101: HTTP/2 101

Discussion HTTP/1.1 review Widespread adoption in 1996 with full standard in 1997 RFC 2068 and later replaced with one in 1999 RFC 2616 Request (URL, method, headers, body) & Response (status code, headers, body) Inherently async Built for HyperText, makes it have problems Head of line blocking combining payloads to 1 response multiple connections (Connection: Keep-Alive vs Close) HTTP Pipelining No cancellation, have to tear down connection No prioritization, round robin over connections iOS/Mac NSURLRequest (NSHTTPURLRequest) and NSURLResponse (NSHTTPURLResponse) NSURLConnection and NSURLSession HTTP/2 Started by Google with SPDY (2012 - 2016), latest is SPDY/3.1 HTTP/2 is a binary protocol, where 1 and 1.1 are text Previous episode on SPDY with M Schore Reached standard in 2015 with RFC 7540 and adopted by Apple with iOS 9, Mac OS X 10.11 Resolves many issues with new features: multiplexing (helps with head of line problem in HTTP/1.1) cancellation header compression Always there plain text, optimal for compression dynamic prioritization be responsible, set lower priority when possible not guaranteed that the server will prioritize because it is optional in HTTP/2 spec push responses (Nolan’s not a fan) not supported by Apple Upgrade to HTTP/2 dynamically with Upgrade Header or ALPN Application Layer Protocol Negotiation, ALPN is during TLS and far more efficient than Upgrade header NPN (Next Protocol Negotiation) Picks Nolan Akamai HTTP/2 Demo - Good info at https://http2.akamai.com HTTP/2 Test - Test supported domains Darryl What Every iOS Developer Should Be Doing With Instruments - Great introduction to Instruments by Kevin Kazmeirczak John ClockKit Tutorial: Add Complication to an Already Existing Watch Project from Kristina Thai Jason RescueTime - Time management software