From 40257baa69138a971c92522b6ad8bd22c5572c98 Mon Sep 17 00:00:00 2001
From: Saddam Azad <saddam.azad@me.com>
Date: Wed, 30 Oct 2024 06:24:18 +0600
Subject: [PATCH] url rewrite

---
 .gitignore     |  2 +-
 lib/hosting.ts | 56 ++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/.gitignore b/.gitignore
index b912b02..1044ef9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,7 +6,7 @@ node_modules
 # CDK asset staging directory
 .cdk.staging
 cdk.out
-*.context.json
+cdk.context*.json
 
 # Logs
 logs
diff --git a/lib/hosting.ts b/lib/hosting.ts
index 648c737..a9d835f 100644
--- a/lib/hosting.ts
+++ b/lib/hosting.ts
@@ -50,9 +50,10 @@ export class HostingConstruct extends Construct {
     public originAccessControl: CfnOriginAccessControl|undefined;
 
     /**
-     * The CloudFront Edge Function
+     * The CloudFront Edge Functions
      */
     private cloudFrontFunction: CloudFrontFunction;
+    private cloudFrontURLRewrite: CloudFrontFunction;
     
 
     constructor(scope: Construct, id: string, props: HostingProps) {
@@ -62,10 +63,12 @@ export class HostingConstruct extends Construct {
 
       this.createHostingBucket(props);
 
+      this.cloudFrontURLRewrite = this.createCloudFrontURLRewrite(props);
+
       if (props.edgeFunctionFilePath) {
         this.cloudFrontFunction = this.createCloudFrontFunction(props);
       }
-      
+
       this.createCloudfrontDistribution(props);
 
       if(props.domain && props.globalCertificateArn && props.hostedZoneId) {
@@ -87,6 +90,11 @@ export class HostingConstruct extends Construct {
       });
     }
 
+    /**
+     * Create a CloudFront Function from edgeFunctionFilePath
+     * @param props HostingProps
+     * @returns cloudfront function
+     */
     private createCloudFrontFunction(props: HostingProps): CloudFrontFunction {
       const cloudFrontFunctionCode = fs.readFileSync(props.edgeFunctionFilePath as string, "utf8");
 
@@ -97,6 +105,38 @@ export class HostingConstruct extends Construct {
 
       return cloudFrontFunction;
     }
+    
+    /**
+     * Create a CloudFront Function for SPA URL rewrite
+     * @param props HostingProps
+     * @returns cloudfront function
+     */
+    private createCloudFrontURLRewrite(props: HostingProps): CloudFrontFunction {
+      const functionCode = `
+          function handler(event) {
+              var request = event.request;
+              var uri = request.uri;
+              
+              // Check whether the URI is missing a file name.
+              if (uri.endsWith('/')) {
+                  request.uri += 'index.html';
+              } 
+              // Check whether the URI is missing a file extension.
+              else if (!uri.includes('.')) {
+                  request.uri += '/index.html';
+              }
+
+              return request;
+          }
+       `;
+
+       const URLRewriteFunction = new CloudFrontFunction(this, 'URLRewriteFunction', {
+        code: CloudFrontFunctionCode.fromInline(functionCode),
+        comment: `CloudFront Function: for SPA URL rewrites`,
+      });
+
+      return URLRewriteFunction;
+    }
 
     /**
      * Creates the bucket to store the static deployment asset files of your site.
@@ -232,12 +272,16 @@ export class HostingConstruct extends Construct {
           cachePolicy: defaultCachePolicy,
           allowedMethods: AllowedMethods.ALLOW_GET_HEAD,
           viewerProtocolPolicy: ViewerProtocolPolicy.REDIRECT_TO_HTTPS,
-          ...(this.cloudFrontFunction ? {
-            functionAssociations: [{
+          functionAssociations: [
+            ...(this.cloudFrontFunction ? [{
                 eventType: FunctionEventType.VIEWER_REQUEST,
                 function: this.cloudFrontFunction
-            }]
-          } : {})
+            }] : []),
+            ...(this.cloudFrontURLRewrite ? [{
+                eventType: FunctionEventType.VIEWER_REQUEST,
+                function: this.cloudFrontURLRewrite
+            }] : [])
+          ],
       };
 
       // imgBehaviour