Revised tenant resolve and added query string resolver.

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/AbpAspNetMultiTenancyModule.cs

@@ -9,6 +9,11 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
     {
         public override void ConfigureServices(IServiceCollection services)
         {
+            services.Configure<MultiTenancyOptions>(options =>
+            {
+                options.TenantResolvers.Insert(0, new QueryStringTenantResolver());
+            });
+
             services.AddAssemblyOf<AbpAspNetMultiTenancyModule>();
         }
     }

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/QueryStringTenantResolver.cs

@@ -0,0 +1,31 @@
+using Volo.Abp.MultiTenancy;
+using Volo.DependencyInjection;
+using Volo.ExtensionMethods.Collections.Generic;
+
+namespace Volo.Abp.AspNetCore.MultiTenancy
+{
+    public class QueryStringTenantResolver : ITenantResolver, ITransientDependency
+    {
+        public const string TenantIdKey = "_Abp.TenantId";
+        
+        public void Resolve(ICurrentTenantResolveContext context)
+        {
+            var httpContext = context.GetHttpContext();
+            if (httpContext == null)
+            {
+                return;
+            }
+
+            if (!httpContext.Request.QueryString.HasValue)
+            {
+                return;
+            }
+
+            var tenantId = httpContext.Request.Query[TenantIdKey];
+            if (!tenantId.IsNullOrEmpty())
+            {
+                context.Tenant = new TenantInfo(tenantId);
+            }
+        }
+    }
+}

src/Volo.Abp.AspNetCore/Volo/Abp/AspNetCore/AbpAspNetCoreModule.cs

@@ -1,5 +1,7 @@
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 using Volo.Abp.Modularity;
 
 namespace Volo.Abp.AspNetCore
@@ -8,6 +10,8 @@ namespace Volo.Abp.AspNetCore
     {
         public void ConfigureServices(IServiceCollection services)
         {
+            services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
+
             services.AddObjectAccessor<IApplicationBuilder>();
             services.AddAssemblyOf<AbpAspNetCoreModule>();
         }

src/Volo.Abp.AspNetCore/Volo/Abp/ServiceProviderAccessorExtensions.cs

@@ -0,0 +1,15 @@
+using JetBrains.Annotations;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Volo.Abp
+{
+    public static class ServiceProviderAccessorExtensions
+    {
+        [CanBeNull]
+        public static HttpContext GetHttpContext(this IServiceProviderAccessor serviceProviderAccessor)
+        {
+            return serviceProviderAccessor.ServiceProvider.GetRequiredService<IHttpContextAccessor>().HttpContext;
+        }
+    }
+}

src/Volo.Abp.AspNetCore/project.json

@@ -4,9 +4,9 @@
   "dependencies": {
     "NETStandard.Library": "1.6.1",
     "Volo.Abp": "1.0.0-*",
-    "Microsoft.AspNetCore.Http.Abstractions": "1.1.0",
     "Microsoft.AspNetCore.Hosting.Abstractions": "1.1.0",
-    "Microsoft.AspNetCore.Routing.Abstractions": "1.1.0"
+    "Microsoft.AspNetCore.Routing.Abstractions": "1.1.0",
+    "Microsoft.AspNetCore.Http": "1.1.0" 
   },
 
   "frameworks": {

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/CurrentTenantResolveContext.cs

@@ -1,9 +1,23 @@
+using System;
+
 namespace Volo.Abp.MultiTenancy
 {
     public class CurrentTenantResolveContext : ICurrentTenantResolveContext
     {
+        public IServiceProvider ServiceProvider { get; }
+
         public TenantInfo Tenant { get; set; }
 
-        public bool Handled { get; set; }
+        public bool? Handled { get; set; }
+
+        internal bool IsHandled()
+        {
+            return Handled == true || (Handled == null && Tenant != null);
+        }
+
+        public CurrentTenantResolveContext(IServiceProvider serviceProvider)
+        {
+            ServiceProvider = serviceProvider;
+        }
     }
 }

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/ICurrentTenantResolveContext.cs

@@ -1,9 +1,9 @@
 namespace Volo.Abp.MultiTenancy
 {
-    public interface ICurrentTenantResolveContext
+    public interface ICurrentTenantResolveContext : IServiceProviderAccessor
     {
         TenantInfo Tenant { get; set; }
 
-        bool Handled { get; set; }
+        bool? Handled { get; set; }
     }
 }

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/ITenantScopeProvider.cs

@@ -1,9 +1,11 @@
 using System;
+using JetBrains.Annotations;
 
 namespace Volo.Abp.MultiTenancy
 {
     public interface ITenantScopeProvider
     {
+        [CanBeNull]
         TenantScope CurrentScope { get; }
 
         IDisposable EnterScope(TenantInfo tenantInfo);

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/MultiTenancyManager.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using Microsoft.Extensions.Options;
 using Volo.DependencyInjection;
 
@@ -8,13 +9,16 @@ namespace Volo.Abp.MultiTenancy
     {
         public TenantInfo CurrentTenant => GetCurrentTenant();
 
+        private readonly IServiceProvider _serviceProvider;
         private readonly ITenantScopeProvider _tenantScopeProvider;
         private readonly MultiTenancyOptions _options;
 
         public MultiTenancyManager(
+            IServiceProvider serviceProvider,
             ITenantScopeProvider tenantScopeProvider,
             IOptions<MultiTenancyOptions> options)
         {
+            _serviceProvider = serviceProvider;
             _tenantScopeProvider = tenantScopeProvider;
             _options = options.Value;
         }
@@ -26,15 +30,27 @@ namespace Volo.Abp.MultiTenancy
                 return _tenantScopeProvider.CurrentScope.Tenant;
             }
 
-            var context = new CurrentTenantResolveContext();
+            return GetCurrentTenantFromResolvers();
+        }
 
-            foreach (var currentTenantResolver in _options.TenantResolvers)
+        protected virtual TenantInfo GetCurrentTenantFromResolvers()
+        {
+            if (!_options.TenantResolvers.Any())
             {
-                currentTenantResolver.Resolve(context);
-                if (context.Handled)
+                return null;
+            }
+
+            var context = new CurrentTenantResolveContext(_serviceProvider);
+
+            foreach (var tenantResolver in _options.TenantResolvers)
+            {
+                tenantResolver.Resolve(context);
+                if (context.IsHandled())
                 {
                     break;
                 }
+
+                context.Handled = null;
             }
 
             return context.Tenant;

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/MultiTenancyOptions.cs

@@ -1,9 +1,11 @@
 using System.Collections.Generic;
+using JetBrains.Annotations;
 
 namespace Volo.Abp.MultiTenancy
 {
     public class MultiTenancyOptions
     {
+        [NotNull]
         public List<ITenantResolver> TenantResolvers { get; }
 
         public MultiTenancyOptions()

src/Volo.Abp.MultiTenancy/Volo/Abp/MultiTenancy/TenantInfo.cs

@@ -4,10 +4,9 @@ namespace Volo.Abp.MultiTenancy
 {
     public class TenantInfo
     {
+        [NotNull]
         public string Id { get; }
 
-        public string Name { get; }
-
         //TODO: Needed for serialization
         [UsedImplicitly]
         private TenantInfo()
@@ -15,13 +14,11 @@ namespace Volo.Abp.MultiTenancy
             
         }
 
-        public TenantInfo([NotNull] string id, [NotNull] string name)
+        public TenantInfo([NotNull] string id)
         {
             Check.NotNull(id, nameof(id));
-            Check.NotNull(name, nameof(name));
 
             Id = id;
-            Name = name;
         }
     }
 }

src/Volo.Abp/Volo/Abp/IServiceProviderAccessor.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Volo.Abp
+{
+    public interface IServiceProviderAccessor
+    {
+        IServiceProvider ServiceProvider { get; }
+    }
+}

test/Volo.Abp.AspNetCore.MultiTenancy.Tests/Volo/Abp/AspNetCore/App/AppModule.cs

@@ -27,7 +27,7 @@ namespace Volo.Abp.AspNetCore.App
 
                 var dictionary = new Dictionary<string, string>
                 {
-                    ["TenantName"] = manager.CurrentTenant?.Name ?? "<host>"
+                    ["TenantId"] = manager.CurrentTenant?.Id ?? ""
                 };
                 
                 await ctx.Response.WriteAsync(dictionary.ToJsonString());

test/Volo.Abp.AspNetCore.MultiTenancy.Tests/Volo/Abp/AspNetCore/MultiTenancy/AspNetCoreMultiTenancy_Tests.cs

@@ -12,9 +12,18 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
         public async Task Should_Use_Host_If_Tenant_Is_Not_Specified()
         {
             var result = await GetResponseAsObjectAsync<Dictionary<string, string>>("http://abp.io");
-            result["TenantName"].ShouldBe("<host>");
+            result["TenantId"].ShouldBe("");
         }
 
-        //TODO: Specify tenant in the header, cookie, url, querystring and so on...
+        [Fact]
+        public async Task Should_Use_QueryString_Tenant_Id_If_Specified()
+        {
+            const string testTenantId = "42";
+
+            var result = await GetResponseAsObjectAsync<Dictionary<string, string>>($"http://abp.io?{QueryStringTenantResolver.TenantIdKey}={testTenantId}");
+            result["TenantId"].ShouldBe(testTenantId);
+        }
+
+        //TODO: Specify tenant in the header, cookie, domain, subdomain, route, querystring and so on...
     }
 }

test/Volo.Abp.MultiTenancy.Tests/Volo/Abp/MultiTenancy/AsyncLocalAmbientTenantScopeProvider_Tests.cs

@@ -10,25 +10,26 @@ namespace Volo.Abp.MultiTenancy
         {
             var scopeProvider = new AsyncLocalTenantScopeProvider();
 
-            scopeProvider.CurrentScope.ShouldBeNull();
+            Assert.Null(scopeProvider.CurrentScope?.Tenant);
 
-            using (scopeProvider.EnterScope(new TenantInfo("1","A")))
+            using (scopeProvider.EnterScope(new TenantInfo("A")))
             {
-                scopeProvider.CurrentScope.Tenant.Name.ShouldBe("A");
+                Assert.Equal("A", scopeProvider.CurrentScope?.Tenant?.Id);
 
-                using (scopeProvider.EnterScope(new TenantInfo("2", "B")))
+                using (scopeProvider.EnterScope(new TenantInfo("B")))
                 {
-                    scopeProvider.CurrentScope.Tenant.Name.ShouldBe("B");
+                    Assert.Equal("B", scopeProvider.CurrentScope?.Tenant?.Id);
 
                     using (scopeProvider.EnterScope(null))
                     {
-                        scopeProvider.CurrentScope.Tenant.ShouldBeNull();
+                        Assert.NotNull(scopeProvider.CurrentScope);
+                        Assert.Null(scopeProvider.CurrentScope.Tenant);
                     }
 
-                    scopeProvider.CurrentScope.Tenant.Name.ShouldBe("B");
+                    Assert.Equal("B", scopeProvider.CurrentScope?.Tenant?.Id);
                 }
 
-                scopeProvider.CurrentScope.Tenant.Name.ShouldBe("A");
+                Assert.Equal("A", scopeProvider.CurrentScope?.Tenant?.Id);
             }
 
             scopeProvider.CurrentScope.ShouldBeNull();

test/Volo.Abp.MultiTenancy.Tests/Volo/Abp/MultiTenancy/MultiTenantManager_TenantResolver_Tests.cs

@@ -14,6 +14,7 @@ namespace Volo.Abp.MultiTenancy
             //Arrange
 
             var manager = new MultiTenancyManager(
+                Substitute.For<IServiceProvider>(),
                 Substitute.For<ITenantScopeProvider>(),
                 new OptionsWrapper<MultiTenancyOptions>(new MultiTenancyOptions())
             );
@@ -28,9 +29,10 @@ namespace Volo.Abp.MultiTenancy
         {
             //Arrange
 
-            var fakeTenant = new TenantInfo(Guid.NewGuid().ToString(), "acme");
+            var fakeTenant = new TenantInfo("A");
 
             var manager = new MultiTenancyManager(
+                Substitute.For<IServiceProvider>(),
                 Substitute.For<ITenantScopeProvider>(),
                 new OptionsWrapper<MultiTenancyOptions>(new MultiTenancyOptions
                     {
@@ -53,13 +55,14 @@ namespace Volo.Abp.MultiTenancy
 
 
         [Fact]
-        public void Should_Get_Current_Tenant_From_Two_Resolvers()
+        public void Should_Get_Current_Tenant_From_Multiple_Resolvers()
         {
             //Arrange
 
-            var fakeTenant = new TenantInfo(Guid.NewGuid().ToString(), "acme");
+            var selectedTenant = new TenantInfo("A");
 
             var manager = new MultiTenancyManager(
+                Substitute.For<IServiceProvider>(),
                 Substitute.For<ITenantScopeProvider>(),
                 new OptionsWrapper<MultiTenancyOptions>(new MultiTenancyOptions
                     {
@@ -67,17 +70,16 @@ namespace Volo.Abp.MultiTenancy
                         {
                             new SimpleTenantResolver(context =>
                             {
-                                context.Tenant = new TenantInfo(Guid.NewGuid().ToString(), "skipped-tenant-1");
+                                context.Tenant = new TenantInfo("B");
+                                context.Handled = false; //Causes go to the next resolver
                             }),
                             new SimpleTenantResolver(context =>
                             {
-                                context.Tenant = fakeTenant;
-                                context.Handled = true;
+                                context.Tenant = selectedTenant;
                             }),
                             new SimpleTenantResolver(context =>
                             {
-                                context.Tenant = new TenantInfo(Guid.NewGuid().ToString(), "skipped-tenant-2");
-                                context.Handled = true;
+                                context.Tenant = new TenantInfo("C");
                             })
                         }
                     }
@@ -86,7 +88,7 @@ namespace Volo.Abp.MultiTenancy
 
             //Assert
 
-            manager.CurrentTenant.ShouldBe(fakeTenant);
+            manager.CurrentTenant.ShouldBe(selectedTenant);
         }
 
         [Fact]
@@ -94,9 +96,10 @@ namespace Volo.Abp.MultiTenancy
         {
             //Arrange
 
-            var oldTenant = new TenantInfo(Guid.NewGuid().ToString(), "old-tenant");
+            var oldTenant = new TenantInfo("A");
 
             var manager = new MultiTenancyManager(
+                Substitute.For<IServiceProvider>(),
                 new AsyncLocalTenantScopeProvider(),
                 new OptionsWrapper<MultiTenancyOptions>(
                     new MultiTenancyOptions
@@ -116,7 +119,7 @@ namespace Volo.Abp.MultiTenancy
 
             //Act
 
-            var overridedTenant = new TenantInfo(Guid.NewGuid().ToString(), "overrided-tenant");
+            var overridedTenant = new TenantInfo("B");
             using (manager.ChangeTenant(overridedTenant))
             {
                 //Assert