInAsync(user, isPersistent: false, info.LoginProvider);
+                    return LocalRedirect(returnUrl);
+                }
+            }
+            foreach (var error in registrationResult.Errors)
+            {
+                ModelState.AddModelError(string.Empty, error.Description);
+            }
+
+            return Page();
         }
 
         public async Task<IActionResult> OnPostConfirmationAsync(string returnUrl = null)
diff --git a/Kemkas.Web/Kemkas.Web.csproj b/Kemkas.Web/Kemkas.Web.csproj
index 80ce963..89d50d7 100644
--- a/Kemkas.Web/Kemkas.Web.csproj
+++ b/Kemkas.Web/Kemkas.Web.csproj
@@ -17,6 +17,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="Microsoft.AspNetCore.Authentication.Google" Version="8.0.0" />
         <PackageReference Include="Microsoft.AspNetCore.DataProtection.EntityFrameworkCore" Version="8.0.0" />
         <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="8.0.0" />
         <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="8.0.0" />
diff --git a/Kemkas.Web/Program.cs b/Kemkas.Web/Program.cs
index 61b09df..8822826 100644
--- a/Kemkas.Web/Program.cs
+++ b/Kemkas.Web/Program.cs
@@ -33,7 +33,13 @@ builder.Services.AddSingleton<IEmailSender, MailgunEmailSender>();
 builder.Services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
     .AddEntityFrameworkStores<ApplicationDbContext>();
 
-builder.Services.AddAuthentication();
+builder.Services.AddAuthentication()
+    .AddGoogle(options =>
+    {
+        var googleAuthNSection = builder.Configuration.GetSection("Authentication:Google");
+        options.ClientId = googleAuthNSection["ClientId"];
+        options.ClientSecret = googleAuthNSection["ClientSecret"];
+    });
 
 builder.Services.AddControllersWithViews().AddJsonOptions(options =>
 {
diff --git a/Kemkas.Web/nginx.conf b/Kemkas.Web/nginx.conf
index e31f974..c45c4e2 100644
--- a/Kemkas.Web/nginx.conf
+++ b/Kemkas.Web/nginx.conf
@@ -70,7 +70,13 @@ http {
             proxy_set_header X-Forwarded-Proto "$scheme";
             proxy_set_header X-Forwarded-Host "$http_host";
             proxy_pass   https://backend;
+        }
+        location /signin-google/ {
             proxy_pass_request_headers on;
+            proxy_set_header X-Forwarded-For "$proxy_add_x_forwarded_for";
+            proxy_set_header X-Forwarded-Proto "$scheme";
+            proxy_set_header X-Forwarded-Host "$http_host";
+            proxy_pass   https://backend;
         }
         
         location /lib/ {
diff --git a/Kemkas.Web/packages.lock.json b/Kemkas.Web/packages.lock.json
index 810fae6..5c2d8c6 100644
--- a/Kemkas.Web/packages.lock.json
+++ b/Kemkas.Web/packages.lock.json
@@ -2,6 +2,12 @@
   "version": 1,
   "dependencies": {
     "net8.0": {
+      "Microsoft.AspNetCore.Authentication.Google": {
+        "type": "Direct",
+        "requested": "[8.0.0, )",
+        "resolved": "8.0.0",
+        "contentHash": "dPE/IiHhBqnJ7WrD72T20+DcHGCaR9F4RmIFap83W1Ts/ze5gBVe4Ii02qJdJzkUniQy5S/v42zpRIgJTPzPqQ=="
+      },
       "Microsoft.AspNetCore.DataProtection.EntityFrameworkCore": {
         "type": "Direct",
         "requested": "[8.0.0, )",