HTTP CDN Caching

HTTP/CDN

Content Distribution Network (CDN)

• Pull - pull when cache misses
• Push - push data when there are updates from application level
• Application server cache - it's better to have multiple micro services so caching would be easier

A time-to-live (TTL) determines how long content is cached. Pull CDNs minimize storage space on the CDN, but can create redundant traffic if files expire and are pulled before they have actually changed.

Reverse Proxy

A reverse proxy is a web server that centralizes internal services and provides unified interfaces to the public. Requests from clients are forwarded to a server that can fulfill it before the reverse proxy returns the server's response to the client.

Additional benefits include:

• Increased security - Hide information about backend servers, blacklist IPs, limit number of connections per client
• Increased scalability and flexibility - Clients only see the reverse proxy's IP, allowing you to scale servers or change their configuration
• SSL termination - Decrypt incoming requests and encrypt server responses so backend servers do not have to perform these potentially expensive operations
  • Removes the need to install X.509 certificates on each server
• Compression - Compress server responses
• Caching - Return the response for cached requests
• Static content - Serve static content directly
  • HTML/CSS/JS
  • Photos
  • Videos
  • Etc