require path works in root but not in elsewhere - node.js

Question

Working in Node.js, I am splitting one working snippet into two snippets that produce the same result. The working snippet has a require statement and is in the root directory. The split two segments work at the first stage in the root directory but the second stage fails and reports the eTrade library cannot be found. Here is the require statement.
var etrade = require('./lib/etrade');
When executed from server.js in the root, everything works but in the split project, capturing the variable now appears in index.js in the routes folder and does not work. The client side reports that the eTrade library cannot be found. There is something here I'm not understanding, probably about how to resolve the path specification in the require.
In the meanwhile, I have made the thing work using a global variable that I pass from app.js in the root to index.js in the routes folder. I can continue development this way, but it would be much better if I understood how to make the first variant work.
please edit the question and show your files hierarchy, then show us how you merge the files? which tools you used, and where was the output
server.js runs in the root and works very well.
app.js runs in the root and is part A of the merged system and works.
index.js run in the root/routes folder and is part B of the merged system and fails.
root/lib/eTrade contains the eTrade modules.
The working snippet (server.js) opens a confirmation window on the eTrade site and the user copy/pastes back a confirmation code which is echoed back to the console on the server side. The failing snippet, which is a combination of A and B, refuses to pass the variable (the confirmation code) to B and because it reports a failure to find the eTrade library, I think the problem is the path in the require statement, which is
var etrade = require('./lib/etrade');
The merged system performs the first part of the task but does not pass the variable to the second part of the task and I think that's because the variable in B is outside of scope.
Here is the working snippet:
/*
* Module dependencies
*/
const port = 3000
var express = require('express')
, stylus = require('stylus')
, nib = require('nib')
, logger = require('morgan')
, routes = require('./routes/index')
, users = require('./routes/users')
,app = express()
function compile(str, path) {
return stylus(str)
.set('filename', path)
.use(nib());
}
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
//app.use('/', routes);
//app.use('/users', users);
app.use(logger('dev'));
app.use(stylus.middleware(
{ src: __dirname + '/public'
, compile: compile
}
));
app.use(express.static(__dirname + '/public'))
//from expressSite
// from readme
var etrade = require('./lib/etrade');
var configuration =
{
useSandbox : true, // true if not provided
key : '', //actual value deleted
secret : '' //actual value deleted
}
var et = new etrade(configuration);
//here we send the user a credentials link
et.getRequestToken(
function(authorizationUrl) {
// Your service requires users, who will need to visit
// the following URL and, after logging in and
// authorizing your service to access their account
// data, paste the E*TRADE provided verification
// code back into your application.
app.get('/', function (req, res) {
res.render('AuthApp',
{ authLink : authorizationUrl }
)
});
console.log("AuthorizationURL " + authorizationUrl + " "); },
function(error) {
console.log("Error encountered while attempting " +
"to retrieve a request token: " +
error);
}
); //end getRequestToken
//user sends confirmation code and we get acesss token
app.get('/users/sendcode', function (req, res) {
console.log('verification code is '+req.query.vCode);
//end get verification code
et.getAccessToken(req.query.vCode,
function() {
// Your app can start using other E*TRADE API now
// begin main interaction
// this is where we should land first after oath
// hand it over to the db page?
//et.listAccounts();
//console.log(a);
res.render('ETQuery');
console.log('thread entered getAccessToken function')
// console.log(AccessToken)
},
function(error) {
console.log("Error encountered while attempting " +
"to exchange request token for access token: " +
error);
}
);
})
app.listen(port, (err) => {
if (err) {
return console.log('something bad happened', err)
}
console.log(`CIA is listening to the FSB on ${port}`)
})
Here is the new part A code in app.js in the root. You can see how I've patched it to use a global.
var etrade = require('./lib/etrade');
var configuration =
{
useSandbox : true, // true if not provided
key : '', //actual value deleted
secret : '' //actual value deleted
}
var et = new etrade(configuration);
// here we send the user a credentials link
et.getRequestToken(
function(authorizationUrl) {
// Your service requires users, who will need to visit
// the following URL and, after logging in and
// authorizing your service to access their account
// data, paste the E*TRADE provided verification
// code back into your application.
// app.get('/', function (req, res) {
// res.render('index',
// { authLink : authorizationUrl }
// )
// });
console.log("AuthorizationURL is " + authorizationUrl + " ");
global.ETauthUrl = authorizationUrl;
},
function(error) {
console.log("Error encountered while attempting " +
"to retrieve a request token: " +
error);
}
); //end getRequestToken
But part B does not capture the token. What is odd here is that the failure is reported as to finding the eTrade library, while that library is nowhere referenced in B. In the working snippet, I cannot pass the token beyond server.js yet but I can report it on the server side after the user pastes it in and hits the send button on the client side. Here is B.
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res) {
res.render('index',
{ authLink : ETauthUrl }
)
});
This works only because of the global variable.

Answer 1

The ./... tells NodeJS to load the applicable code from the current directory. This will work in server.js, from the root of the app. However, to properly reference said file from another directory, you'll need to properly reference it's path.
E.g. given:
bootstrap/
├── lib/
│ ├── etrade.js
├── modules/
│ ├── foo.js
| ├── bar/
| ├── bar.js
└── server.js
You'll need to reference etrade in server.js as:
var etrade = require('./lib/etrade');
And in modules/foo.js as:
var etrade = require('../lib/etrade');
And in modules/bar/bar.js as:
var etrade = require('../../lib/etrade');
More on how NodeJS require resolves files.
require(X) from module at path Y
1. If X is a core module, a. return the core module b. STOP
2. If X begins with './' or '/' or '../' a. LOAD_AS_FILE(Y + X) b. LOAD_AS_DIRECTORY(Y + X)
3. LOAD_NODE_MODULES(X, dirname(Y))
4. THROW "not found"
LOAD_AS_FILE(X)
1. If X is a file, load X as JavaScript text. STOP
2. If X.js is a file, load X.js as JavaScript text. STOP
3. If X.json is a file, parse X.json to a JavaScript Object. STOP
4. If X.node is a file, load X.node as binary addon. STOP
LOAD_AS_DIRECTORY(X)
1. If X/package.json is a file, a. Parse X/package.json, and look for "main" field. b. let M = X + (json main field) c. LOAD_AS_FILE(M)
2. If X/index.js is a file, load X/index.js as JavaScript text. STOP
3. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP
4. If X/index.node is a file, load X/index.node as binary addon. STOP
LOAD_NODE_MODULES(X, START)
1. let DIRS=NODE_MODULES_PATHS(START)
2. for each DIR in DIRS: a. LOAD_AS_FILE(DIR/X) b. LOAD_AS_DIRECTORY(DIR/X)
NODE_MODULES_PATHS(START)
1. let PARTS = path split(START)
2. let I = count of PARTS - 1
3. let DIRS = []
4. while I >= 0, a. if PARTS[I] = "node_modules" CONTINUE b. DIR = path join(PARTS[0 .. I] + "node_modules") c. DIRS = DIRS + DIR d. let I = I - 1
5. return DIRS