问题
I start developing a software, app coded using html + js I need to send this app notification from the server (java code) the app using nginx for routiong and is hosted in AWS. I investigated this subject of real time notification and I get confused between web sockets to long polling In what situations would AJAX long/short polling be preferred over HTML5 WebSockets?
In some articles I read that long polling is an old unlike websocket which is newer and better (In what situations would AJAX long/short polling be preferred over HTML5 WebSockets? ) I start inspect element of gmail facebook whatsapp web pages. I saw that Gmail+ facebook using long polling Unlike whatsapp which using Websocket. So why these companies still choose to use long polling? https://www.quora.com/Does-Facebook-use-WebSockets-for-any-of-their-applications-Are-they-really-useful-at-that-scale-especially-since-they-impose-a-stateful-architecture
回答1:
A couple of reasons why some companies are still using long-polling:
- WebSocket support is still not 100%, even though the legacy browsers without support are slowly dying out. So if you're a company like Google where products have to work on pretty much every browser out there, you still need a non-WebSocket fallback solution.
- If you already have a working solution then the costs of moving to WebSocket may well outweigh the savings it brings.
回答2:
WebSockets it's better, it just drains less power, the client does not have to be asking for content every X time, the only downfall it's that old browsers does not support them.
You have a full comparasion in this other question if you want to have more information.
In what situations would AJAX long/short polling be preferred over HTML5 WebSockets?
来源：https://stackoverflow.com/questions/36290520/longpolling-vs-websockets