A simple Node.js REST server simulator for Testing
Problem
You are developing a client application (AngularJS) and you need to receive the data from a REST API service.
Often you don’t have the access to the remote service or it doesn’t have the required data for your tests (dinamically generated data).
A direct access to a test .json file is not possible from the client because of security restrictions of the browser (the browser should not be able to play with the filesystem).
Solution – Concept
A client app can request (GET) a pre-defined page to a local server and receive the JSON file for the test.
The server can be implemented in Node.js and it serves static files content as response to http requests.

Solution – Implementation
The code and the installation procedure are here: https://github.com/marco76/node_rest_server/
The structure of the code is very simple:
Here an example of response:
Solution – Details
The file server.js create a new http server and waits for http requests.
It instantiates a loaderModule that contain the class that will retrieve the JSON data.
// import the function from the module var loaderModule = require('./ResponseLoader.js'); // create an instance of the prototype var loader = new loaderModule("loader"); function requestService(request, response){ // url == filename without extension var url = request.url; // home page called if (url=="/"){ url = "/index"; } // call the method that load the static page loader.load(url); // prepare the http response response.statusCode = 200; response.setHeader('Content-Type', 'application/json'); // add the JSON content response.end(loader.getJson()); }
The second important Javascript file is the function that receives the request to load a file and retrieves the content:
function ResponseLoader (name){ // the content of the file is stored in this variable var json; // method that load the file on the base of the URL ResponseLoader.prototype.load = function(url){ console.log("requested file: " + url); // url: hello -> file: [current directory]/json/hello.json fs.readFile( __dirname + '/json' +url+'.json', function (err, data) { if (err) { console.log('error'); throw err; } // the content of the file is assigned to the variable json = data; console.log(name + " : " +data.toString()); }) }; // give me the json content ResponseLoader.prototype.getJson = function (){ console.log(name + " : return json"); return json; };
The features are very basic but they can be easily extended. The code is modularized using the ‚module‘ feature of node.js.
If you come from Java / .NET : the import of modules is not standard in JavaScript until ECMAScript 6.