mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-13 20:11:19 -04:00
d735c0fbf9
- tests for cookiestring and querystring - fixed Cakefile with a concat so it works fine in both browser and local test
501 lines
14 KiB
CoffeeScript
501 lines
14 KiB
CoffeeScript
###
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A Coffeescript WebRTC snowflake proxy
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Using Copy-paste signaling for now.
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Uses WebRTC from the client, and websocket to the server.
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Assume that the webrtc client plugin is always the offerer, in which case
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this must always act as the answerer.
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TODO(keroserene): Complete the websocket + webrtc ProxyPair
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###
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if 'undefined' == typeof module || 'undefined' != typeof module.exports
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console.log 'not in browser.'
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else
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window.PeerConnection = window.RTCPeerConnection ||
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window.mozRTCPeerConnection ||
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window.webkitRTCPeerConnection
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window.RTCIceCandidate = window.RTCIceCandidate || window.mozRTCIceCandidate;
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window.RTCSessionDescription = window.RTCSessionDescription ||
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window.mozRTCSessionDescription
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Query =
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###
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Parse a URL query string or application/x-www-form-urlencoded body. The
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return type is an object mapping string keys to string values. By design,
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this function doesn't support multiple values for the same named parameter,
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for example "a=1&a=2&a=3"; the first definition always wins. Returns null on
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error.
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Always decodes from UTF-8, not any other encoding.
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http://dev.w3.org/html5/spec/Overview.html#url-encoded-form-data
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###
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parse: (qs) ->
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result = {}
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strings = []
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strings = qs.split '&' if qs
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return result if 0 == strings.length
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for string in strings
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j = string.indexOf '='
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if j == -1
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name = string
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value = ''
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else
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name = string.substr(0, j)
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value = string.substr(j + 1)
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name = decodeURIComponent(name.replace(/\+/g, ' '))
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value = decodeURIComponent(value.replace(/\+/g, ' '))
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result[name] = value if name not of result
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result
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# params is a list of (key, value) 2-tuples.
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buildString: (params) ->
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parts = []
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for param in params
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parts.push encodeURIComponent(param[0]) + '=' +
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encodeURIComponent(param[1])
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parts.join '&'
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Params =
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getBool: (query, param, defaultValue) ->
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val = query[param]
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return defaultValue if undefined == val
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return true if "true" == val || "1" == val || "" == val
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return false if "false" == val || "0" == val
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return null
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# Parse a cookie data string (usually document.cookie). The return type is an
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# object mapping cookies names to values. Returns null on error.
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# http://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-8747038
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parseCookie: (cookies) ->
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result = {}
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strings = []
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strings = cookies.split ';' if cookies
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for string in strings
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j = string.indexOf '='
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return null if -1 == j
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name = decodeURIComponent string.substr(0, j).trim()
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value = decodeURIComponent string.substr(j + 1).trim()
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result[name] = value if !(name in result)
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result
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# repr = (x) ->
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# return 'null' if null == x
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# return 'undefined' if 'undefined' == typeof x
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# if 'object' == typeof x
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# elems = []
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# for k in x
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# elems.push(maybe_quote(k) + ': ' + repr(x[k]));
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# return "{ " + elems.join(", ") + " }";
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# } else if (typeof x === "string") {
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# return quote(x);
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# } else {
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# return x.toString();
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# safe_repr = (s) -> SAFE_LOGGING ? "[scrubbed]" : repr(s)
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safe_repr = (s) -> SAFE_LOGGING ? "[scrubbed]" : JSON.stringify(s)
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# HEADLESS is true if we are running not in a browser with a DOM.
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DEBUG = false
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if window && window.location
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query = Query.parse(window.location.search.substr(1))
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DEBUG = Params.getBool(query, "debug", false)
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HEADLESS = "undefined" == typeof(document)
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# TODO: Different ICE servers.
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config = {
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iceServers: [
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{ urls: ["stun:stun.l.google.com:19302"] }
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]
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}
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# DOM elements
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$chatlog = null
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$send = null
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$input = null
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# TODO: Implement
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class Badge
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# Janky state machine
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MODE =
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INIT: 0
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WEBRTC_CONNECTING: 1
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WEBRTC_READY: 2
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# Minimum viable snowflake for now - just 1 client.
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class Snowflake
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# PeerConnection
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pc: null
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rateLimit: 0
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proxyPairs: []
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relayAddr: null
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badge: null
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$badge: null
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MAX_NUM_CLIENTS = 1
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CONNECTIONS_PER_CLIENT = 1
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state: MODE.INIT
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constructor: ->
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if HEADLESS
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# No badge
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else if DEBUG
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@$badge = debug_div
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else
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@badge = new Badge()
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@$badgem = @badge.elem
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@$badge.setAttribute("id", "snowflake-badge") if (@$badge)
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setRelayAddr: (relayAddr) ->
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# TODO: User-supplied for now, but should fetch from facilitator later.
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@relayAddr = relayAddr
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log "Input offer from the snowflake client:"
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@beginWebRTC()
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# Initialize WebRTC PeerConnection
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beginWebRTC: ->
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log "Starting up Snowflake..."
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@state = MODE.WEBRTC_CONNECTING
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@pc = new PeerConnection(config, {
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optional: [
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{ DtlsSrtpKeyAgreement: true }
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{ RtpDataChannels: false }
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]
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})
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@pc.onicecandidate = (evt) =>
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# Browser sends a null candidate once the ICE gathering completes.
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# In this case, it makes sense to send one copy-paste blob.
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if null == evt.candidate
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log "Finished gathering ICE candidates."
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Signalling.send @pc.localDescription
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# OnDataChannel triggered remotely from the client when connection succeeds.
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@pc.ondatachannel = (dc) =>
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console.log dc;
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channel = dc.channel
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log "Data Channel established..."
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@prepareDataChannel channel
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prepareDataChannel: (channel) ->
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channel.onopen = =>
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log "Data channel opened!"
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@state = MODE.WEBRTC_READY
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# TODO: Prepare ProxyPair onw.
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@beginProxy()
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channel.onclose = =>
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log "Data channel closed."
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@state = MODE.INIT;
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$chatlog.className = ""
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channel.onerror = =>
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log "Data channel error!"
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channel.onmessage = (msg) =>
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line = recv = msg.data
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console.log(msg);
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# Go sends only raw bytes...
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if "[object ArrayBuffer]" == recv.toString()
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bytes = new Uint8Array recv
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line = String.fromCharCode.apply(null, bytes)
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line = line.trim()
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log "data: " + line
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# Receive an SDP offer from client plugin.
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receiveOffer: (desc) =>
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sdp = new RTCSessionDescription desc
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try
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err = @pc.setRemoteDescription sdp
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catch e
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log "Invalid SDP message."
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return false
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log("SDP " + sdp.type + " successfully received.")
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@sendAnswer() if 'offer' == sdp.type
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true
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sendAnswer: =>
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next = (sdp) =>
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log "webrtc: Answer ready."
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@pc.setLocalDescription sdp
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promise = @pc.createAnswer next
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promise.then next if promise
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# Poll facilitator when this snowflake can support more clients.
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proxyMain: ->
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if @proxyPairs.length >= @MAX_NUM_CLIENTS * @CONNECTIONS_PER_CLIENT
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setTimeout(@proxyMain, @facilitator_poll_interval * 1000)
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return
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params = [["r", "1"]]
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params.push ["transport", "websocket"]
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params.push ["transport", "webrtc"]
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beginProxy: (client, relay) ->
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for i in [1..CONNECTIONS_PER_CLIENT]
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@makeProxyPair client, relay
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makeProxyPair: (client, relay) ->
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pair = new ProxyPair(client, relay, @rate_limit);
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@proxyPairs.push pair
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pair.onCleanup = (event) =>
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# Delete from the list of active proxy pairs.
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@proxyPairs.splice(@proxy_pairs.indexOf(pair), 1)
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@badge.endProxy() if @badge
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try
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pair.connectRelay()
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catch err
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log 'ERROR: ProxyPair exception while connecting.'
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log err
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return
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@badge.beginProxy if @badge
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cease: ->
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while @proxyPairs.length > 0
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@proxyPairs.pop().close()
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disable: ->
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log "Disabling Snowflake."
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@cease()
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@badge.disable() if @badge
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die: ->
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log "Snowflake died."
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@cease()
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@badge.die() if @badge
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DEFAULT_PORTS =
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http: 80
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https: 443
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# Build an escaped URL string from unescaped components. Only scheme and host
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# are required. See RFC 3986, section 3.
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buildUrl = (scheme, host, port, path, params) ->
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parts = []
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parts.push(encodeURIComponent scheme)
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parts.push '://'
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# If it contains a colon but no square brackets, treat it as IPv6.
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if host.match(/:/) && !host.match(/[[\]]/)
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parts.push '['
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parts.push host
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parts.push ']'
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else
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parts.push(encodeURIComponent host)
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if undefined != port && DEFAULT_PORTS[scheme] != port
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parts.push ':'
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parts.push(encodeURIComponent port.toString())
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if undefined != path && '' != path
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if !path.match(/^\//)
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path = '/' + path
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###
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Slash is significant so we must protect it from encodeURIComponent, while
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still encoding question mark and number sign. RFC 3986, section 3.3: "The
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path is terminated by the first question mark ('?') or number sign ('#')
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character, or by the end of the URI. ... A path consists of a sequence of
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path segments separated by a slash ('/') character."
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###
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path = path.replace /[^\/]+/, (m) ->
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encodeURIComponent m
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parts.push path
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if undefined != params
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parts.push '?'
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parts.push Query.buildString params
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parts.join ''
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makeWebsocket = (addr) ->
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url = buildUrl 'ws', addr.host, addr.port, '/'
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if have_websocket_binary_frames()
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ws = new WebSocket url
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else
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ws = new WebSocket url 'base64'
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###
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"User agents can use this as a hint for how to handle incoming binary data: if
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the attribute is set to 'blob', it is safe to spool it to disk, and if it is
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set to 'arraybuffer', it is likely more efficient to keep the data in memory."
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###
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ws.binaryType = 'arraybuffer'
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ws
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# TODO: Implement
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class ProxyPair
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constructor: (@clientAddr, @relayAddr, @rateLimit) ->
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# Assumes WebRTC part is already connected.
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# TODO: Put the webrtc stuff in ProxyPair, so that multiple webrtc connections
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# can be established.
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connectRelay: ->
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log "Snowflake: connecting to relay"
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@relay = makeWebsocket(@relayAddr);
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@relay.label = 'Relay'
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@relay.onopen = =>
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log "Snowflake: " + ws.label + "connected"
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@relay.onclose = @onClose
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@relay.onerror = @onError
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@relay.onmessage = @onRelayToClientMessage
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onClientToRelayMessage: (event) ->
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@c2r_schedule.push event.data
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@flush()
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onRelayToClientMessage: (event) ->
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@r2c_schedule.push event.data
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@flush()
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onClose: (event) ->
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ws = event.target
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log(ws.label + ': closed.')
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@flush()
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@maybeCleanup()
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onError: (event) ->
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ws = event.target
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log ws.label + ': error.'
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this.close();
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# we can't rely on onclose_callback to cleanup, since one common error
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# case is when the client fails to connect and the relay never starts.
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# in that case close() is a NOP and onclose_callback is never called.
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@maybeCleanup()
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isOpen: (ws) -> undefined != ws && WebSocket.OPEN == ws.readyState
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isClosed: (ws) -> undefined == ws || WebSocket.CLOSED == ws.readyState
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maybe_cleanup: ->
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if @running && @isClosed(client) && @isClosed @relay
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@running = false
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@cleanup_callback()
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true
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false
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# Send as much data as the rate limit currently allows.
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###
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flush: ->
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clearTimeout @flush_timeout_id if @flush_timeout_id
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@flush_timeout_id = null
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busy = true
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checkChunks = ->
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busy = false
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# if @isOpen @clientthis.client_s) &&
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# this.client_s.bufferedAmount < MAX_BUFFER &&
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# this.r2c_schedule.length > 0) {
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# chunk = this.r2c_schedule.shift();
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# this.rate_limit.update(chunk.length);
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# this.client_s.send(chunk);
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# busy = true;
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#
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if @isOpen @relay &&
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@relay.bufferedAmount < MAX_BUFFER &&
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@c2r_schedule.length > 0
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chunk = @c2r_schedule.shift()
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@rate_limit.update chunk.length
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@relay.send chunk
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busy = true
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checkChunks() while busy && !@rate_limit.is_limited()
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if @isClosed @relay &&
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# !isClosed(this.client_s) &&
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# @client_s.bufferedAmount === 0 &&
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@r2c_schedule.length == 0
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# log("Client: closing.");
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# this.client_s.close();
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# if (is_closed(this.client_s) &&
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# !is_closed(this.relay_s) &&
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# this.relay_s.bufferedAmount === 0 &&
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# this.c2r_schedule.length === 0) {
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# log("Relay: closing.");
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# this.relay_s.close();
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# }
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while busy && !@rate_limit.is_limited()
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if this.r2c_schedule.length > 0 ||
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(@isOpen(@client) && @client.bufferedAmount > 0) ||
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@c2r_schedule.length > 0 ||
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(@isOpen(@relay) && @relay.bufferedAmount > 0)
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@flush_timeout_id = setTimeout @flush, @rate_limit.when() * 1000
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###
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#
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## -- DOM & Input Functionality -- ##
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#
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snowflake = null
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welcome = ->
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log "== snowflake browser proxy =="
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log "Input desired relay address:"
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# Log to the message window.
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log = (msg) ->
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$chatlog.value += msg + "\n"
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console.log msg
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# Scroll to latest
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$chatlog.scrollTop = $chatlog.scrollHeight
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Interface =
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# Local input from keyboard into message window.
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acceptInput: ->
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msg = $input.value
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switch snowflake.state
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when MODE.INIT
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# Set target relay.
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snowflake.setRelayAddr msg
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when MODE.WEBRTC_CONNECTING
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Signalling.receive msg
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when MODE.WEBRTC_READY
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log "No input expected - WebRTC connected."
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# data = msg
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# log(data)
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# channel.send(data)
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else
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log "ERROR: " + msg
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$input.value = ""
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$input.focus()
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# Signalling channel - just tells user to copy paste to the peer.
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# Eventually this should go over the facilitator.
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Signalling =
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send: (msg) ->
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log "---- Please copy the below to peer ----\n"
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log JSON.stringify(msg)
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log "\n"
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receive: (msg) ->
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recv = ""
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try
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recv = JSON.parse msg
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catch e
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log "Invalid JSON."
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return
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desc = recv['sdp']
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if !desc
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log "Invalid SDP."
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return false
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snowflake.receiveOffer recv if desc
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init = ->
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$chatlog = document.getElementById('chatlog')
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$chatlog.value = ""
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$send = document.getElementById('send')
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$send.onclick = Interface.acceptInput
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$input = document.getElementById('input')
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$input.focus()
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$input.onkeydown = (e) =>
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if 13 == e.keyCode # enter
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$send.onclick()
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snowflake = new Snowflake()
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welcome()
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window.onload = init if window
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