Create poe.js

poe.js

@@ -0,0 +1,104 @@
+var express = require('express');
+var http = require('http');
+var bodyParser = require('body-parser');
+const logger = require('morgan');
+
+var app = express();
+
+app.use(logger('dev'));
+app.use(bodyParser.json());
+
+app.listen(3001);
+
+const poe_url = '/poe';
+const poe_link = '/link';
+const poe_token_link = '/token';
+
+const poe_router = express.Router();
+
+
+//TODO implement garbage collection strategy to clean up the result cache
+var token = 0;
+
+var tokens = {};
+
+function getToken() {
+	var newtoken = token++;
+
+	tokens[newtoken] = { state: 'new'};
+
+	return newtoken;
+}
+
+function seenToken(t) {
+	if (tokens[t]) {
+		if (tokens[t].state == 'new') {
+			tokens[t].state = 'seen';
+			return false;
+		}
+		return true;
+	}
+	return;
+}
+
+function setResponse(t,r) {
+	tokens[t].res = r;
+}
+
+function getResponse(t) {
+	return tokens[t].res;
+}
+
+
+poe_router.get('/debug', function(req, res) {
+
+	res.send(tokens);
+
+});
+
+
+poe_router.get(poe_token_link, function(req, res) {
+
+	res.status(204);
+	res.set('Cache-control', 'no-cache');
+	res.set('Link', poe_url + poe_link+'?poe='+getToken()+'; rel=poe');
+
+    res.send();
+});
+
+poe_router.get(poe_link, function(req, res) {
+	var token = req.query.poe;
+	res.send(getResponse(token));
+});
+
+poe_router.post(poe_link, function(req, res) {
+
+	var token = req.query.poe;
+
+	const seen = seenToken(token);
+
+	console.log(token+' '+seen);
+
+	if (seen) {
+		res.status(405).end();
+		return;
+	}
+	if (seen === undefined) {
+		res.status(404).end();
+		return;
+	}
+
+	//process request
+	var response = "Hello World \n"+JSON.stringify(req.query);
+
+	//save the response in case it got lost and the client is trying to get it later
+	//this will crash if the token has not been initialized before
+	setResponse(token, response);
+
+    res.send(response);
+
+    //log that the response has been sent successfully?
+});
+
+app.use(poe_url, poe_router);
+