ExpressJs server along with command line interface - node.js

Question

I'm developing a REST API server using express.js but I would like to allow the developer to issue command trough the command line.
It is a development server that read a config.json, create endpoint and store data in-memory.
I would like to give the developer the ability to reload the base data without restarting the express server.
Any idea?

Answer 1

I just thought of what seems to me like a more elegant solution to your problem that you may be interested in: having the server automatically reload the config.json file whenever it changes. This is trivial to implement in Node.js:
const fs = require("fs"),
path = require("path");
var filePath = path.join(__dirname, "config.json");
fs.watch(filePath, function(event) {
if (event === "change") {
var file = require(filePath); // require loads JSON as a JS object
// do something with the newly loaded file here
console.log("Detected change, config file automatically reloaded.");
}
});

Answer 2

Perhaps a better option would be to add a route to the app like so (since the server will be blocking, and therefore not allow any command-line input on the same process):
"use strict";
const http = require("http"),
path = require("path"),
express = require("express"),
PORT = 8000;
var app = express();
function loadConfigFile(callback) {
var configFile = false;
try { // load config file if it exists
configFile = require(path.join(__dirname, "config.json"));
} catch(e) { // ignore if the config file doesn't exist
if (e.code !== "MODULE_NOT_FOUND") {
throw e
}
}
callback(configFile); // argument will be false if file does not exist
}
function authenticateAdminUser(req) { return true; } // dummy logic
app.get("/admin/reload", function(req, res, next) {
if (!authenticateAdminUser(req)) {
let err = new Error("Forbidden");
err.StatusCode = 403;
return next(err);
}
loadConfigFile(function(file) {
if (file) {
// do something with the file here
}
res.send("Reloaded config file successfully.");
});
});
loadConfigFile(function(file) {
if (file) {
// do something with the file here
}
app.listen(PORT, function() {
console.log("Server started on port " + PORT + ".");
});
});