forEach not working as expected in NodeJs - javascript

I am uploading the excel sheet in DB with the help of Nodejs, I am unable to authenticate and return the error as already exists the userid when the item.USER_ID already exists in DB. my server goes crashes and returns an error as Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
Please help in the code how I fix this issue and make it, If the item.USER_ID already exists return error else insert.
var XLSX = require("xlsx");
const fs = require("fs");
try {
const transaction = await con.transaction();
var workbook = XLSX.readFile("myfile.xlsx");
let json_data = XLSX.utils.sheet_to_json(workbook.Sheets.Sheet1);
let count = 0;
json_data.map(async (item) => {
let stmt1 = await con.query("SELECT * FROM `table` WHERE `user_id` = :userid", { replacements: { userid: item.USER_ID }, type: con.QueryTypes.SELECT });
if (stmt1.length > 0) {
await transaction.rollback();
return res.json({ message: "already exist the userid" });
} else {
let stmt2 = await con.query("INSERT INTO `table` (`user_id` , `user_name`) VALUES ( :user_id , :user_name)", {
replacements: {
user_id: item.USER_ID,
user_name: item.USER_NAME,
},
type: con.QueryTypes.INSERT,
transaction: transaction,
});
count++;
if (count == json_data.length) {
await transaction.commit();
return res.json({ message: "file uploaded successfully.." });
}
}
});
} catch (err) {
await transaction.rollback();
return res.json({ code: 500, message: { msg: "SQL ERROR" }, error: err.stack, status: "error" });
}

Here in your code, you are calling the res.json({ message: "file uploaded successfully.." }) inside json_data.map function.
since you are calling the res.json function inside an array, it'll be called as many times as of elements present in the array and as we know, we can sent only 1 response at a time for a request.
Because of which you're catching the errors Cannot set headers after they are sent to the client
just remove that res.json inside the map function, add it at the last of that particular map function.
I know you might question for the condition count == json_data.length you added to the code but javascript is async and this particular block can be executed before to that.
Hope this answer helps you! Please comment if you get any errors or have questions.

Related

React: TypeError Cannot read properties of undefined (reading '0')

I am working on a React App, and i'm trying to get some data using an axios GET request from my node backend.
the Api Endpoint i'm currently using that regard this problem is the following:
// NodeJS Backend
app.get('/v1/companys/user/:user_uuid', verify, (req, res) => { // GET - Company by User UUID
const selectQuery = 'SELECT * FROM companys WHERE uuid = (SELECT company_uuid FROM users WHERE uuid = ?)';
connection.query(selectQuery, [req.params.user_uuid], (err, results) => {
if(err) {
res.send(err)
} else if (results.length === 0) {
res.json({status: 404, message: 'Company not found'})
} else {
res.json({data: results})
}
});
});
This is my Front End:
// ReactJS FrontEnd
const companyLogo = userCompany ? userCompany.logo_url : null;
console.log(userCompany);
useEffect(() => {
const getUserCompany = async () => {
try {
await axios.get(process.env.REACT_APP_API_URL + 'companys/user/' + userUuid).then((response) => {
console.log("response "+ response);
let res = response.data.data[0];
console.log(res);
setUserCompany(res);
});
} catch (error) {
console.log(error);
}
};
getUserCompany();
}, [userUuid]);
There app works fine, but on the console the following error appear:
The object below the error is in fact the thing that i need (companyLogo)
I was wondering if someone know what am I doing wrong on my frontend to fix the TypeError.
Thanks for the help!
If you use optional chaining (?.) to catch possible null/undefined values, you'll most likely fix the issue.
So like this: let res = response.data.data?.[0];

recursive calls in Javascript API (Promises)

I am trying to fetch data from one MongoDB collection and with that result, I am passing that value into another function to get the data from GridFS files for same id.
router.get('/employee/:id', async(req,res) =>{
let gID = req.params.id;
var getUser = await User.find({id:gID});
//console.log(res);
console.log(getUser);
if(getUser){
try{
gfs.files.find({objectID:getUser.id}).toArray(async (err, files) => {
if (!files || files.length === 0) {
res.send({
message: "No User Found",
});
} else {
res.send({
message: "data fetched",
data: getUser,
image: files
});
}
});
}catch(err){
res.send({
message:err.code,
data:err
});
}
}else{
res.send({
message:"error in getting the data",
});
}
})
I tried of this but I am not able to get the expected result, I am getting the user information from getUser but I am not able to fetch the file tagged with that user from GridFS. Can anyone tell me where I am lagging and how could I correct this.

How to get data with just inserted data with Sequelize in PostgreSql?

I want to get updated table values after I add user to my "WOD" table. For instance, I have 2 users in my WOD table and after I add third user , I want to return a response to client with I have just inserted data (third guy). But now , I can only return first 2 users because I can not take updated values. Of course I can make another query to get updated table values after I insert, but is there any better solution ? Here is my codes;
const addUser = async (req, res) => {
try {
const { userId, wodId } = req.body;
if (!userId || !wodId) {
res.status(400).send({ status: false, message: 'need userId and wodId' });
}
const wod = await Wod.findByPk(wodId, {
include: [
{
model: User,
as: 'Participants',
through: { attributes: [] }
}
]
});
//check capacity if full.
if (wod.Participants.length >= wod.capacity) {
res
.status(403)
.send({ status: false, message: 'Capacity of this class is full!' });
}
const result = await wod.addParticipants(userId);
res.status(201).json({ status: !!result, wod });
} catch (error) {
res.status(500).send({ status: result, message: error.message });
console.log(error.message);
}
};
As a result of many-to-many association sequelize.sync will generate some functions for us. You are used addParticipants function and this returns an array that added to the assocation(userwod) table.
In this array you will find some id fields(join table fields) because you just run like this INSERT INTO 'user_wods' ('user_id''wod_id') VALUES (2,1). If you want to return the added user's information then you should run a SELECT * FROM 'user' WHERE 'id'=2.
You must call reload function for fetch the third guy.
await wod.reload()

Wait for AWS SNS publish callback to return a value to calling method

I am attempting to send a text message when a user requests to reset their password. I would like to wait for the message to be sent to alert the user if it was successful or not. I am currently attempting to do it as follows:
async function sendResetPasswordTextMessage(req, res) {
let result = {};
let phoneNumber = req.body.phoneNumber;
if (phoneNumber === undefined) {
return sendInvalidParametersMessage(res);
}
phoneNumber = phoneNumber.toString();
const userProfile = await models.UserProfile.findOne({
where: {
phoneNumber: phoneNumber
}
});
************************** RELEVANT CODE TO ISSUE *************************
if (userProfile) {
const message = "Your username is:\n" + userProfile.username;
const sent = await AWSSNSClient.sendMessage(message, phoneNumber);
if (!sent) {
result.error = setTitleAndMessage("Error", "An error occurred");
} else {
result.success = setTitleAndMessage("Success", "Message sent");
}
}
return res.send(result);
***************************************************************************
}
In my other class AWSSNSClient, I have the following sendMessage function:
function sendMessage(message, phoneNumber) {
const params = {
Message: message,
MessageStructure: "string",
PhoneNumber: "+1" + phoneNumber
};
let sent = false;
sns.publish(params, function(err, data) {
if (err) {
console.log(err, err.stack); // an error occurred
}
else {
sent = true;
}
});
return sent;
}
I cannot figure out how to make sendMessage wait for sns.publish to return before it returns itself. I have tried making it an async method and adding await on sns.publish, but the function still returns before sent gets set to true.
I know that the messages are sending without error because I am receiving them and no console logs are printed.
Stumbled on this one via Google trying to figure this out myself today - short answer that I am now using:
You can now do this with Async/Await — and Call the AWS service (SNS for example) with a .promise() extension to tell aws-sdk to use the promise-ified version of that service function (SNS) instead of the call back based version.
The only caveat here is the containing function must ALSO be async to utilize the await syntax.
For example:
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn
}, async function (err, data) {
if (err) {
console.log("SNS Push Failed:");
console.log(err.stack);
return;
}
console.log('SNS push suceeded: ' + data);
return data;
}).promise();
The important part is the .promise() on the end there. Full docs on using aws-sdk in an async / promise based manner can be found here: https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/using-promises.html
In order to run another aws-sdk task you would similarly add await and the .promise() extension to that function (assuming that is available).
For anyone who runs into this thread and is actually looking to simply push multiple aws-sdk promises to an array and wait for that WHOLE array to finish (without regard to which promise executes first) I ended up with something like this:
let snsPromises = [] // declare array to hold promises
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn
}, async function (err, data) {
if (err) {
console.log("Search Push Failed:");
console.log(err.stack);
return;
}
console.log('Search push suceeded: ' + data);
return data;
}).promise();
snsPromises.push(snsResult)
await Promise.all(snsPromises)
Hope that helps someone that randomly stumbles on this via google like I did!
stackdave will that actually wait?
Necevil "Search push suceeded will get logged twice" because you're mixing calling operations by passing a callback and using promises. You should only use one method of getting the result
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn}).promise()
will do the trick
You can simply use callbacks for that. Modify your sendMessge like this
function sendMessage(message, phoneNumber, cb) {
const params = {
Message: message,
MessageStructure: "string",
PhoneNumber: "+1" + phoneNumber
};
sns.publish(params, cb);
}
then on your main file you can supply callback like this
if (userProfile) {
const message = "Your username is:\n" + userProfile.username;
AWSSNSClient.sendMessage(message, phoneNumber, (err, data) => {
if (err) {
result.error = setTitleAndMessage("Error", "An error occurred");
}
else {
result.success = setTitleAndMessage("Success", "Message sent");
}
res.send(result);
});
}
Here the right updated API, August 2018, Necevil answer send the sms twice.
// using config.env
AWS.config.region = 'eu-west-1';
AWS.config.update({
accessKeyId: process.env.AMAZON_SMS_ID,
secretAccessKey: process.env.AMAZON_SMS_TOKEN,
});
// parameters
let params = {
Message: contentSMS, // here your sms
PhoneNumber: mobile, // here the cellphone
};
const snsResult = await sns.publish(params, async (err, data) => {
if (err) {
console.log("ERROR", err.stack);
}
console.log('SNS ok: ' , JSON.stringify (data));
});
If you're having issues with duplicate SNS messages being sent, I fixed this issue by utilizing examples from AWS:
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set region
AWS.config.update({region: 'REGION'});
// Create publish parameters
var params = {
Message: 'MESSAGE_TEXT', /* required */
TopicArn: 'TOPIC_ARN'
};
// Create promise and SNS service object
var publishTextPromise = new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise();
// Handle promise's fulfilled/rejected states
publishTextPromise.then(
function(data) {
console.log("Message ${params.Message} send sent to the topic ${params.TopicArn}");
console.log("MessageID is " + data.MessageId);
}).catch(
function(err) {
console.error(err, err.stack);
});
By utilizing a traditional .then() I was able to squash the duplicate message bug mentioned in comments above.
You can create a async function what use the promise method
async function sendMessage(message, phoneNumber){
const params = {
Message: message,
PhoneNumber: phoneNumber
};
return new Promise((resolve, reject) => {
SNS.publish(params, (err, data) => {
if (err) {
console.log("Search Push Failed:");
console.log(err.stack);
return reject(err);
} else {
console.log('Search push suceeded:' + phoneNumber);
return resolve(data);
}
})
});
}
and then you can call
var s= await sendMessage(message,phoneNumber);

Mongoose - Create document if not exists, otherwise, update- return document in either case

I'm looking for a way to refactor part of my code to be shorter and simpler, but I don't know Mongoose very well and I'm not sure how to proceed.
I am trying to check a collection for the existence of a document and, if it doesn't exist, create it. If it does exist, I need to update it. In either case I need to access the document's contents afterward.
What I've managed to do so far is query the collection for a specific document and, if it's not found, create a new document. If it is found, I update it (currently using dates as dummy data for this). From there I can access either the found document from my initial find operation or the newly saved document and this works, but there must be a better way to accomplish what I'm after.
Here's my working code, sans distracting extras.
var query = Model.find({
/* query */
}).lean().limit(1);
// Find the document
query.exec(function(error, result) {
if (error) { throw error; }
// If the document doesn't exist
if (!result.length) {
// Create a new one
var model = new Model(); //use the defaults in the schema
model.save(function(error) {
if (error) { throw error; }
// do something with the document here
});
}
// If the document does exist
else {
// Update it
var query = { /* query */ },
update = {},
options = {};
Model.update(query, update, options, function(error) {
if (error) { throw error; }
// do the same something with the document here
// in this case, using result[0] from the topmost query
});
}
});
I've looked into findOneAndUpdate and other related methods but I'm not sure if they fit my use case or if I understand how to use them correctly. Can anyone point me in the right direction?
(Probably) Related questions:
How to check if that data already exist in the database during update (Mongoose And Express)
Mongoose.js: how to implement create or update?
NodeJS + Mongo: Insert if not exists, otherwise - update
Return updated collection with Mongoose
Edit
I didn't come across the question pointed out to me in my searching, but after reviewing the answers there I've come up with this. It's certainly prettier, in my opinion, and it works, so unless I'm doing something horribly wrong I think my question can probably be closed.
I would appreciate any additional input on my solution.
// Setup stuff
var query = { /* query */ },
update = { expire: new Date() },
options = { upsert: true };
// Find the document
Model.findOneAndUpdate(query, update, options, function(error, result) {
if (!error) {
// If the document doesn't exist
if (!result) {
// Create it
result = new Model();
}
// Save the document
result.save(function(error) {
if (!error) {
// Do something with the document
} else {
throw error;
}
});
}
});
You are looking for the new option parameter. The new option returns the newly created document(if a new document is created). Use it like this:
var query = {},
update = { expire: new Date() },
options = { upsert: true, new: true, setDefaultsOnInsert: true };
// Find the document
Model.findOneAndUpdate(query, update, options, function(error, result) {
if (error) return;
// do something with the document
});
Since upsert creates a document if not finds a document, you don't need to create another one manually.
Since you wish to refactor parts of your code to be shorter and simpler,
Use async / await
Use .findOneAndUpdate() as suggested in this answer
let query = { /* query */ };
let update = {expire: new Date()};
let options = {upsert: true, new: true, setDefaultsOnInsert: true};
let model = await Model.findOneAndUpdate(query, update, options);
///This is simple example explaining findByIDAndUpdate from my code added with try catch block to catch errors
try{
const options = {
upsert: true,
new: true,
setDefaultsOnInsert: true
};
const query = {
$set: {
description: req.body.description,
title: req.body.title
}
};
const survey = await Survey.findByIdAndUpdate(
req.params.id,
query,
options
).populate("questions");
}catch(e){
console.log(e)
}
Here is an example I am using. I have to return custom responses for UI updates etc. This can be even shorter. User is
const UserScheme = mongoose.Schema({
_id: String,
name: String,
city: String,
address: String,
},{timestamps: true});
const User = mongoose.model('Users', UserScheme);
async function userUpdateAdd(data){
var resp = '{"status": "error"}';
if(data){
var resp = await User.updateOne({ _id: data._id }, data).then(function(err, res){
console.log("database.userUpdateAdd -> Update data saved in database!");
if(err){
var errMessage = err.matchedCount == 0 ? "User Record does not exist, will create new..." : "Record not updated";
// If no match, create new
if(err.matchedCount == 0){
const create_user = new User(data);
resp = create_user.save().then(function(){
console.log("database.userUpdateAdd -> Data saved to database!");
return '{"status":"success", "message": "New User added successfully"}';
});
return resp;
}
// Exists, return success update message
if(err.matchedCount == 1){
return '{"status": "success", "message" : "Update saved successfully"}';
} else {
return '{"status": "error", "code": "' + err.modifiedCount + '", "message": "' + errMessage + '"}';
}
}
})
.catch((error) => {
//When there are errors We handle them here
console.log("database.userUpdateAdd -> Error, data not saved! Server error");
return '{"status": "error", "code": "400", "message": "Server error!"}';
});
}
return resp;
}
Here's an example:
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/rsvp', {useNewUrlParser: true, useUnifiedTopology: true});
const db = mongoose.connection;
db.on('error', () => {
console.log('mongoose connection error');
});
db.once('open', () => {
console.log('mongoose connected successfully');
});
const rsvpSchema = mongoose.Schema({
firstName: String,
lastName: String,
email: String,
guests: Number
});
const Rsvp = mongoose.model('Rsvp', rsvpSchema);
// This is the part you will need... In this example, if first and last name match, update email and guest number. Otherwise, create a new document. The key is to learn to put "upsert" as the "options" for the argument.
const findRsvpAndUpdate = (result, callback) => {
Rsvp.findOneAndUpdate({firstName: result.firstName, lastName: result.lastName}, result, { upsert: true }, (err, results) => {
if (err) {
callback(err);
} else {
callback(null, results);
}
})
};
// From your server index.js file, call this...
app.post('/rsvps', (req, res) => {
findRsvpAndUpdate(req.body, (error, result) => {
if (error) {
res.status(500).send(error);
} else {
res.status(200).send(result);
}
})
});

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