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PONode.js Callback Issues
 

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    <p>Been working on a Node.js restful web service that is hosted on OpenShift. Currently I have had success with simple method calls and such, but can not seem to get the http response to work through an asynchronous callback. </p> <p>Here is what I currently have:</p> <pre><code>var http = require("http"); var url = require("url"); // used to get the requested method name as well as parameters var util = require("util"); // global variables // router function function route(pathname, query, callbackFunc) { //return executeMethod(pathname, query); var returnValue; switch (pathname.toUpperCase()) { case "/ADD": returnValue = add(query['num1'], query['num2']); //util.process.nextTick(function() { //callbackFunc(null, returnValue); //}); break; case "/ADDASYNC": //addAsync(query['num1'], query['num2'], callback); break; default: returnValue = "method not found"; break; } //return returnValue; //return "Route for request " + pathname + " complete, query: " + query; } // actual web method execution function add(num1, num2){ //return "add method called with values: " + num1 + " " + num2; return parseFloat(num1) + parseFloat(num2); } function addAsync(num1, num2, callback){ //util.process.nextTick(function(){ // var value = parseFloat(num1) + parseFloat(num2); // util.process.nextTick(function(){ // callback(value); // }); //}); } // main request handler for server function onRequest(request, response) { var pathname = url.parse(request.url).pathname; var query = url.parse(request.url, true).query; console.log("Request for " + pathname + " Recieved"); response.setTimeout(500); var myCallback = function(err, data){ if(err){ response.writeHead(200, {"Content-Type": "text/plain"}); response.write('an error occured with requested method'); response.end(); }else{ response.writeHead(200, {"Content-Type": "text/plain"}); response.write(data); response.end(); } } //var finalValue = route(pathname, query); //var finalValue = 0; (function(){route(pathname, query, myCallback)})(); response.writeContinue(); //process.nextTick(myCallback(null, 'hello world')); setTimeout(function(){ myCallback(null, "hello world"); }, 15); //myCallback(); //response.writeHead(200, {"Content-Type": "text/plain"}); //response.write("Hello World. You requested: " + pathname + " with type " + pathname.type + ", value: " + finalValue); //response.end(); } // create the server and signal console of start http.createServer(onRequest).listen(8080, process.env.OPENSHIFT_INTERNAL_IP); // for debug //http.createServer(onRequest).listen(process.env.PORT, process.env.IP); console.log("Server has started. Listening to port: " + 8080 + " ip address: " + process.env.OPENSHIFT_INTERNAL_IP); </code></pre> <p>If I call the myCallback method directly inside the onRequest method, then I get a response back without any issues; however, calling the myCallback function inside the onRequest or route methods using process.nextTick or setTimeout does not seem to be working. I am working on this project using the Cloud9 IDE with direct git push to OpenShift so I am having some difficulties with my debug but have tried quite a few different approaches with no success, including setting the request.setTimeout function to provide some time for the timer/process event to fire. My current OpenShift app is running Node.js 0.6. Is there anything Obvious that could be causing issues that I might be missing?</p>
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    1. COCan you post a link to a gist of what the non-working code looks like? Above I do not see a timeout nor the route method.
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    2. COI edited my original response to include my complete code.
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    3. COTwo questions: why are you doing "var myCallback = function(err,data)" instead of just "function myCallback(err,data)"? And, why are you doing "util.process.nextTick" instead of just "process.nextTick"?
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