From d83bb3b8341d6de6ac68e4277d7ee8eda79a2a6f Mon Sep 17 00:00:00 2001
From: Sipke Schoorstra <sipkeschoorstra@outlook.com>
Date: Sun, 9 Feb 2025 08:24:55 +0100
Subject: [PATCH] Add customizable tenant header support for HTTP routing

Introduced `MultitenancyHttpOptions` to configure the tenant header name used for HTTP routing. Updated `HeaderTenantResolver` to utilize this option and modified the server setup to allow overriding the default header name. This enables more flexible multitenancy configurations.
---
 src/apps/Elsa.Server.Web/Program.cs           |  6 ++++-
 .../Features/MultitenantHttpRoutingFeature.cs | 24 +++++++++++++++++++
 .../Options/MultitenancyHttpOptions.cs        |  6 +++++
 .../Resolvers/HeaderTenantResolver.cs         |  7 ++++--
 4 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 src/modules/Elsa.Tenants.AspNetCore/Options/MultitenancyHttpOptions.cs

diff --git a/src/apps/Elsa.Server.Web/Program.cs b/src/apps/Elsa.Server.Web/Program.cs
index e22f276fd..32fdbfc5c 100644
--- a/src/apps/Elsa.Server.Web/Program.cs
+++ b/src/apps/Elsa.Server.Web/Program.cs
@@ -659,7 +659,11 @@ services
                 }
             });
 
-            elsa.UseTenantHttpRouting();
+            elsa.UseTenantHttpRouting(tenantHttpRouting =>
+            {
+                // Override the tenant header name with a custom one.
+                tenantHttpRouting.WithTenantHeader("X-Company-Id");
+            });
         }
 
         elsa.InstallDropIns(options => options.DropInRootDirectory = Path.Combine(Directory.GetCurrentDirectory(), "App_Data", "DropIns"));
diff --git a/src/modules/Elsa.Tenants.AspNetCore/Features/MultitenantHttpRoutingFeature.cs b/src/modules/Elsa.Tenants.AspNetCore/Features/MultitenantHttpRoutingFeature.cs
index 2def1e4d6..bdf0df3b8 100644
--- a/src/modules/Elsa.Tenants.AspNetCore/Features/MultitenantHttpRoutingFeature.cs
+++ b/src/modules/Elsa.Tenants.AspNetCore/Features/MultitenantHttpRoutingFeature.cs
@@ -3,6 +3,7 @@ using Elsa.Features.Abstractions;
 using Elsa.Features.Attributes;
 using Elsa.Features.Services;
 using Elsa.Http.Features;
+using Elsa.Tenants.AspNetCore.Options;
 using Elsa.Tenants.AspNetCore.Services;
 using Elsa.Tenants.Features;
 using Microsoft.Extensions.DependencyInjection;
@@ -13,6 +14,26 @@ namespace Elsa.Tenants.AspNetCore.Features;
 [DependencyOf(typeof(TenantsFeature))]
 public class MultitenantHttpRoutingFeature(IModule module) : FeatureBase(module)
 {
+    private Action<MultitenancyHttpOptions> _configureMultitenancyHttpOptions = _ => { };
+
+    /// <summary>
+    /// Configures the MultitenantHttpRoutingFeature to use a specific tenant header name.
+    /// </summary>
+    /// <param name="headerName">The name of the HTTP header used to identify the tenant.</param>
+    /// <returns>The current instance of <see cref="MultitenantHttpRoutingFeature"/> for fluent configuration.</returns>
+    public MultitenantHttpRoutingFeature WithTenantHeader(string headerName) => WithMultitenancyHttpOptions(options => options.TenantHeaderName = headerName);
+
+    /// <summary>
+    /// Configures the MultitenantHttpRoutingFeature with custom multitenancy HTTP options.
+    /// </summary>
+    /// <param name="configure">The action to configure <see cref="MultitenancyHttpOptions"/>.</param>
+    /// <returns>The current instance of <see cref="MultitenantHttpRoutingFeature"/> for fluent configuration.</returns>
+    public MultitenantHttpRoutingFeature WithMultitenancyHttpOptions(Action<MultitenancyHttpOptions> configure)
+    {
+        _configureMultitenancyHttpOptions = configure;
+        return this;
+    }
+    
     public override void Configure()
     {
         Module.Configure<HttpFeature>(feature =>
@@ -24,6 +45,9 @@ public class MultitenantHttpRoutingFeature(IModule module) : FeatureBase(module)
 
     public override void Apply()
     {
+        // Multitenancy HTTP options.
+        Services.Configure(_configureMultitenancyHttpOptions);
+        
         // Tenant resolvers.
         Services
             .AddScoped<ITenantResolver, RoutePrefixTenantResolver>()
diff --git a/src/modules/Elsa.Tenants.AspNetCore/Options/MultitenancyHttpOptions.cs b/src/modules/Elsa.Tenants.AspNetCore/Options/MultitenancyHttpOptions.cs
new file mode 100644
index 000000000..877400eb6
--- /dev/null
+++ b/src/modules/Elsa.Tenants.AspNetCore/Options/MultitenancyHttpOptions.cs
@@ -0,0 +1,6 @@
+namespace Elsa.Tenants.AspNetCore.Options;
+
+public class MultitenancyHttpOptions
+{
+    public string TenantHeaderName { get; set; } = "X-Tenant-Id";
+}
\ No newline at end of file
diff --git a/src/modules/Elsa.Tenants.AspNetCore/Resolvers/HeaderTenantResolver.cs b/src/modules/Elsa.Tenants.AspNetCore/Resolvers/HeaderTenantResolver.cs
index 06d36e387..697049285 100644
--- a/src/modules/Elsa.Tenants.AspNetCore/Resolvers/HeaderTenantResolver.cs
+++ b/src/modules/Elsa.Tenants.AspNetCore/Resolvers/HeaderTenantResolver.cs
@@ -1,12 +1,14 @@
 using Elsa.Common.Multitenancy;
+using Elsa.Tenants.AspNetCore.Options;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Options;
 
 namespace Elsa.Tenants.AspNetCore;
 
 /// <summary>
 /// Resolves the tenant based on the header in the request.
 /// </summary>
-public class HeaderTenantResolver(IHttpContextAccessor httpContextAccessor) : TenantResolverBase
+public class HeaderTenantResolver(IHttpContextAccessor httpContextAccessor, IOptions<MultitenancyHttpOptions> options) : TenantResolverBase
 {
     protected override TenantResolverResult Resolve(TenantResolverContext context)
     {
@@ -15,7 +17,8 @@ public class HeaderTenantResolver(IHttpContextAccessor httpContextAccessor) : Te
         if (httpContext == null)
             return Unresolved();
 
-        var tenantId = httpContext.Request.Headers["X-Tenant-Id"].FirstOrDefault();
+        var headerName = options.Value.TenantHeaderName;
+        var tenantId = httpContext.Request.Headers[headerName].FirstOrDefault();
 
         return AutoResolve(tenantId);
     }