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Express/Postgres User registration controller

To simplify the situation I'll just post the following controller for an express route which interactions with a Postgres Database. My question is about error handling. If an error occurs it will be caught within the catch clause. But how can I access the errors thrown by the database queries itself. If I make several await several queries and one of them fails I need probably to restore stuff in the database? For example if the insertion of the user in the user table is a success, but the following query of inserting the user in another table fails, I need to delete the user from the user table again. How does one model such flows?
//
// Register User
//
export const registerUser = async (request, response, next) => {
try {
const usersWithSameMail = await client.query(`SELECT * FROM public.users WHERE email = '${user.email}'`);
if(usersWithSameMail.rows.length > 0){
return response.status(403).json({"code": "ERROR", "message": "Email is already registered"})
} else {
await client.query(`
INSERT INTO public.users(first_name, last_name, email, password)
VALUES ('${user.first_name}', '${user.last_name}', '${user.email}', crypt('${user.password}', gen_salt('bf', 8)));
`);
// more await statements...
return response.status(200).json({"code": "INFO", "message": "Verification mail sent to user"});
}
} catch (error) {
return response.status(500).json({"code": "ERROR", "message": "Error occured while registering the user. Please try again."});
}
}```

You can use middlewares chaining your routes handler. In order to it work, you will have to change your current working code to use Single-responsibility principle. Do only one responsability per middleware and chain all handlers to work as one.
Lets say you want to insert new user, to perform this operation we should:
lookup if email is unique
hash password
Insert new user
return inserted data in postgres back as a response
Following the middleware chaining we should implement a function for each action and chain each action in route definition:
const postgres = require('../../lib/postgres');
const crypto = require('crypto');
exports.insertedData = (req, res) => {
res.status(200).json(req.employee);
};
exports.hashPassword = (req, res, next) => {
crypto.scrypt(req.body.password.toString(), 'salt', 256, (err, derivedKey) => {
if (err) {
return res.status(500).json({ errors: [{ location: req.path, msg: 'Could not hash password'}] });
}
req.body.kdfResult = derivedKey.toString('hex');
next();
});
};
exports.lookupEmailUnique = (req, res, next) => {
const sql = 'SELECT e.email FROM public.users e WHERE e.email=$1';
postgres.query(sql, [req.body.email], (err, result) => {
if (err) {
return res.status(500).json({ errors: [{ location: req.path, msg: 'Could not query database' }] });
}
if (result.rows.length > 0) {
return response.status(403).json({"code": "ERROR", "message": "Email is already registered"})
}
next()
});
}
exports.insertNewUser = (req, res, next) => {
const sql = 'INSERT INTO public.users(first_name, last_name, email, password) VALUES ($1,$2,$3,$4} RETURNING *';
postgres.query(sql, [req.body.first_name, req.body.last_name, req.body.email, req.body.kdfResult], (err, result) => {
if (err) {
return res.status(500).json({ errors: [{ location: req.path, msg: 'Could not query database'}] });
}
req.employee = result.rows[0];
next();
});
};
here is your route declaration:
const router = require('express').Router();
const userService = require('../controllers/user.controller');
router.post('/register', userService.lookupEmailUnique, userService.hashPassword, userService.insertNewUser, userService.insertedData);
module.exports = router;
Here in routes you are using the middeware to do the chaning, you only pass the control to next middleware if all conditions are met and has full control from database erros.
In my example I do not used the async/await but I can change my example to have a version using async/await.
example middleware with transaction
exports.deletePostagem = async (req, res, next) => {
try {
await postgres.query('BEGIN');
const sql2 = 'UPDATE comentario SET postagem = null WHERE postagem = $1';
await postgres.query(sql2, [req.params.id]);
const sql3 = 'DELETE FROM postagem WHERE id = $1';
await postgres.query(sql3, [req.params.id]);
await postgres.query('COMMIT');
res.status(204).json();
res.end();
} catch (err) {
await postgres.query('ROLLBACK');
return res.status(500).json({ errors: [{msg: 'Could not perform operation' }]})
}
}
I used this only as an example, but in my projects I always have a middeware for validate/sanitize the data that comes in request before using in database query prepared statements.

based on transaction documentation in node.js you can use rollback
export const registerUser = async (request, response, next) => {
try {
let error = null;
const client; // create a client, connect to the db
try {
await client.query("begin");
await client.query("first query");
await client.query("second query");
await client.query("third query");
await client.query("commit"); //do commit when is finished all queries
} catch (error) {
error = error;
await client.query("rollback");
} finally {
client.release(); // close the connection
}
if (error) {
return response.status(500).json({ message: error }); // error message
}
return response.status(200).json({ message: "My message" }); // success message
} catch (err) {
return response.status(500).json({ message: err });
}
}

res.json not returning response

My res.json in my first block of code works, but in the else part of my if statement, it does not. The block that doesnt work, checks for a record in a database then im trying to return the response but im not receiving it.
I've checked and the response is a string, I thought it would have worked as the top part of the code successfully returns the string and it shows in dialogflow (where im trying to return it)
The response is successfully consoled right before the res.json but I do not receive it from the source of the request.
code:
app.post('/webhook/orderinfo', (req, res) => {
const intent = req.body.queryResult.intent.displayName;
const domain = "chatbotdemo.myshopify.com";
const order = req.body.queryResult.parameters["number-sequence"];
if (intent.includes('Order Number')) {
url = "https://test-hchat.com/api/orders/" + domain + "/" + order;
request(url)
.then(function (response) {
order_res = JSON.parse(response)
order_res["fullfillmentText"] = "Hi, Please find your order details below:";
res.json({
"fulfillmentText": JSON.stringify(order_res)
})
})
.catch(function (err) {
console.log(err)
});
// THIS PART DOESNT RETURN THE RESPONSE.
} else {
const domain = 'testStore'
db.getClientsDialog(domain, intent, (response) => {
const fullResponse = response.response
res.json({
fullResponse
})
})
}
});
The database code:
getClientsDialog: function (domain, intent, callback) {
MongoClient.connect('mongodb://efwefewf#wefwef.mlab.com:15799/wefwef', function (err, client) {
if (err) throw err;
var db = client.db('asdsad');
db.collection('dialog').findOne({ domain: domain, intent: intent }, function (err, doc) {
if (!err) {
callback(doc)
} else {
throw err;
callback(err)
}
client.close();
});
console.dir("Called findOne");
});
}
Could it be because this second use of the res.json in the else statement, is trying to call the db first and therefore the link is lost to send the data back?

Delete object by Id using mongoose

I'm trying to create API to delete document on mongodb using mongoose.
Here's my route
router
.route("/tasks")
.delete('/:id', function (res, err) {
taskSchema.findByIdAndRemove(req.params.id, (err, tasks) => {
if (err) return res.status(500).send(err);
const response = {
message: "Todo successfully deleted",
id: req.params.id
};
return res.status(200).send(response);
});
});
I get this error
Error: Route.delete() requires a callback function but got a [object String]

/tasks and /tasks/:id are two different routes and you should handle them as such, if you use /tasks to display all tasks, make a route for that, and make a second route for every interaction that you already have an ID for; aka deleting, updating, and use the route without the ID for interactions you don't have an ID for, like creating tasks:
router
.route("/tasks")
.get(/* return all tasks */)
.post(/* create a task */);
router
.route("/tasks/:id")
.delete(function (req, res) {
taskSchema.findByIdAndRemove(req.params.id, (err, tasks) => {
if (err) return res.status(500).send(err);
const response = {
message: "Todo successfully deleted",
id: req.params.id
};
return res.status(200).send(response);
});
});

ExpressJS variable undefined

I have an ExpressJS app that when a user makes a POST request to a route, it should lookup the ID in the MongoDB using req.params.formId
I have some console.log statements tfor debugging and so I can see what info is being returned.
The route should lookup the ID passed and when it finds it, use the req.body data and also a field from the MongoDB document but this just seems to return as undefined
Here is the code for the route:
app.post("/api/v1/forms/:formId", (req, res) => {
const { name, email, message } = req.body;
console.log(req.body);
Form.findById(req.params.formId, Form.recipient, err => {
if (err) {
res.send(err);
} else {
const formRecipient = Form.recipient;
const newForm = {
name,
email,
message,
recipient: formRecipient
};
console.log(newForm);
const mailer = new Mailer(newForm, contactFormTemplate(newForm));
try {
mailer.send();
res.send(req.body);
} catch (err) {
res.send(err);
}
}
});
});
So an example, if I make a POST request to localhost:5000/api/v1/forms/5ad90544883a6e34ec738c19 the console.log of newForm shows { name: ' Mr Tester',
email: 'person#example.com',
message: 'Hi there',
recipient: undefined }
The forms Mongoose schema has a field named recipient

the correct way is to provide the fields you want to get as the second argument:
Form.findById(req.params.formId, 'recipient', (err, form) => {
if (err) {
// error handling code
} else {
const formRecipient = form.recipient;
}
...
});
here's the Docs

Having issues editing an existing DB entry with Sails and Waterline

I'm using SailsJS as an API with Waterline connected to a MongoDB. I'm trying to put together an endpoint to edit existing DB entries but can't seem to get it to work and I'm hitting a wall as to why.
My route:
'post /edit/safety/:id': {
controller: 'SafetyController',
action: 'editSafety'
},
My controller function:
editSafety: function editSafety(req, res) {
var id = req.params.id;
Safety.findOneById(id).then((err, safety) => {
if (err) {
res.send(500, err);
return;
}
if (!safety) {
res.send(404, err);
return;
}
safety.title = req.body.title;
safety.description = req.body.description;
safety.status = req.body.status;
safety.save((err, updatedSafety) => {
if (err) {
re.send(500, err);
return;
}
res.send(200, updatedSafety);
});
});
},
Any push in the right direction would be greatly appreciated.

I don't recognize the Safety.findOneById method - is this something you have custom built? If not, then it is likely your problem.
Try swapping it for either:
Safety.findOne(id)
or
Safety.findOne({id: id})
Note that the returned object will be a model instance if the record exists, and undefined otherwise. If you decide to go with Safety.find instead then the returned value will be an array containing all models matching the query.

Looks like the main issue was transposing the response and err objects. It was successfully completing the query, but loading it into the err object which gets caught and a 500 error is thrown. So I changed that and simplified in a few other places.
editSafety: function editSafety(req, res) {
var id = req.params.id;
Safety.findOne(id).then((response, err) => {
var safety = response;
if (err) {
res.send(500, err);
return;
}
if (!response) {
res.send(404, err);
return;
}
safety.title = req.body.title;
safety.description = req.body.description;
safety.status = req.body.status;
Safety.update({
id: id
}, safety)
.then((result) => {
res.json(200, 'Ok!');
})
.catch((err) => {
sails.log.error('SafetyController.editSafety', err);
})
});
},