From a7b0752b558253a08072263aff7ace4b6017e11b Mon Sep 17 00:00:00 2001
From: Daisuke <nakada0907@outlook.com>
Date: Sun, 1 Feb 2026 17:34:11 +0900
Subject: [PATCH] fix(cloudfront): rewrite extensionless paths to index

- append /index.html for extensionless requests
- document CloudFront Function behavior in README
---
 README.md                          |  1 +
 infra/cfn/template-cloudfront.yaml | 14 +++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index a9222c2..bbf275d 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,7 @@ It includes CloudFormation templates for provisioning all necessary components,
 - **Lambda (Go)**: Custom deployment logic executed within the pipeline
 - **ECR**: Container repository for Lambda packaging
 - **Secrets Manager**: Secure storage for deployment keys
+- **CloudFront Function**: Appends `/index.html` for extensionless paths (e.g. `/blog/2`, `/tags`)
 
 All infrastructure is declaratively managed via CloudFormation templates under `infra/cfn/`.
 
diff --git a/infra/cfn/template-cloudfront.yaml b/infra/cfn/template-cloudfront.yaml
index 9af45b4..7ae064e 100644
--- a/infra/cfn/template-cloudfront.yaml
+++ b/infra/cfn/template-cloudfront.yaml
@@ -20,10 +20,18 @@ Resources:
         function handler(event) {
           var request = event.request;
           var uri = request.uri;
-          if (uri.endsWith("/")) {
-            request.uri += "index.html";
-          } else if (uri === "") {
+          if (uri === "" || uri === "/") {
             request.uri = "/index.html";
+            return request;
+          }
+          if (uri.endsWith("/")) {
+            request.uri = uri + "index.html";
+            return request;
+          }
+          var lastSlash = uri.lastIndexOf("/");
+          var lastDot = uri.lastIndexOf(".");
+          if (lastDot <= lastSlash) {
+            request.uri = uri + "/index.html";
           }
           return request;
         }