cloudfront

CloudFront/CloudFront Functions.md

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+# [[_CloudFront]] Functions

CloudFront/CloudFront Index.md

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-# CloudFront Index

CloudFront/Lambda@Edge.md

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+# Lambda@Edge
+Supported Languages:
+- Python
+- JavaScript
+

CloudFront/_CloudFront.md

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+# _CloudFront
+## What is it?
+[[_CloudFront|CloudFront]] is a CDN. It can be used for:
+- Static & Dynamic content
+- Video Streaming
+- Web Sockets
+
+## Benefits
+- [[_CloudFront|CloudFront]] can be fronted with [[AWS WAF]] for OWASP's top 10 protection.
+- [[_CloudFront|CloudFront]] can stream [[Videos On Demand]] using [[ISS Microsoft Smooth Streaming]]
+
+## Core components
+**Origin**: Location where all original files are located. Examples include: S3, EC2, ELB, Route53.
+**Edge Locations**: Compute located strategically close to end users.
+**Regional Caches**: Compute located in board geographical locations to speed up requests for edge locations.
+**Distribution**: A collection of Edge locations and Regional Cache that defines how cached content should behave. 
+  
+## [[Lambda@Edge]] and [[CloudFront Functions]]
+The order that the functions trigger within CloudFront is:
+| Order | Stage | L@E | CF Fns |  Description | Example Use Cases |
+|--|---|---|---|---|--|
+| 1 |  Viewer Request |  ✔️ |  ✔️ |  When CloudFront receives a request from the viewer. | Redirection (`HTTP` -> `HTTPS`), Cookie Inspection for Auth, Modify Headers for A/B Testing  |
+| 2 |  Origin Request |  ✔️ |  ❌ |  Before CloudFront forwards the request to the origin. | Add security headers (CSP/HSTS), set cookies for client side tracking, customise error messages |
+| 3 |  Origin Response |  ✔️ |  ❌ |  After CloudFront receives the request from the origin. | Rewrite URLs for SEO or routing, inject headers for origin authentication, selective content serving based on user agent (desktop/mobile mode). |
+| 4 |  Viewer Response |  ✔️ |  ✔️ |  Before CloudFront returns the response to the viewer. | Modify headers to control caching, update URLs in HTML for versioning, customise error responses from origin.  |
+
+```mermaid
+sequenceDiagram
+    participant Viewer
+    participant Edge
+    participant Origin
+
+    Viewer->>Edge: Viewer Request
+    Edge->>Origin: Origin Request
+    Origin->>Edge: Origin Response
+    Edge->>Viewer: Viewer Response
+```
+