Passing req.params around in Node MVC - javascript

I'm trying to figure out how to pass req.params around using Express in the context of MVC.
I know how to properly reference req.params but when I split my app.js up into models and controllers I'm quite lost.
Code for reference:
routes.js
app.get('/category/:category', descriptor.getSingleCategory)
model.js
let getSingleCat = (cb) => {
let queryString = 'SELECT * FROM categories WHERE category_id = $1'
let queryValue = [req.params.category]
db.query(queryString, queryValue, cb)
}
controller.js
const getSingleCategory = (req, response) => {
console.log(req.params.category);
db.desc.getSingleCat((err, queryRes) => {
if (err) {
//render something went wrong
response.send('something went wrong')
} else {
response.send(queryRes.rows)
}
})
}
I've checked all requires and they are working correctly. Is there a vanilla way of passing req.params around without using middleware?

The only way to use the req.params in the model, is by sending it as parameters as the following example:
model.js
let getSingleCat = (params, cb) => {
let queryString = 'SELECT * FROM categories WHERE category_id = $1'
let queryValue = params.category
db.query(queryString, queryValue, cb)
}
controller.js
const getSingleCategory = (req, response) => {
console.log(req.params.category);
db.desc.getSingleCat(req.params, (err, queryRes) => {
if (err) {
//render something went wrong
response.send('something went wrong')
} else {
response.send(queryRes.rows)
}
})
}
You can't use global vars, so this is the only way to do it. Also, this variable (req) can only be accessed in the functions bound to an endpoint that will receive an actual request.

Related

Unhandled Rejection (SyntaxError): Unexpected end of JSON input with Get request fetch

I am trying to do a MVC architecture tutorial from Codecademy's website: https://www.codecademy.com/article/mvc-architecture-for-full-stack-app
I finished the tutorial but when I run everything, I get this error:
It seems that what I'm returning is not valid JSON. So I think the problem is that the endpoint may be causing the error. But I'm not too sure. Here is the code where the error is triggered:
src/utils/index.js:
export const fetchExpenses = async (date) => {
const selectDate = new Date(date).getTime() || new Date().getTime();
const res = await fetch(`/api/expense/list/${selectDate}`);
console.log('result',res);
return res.json();
};
Here is the code from app.js in the "view" portion of my code:
useEffect(() => {
// update view from model w/ controller
fetchExpenses().then((res) => setExpenses(res));
}, []);
It seems the problem is the communication between the view and the controller. When I create an expense, it actually is updated in the database:
Any ideas why this error is happening?
Edit 1:
Here is the network response when I try to create a new expense in my application. So it seems that when I create a new expense, the fetchExpenses() is automatically called to display a list of current expenses.
this the raw response I get from fetchExpenses() :
Edit 2:
Here is what the header shows from the response:
The endpoint is causing the error, but I'm not sure why. Here is the endpoint:
export const createExpense = async (data) => {
const res = await fetch(`/api/expense/create`, {
method: 'POST',
body: data,
});
return resHandler(res, 201);
};
and here is resHandler() which createExpense() returns:
export const resHandler = async (res, status) => {
if (res.status === status) {
return null;
}
const data = await res.json();
if (data && data.emptyFields) {
return data.emptyFields;
}
return null;
};
Here is the code from the controller when an expense is created:
exports.create = (req, res) => {
const form = new formidable.IncomingForm();
form.keepExtensions = true;
form.parse(req, async (err, fields) => {
const { title, price, category, essential, created_at } = fields;
// check for all fields
if (fieldValidator(fields)) {
return res.status(400).json(fieldValidator(fields));
}
try {
const newExpense = await pool.query(
'INSERT INTO expenses (title, price, category, essential, created_at) VALUES ($1, $2, $3, $4, $5)',
[title, price, category, essential, created_at]
);
return res.status(201).send(`User added: ${newExpense.rows}`);
} catch (error) {
return res.status(400).json({
error,
});
}
});
};
Edit 3
Here is the route /api/expense/list/{dateTime}:
const express = require('express');
const router = express.Router();
const { create, expenseById,
read, update, remove, expenseByDate } = require('../controllers');
router.get('/expense/list/:expenseDate', expenseByDate, read);
module.exports = router;
And here is my controllers.js that deal with the route above:
exports.expenseByDate = async (req, res, next, date) => {
try {
const expenseQuery = await pool.query(
'SELECT * FROM expenses WHERE created_at BETWEEN $1 AND $2',
[
startOfDay(new Date(Number(date))).toISOString(),
endOfDay(new Date(Number(date))).toISOString(),
]
);
const expenseList = expenseQuery.rows;
req.expense =
expenseList.length > 0
? expenseList
: `No expenses were found on this date.`;
return next();
} catch (error) {
return res.status(400).json({
error,
});
}
};
exports.read = (req, res) => res.json(req.expense);
The reason you are getting an Unhandled Rejection (SyntaxError): Unexpected end of JSON input error is because your client app is expecting a JSON response and the express app /api/expense/list/{dateTime} route is not returning valid JSON.
The app is not returning valid JSON because the expenseByDate controller callback has an incorrect function signature so it is not getting called.
exports.expenseByDate = async (req, res, next, date) => <-- "date" is not a valid parameter.
This leads the read controller to return an undefined value to the json response.
exports.read = (req, res) => res.json(req.expense); <-- req.expense is undefined.
res.json(undefined) ultimately returns an empty response to the client which can't be parsed and thus an error is thrown.
Solution
You can fix this error by correcting the expenseByDate controller to have a valid function signature by removing the fourth method parameter. To access a route parameter you should use req.params.
exports.expenseByDate = async (req, res, next, date) => {
const date = req.params.expenseDate;
...
}

Mock a middleware function using jest

This is my middleware,
export const parseUser = (req, res, next) => {
const token_header = req.header('Authorization');
if (token_header) {
req.user = jwt_decode(token_header.split(' ')[1].split(' ')[0]);
req.token = token_header.split(' ')[1].split(' ')[0];
next();
} else {
next();
}
};
this is my router,
router.get('/get/', parseUser, swaggerValidation.validate,
async(req, res) => {
...
} catch (err){
...
}
});
i am trying to mock the parseUser function and assign req.user and req.token values using jest and pass it, i need those values to authorize user and need the value assigned to do database query, I am using jest to mock the functions, I have tried google and stackoverflow, i was not able to solve it with those example, i have tried below methods and others,
jest.mock('../../utils/permission');
const mockedParseUser = jest.mocked(parseUser, true)
mockedParseUser.mockReturnValueOnce({req.user: "value", req.token: "value");
i have also tried,
const return = {req.user: "value", req.token: "value"}
const mockedReturn = jest.fn((): any => return}
jest.spyOn('../../utils/permission', parseUser).mockImpementation((): any => mockReturn())
Nothing worked for me, can someone help me with mocking the parseUser().

How to check whether request url params are not null in node js app?

I am new to node js programming and trying to develop an API using node js, I am able to retrieve the expected output from the built API but I would like to perform some exception handling. For that I would like to check whether the request params coming from URL are not null. Below is my code:
async function getDetails(input) {
// using knex to execute query
return queries.getbymultiwhere('table_name',{
name:input.name,
id:input.id,
role:input.role
})
}
router.get('/:name/:id/:role',(req,res)=>{
getDetails({
name:req.params.name,
id:req.params.id,
role:req.params.role}).then(Results=>{ Do something with results}
})
In above code I want to check that name, id and role param values are not null.
Any helpful solution will be appreciated.
Thank you!
You can create a middleware which checks those parameters.
function check(fields) {
return (req, res, next) => {
const fails = [];
for(const field of fields) {
if(!req.query[field]) {
fails.push(field);
}
}
if(fails.length > 0){
res.status(400).send(`${fails.join(',')} required`);
}else{
next();
}
};
}
app.get('/api', check(['name', 'id', 'role']), (req, res) => {
getDetails()...
});

Adding multiple BigQuery JSON credential files in Node project

I've been working on a Node project that involves fetching some data from BigQuery. Everything has been fine so far; I have my credential.json file (from BigQuery) and the project works as expected.
However, I want to implement a new feature in the project and this would involve fetching another set of data from BigQuery. I have an entirely different credential.json file for this new dataset. My project seems to recognize only the initial credential.json file I had (I named them differently though).
Here's a snippet of how I linked my first credential.json file:
function createCredentials(){
try{
const encodedCredentials = process.env.GOOGLE_AUTH_KEY;
if (typeof encodedCredentials === 'string' && encodedCredentials.length > 0) {
const google_auth = atob(encodedCredentials);
if (!fs.existsSync('credentials.json')) {
fs.writeFile("credentials.json", google_auth, function (err, google_auth) {
if (err) console.log(err);
console.log("Successfully Written to File.");
});
}
}
}
catch (error){
logger.warn(`Ensure that the environment variable for GOOGLE_AUTH_KEY is set correctly: full errors is given here: ${error.message}`)
process.kill(process.pid, 'SIGTERM')
}
}
Is there a way to fuse my two credential.json files together? If not, how can I separately declare which credential.json file to use?
If not, how can I separately declare which credential.json file to use?
What I would do I would create a function which is the exit point to BigQuery and pass an identifier to your function which credential to generate, This credential will then be used when calling BigQuery.
The below code assume you changed this
function createCredentials(){
try{
const encodedCredentials = process.env.GOOGLE_AUTH_KEY;
To this:
function createCredentials(auth){
try{
const encodedCredentials = auth;
And you can use it like this
import BigQuery from '#google-cloud/bigquery';
import {GoogApi} from "../apiManager" //Private code to get Token from client DB
if (!global._babelPolyfill) {
var a = require("babel-polyfill")
}
describe('Check routing', async () => {
it('Test stack ', async (done, auth) => {
//Fetch client Auth from local Database
//Replace the 2 value below with real values
const tableName = "myTest";
const dataset = "myDataset";
try {
const bigquery = new BigQuery({
projectId: `myProject`,
keyFilename: this.createCredentials(auth)
});
await bigquery.createDataset(dataset)
.then(
args => {
console.log(`Create dataset, result is: ${args}`)
})
.catch(err => {
console.log(`Error in the process: ${err.message}`)
})
} catch (err) {
console.log("err", err)
}
})
})

Asynchronous callbacks in JavaScript

PHP dev here, I'm wrestling with NodeJS for a while and I still can't wrap my head around the idea of asynchrony is JS/Node.
Look at this (ExpressJS):
router.get('/:id', function (req, res, next) {
var id = req.params.id;
var db = new Firebase('some_firebase_db');
db.child("users/"+id).once('value', function (snapshot) {
var user = snapshot.val();
if (user) {
db.child("messages/"+id).once('value', function (snapshot) {
res.render('user/messages', {
'user': user,
'messages': snapshot.val()
});
});
} else {
res.render('404');
}
});
});
To make database value accessible for a res object I need to render views inside the fetching data callbacks.
So when I need, say, make 6 requests to my DB I will have to embed my res object in 6 callbacks?
Or is there different approach that will make the code more readable keeping it asynchronous?
Ultimately, I need a way to fetch data from db multiple times in one request that will not make my code look like Christmas tree.
You can make it more readable even without using async or Promise:
router.get('/:id', function(req, res, next) {
var id = req.params.id;
var db = new Firebase('some_firebase_db');
db.child("users/" + id).once('value', userResult);
function userResult(snapshot) {
var user = snapshot.val();
if (user) {
db.child("messages/" + id).once('value', messageResult);
} else {
res.render('404');
}
}
function messageResult(snapshot) {
res.render('user/messages', {
'user': user,
'messages': snapshot.val()
});
}
});
But using async or Promise would be a better solution.

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