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| -rw-r--r-- | socket.js | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/socket.js b/socket.js new file mode 100644 index 0000000..4a030f5 --- /dev/null +++ b/socket.js @@ -0,0 +1,67 @@ +/* socket.js, a simple wrapper for a YWOT websocket connection */ + +class retryws extends EventEmitter{ // a wrapper on ws that retries on failure + constructor(addr) { + let sock; + this.sockdown = true; + this.send = (message) => { + if (sockdown){ + throw "Socket is down!"; + } + sock.send(message); + } + function sockinit(){ // addr is not expected to change, so not handed as input; similarly, sock is not passed in a chain because behavior is expected to be serial (either initializing or retrying) + sock = new ws(addr); + sock.on('open', () => { this.emit('open'); sockdown = false; }); + sock.on('close', (err) => { setTimeout(sockinit,1000); sockdown = true; this.emit('close'); }); + sock.on('error', (err) => { sock.close(); }); + sock.on('message', (message) => { this.emit('message',message); }); + } + } +} + + +class Socket extends retryws { + constructor(world='') { // Takes the name of the world, which can be an empty string. + let loc = (name = '') ? '' : `/${name}`; + let addr = `wss://www.yourworldoftext.com/${loc}ws`; + super(addr); + this.on('message', (msg)=>{ + msg = JSON.parse(msg); + switch (message.kind){ + case 'write': + this.emit('write', message.accepted, message.rejected); break; // A confirmation message for writes (accepted/rejected updates) + case 'cursor': + this.emit('cursor', message.positions, message.sender); break; // Must be used for self-identification + case 'tileUpdate': + this.emit('tileUpdate', message.sender, message.source, message.tiles); break; // Any change by another user or possibly oneself + case 'fetch': + this.emit('fetch', message.tiles); break; // The response to a fetch request + } + } + + this.fetch = function(coords){ //coords is a list of quadruplets, each a min/max pair of y/x coordinate pairs which describes at most 1000 tiles + //Unchecked for speed + for (var i=0; i<coords.length; i++){ + coords[i] = {"minY":coords[i][0], "minX":coords[i][1], "maxY":coords[i][2], "maxX":coords[i][3]}; + } + this.send(`{"fetchRectangles":${JSON.stringify(coords)},"kind":"fetch","v":"3"}`); + } + + this.write = function(chars){ //chars is an list of triplets [ tile coordinate (y/x), pixel coordinate (y/x < 16), char ] + if (chars.length > 200){ + throw "Too many characters to write"; + } + for (var i=0; i<chars.length; i++){ + chars[i].splice(4,0,0); // + chars[i].push(i); + } + this.send(`{"edits":${JSON.stringify(chars)},"kind":"write"}`; + } + + this.cursor = function(coords){ //coords is just one quadruplet analagous to fetch; I think the api could handle more, but it's unnecessary for now. + this.send(`"kind":"cursor","positions":[${JSON.stringify(coords)}]}`; + } + + } +} |