app/Http/Controllers/Auth/LoginController.php

@@ -152,6 +152,19 @@ class LoginController extends Controller
         return $this->processSocialMediaLogin($request, 'facebook_id', $facebookUser);
     }
 
+    /**
+     * Obtain the user information from Twitter.
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function handleTwitterCallback(Request $request)
+    {
+        $socialite = $this->setSocialiteConfigs();
+        $twitterUser = $socialite->driver('twitter')->user();
+
+        return $this->processSocialMediaLogin($request, 'twitter_id', $twitterUser);
+    }
+
     private function processSocialMediaLogin(Request $request, $socialMediaIdField, $socialMediaUser)
     {
         $userBySocialMediaId = User::where($socialMediaIdField, $socialMediaUser->getId())->first();
@@ -163,7 +176,11 @@ class LoginController extends Controller
             return redirect(route('home'));
         }
 
-        $userByEmailAddress = User::where('email', $socialMediaUser->email)->first();
+        // Some providers (*cough*Twitter*cough*) don't give e-mail addresses without explicit permission/additional
+        // verification
+        if (!is_null($socialMediaUser->email))
+        {
+            $userByEmailAddress = User::where('email', $socialMediaUser->getEmail())->first();
 
             if (!is_null($userByEmailAddress))
             {
@@ -178,6 +195,7 @@ class LoginController extends Controller
 
                 return redirect(route('auth.login_sso'));
             }
+        }
 
         // We don't have an existing user - prompt for registration
         $request->getSession()->put('ssoRegisterData', [

app/User.php

@@ -16,7 +16,7 @@ class User extends Authenticatable
      * @var array
      */
     protected $fillable = [
-        'name', 'email', 'password', 'is_admin', 'is_activated', 'activation_token', 'enable_profile_page', 'profile_alias', 'facebook_id'
+        'name', 'email', 'password', 'is_admin', 'is_activated', 'activation_token', 'enable_profile_page', 'profile_alias', 'facebook_id', 'twitter_id'
     ];
 
     /**

database/migrations/2018_08_16_132300_add_user_twitter_id_column.php

@@ -0,0 +1,34 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class AddUserTwitterIdColumn extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('users', function (Blueprint $table)
+        {
+            $table->string('twitter_id')->nullable(true);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('users', function (Blueprint $table)
+        {
+            $table->dropColumn('twitter_id');
+        });
+    }
+}

resources/views/themes/base/partials/register.blade.php

@@ -16,7 +16,7 @@
         <label for="name" class="col-md-4 col-form-label text-md-right">@lang('forms.realname_label')</label>
 
         <div class="col-md-6">
-            <input id="name" type="text" class="form-control{{ $errors->has('name') ? ' is-invalid' : '' }}" name="name" value="{{ old('name', $is_sso ? $register_data['name'] : '') }}"{{ $is_sso ? ' autofocus' : '' }}>
+            <input id="name" type="text" class="form-control{{ $errors->has('name') ? ' is-invalid' : '' }}" name="name" value="{{ old('name', $is_sso ? $register_data['name'] : '') }}"{{ !$is_sso ? ' autofocus' : '' }}>
 
             @if ($errors->has('name'))
                 <div class="invalid-feedback">
@@ -30,11 +30,11 @@
         <label for="email" class="col-md-4 col-form-label text-md-right">@lang('forms.email_label')</label>
 
         <div class="col-md-6">
-            @if ($is_sso)
+            @if ($is_sso && !empty($register_data['email']))
                 <input type="hidden" name="email" value="{{ $register_data['email'] }}">
                 <input id="email" type="email" class="form-control" value="{{ $register_data['email'] }}" readonly>
             @else
-                <input id="email" type="email" class="form-control{{ $errors->has('email') ? ' is-invalid' : '' }}" name="email" value="{{ old('email', $is_sso ? $register_data['email'] : '') }}">
+                <input id="email" type="email" class="form-control{{ $errors->has('email') ? ' is-invalid' : '' }}" name="email" value="{{ old('email', $is_sso ? $register_data['email'] : '') }}"{{ $is_sso && empty($register_data['email']) ? ' autofocus' : '' }}>
             @endif
 
             @if ($errors->has('email'))
@@ -49,7 +49,7 @@
         <label for="password" class="col-md-4 col-form-label text-md-right">@lang('forms.password_label')</label>
 
         <div class="col-md-6">
-            <input id="password" type="password" class="form-control{{ $errors->has('password') ? ' is-invalid' : '' }}" name="password"{{ $is_sso ? ' autofocus' : '' }}>
+            <input id="password" type="password" class="form-control{{ $errors->has('password') ? ' is-invalid' : '' }}" name="password"{{ $is_sso && !empty($register_data['email']) ? ' autofocus' : '' }}>
 
             @if ($errors->has('password'))
                 <div class="invalid-feedback">