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using foreach inside foreach and losing the variable from the first foreach, mongodb

I want to look in a collection for every "open" project, than find for every project the signd in users in a different collection. But after the first .finally() the variable ´code = users´ is empty instead to save the users from the .foreach.
var code = "";
var project_details = "";
var users = "";
var endcode= "";
MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
if (err) throw err;
const db = client.db(dbname);
//find projects which are open
let collection = db.collection('project');
collection.find({ status: "open" }).forEach(function (project) {
//find users that signd in for that project
let collection = db.collection('users');
collection.find({ project: project.id }).forEach(function (user) {
users = user.name + users;
})
.catch((err) => { console.log(err); })
.finally(() => {
code = users;
});
//console.log(code); is empty and this point
//foreach project
project_details = "Project:" + project.name + ", Users: " + code;
endcode = endcode + project_details;
})
.catch((err) => { console.log(err); })
.finally(() => {
res.render('projects', { code: endcode });
client.close();
});
//////
});
The expected result in endcode should be "Project: Projectname1, Users: User1,User2 Project: Projectname2, Users: User3,User4 ....
How can I prevent from losing the written variable code?

Trouble setting a players ID and Username through callback

With an HTML5 game I am developing at the moment, I get the player's username and ID through a token sent in by the client which are all stored in a database. Everything was working perfectly up until I had to actually set the values for the player.
I've been searching all over the internet for similar problems that I am facing, and have come up with nothing. I am not sure if this is a variable scope problem or if I am taking the wrong approach to doing this.
Anyways, here's both the socket.player and getUserSession function
var newUserID;
var newUsersName;
socket.player = {
id: newUserID,
x: randomInt(100,400),
y: randomInt(100,400),
username: newUsersName
}
function getUserSession(sessionKey, callback){
var sql = "SELECT * FROM game_sessions WHERE unique_key=? AND still_active=?";
var stillActive = 1;
var returnData = [];
db.query(sql, [sessionKey, stillActive], function(err, result){
if (err){
throw err;
}
var numFound = result.length;
if (numFound == 1) {
//session was found
var userID = result[0].user_id;
returnData.push(result[0].user_id);
var sql2 = "SELECT * FROM users WHERE id=?";
db.query(sql2, [userID], function(err, result){
if (err){
throw err;
}
var uName = result[0].username;
returnData.push(result[0].username);
return callback(returnData);
});
}
});
}
And the callback function:
getUserSession(data.token, function(result){
newUserID = result[0];
newUsersName = result[1];
socket.broadcast.emit('newclient',socket.player);
});

I would do something like this:
function sqlQuery(sql, params) {
return new Promise((resolve, reject) => {
db.query(sql, params, function(err, result) {
if (err) {
return reject(err);
}
return resolve(result);
});
});
}
function getUserSession(sessionKey, callback){
const sql = "SELECT * FROM game_sessions WHERE unique_key=? AND still_active=?";
const stillActive = 1;
let returnData = [];
try {
return sqlQuery(sql, [sessionKey, stillActive])
.then(result => {
if (result.length === 1) {
//session was found
const userID = result[0].user_id;
returnData.push(result[0].user_id);
const sql2 = "SELECT * FROM users WHERE id=?";
return sqlQuery(sql2, [userID])
.then(result => {
const uName = result[0].username;
returnData.push(result[0].username);
return callback(returnData);
})
}
})
} catch (err) {
//handle err
}
}
Edit: if the callback function being passed in is an aync function, you'll probably need to modify the above snippet to await it.

Express dosn't get return of other function querying Mongodb [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 3 years ago.
I'm working in a simple API Key authentication, I just want to verify the given key against the user provied key.
I have a seperate file with the function querying the database, and returning true/false and the user object.
But in my route.js file, the return object is undefined even tough in my auth.js file it isn't.
I tried making the the function in router.get an async function using express-promise-router and making the function an await return var user = await auth.verify(req.params.uid, req.get("token")) but I don't realy know how async works.
router.js
[...]
router.get('/list/:uid', function(req, res) {
var user = auth.verify(req.params.uid, req.get("token"))
console.log("User: " + user) // <-- Undefined
if (user.status) {
res.send("Success")
} else {
res.status(403)
res.json({status: 403, error: "Unkown User / Token"})
}
})
[...]
auth.js
var db = require('./db')
var ObjectId = require('mongodb').ObjectId;
module.exports = {
verify: (uid, key) => {
try {
var collection = db.get().collection('users')
const obj_id = new ObjectId(uid)
const query = { _id: obj_id }
collection.find(query).limit(1).toArray(function(err, user) {
var status = 0;
var usr = {};
if (err) {throw err}else{status=1}
if (user.length <= 0) {throw "NotExistingExc"; status = 0}else{
usr = user[0];
if (key != usr.api) status = 0
}
var returnObj = {
status: status,
user: usr
} /* --> Is {
status: 1,
user: {
_id: d47a2b30b3d2770606942bf0,
name: 'Sh4dow',
groups: [ 0 ],
api: 'YWFiMDI1MGE4NjAyZTg0MWE3N2U0M2I1NzEzZGE1YjE='
}
}
*/
return returnObj;
})
} catch (e) {
console.error(e)
return {
status: 0,
user: {},
error: e
}
}
}
}
db.js (Idk if needed)
var MongoClient = require('mongodb').MongoClient
var state = {
db: null,
}
exports.connect = function(url, done) {
if (state.db) return done()
MongoClient.connect(url, { useNewUrlParser: true }, function(err, db) {
if (err) return done(err)
state.db = db
done()
})
}
exports.get = function() {
return state.db.db("database")
}
exports.close = function(done) {
if (state.db) {
state.db.close(function(err, result) {
state.db = null
state.mode = null
done(err)
})
}
}
I want to have the returnObjin auth.js in the router.get of my route.js file.

Make auth.verify return a Promise which we can then await for it inside router, You can just make the callback async no need for express-promise-router
router.get('/list/:uid', async function(req, res) {
try {
var user = await auth.verify(req.params.uid, req.get("token"))
console.log("User: " + user)
if (user.status) {
res.send("Success")
} else {
res.status(403).json({status: 403, error: "Unkown User / Token"})
}
} catch (e) {
console.error(e)
res.status(/* */).json(/* */)
}
})
auth
module.exports = {
verify: (uid, key) => new Promise((resolve, reject) => {
var collection = db.get().collection('users')
const obj_id = new ObjectId(uid)
const query = { _id: obj_id }
collection.find(query).limit(1).toArray(function(err, user) {
var status = 0;
var usr = {};
if (err) {
reject(err)
return
} else {
status = 1
}
if (user.length <= 0) {
reject(new Error("NotExistingExc"))
return
} else {
usr = user[0]
if (key != usr.api) status = 0
}
var returnObj = {
status: status,
user: usr
}
resolve(returnObj);
})
}
}

In short, the reason you get undefined is because the code in auth.js is asyncronous. But you're really close. The toArray method in MongoDB returns a promise, so you need to make sure you return that promise and then use it in the router correctly.
In auth.js, make sure verify returns a promise - just add return!
return collection.find(query).limit(1).toArray(...)
And then, change your usage of the verify to the async/await you originally tried:
router.get('/list/:uid', async function(req, res) {
var user = await auth.verify(req.params.uid, req.get("token"))
// More code here...
})

How to access a function in a function with `this`

My question is similar to this.
However, mine runs in Node.js and it seems like a bit more complicated.
The server side wasn't built by me, but someone else that I can't contact. And he wrote code very differently.
And I have db.js and it looks like this:
And routes/email.js it uses db.js like this:
And when I click a button. I get this error:
db.emailRequest is not a function
in db.js, at the end of the file. It originally had this:
module.exports = new dbHelper;
And my style to use db.js in routers.
db.get().query(sql, input, function(err,res){
//TODO:
});
But it didn't work. So, I changed the end of db.js like this:
exports.get = function(){
console.log("exports.get");
return pool;
}
And also added some code in app.js like this:
db.connect(function(err){
if(err){
console.log('Unable to connect to MariaDB');
process.exit(1);
}
});
What should I do?
The full code of db.js is here:
const mariadb = require('mariadb');
var pool;
exports.connect = function(done){
console.log("Trying to connect DB...");
pool = mariadb.createPool({
host: 'localhost',
user: 'root',
password: 'xxxxxxx',
database:"XXXXX",
connectionLimit: 5 // Why 5 ???
});
pool.getConnection()
.then(conn => {
console.log("DB connected. id: " + conn.threadId);
conn.end(); //release to pool
}).catch(err => {
console.log("DB failed connection: " + err);
});
}
function makeToken(){
console.log("makeToken()");
var text = "";
var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
for(var i=0;i<32;i++){
text+=possible.charAt(Math.floor(Math.random()*possible.length));
}
return text;
}
function dbHelper() {
console.log("dbHelper()");
this.emailRequest = function(email,num){
console.log("emailRequest");
pool.getConnection().then(conn => {
conn.query("INSERT INTO email_verification(email, code) VALUES(?,?)",[email,num]);
conn.end(); //release to pool
})
.catch(err => {
console.log("not connected due to error: " + err);
});
}
// wait and process until getting return value because rv is needed.
this.verify = async function(email,num){
console.log("verify");
let conn;
var result = false;
try {
conn = await pool.getConnection();
// within 3minutes
const rows = await conn.query("SELECT count(*) FROM email_verificaiton WHERE email=? AND code=? AND req_time >= NOW() - INTERVAL 3 MINUTE",[email,num]);
if(rows[0]["count(*)"]>0){
result = true;
}
} catch (err) {
throw err;
} finally {
if (conn) conn.end();
}
return result;
}
this.verifyUpdate = function(email,num){
console.log("verifyUpdate");
pool.getConnection()
.then(conn => {
conn.query("UPDATE email_verification SET status = 1 WHERE email=? AND code=?",[email,num]);
conn.end(); //release to pool
})
.catch(err => {
console.log("not connected due to error: " + err);
});
}
// wait and process until getting return value because rv is needed.
this.emailRegister = async function(email,pass,nick,devid){
console.log("emailRegister");
let conn;
var result;
try {
conn = await pool.getConnection();
var rows = await conn.query("SELECT count(*) FROM email_verification WHERE email=? AND status = 1",[email]);
if(rows[0]["count(*)"]>0){
rows = await conn.query("SELECT count(*) FROM member WHERE email=?",[email]);
if(rows[0]["count(*)"]==0){
var token = makeToken();
rows = await conn.query("INSERT INTO member (email,password,username,device_id,login_method,token) VALUES(?,?,?,?,0,?)",[email,pass,nick,devid,token]);
if(rows["affectedRows"]>0){
result = {result:true, code:200, message: "success",data:[{email:email,token:token}]};
} else{
result = {result:false,code:401, message:"db error"};
}
}else {
result = {result:false,code:402, message:"already registered id"};
}
} else {
result = {result:false,code:403, meesage:"email not verified"};
}
} catch (err) {
throw err;
} finally {
if (conn) conn.end();
}
return result;
}
// wait and process until getting return value because rv is needed.
this.emailLogin = async function(email,pass,devid){
console.log("emailLogin");
let conn;
var result;
try {
conn = await pool.getConnection();
rows = await conn.query("SELECT * FROM member WHERE email=?",[email]);
if(rows.length==1){
if(rows[0]["password"]==pass){
var token = makeToken();
rows = await conn.query("UPDATE member SET device_id = ?, token = ? WHERE email=?",[devid,token,email]);
console.log(rows)
if(rows["affectedRows"]>0){
result = {result:true,message:"Sign up Success.", code:200, data:[{email:email,token:token}]};
} else{
result = {result:false,message:"db error",code:401};
}
} else {
result = {result:false,message:"wrong password",code:402};
}
}else {
result = {result:false,message:"not registered id",code:403};
}
} catch (err) {
throw err;
} finally {
if (conn) conn.end();
}
return result;
}
}
//module.exports = new dbHelper;
exports.get = function(){
console.log("exports.get");
return pool;
}

How can I avoid logging into SalesForce databases on every router in Express.js?

I need to do this to log into SalesForce Databases and pass a query. Now I will be passing a lot of queries on many routers of express.js and its a real pain to login in every router. Please let me know if you know how I can avoid this.
var conn = new jsforce.Connection({
oauth2 : salesforce_credential.oauth2
});
var username = salesforce_credential.username;
var password = salesforce_credential.password;
// I want to avoid this login on every router
conn.login(username, password, function(err, userInfo) {
if (err) {
return console.error(err);
}
conn.query("SELECT id FROM Sourcing__c WHERE id = 'req.session.ref'",function(err, result) {
if (err) {
return console.error(err);
}
if(result.records.length === 0){
req.session.ref = "";
}
var body = {
"Auth__c": req.user.id,
"Stus__c": "Pending - New Hire",
"Record": "012lvIAC",
"Sourcing__c": req.session.ref
};
conn.sobject("SFDC_Employee__c").create(body, function(err, ret) {
if (err || !ret.success) {
return console.error(err, ret);
}
console.log("Created record id : " + ret.id);
// ...
});
});
});

You may save the login status and check it every time when do a query,
here I add a property on conn (the instance of 'jsforce.Connection'), I'm not sure but I think there may be a method or property that show the login status of the 'conn', you may dig into its documents.
var conn = new jsforce.Connection({
oauth2 : salesforce_credential.oauth2
});
var username = salesforce_credential.username;
var password = salesforce_credential.password;
conn._isLogin = false;
// here in your route handler
if (!conn._isLogin) {
conn.login(username, password, function(err, userInfo) {
if (err) {
return console.error(err);
}
conn._isLogin = true;
doQuery(conn);
});
} else {
doQuery(conn);
}
function doQuery (conn) {
conn.query("SELECT id FROM Sourcing__c WHERE id = 'req.session.ref'",function(err, result) {
if (err) {
return console.error(err);
}
if(result.records.length === 0){
req.session.ref = "";
}
var body = {
"Auth__c": req.user.id,
"Stus__c": "Pending - New Hire",
"Record": "012lvIAC",
"Sourcing__c": req.session.ref
};
conn.sobject("SFDC_Employee__c").create(body, function(err, ret) {
if (err || !ret.success) {
return console.error(err, ret);
}
console.log("Created record id : " + ret.id);
// ...
});
});
}