Loading Node.js modules dynamically based on route

Question

I\'m doing a project in Node.js using express. Here\'s my directory structure:

root
|-start.js
|-server.js
|-lib/
|    api/
|        user_getDetails.js
|             


        

Answer 1

If you know where your scripts are, i.e. you have an initial directory, for example DIR, then you can work with fs, for example:

server.js

var fs = require('fs');
var path_module = require('path');
var module_holder = {};

function LoadModules(path) {
    fs.lstat(path, function(err, stat) {
        if (stat.isDirectory()) {
            // we have a directory: do a tree walk
            fs.readdir(path, function(err, files) {
                var f, l = files.length;
                for (var i = 0; i < l; i++) {
                    f = path_module.join(path, files[i]);
                    LoadModules(f);
                }
            });
        } else {
            // we have a file: load it
            require(path)(module_holder);
        }
    });
}
var DIR = path_module.join(__dirname, 'lib', 'api');
LoadModules(DIR);

exports.module_holder = module_holder;
// the usual server stuff goes here

Now your scripts need to follow the following structure (because of the require(path)(module_holder) line), for example:

user_getDetails.js

function handler(req, res) {
    console.log('Entered my cool script!');
}

module.exports = function(module_holder) {
    // the key in this dictionary can be whatever you want
    // just make sure it won't override other modules
    module_holder['user_getDetails'] = handler;
};

and now, when handling a request, you do:

// request is supposed to fire user_getDetails script
module_holder['user_getDetails'](req, res);

This should load all your modules to module_holder variable. I didn't test it, but it should work (except for the error handling!!!). You may want to alter this function (for example make module_holder a tree, not a one level dictionary) but I think you'll grasp the idea.

This function should load once per server start (if you need to fire it more often, then you are probably dealing with dynamic server-side scripting and this is a baaaaaad idea, imho). The only thing you need now is to export module_holder object so that every view handler can use it.