Origin

CloudFront/_CloudFront.md

@@ -93,3 +93,36 @@ You can make your own **Caching Policy**:
     - **Cookies**: which cookies are a part of the **Cache Key**.
     - **Query String**: which query string parameters are a part of the **Cache Key**.
     - **Compression Support**: What compression format is part of the **Cache Key**.
+
+### Origin Request
+Happens when there is a cache miss and CloudFront must reach out to Origin to retrieve data.
+
+**Origin Request** always returns:
+- URL Path
+- Request Body (if present)
+- Specific HTTP Headers:
+    - Host
+    - User Agent
+    - `X-Amz-Cf-Id`
+
+**Origin Request** doesn't include these by default:
+- URL Query String
+- Cookies
+- All other HTTP Headers
+
+**Cache Key** information (set by the **Cache Policy**) are automatically included in **Origin Requests**:
+- URL Query Strings
+- HTTP Headers
+- Cookies
+
+### Response Header Policy
+Allows you to modify the HTTP Headers in the response that viewers will see.
+AWS has managed policies for you to use and you can make your own also.
+
+⚠️ If you are dealing with CORS, you will be setting things here, as this will mess with them.
+
+## Origin Access Identity
+**OAI** makes sure that an S3 bucket is only accessible through **CloudFront** and not the internet. 
+Lots of drawbacks. 
+
+