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PORedis long-polling Pub/Sub frequent message blocking
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copied!<p>I'm trying to wrap my head around the Redis Pub/Sub API and setup a long-polling server.</p> <p>This lua script subscribes to a 'test' channel and returns new messages received:</p> <p>nginx.conf:</p> <pre><code>location /poll { lua_need_request_body on; default_type 'text/plain'; content_by_lua_file '/usr/local/nginx/html/poll.lua'; } </code></pre> <p>poll.lua:</p> <pre><code>local redis = require "redis"; local red = redis:new(); local cjson = require "cjson"; red:set_timeout(30000) -- 30 sec local resCon, err = red:connect("127.0.0.1", 6379) if not resCon then ngx.print("error") return end local resSub, err = red:subscribe('r:' .. ngx.var["arg_r"]:gsub('%W','')) if not resSub then ngx.print("error") return end if resSub == ngx.null then ngx.print("error") return end local resMsg, err = red:read_reply() if not resMsg then ngx.say("0") return end ngx.say(cjson.encode(resMsg)) </code></pre> <p>client.js:</p> <pre><code>var tmpR = 'test'; function poll() { $.get('/poll', {'r':tmpR}, function(data){ if (data !== "error") { console.log(data); window.setTimeout(function(){ poll(); },1000); } else { console.log('poll fail'); } }) } </code></pre> <p>Now, if I send <code>publish r:test hello</code> from redis-cli, I receive the message on the client and the server responds to redis-cli with <code>1</code>. But, if I send two messages quickly, the second message doesn't broadcast and the server responds with <code>0</code>.</p> <p>Are my channels only capable of receiving a message per second, or, is this a throttle on the frequency of messages a user can broadcast to a channel?</p> <p>Is this the right way to approach this polling server on nginx assuming many users may be connected at one time? Would it be more efficient to use GET requests on a timer?</p>

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