Returning remote API data within Express app - javascript

I have an express app where I just return data from another remote API. Below is the file snippet. I cannot use normal node-fetch or request as my remote API uses NTLM auth.
const express = require('express');
const router = express.Router();
const httpntlm = require('httpntlm');
const url = 'http://myremoteapi.com/products';
router.get('/', function(req, res, next) {
httpntlm.get(
{
url,
username: 'my_user',
password: 'my_pass
},
(err, resp) => {
if (err) return err;
res.send(JSON.parse(resp.body));
}
);
});
module.exports = router;
Everything works fine.
Now, I'd like to take the remote API call outside the router method in a function called getData.
const express = require('express');
const router = express.Router();
const httpntlm = require('httpntlm');
const url = 'http://myremoteapi.com/products';
const getData = httpntlm.get(
{
url,
username: 'my_user',
password: 'my_pass
},
(err, resp) => {
if (err) return err;
return JSON.parse(resp.body);
}
);
router.get('/', function(req, res, next) {
res.send(getData) // returns undefined
});
module.exports = router;
I am unable to get the same result. Also, I found that the httpntlm method does not return a Promise which I can resolve.

One way to solve this is to create the Promise yourself:
const express = require('express');
const router = express.Router();
const httpntlm = require('httpntlm');
const url = 'http://myremoteapi.com/products';
const getData = () => new Promise((resolve, reject) => {
httpntlm.get({
url,
username: 'my_user',
password: 'my_pass'
},
(err, resp) => {
if (err) reject(err);
else resolve(JSON.parse(resp.body));
}
);
});
router.get('/', function(req, res, next) {
getData().then(data => res.send(data));
});
module.exports = router;
By wrapping httpntlm.get like that it becomes thenable, and by making getData a function the data is fetched anew whenever you call it.

Related

Cannot access variable using await-async function

I tried using Async-Await in NodeJs RESTful API but I seem to get an error I cannot resolve.
Here is my db.js:
const User = require('../models/User'),
user = {};
user.findUserByUsername = async function (username) => {
try {
const user = await User.findOne({username});
if (user)
return {data: user, status: 200};
return {message: `Cannot find user with username: ${username}`, status: 404};
} catch (err) {
return err;
}
};
module.exports = user;
And here is my api.js:
const express = require('express'),
router = express.Router(),
user = require('../db/db');
router.get('/user', async (req, res, next) => {
const user = await user.findUserByUsername(req.query.username);
// ^
// Cannot access 'user' before initialization
if (!user.status)
return next(user);
res.status(user.status);
res.doc = user.status === 404 ? user.message : user.data;
next();
});
module.exports = router;
When making a HTTP request, my server is crashing at that point. Where is my mistake?
You're mixing your variable names up. You have user as an import, but you also have user as a variable you're trying to assign to as a result of findUserByUsername.
Use different variable names, and follow the capitalization convention for this sort of database lookup:
const express = require('express'),
router = express.Router(),
User = require('../db/db');
router.get('/user', async (req, res, next) => {
const user = await User.findUserByUsername(req.query.username);

Express.js why does placement of app.use() affect test results?

I am practicing my knowledge in Express.js .
I have one recipe router with the code below:
const express = require("express");
const router = express.Router();
const Recipe = require("../models/recipe.model");
const createRecipeItem = async recipeData => {
await Recipe.init();
const doc = Recipe(recipeData);
await doc.save();
};
router.post("/", async (req, res, next) => {
try {
await createRecipeItem(req.body);
} catch (err) {
next(err);
}
res.status(201).send(req.body);
});
module.exports = router;
I have another supply router, the code is below:
const express = require("express");
const router = express.Router();
const Supply = require("../models/supply.model");
const createSupplyItem = async supplyData => {
await Supply.init();
const doc = Supply(supplyData);
await doc.save();
};
const updateItem = async (name, itemData) => {
const result = await Supply.findOneAndUpdate({ name }, itemData, {
new: true
});
return result;
};
router.post("/", async (req, res, next) => {
try {
await createSupplyItem(req.body);
} catch (err) {
next(err);
}
const respObj = {};
respObj.name = req.body.name;
respObj.qty = req.body.qty;
res.status(201).send(respObj);
});
router.patch("/:name", async (req, res, next) => {
const updatedItem = await updateItem(req.params.name, req.body);
const response = {};
response.name = updatedItem.name;
response.qty = updatedItem.qty;
res.status(200).send(response);
});
module.exports = router;
I wrote tests for the two routers using supertest
Inside my app.js my code is written like this:
const supplyRouter = require("./routes/supply.route");
const recipeRouter = require("./routes/recipe.route");
app.use("/recipes", recipeRouter);
app.use("/supplies", supplyRouter);
when the code is written like this:
app.use("/recipes", recipeRouter);
app.use("/supplies", supplyRouter);
All my test passed. However, when I change the order of when I call app.use() the test would fail.
app.use("/supplies", supplyRouter);
app.use("/recipes", recipeRouter);
The test would fail with the error Cannot set headers after they are sent to the client for the POST /supplies method. I have no clear understanding why this happens. Appreciate any insight. Thank you!
I cannot pass my test correctly because I didn't have proper understanding of the flow of the code.
router.post("/", async (req, res, next) => {
try {
await createSupplyItem(req.body);
} catch (err) {
next(err);
}
const respObj = {};
respObj.name = req.body.name;
respObj.qty = req.body.qty;
res.status(201).send(respObj);
});
For the above code, when there is an error, express will run two paths of the code namely the path inside the catch block and the last line of the code
res.status(201).send(respObj);
Because it is trying to run two paths, I received the error Cannot set headers after they are sent to the client.
The correct code is written below.
router.post("/", async (req, res, next) => {
try {
await createSupplyItem(req.body);
const respObj = {};
respObj.name = req.body.name;
respObj.qty = req.body.qty;
res.status(201).send(respObj);
} catch (err) {
if (err.name === "ValidationError") {
err.statusCode = 400;
} else if (err.name === "MongoError") {
err.statusCode = 400;
}
next(err);
}
});

How to integrate rate-limiter-flexible in existing node.js express setup?

I use node.js, passport and jwt bearer token to protect my routes. What I don't have yet is rate limiting and blocking of ip/user if too many false attempts. What's the best way to implement it for my setup?
I want to give it a try with rate-limiter-flexible. But how can I integrate e.g. the Login Example from here: https://github.com/animir/node-rate-limiter-flexible/wiki/Overall-example#login-endpoint-protection in my setup below?
helpers/rateLimiter.js
const express = require('express');
const redis = require('redis');
const { RateLimiterRedis } = require('rate-limiter-flexible');
/* What goes here? Example https://github.com/animir/node-rate-limiter-flexible/wiki/Overall-example#login-endpoint-protection doesn't seem to apply */
Those are my routes:
routes/index.js
const express = require('express');
const router = require('express-promise-router')();
const passport = require('passport');
const passLogin = passport.authenticate('local-login', { session: false, failWithError: true });
const { rateLimiter } = require('../helpers/rateLimiter');
...
router.route('/v1/login')
.post( rateLimiter, passLogin, function(err, req, res, next) {
return res.status(401).send({ status: 401, success: false })
}, controller.login );
router.route('/v1/abc/search')
.post( passJWT_ABC, function(err, req, res, next) {
return res.status(401).send({ status: 401, success: false })
}, controller.search );
You should export middleware in this case.
const express = require('express');
const redis = require('redis');
const { RateLimiterRedis } = require('rate-limiter-flexible');
async function loginRoute(req, res) {
// code from example https://github.com/animir/node-rate-limiter-flexible/wiki/Overall-example#login-endpoint-protection
}
export default async (req, res, next) => {
try {
await loginRoute(req, res);
next();
} catch (err) {
res.status(500).end();
}
}
And then you should take care of how authorise(), user.isLoggedIn and user.exists checks work with your application login approach.
There is an example with passport-local, should be useful for you as well https://github.com/passport/express-4.x-local-example/blob/67e0f735fc6d2088d7aa9b8c4eb25bc0052653ec/server-secure.js

Why do I get "is not a function" error?

I want to write my test classes for server app. I need to refactor my routers to controller arch.
I return functions on controller's return value. But on my router I see Error. Do you have any idea? Which point am I passing?
Controller:
const express = require('express');
const controller = (Project) => {
const projectMidlleware = require('../middleware/v1/projectMiddleware')(Project)
const put = (req, res, next) => {
projectMidlleware.create(req.query.name, (project) => {
res.status(200).send(project.api_key);
next();
});
}
const findProject = (req, res, next) => {
const apikey = req.headers["s-apikey"] || req.query.apikey || req.body.apikey;
projectMidlleware.findByApikey(apikey, (err, project) => {
if (err) {
next({
message: err.message,
code: 500
});
return;
}
req.body.project = project;
next();
});
}
return {
put,
findProject
}
}
module.exports = controller;
Router:
const express = require("express");
const router = express.Router();
const projectController = require('../../controllers/projectController');
const profileController = require('../../controllers/profileController');
//return profiles for project
router.get("/",
projectController.findProject(),
profileController.get()
);
module.exports = router;
const projectController = require('../../controllers/projectController')();
You have a function that returns an object with methods but you don't call the function and the methods exist on the returned object, not the function itself. This pattern is fairly common in node but I would actually do this for clarity:
const projectController = require('../../controllers/projectController');
const controller = projectController();
and then use that.

How to pass json object from controller to router?

I have a data in controller from mongodb now i want to send this json object to router so i can send to client side using api , with below code i am getting an error TypeError: Cannot read property 'json' of undefined Any idea what is implemented wrong ?
controller.js
var Diagram = require('./diagram.model');
var mongoose = require('mongoose');
module.exports = function index(req,res) {
Diagram.find({}, function(err, result) {
if (!err) {
console.log('Response from controller', result);
return res.json(result);
}
});
}
router.js
var express = require('express');
var controller = require('./diagram.controller');
var router = express.Router();
console.log('THis is in router',controller.index);
router.get('/getAllDiagram',controller.index);
module.exports = router;
I think the module.exports (see my comment above) is the problem. What do you think about writing your request handling straightforward first (so that you have a feeling of success (: ):
const express = require('express');
const app = express();
app.get('/getAllDiagram', (req, res) => {
Diagram.find({}, function(err, result) {
if (err) {
console.error(`Error in finding diagram: ${err.message}`);
return res.status(500);
}
res.json(result);
});
});
app.listen(8080);
Advanced version
controller.js
const Diagram = require('./diagram.model');
module.exports.index = (req, res) => {
Diagram.find({}, function(err, result) {
if (err) {
console.error(`Error in finding diagram: ${err.message}`);
return res.status(500);
}
res.json(result);
});
};
router.js
const express = require('express');
const controller = require('./controller');
const router = express.Router();
router.get('/getAllDiagram', controller.index);
module.exports = router;
app.js
const express = require('express');
const router = require('./router');
const app = express();
app.use(router);
app.listen(8080);
Important: Please check the module.exports.index declaration. That was wrong in your code snippet.

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