index.js

/*jshint node: true*/

/* global exports, module, process */

/**
 * Index.js
 * Creates an express app to manage mock response
 */

var express = require('express'),
        fs = require('fs'),
        path = require('path'),
        bodyParser = require('body-parser');

var defaultConfig = require('./config');
var constants = require('./constants.json');
var _ = require('lodash');

(function () {
    var node_rest_mock = {};

    exports.startMock = node_rest_mock.startMock = function (config, app) {
        if (!app) {
            app = createApp();
        }
        // merge the config with the default config
        config = _.merge(defaultConfig, config);

        addGETStubs(config, app);
        addPOSTStubs(config, app);

        // Don't want these for an existing express app
        if (!module.parent) {
            catchAll(app);
            start(config, app);
        }
    };
    // kick start the server when run standalone
    if (!module.parent) {
        node_rest_mock.startMock();
    }
})();

function addGETStubs(config, app) {

    app.get('/stubService/*', function (req, res) {
        try {
            var call_param = req.params[0];
            // Send file content as response
            res.setHeader('Content-Type', 'application/json');
            var filePath = process.cwd() + path.sep + config.stub_dir + path.sep + call_param + '.json';

            res.sendFile(filePath, {}, function (err) {
                res.status(404).end(JSON.stringify(constants.ERR.File_Not_Found));
            });
        } catch (ex) {
            res.status(404).end(ex.message);
        }
    });
}

function addPOSTStubs(config, app) {

    app.post('/stubService/*', function (req, res) {
        var reqPath, respPath, x, y;
        try {
            var call_param = req.params[0];
            reqPath = process.cwd() + path.sep + config.stub_dir + path.sep + call_param + '.json';

            /** finds the response path*/
            x = call_param.split('/');
            x[x.length - 1] = 'postresp/' + x[x.length - 1];
            respPath = process.cwd() + path.sep + config.stub_dir + path.sep + x.join('/') + '.json';

            // Writes the request body to the file
            fs.writeFile(reqPath, JSON.stringify(req.body), function (err) {
                if (err) {
                    // NodeJS can create a file, it needs the directory to be present
                    if (err.code === 'ENOENT') {
                        res.status(500).end(JSON.stringify(constants.ERR.ENOENT));
                    } else {
                        res.status(500).end(err.toString());
                    }
                } else {
                    fs.exists(respPath, function (exists) {
                        if (exists) {
                            // If response path exists, send file as response
                            res.sendFile(respPath, {}, function (err) {
                                res.status(404).end(JSON.stringify(constants.ERR.File_Not_Found));
                            });
                        } else {
                            // If reponse path doesn't exists, send success response
                            res.status(200).end(JSON.stringify(constants.SUCCESS));
                        }
                    });
                }
            });
        } catch (ex) {
            res.status(404).end(ex.message);
        }
    });
}

function start(config, app) {
    // Run the application on the port 
    var port = config.server_port;
    if (app.get('env')) {
        port = process.env.PORT || config.server_port;
    }
    // Starts the app
    app.listen(port, function () {
        console.log('App Started at port number ' + port);
    });
}

function createApp() {
    // Creates express app
    var app = express();

    // parse application/x-www-form-urlencoded 
    app.use(bodyParser.urlencoded({
        extended: false
    }));
    // parse application/json 
    app.use(bodyParser.json());

    /**
     * Allows access to all origin
     */
    app.all("*", function (req, res, next) {
        // Specify the origin if you want to control the CORS origin
        res.header('Access-Control-Allow-Origin', '*');
        res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
        res.header('Access-Control-Allow-Headers', 'Content-Type');

        // Uncomment to allow with credentials. You'd need to give specific origin in that case
        //res.header('Access-Control-Allow-Credentials', true);
        next();
    });
    return app;
}

/**
 * Sucess response for all other requests
 * @param {Express} app Express App
 */
function catchAll(app) {
    app.all('*', function (req, res) {
        try {
            res.status(200).end(JSON.stringify(constants.SUCCESS));
        } catch (ex) {
            res.status(404).end(ex.message);
        }
    });
}