From 87b684d79a5d8f2a3782b8933febad8e2f866810 Mon Sep 17 00:00:00 2001
From: Maarten Balliauw <maarten@maartenballiauw.be>
Date: Wed, 19 Mar 2025 09:55:57 +0100
Subject: [PATCH] Add Swagger support for API documentation in development

Integrated Swashbuckle for API documentation and updated service configuration to include Swagger and Swagger UI. Added middleware to handle anti-forgery headers for Swagger UI requests in development mode.
---
 .../FrontendHost/FrontendHost.csproj          |  2 ++
 BFF/v3/JsBffSample/FrontendHost/Program.cs    | 23 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/BFF/v3/JsBffSample/FrontendHost/FrontendHost.csproj b/BFF/v3/JsBffSample/FrontendHost/FrontendHost.csproj
index 83a4b445..4e118929 100644
--- a/BFF/v3/JsBffSample/FrontendHost/FrontendHost.csproj
+++ b/BFF/v3/JsBffSample/FrontendHost/FrontendHost.csproj
@@ -10,6 +10,8 @@
     <PackageReference Include="Duende.BFF.Yarp" Version="3.0.0" />
     
     <PackageReference Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="8.0.6" />
+    
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="8.0.0" />
   </ItemGroup>
 
 </Project>
diff --git a/BFF/v3/JsBffSample/FrontendHost/Program.cs b/BFF/v3/JsBffSample/FrontendHost/Program.cs
index 782129a3..cc058e08 100644
--- a/BFF/v3/JsBffSample/FrontendHost/Program.cs
+++ b/BFF/v3/JsBffSample/FrontendHost/Program.cs
@@ -1,8 +1,13 @@
+using Duende.Bff;
 using Duende.Bff.Yarp;
+using Microsoft.Extensions.Options;
+using Swashbuckle.AspNetCore.SwaggerUI;
 
 var builder = WebApplication.CreateBuilder(args);
 
 builder.Services.AddControllers();
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
 
 builder.Services.AddBff()
     .AddRemoteApis();
@@ -58,6 +63,24 @@
 app.UseRouting();
 
 app.UseAuthentication();
+
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+
+    app.Use(async (context, next) =>
+    {
+        var swaggerUIOptions = context.RequestServices.GetRequiredService<IOptions<SwaggerUIOptions>>().Value;
+        if (context.Request.Headers.Referer.Any(it => it.EndsWith($"/{swaggerUIOptions.RoutePrefix}/index.html")))
+        {
+            var bffOptions = context.RequestServices.GetRequiredService<IOptions<BffOptions>>().Value;
+            context.Request.Headers[bffOptions.AntiForgeryHeaderName]= bffOptions.AntiForgeryHeaderValue;
+        }
+        await next();
+    });
+}
+
 app.UseBff();
 app.UseAuthorization();