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Why not just use websockets? I use socket.io on my site. I keep track of socket IDs in memory, if a connection is lost, I get a disconnect event, and vice versa

by nevi-me 10y ago

Why not just use websockets? I use socket.io on my site. I keep track of socket IDs in memory, if a connection is lost, I get a disconnect event, and vice versa. Socket events are sent to users when the number changes. I manage the frequency of socket emits using RxJS, to prevent sending too many changes to users. https://movinggauteng.co.za https://movinggauteng.co.za, there's a counter at the top of the page. EDIT: Only saw a comment about why the OP used Ajax after posting this.

WWKong 10y ago
Can I get your help in deploying socket.io to Google App Engine? Is it possible? It works locally for me but Google app engine seems to close out the websocket. http://stackoverflow.com/questions/37401250/how-do-i-deploy-socket-io-to-google-app-engine http://stackoverflow.com/questions/37401250/how-do-i-deploy-...
simplify 10y ago
Websockets would overkill for this kind of feature – you don't need realtime two-way communication. Server sent events (SSE) [1] are a much better alternative; it's a simple, long-lived HTTP request where the server can push data to the client. They're built into most browsers [2], and the client-side polyfill [3] is small (2kb gzipped). [1] https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events https://developer.mozilla.org/en-US/docs/Web/API/Server-sent... [2] http://caniuse.com/#search=server-sent%20events http://caniuse.com/#search=server-sent%20events [3] https://github.com/Yaffle/EventSource https://github.com/Yaffle/EventSource
- nevi-me 10y ago
  Fair enough, but what happens if I open a page, send an Ajax call to say "add 1 user", then promptly close that page? I don't know what OP is doing to detect that a user is no longer on the site. The reasons why I used WebSockets are that I get a disconnect event immediately, and I was already using WebSockets for other features on the site
  - simplify 10y ago
    It's a long-lived HTTP request. The server automatically knows if a client disconnects; that's a feature built into all HTTP server libraries everywhere. But yes, if you're already using websockets for other features, there's no reason not to continue to use them, as you explained :)

by nevi-me 10y ago

WWKong 10y ago

Can I get your help in deploying socket.io to Google App Engine? Is it possible? It works locally for me but Google app engine seems to close out the websocket. http://stackoverflow.com/questions/37401250/how-do-i-deploy-socket-io-to-google-app-engine http://stackoverflow.com/questions/37401250/how-do-i-deploy-...

simplify 10y ago

Websockets would overkill for this kind of feature – you don't need realtime two-way communication. Server sent events (SSE) [1] are a much better alternative; it's a simple, long-lived HTTP request where the server can push data to the client. They're built into most browsers [2], and the client-side polyfill [3] is small (2kb gzipped). [1] https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events https://developer.mozilla.org/en-US/docs/Web/API/Server-sent... [2] http://caniuse.com/#search=server-sent%20events http://caniuse.com/#search=server-sent%20events [3] https://github.com/Yaffle/EventSource https://github.com/Yaffle/EventSource

nevi-me 10y ago
Fair enough, but what happens if I open a page, send an Ajax call to say "add 1 user", then promptly close that page? I don't know what OP is doing to detect that a user is no longer on the site. The reasons why I used WebSockets are that I get a disconnect event immediately, and I was already using WebSockets for other features on the site
- simplify 10y ago
  It's a long-lived HTTP request. The server automatically knows if a client disconnects; that's a feature built into all HTTP server libraries everywhere. But yes, if you're already using websockets for other features, there's no reason not to continue to use them, as you explained :)