{"id":8086,"date":"2015-11-26T13:35:16","date_gmt":"2015-11-26T13:35:16","guid":{"rendered":"https:\/\/unknownerror.org\/index.php\/2015\/11\/26\/automattic-socket-io\/"},"modified":"2022-08-30T15:03:01","modified_gmt":"2022-08-30T15:03:01","slug":"automattic-socket-io","status":"publish","type":"post","link":"https:\/\/unknownerror.org\/index.php\/2015\/11\/26\/automattic-socket-io\/","title":{"rendered":"Automattic\/socket.io"},"content":{"rendered":"

<\/p>\n

How to use<\/h2>\n

The following example attaches socket.io to a plain Node.JS HTTP server listening on port 3000<\/code>.<\/p>\n

var server = require('http').createServer();\nvar io = require('socket.io')(server);\nio.on('connection', function(socket){\n  socket.on('event', function(data){});\n  socket.on('disconnect', function(){});\n});\nserver.listen(3000);\n<\/code><\/pre>\n
Standalone<\/h3>\n
var io = require('socket.io')();\nio.on('connection', function(socket){});\nio.listen(3000);\n<\/code><\/pre>\n
In conjunction with Express<\/h3>\n
Starting with 3.0<\/strong>, express applications have become request handler functions that you pass to http<\/code> or http<\/code> Server<\/code> instances. You need to pass the Server<\/code> to socket.io<\/code>, and not the express application function.<\/p>\n
var app = require('express')();\nvar server = require('http').createServer(app);\nvar io = require('socket.io')(server);\nio.on('connection', function(){ \/* \u2026 *\/ });\nserver.listen(3000);\n<\/code><\/pre>\n
In conjunction with Koa<\/h3>\n
Like Express.JS, Koa works by exposing an application as a request handler function, but only by calling the callback<\/code> method.<\/p>\n
var app = require('koa')();\nvar server = require('http').createServer(app.callback());\nvar io = require('socket.io')(server);\nio.on('connection', function(){ \/* \u2026 *\/ });\nserver.listen(3000);\n<\/code><\/pre>\n
API<\/h2>\n
Server<\/h3>\n
Exposed by require('socket.io')<\/code>.<\/p>\n
Server()<\/h3>\n
Creates a new Server<\/code>. Works with and without new<\/code>:<\/p>\n
var io = require('socket.io')();\n\/\/ or\nvar Server = require('socket.io');\nvar io = new Server();\n<\/code><\/pre>\n
Server(opts:Object)<\/h3>\n
Optionally, the first or second argument (see below) of the Server<\/code> constructor can be an options object.<\/p>\n
The following options are supported:<\/p>\n
    \n
  • serveClient<\/code> sets the value for Server#serveClient()<\/li>\n
  • path<\/code> sets the value for Server#path()<\/li>\n<\/ul>\n
    The same options passed to socket.io are always passed to the engine.io<\/code> Server<\/code> that gets created. See engine.io options as reference.<\/p>\n
    Server(srv:http#Server, opts:Object)<\/h3>\n
    Creates a new Server<\/code> and attaches it to the given srv<\/code>. Optionally opts<\/code> can be passed.<\/p>\n
    Server(port:Number, opts:Object)<\/h3>\n
    Binds socket.io to a new http.Server<\/code> that listens on port<\/code>.<\/p>\n
    Server#serveClient(v:Boolean):Server<\/h3>\n
    If v<\/code> is true<\/code> the attached server (see Server#attach<\/code>) will serve the client files. Defaults to true<\/code>.<\/p>\n
    This method has no effect after attach<\/code> is called.<\/p>\n
    \/\/ pass a server and the `serveClient` option\nvar io = require('socket.io')(http, { serveClient: false });\n\n\/\/ or pass no server and then you can call the method\nvar io = require('socket.io')();\nio.serveClient(false);\nio.attach(http);\n<\/code><\/pre>\n
    If no arguments are supplied this method returns the current value.<\/p>\n
    Server#path(v:String):Server<\/h3>\n
    Sets the path v<\/code> under which engine.io<\/code> and the static files will be served. Defaults to \/socket.io<\/code>.<\/p>\n
    If no arguments are supplied this method returns the current value.<\/p>\n
    Server#adapter(v:Adapter):Server<\/h3>\n
    Sets the adapter v<\/code>. Defaults to an instance of the Adapter<\/code> that ships with socket.io which is memory based. See socket.io-adapter.<\/p>\n
    If no arguments are supplied this method returns the current value.<\/p>\n
    Server#origins(v:String):Server<\/h3>\n
    Sets the allowed origins v<\/code>. Defaults to any origins being allowed.<\/p>\n
    If no arguments are supplied this method returns the current value.<\/p>\n
    Server#origins(v:Function):Server<\/h3>\n
    Sets the allowed origins as dynamic function. Function takes two arguments origin:String<\/code> and callback(error, success)<\/code>, where success<\/code> is a boolean value indicating whether origin is allowed or not.<\/p>\n
    Potential drawbacks<\/strong>:<\/p>\n
      \n
    • in some situations, when it is not possible to determine origin<\/code> it may have value of *<\/code><\/li>\n
    • As this function will be executed for every request, it is advised to make this function work as fast as possible<\/li>\n
    • If socket.io<\/code> is used together with Express<\/code>, the CORS headers will be affected only for socket.io<\/code> requests. For Express can use cors<\/li>\n<\/ul>\n
      Server#sockets:Namespace<\/h3>\n
      The default (\/<\/code>) namespace.<\/p>\n
      Server#attach(srv:http#Server, opts:Object):Server<\/h3>\n
      Attaches the Server<\/code> to an engine.io instance on srv<\/code> with the supplied opts<\/code> (optionally).<\/p>\n
      Server#attach(port:Number, opts:Object):Server<\/h3>\n
      Attaches the Server<\/code> to an engine.io instance that is bound to port<\/code> with the given opts<\/code> (optionally).<\/p>\n
      Server#listen<\/h3>\n
      Synonym of Server#attach<\/code>.<\/p>\n
      Server#bind(srv:engine#Server):Server<\/h3>\n
      Advanced use only. Binds the server to a specific engine.io Server<\/code> (or compatible API) instance.<\/p>\n
      Server#onconnection(socket:engine#Socket):Server<\/h3>\n
      Advanced use only. Creates a new socket.io<\/code> client from the incoming engine.io (or compatible API) socket<\/code>.<\/p>\n
      Server#of(nsp:String):Namespace<\/h3>\n
      Initializes and retrieves the given Namespace<\/code> by its pathname identifier nsp<\/code>.<\/p>\n
      If the namespace was already initialized it returns it right away.<\/p>\n
      Server#emit<\/h3>\n
      Emits an event to all connected clients. The following two are equivalent:<\/p>\n
      var io = require('socket.io')();\nio.sockets.emit('an event sent to all connected clients');\nio.emit('an event sent to all connected clients');\n<\/code><\/pre>\n
      For other available methods, see Namespace<\/code> below.<\/p>\n
      Server#close<\/h3>\n
      Closes socket server<\/p>\n
      var Server = require('socket.io');\nvar PORT   = 3030;\nvar server = require('http').Server();\n\nvar io = Server(PORT);\n\nio.close(); \/\/ Close current server\n\nserver.listen(PORT); \/\/ PORT is free to use\n\nio = Server(server);\n<\/code><\/pre>\n
      Server#use<\/h3>\n
      See Namespace#use<\/code> below.<\/p>\n
      Namespace<\/h3>\n
      Represents a pool of sockets connected under a given scope identified by a pathname (eg: \/chat<\/code>).<\/p>\n
      By default the client always connects to \/<\/code>.<\/p>\n
      Events<\/h4>\n
        \n
      • \n
        connection<\/code> \/ connect<\/code>. Fired upon a connection.<\/p>\n
        Parameters:<\/p>\n
          \n
        • Socket<\/code> the incoming socket.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
          Namespace#name:String<\/h3>\n
          The namespace identifier property.<\/p>\n
          Namespace#connected:Object<\/h3>\n
          Hash of Socket<\/code> objects that are connected to this namespace indexed by id<\/code>.<\/p>\n
          Namespace#clients(fn:Function)<\/h3>\n
          Gets a list of client IDs connected to this namespace (across all nodes if applicable).<\/p>\n
          An example to get all clients in a namespace:<\/p>\n
          var io = require('socket.io')();\nio.of('\/chat').clients(function(error, clients){\n  if (error) throw error;\n  console.log(clients); \/\/ => [PZDoMHjiu8PYfRiKAAAF, Anw2LatarvGVVXEIAAAD]\n});\n<\/code><\/pre>\n
          An example to get all clients in namespace\u2019s room:<\/p>\n
          var io = require('socket.io')();\nio.of('\/chat').in('general').clients(function(error, clients){\n  if (error) throw error;\n  console.log(clients); \/\/ => [Anw2LatarvGVVXEIAAAD]\n});\n<\/code><\/pre>\n
          As with broadcasting, the default is all clients from the default namespace (\u2019\/\u2019):<\/p>\n
          var io = require('socket.io')();\nio.clients(function(error, clients){\n  if (error) throw error;\n  console.log(clients); \/\/ => [6em3d4TJP8Et9EMNAAAA, G5p55dHhGgUnLUctAAAB]\n});\n<\/code><\/pre>\n
          Namespace#use(fn:Function):Namespace<\/h3>\n
          Registers a middleware, which is a function that gets executed for every incoming Socket<\/code> and receives as parameter the socket and a function to optionally defer execution to the next registered middleware.<\/p>\n
          var io = require('socket.io')();\nio.use(function(socket, next){\n  if (socket.request.headers.cookie) return next();\n  next(new Error('Authentication error'));\n});\n<\/code><\/pre>\n
          Errors passed to middleware callbacks are sent as special error<\/code> packets to clients.<\/p>\n
          Socket<\/h3>\n
          A Socket<\/code> is the fundamental class for interacting with browser clients. A Socket<\/code> belongs to a certain Namespace<\/code> (by default \/<\/code>) and uses an underlying Client<\/code> to communicate.<\/p>\n
          Socket#rooms:Array<\/h3>\n
          A list of strings identifying the rooms this socket is in.<\/p>\n
          Socket#client:Client<\/h3>\n
          A reference to the underlying Client<\/code> object.<\/p>\n
          Socket#conn:Socket<\/h3>\n
          A reference to the underlying Client<\/code> transport connection (engine.io Socket<\/code> object).<\/p>\n
          Socket#request:Request<\/h3>\n
          A getter proxy that returns the reference to the request<\/code> that originated the underlying engine.io Client<\/code>. Useful for accessing request headers such as Cookie<\/code> or User-Agent<\/code>.<\/p>\n
          Socket#id:String<\/h3>\n
          A unique identifier for the socket session, that comes from the underlying Client<\/code>.<\/p>\n
          Socket#emit(name:String[, \u2026]):Socket<\/h3>\n
          Emits an event to the socket identified by the string name<\/code>. Any other parameters can be included.<\/p>\n
          All datastructures are supported, including Buffer<\/code>. JavaScript functions can\u2019t be serialized\/deserialized.<\/p>\n
          var io = require('socket.io')();\nio.on('connection', function(socket){\n  socket.emit('an event', { some: 'data' });\n});\n<\/code><\/pre>\n
          Socket#join(name:String[, fn:Function]):Socket<\/h3>\n
          Adds the socket to the room<\/code>, and fires optionally a callback fn<\/code> with err<\/code> signature (if any).<\/p>\n
          The socket is automatically a member of a room identified with its session id (see Socket#id<\/code>).<\/p>\n
          The mechanics of joining rooms are handled by the Adapter<\/code> that has been configured (see Server#adapter<\/code> above), defaulting to socket.io-adapter.<\/p>\n
          Socket#leave(name:String[, fn:Function]):Socket<\/h3>\n
          Removes the socket from room<\/code>, and fires optionally a callback fn<\/code> with err<\/code> signature (if any).<\/p>\n
          Rooms are left automatically upon disconnection<\/strong>.<\/p>\n
          The mechanics of leaving rooms are handled by the Adapter<\/code> that has been configured (see Server#adapter<\/code> above), defaulting to socket.io-adapter.<\/p>\n
          Socket#to(room:String):Socket<\/h3>\n
          Socket#in(room:String):Socket<\/h3>\n
          Sets a modifier for a subsequent event emission that the event will only be broadcasted<\/em> to sockets that have joined the given room<\/code>.<\/p>\n
          To emit to multiple rooms, you can call to<\/code> several times.<\/p>\n
          var io = require('socket.io')();\nio.on('connection', function(socket){\n  socket.to('others').emit('an event', { some: 'data' });\n});\n<\/code><\/pre>\n
          Socket#compress(v:Boolean):Socket<\/h3>\n
          Sets a modifier for a subsequent event emission that the event data will only be compressed<\/em> if the value is true<\/code>. Defaults to true<\/code> when you don\u2019t call the method.<\/p>\n
          var io = require('socket.io')();\nio.on('connection', function(socket){\n  socket.compress(false).emit('an event', { some: 'data' });\n});\n<\/code><\/pre>\n
          Client<\/h3>\n
          The Client<\/code> class represents an incoming transport (engine.io) connection. A Client<\/code> can be associated with many multiplexed Socket<\/code> that belong to different Namespace<\/code>s.<\/p>\n
          Client#conn<\/h3>\n
          A reference to the underlying engine.io<\/code> Socket<\/code> connection.<\/p>\n
          Client#request<\/h3>\n
          A getter proxy that returns the reference to the request<\/code> that originated the engine.io connection. Useful for accessing request headers such as Cookie<\/code> or User-Agent<\/code>.<\/p>\n
          Debug \/ logging<\/h2>\n
          Socket.IO is powered by debug. In order to see all the debug output, run your app with the environment variable DEBUG<\/code> including the desired scope.<\/p>\n
          To see the output from all of Socket.IO’s debugging scopes you can use:<\/p>\n
          DEBUG=socket.io* node myapp\n<\/code><\/pre>\n
          License<\/h2>\n
          MIT<\/p>\n","protected":false},"excerpt":{"rendered":"
          How to use The following example attaches socket.io to a plain Node.JS HTTP server listening on port 3000. var server = require(‘http’).createServer(); var io = require(‘socket.io’)(server); io.on(‘connection’, function(socket){ socket.on(‘event’, function(data){}); socket.on(‘disconnect’, function(){}); }); server.listen(3000); Standalone var io = require(‘socket.io’)(); io.on(‘connection’, function(socket){}); io.listen(3000); In conjunction with Express Starting with 3.0, express applications have become request handler […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-8086","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/8086","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=8086"}],"version-history":[{"count":1,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/8086\/revisions"}],"predecessor-version":[{"id":8637,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/8086\/revisions\/8637"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=8086"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=8086"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=8086"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}