Why pubnub javascript sdk (?) choses XHR over Websocket?
I'm developing simple browser real-time multiplayer (2 players in a gameplay atm) game. It involves fast and frequent player moves and changes of direction, so informations must be exchanged very quickly - I decided to try websockets (would be happy to use pubnub service instead of self-hosting socket server).
My problem is, pubnub always decides to use xhr fallback instead of websockets - don't know why. Are there any specific requirements that must be fulfilled to run communication via websockets? Http is obviously too slow and kills the experience. I'm using latest Chrome on a Mac, so browser compatibility is not an issue.
Or maybe, there is so many variables to determine communication protocol, that the question cannot be answered? And my only solution is to use self-hosted socket server?
Realtime Protocol WebSockets and XHR with PubNub
Modern data stream networks and open source solutions start with XHR. For several reasons this is optimal to start with including speed. Performance is dependent on the speed of light and how fast Ethernet Frames are able to be transmitted between devices on the internet. This is the foundation for protocol independence and the core determinator for latency and speed of messages across the internet. The PubNub client SDKs, such as JavaScript, do not provide a setting to force a particular protocol.
How PubNub Works
See How PubNub Works scroll down for mouse demo.
PubNub is the fastest global data stream network available today with 15 data centers world wide to support your high speed and low latency requirements. Over 1/4 billion devices connected to the PubNub data stream network experience send/receive speeds from 10ms to 100ms per message.
What is Protocol Independence?
The people behind the PubNub Data Stream Network believe in the Protocol Independence and the open mobile web; meaning that we will use the best protocol to get connectivity through any environment. Protocols, like WebSockets , can get tripped up by cell tower switching, double NAT environments, and even some anti-virus software or proxy boarder authorities.
PubNub provides client libraries specifically so we can auto-switch the protocol and remove socket-level complexities making it easy for developers to build apps that can communicate in realtime.
PubNub has used a variety of protocols over time, like WebSockets , MQTT, COMET, BOSH, long polling and others, and we are exploring currently prototyping future designs using SPDY, HTTP 2.0, and others. The bottom line is that PubNub will work in every network environment, and has very low network bandwidth overhead, as well as low battery drain on mobile devices.
您也可以尝试使用WebSockets作为第一选项协议（包括XHR回退）的其他云服务，如Pusher和Realtime（我工作的公司）。
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