1 files changed, 37 insertions, 0 deletions
diff --git a/src/SMAPI.Web.LegacyRedirects/Framework/LambdaRewriteRule.cs b/src/SMAPI.Web.LegacyRedirects/Framework/LambdaRewriteRule.cs
new file mode 100644
index 00000000..e5138e5c
--- /dev/null
+++ b/src/SMAPI.Web.LegacyRedirects/Framework/LambdaRewriteRule.cs
@@ -0,0 +1,37 @@
+using System;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace SMAPI.Web.LegacyRedirects.Framework
+{
+    /// <summary>Rewrite requests to prepend the subdomain portion (if any) to the path.</summary>
+    /// <remarks>Derived from <a href="https://stackoverflow.com/a/44526747/262123" />.</remarks>
+    internal class LambdaRewriteRule : IRule
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>Rewrite an HTTP request if needed.</summary>
+        private readonly Action<RewriteContext, HttpRequest, HttpResponse> Rewrite;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="rewrite">Rewrite an HTTP request if needed.</param>
+        public LambdaRewriteRule(Action<RewriteContext, HttpRequest, HttpResponse> rewrite)
+        {
+            this.Rewrite = rewrite ?? throw new ArgumentNullException(nameof(rewrite));
+        }
+
+        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
+        /// <param name="context">The rewrite context.</param>
+        public void ApplyRule(RewriteContext context)
+        {
+            HttpRequest request = context.HttpContext.Request;
+            HttpResponse response = context.HttpContext.Response;
+            this.Rewrite(context, request, response);
+        }
+    }
+}