I am wondering if this Mongoose Model scenario will work and am currently unable to test it.
var xSchema = new mongoose.Schema({
Data: String
});
xSchema.methods.getData = function(ID){
SSS.findById(ID, function(err, found){
if(err) throw err;
return found;
}
}
SSS = mongoose.model('x', xSchema);
Will SSS.getData() return Data properly?
Here is my test codes, please make sure the first parameter of mongoose.model should be same as SSS, just as my codes show below.
var xSchema = new mongoose.Schema({
Data: String
});
xSchema.methods.getData = function(ID, callback){
SSS.findById(ID, function(err, found){
if(err) throw err;
else
callback && callback(found);
});
}
var SSS = mongoose.model('SSS', xSchema);
function findX() {
var s1 = new SSS({data: 'dd'});
// the `"56d7c1b29741d2982750c725"` is the `_id` of `{Data: 'test'}`
s1.getData("56d7c1b29741d2982750c725", function(d) {
console.log(d);
})
}
function saveX() {
var s = new SSS({Data: 'test'});
s.save(function (err) {
if (err)
console.log(err);
else
console.log('save sss successfully');
});
}
The xSchema.methods define the instance method, maybe the Statics method would be better in your case
xSchema.statics.getData = function (ID, cb) {
Then you can access this method through
SSS.getData(ID, cb)
Related
Currently I'm working on a node.js application, with a register function. For this function I need to check a username is already taken or not. Unfortunately the SQL module in node just accepts a callback function from which I cannot send any booleans back.
Here is some code from my controller module:
async function createUser(req, res) {
try {
const salt = await bcrypt.genSalt(); //standard ist 10
const hashedPassword = await bcrypt.hash(req.body.password, salt);
const newUser = {
userName: req.body.username,
userPassword: hashedPassword
};
const userExists = model.checkIfUserExists(newUser.userName);
if (userExists == false){
// create new user
} else {
// Send json back "user already exists
}
res.status(201).json(newUser);
} catch {
res.status(500);
}
}
And here is the code of the model:
function checkIfUserExists(Username){
console.log("Checking if user exists");
let sql = "select * from users where user_name = ?";
db_conn.query(sql, Username, (err, result) => {
if (err){
throw err;
}
console.log(result);
if (result.length > 0){
return true;
} else {
return false;
}
});
}
Unfortunately the "checkIfUserExists" method never returns back a true or false which leads to the "userExists " variable to be null.
I'd like to know how to do return the bollean there or how to solve the problem in a more elegant way.
Please help me to fix this code. Thanks :)
You can either pass a callback to checkIfUserExists or use promises. If I were you, and since you are already using async/await, I would make your return of checkIfUserExists be a promise. So...your code could become
function checkIfUserExists(Username) {
return new Promise((resolve,reject) => {
console.log("Checking if user exists");
let sql = "select * from users where user_name = ?";
db_conn.query(sql, Username, (err, result) => {
if (err) {
throw err;
}
console.log(result);
if (result.length > 0) {
resolve()
} else {
reject()
}
});
})
}
Then, your code that calls this function would be:
async function createUser(req, res) {
try {
const salt = await bcrypt.genSalt(); //standard ist 10
const hashedPassword = await bcrypt.hash(req.body.password, salt);
const newUser = {
userName: req.body.username,
userPassword: hashedPassword
};
await model.checkIfUserExists(newUser.userName).catch(() => {
// Send json back "user already exists
});
// create user
res.status(201).json(newUser);
} catch {
res.status(500);
}
}
First check your catch statement and also add await before model.checkIfUserExists(newUser.userName)
async function createUser(req, res) {
try {
const salt = await bcrypt.genSalt(); //standard ist 10
const hashedPassword = await bcrypt.hash(req.body.password, salt);
const newUser = {
userName: req.body.username,
userPassword: hashedPassword
};
const userExists = await model.checkIfUserExists(newUser.userName);
if (userExists == false){
// create new user
} else {
// Send json back "user already exists
}
res.status(201).json(newUser);
} catch(ex) {
res.status(500);
}
}
return promise from this function:
function checkIfUserExists(Username){
return new Promise((resolve, reject) => {
console.log("Checking if user exists");
let sql = "select * from users where user_name = ?";
db_conn.query(sql, Username, (err, result) => {
if (err){
return reject(err);
}
console.log(result);
if (result.length > 0){
return resolve(true);
} else {
return resolve(false);
}
});
})
}
I am new to Node.js (3 days total experience). I am using Node.js and the tedious package to query a database (azure SQL). I use the example as explained here: https://learn.microsoft.com/en-us/azure/azure-sql/database/connect-query-nodejs?tabs=macos
const connection = new Connection(config);
// Attempt to connect and execute queries if connection goes through
connection.on("connect", err => {
if (err) {
console.error(err.message);
} else {
console.log("Reading rows from the Table...");
// Read all rows from table
const request = new Request(
"SELECT * FROM clients",
(err, rowCount, columns) => {
if (err) {
console.error(err.message);
} else {
console.log(`${rowCount} row(s) returned`);
}
}
);
request.on("row", columns => {
columns.forEach(column => {
console.log("%s\t%s", column.metadata.colName, column.value);
});
});
connection.execSql(request);
}
});
I have two issues:
I do not know how to get the queried data into an object and
If I run the script it does print the items to the console, but it doesn't close the connection after it has done so. If I add a connection.close() at the bottom, it will close the connection before its done. I get the feeling that node.js executes everything at the same time (I am used to Python..).
Update
I found a way to close the connection, to my understanding the request object has several "events" that are predefined by the library. It seems I need to add the event "done" through request.on('done', ...) in order to make sure that it can even BE done. My updated code looks like this:
var connection = new Connection(config);
connection.connect(function(err) {
// If no error, then good to go...
executeStatement();
}
);
connection.on('debug', function(text) {
//remove commenting below to get full debugging.
//console.log(text);
}
);
function executeStatement() {
request = new Request("SELECT * FROM clients", function(err, rowCount) {
if (err) {
console.log(err);
} else {
console.log(rowCount + ' rows');
}
connection.close();
});
request.on('row', function(rows) {
_.forEach(rows, function(value, collection){
console.log(value)
console.log(value.value);
console.log(value.metadata.colName)
console.log(collection)
})
});
request.on('done', function(rowCount, more) {
console.log(rowCount + ' rows returned');
});
// In SQL Server 2000 you may need: connection.execSqlBatch(request);
connection.execSql(request);
}
Anyways, your help would be much appreciated!
Regards
Pieter
The package tedious is synchronous package, it uses the callback to return results. So when we call connection.close(), it will disable connection and stop the callback function. If will want to close the connection, I suggest you use async package to implement it.
For example
const { Connection, Request } = require("tedious");
const async = require("async");
const config = {
authentication: {
options: {
userName: "username", // update me
password: "password", // update me
},
type: "default",
},
server: "your_server.database.windows.net", // update me
options: {
database: "your_database", //update me
encrypt: true,
validateBulkLoadParameters: true,
},
};
const connection = new Connection(config);
let results=[]
function queryDatabase(callback) {
console.log("Reading rows from the Table...");
// Read all rows from table
const request = new Request("SELECT * FROM Person", (err, rowCount) => {
if (err) {
callback(err);
} else {
console.log(`${rowCount} row(s) returned`);
callback(null);
}
});
request.on("row", (columns) => {
let result={}
columns.forEach((column) => {
result[column.metadata.colName]=column.value
console.log("%s\t%s", column.metadata.colName, column.value);
});
// save result into an array
results.push(result)
});
connection.execSql(request);
}
function Complete(err, result) {
if (err) {
callback(err);
} else {
connection.close();
console.log("close connection");
}
}
connection.on("connect", function (err) {
if (err) {
console.log(err);
} else {
console.log("Connected");
// Execute all functions in the array serially
async.waterfall([queryDatabase], Complete);
}
});
connection.connect();
Besides, you also can use the package mssql. It supports asynchronous methods and depends on package tedious. We can directly call close after querying.
For example
const mssql = require("mssql");
const config = {
user: "username",
password: "password",
server: "your_server.database.windows.net",
database: "your_database",
options: {
encrypt: true,
enableArithAbort: true,
},
};
let pool = new mssql.ConnectionPool(config);
async function query() {
try {
await pool.connect();
const request = pool.request();
const result = await request.query("SELECT * FROM Person");
console.dir(result.recordset);
await pool.close();
console.log(pool.connected);
} catch (error) {
throw error;
}
}
query().catch((err) => {
throw err;
});
You can custom a class first and declare an Array to save ojects such as:
let sales = new Array();
class SalesLT{
constructor(catagryName,productName){
this.catagryName = catagryName;
this.productName = productName;
}
Here my sql statement returns 2 properties, so every time the loop takes out two elements from the ColumnValue[].
request.on("row", columns => {
for(let i=0; i<columns.length; i=i+2){
let sale = new SalesLT(columns[i].value,columns[i+1].value);
sales.push(sale);
}
sales.forEach( item => {
console.log("%s\t%s",item.catagryName, item.productName)
})
});
The code is as follows:
const { Connection, Request } = require("tedious");
let sales = new Array();
class SalesLT{
constructor(catagryName,productName){
this.catagryName = catagryName;
this.productName = productName;
}
}
// Create connection to database
const config = {
authentication: {
options: {
userName: "<***>", // update me
password: "<***>" // update me
},
type: "default"
},
server: "<****>.database.windows.net", // update me
options: {
database: "<***>", //update me
encrypt: true
}
};
const connection = new Connection(config);
// Attempt to connect and execute queries if connection goes through
connection.on ("connect", err => {
if (err) {
console.error(err.message);
} else {
queryDatabase();
}
});
function queryDatabase() {
console.log("Reading rows from the Table...");
// Read all rows from table
const request = new Request(
`SELECT TOP 2 pc.Name as CategoryName,
p.name as ProductName
FROM [SalesLT].[ProductCategory] pc
JOIN [SalesLT].[Product] p ON pc.productcategoryid = p.productcategoryid`,
(err, rowCount) => {
if (err) {
console.error(err.message);
} else {
console.log(`${rowCount} row(s) returned`);
}
connection.close();
}
);
request.on("row", columns => {
for(let i=0; i<columns.length; i=i+2){
let sale = new SalesLT(columns[i].value,columns[i+1].value);
sales.push(sale);
}
sales.forEach( item => {
console.log("%s\t%s",item.catagryName, item.productName)
})
});
connection.execSql(request);
}
this article should help you, to solve all the issues you are facing...which were the same I had when I started using Node :)
https://devblogs.microsoft.com/azure-sql/promises-node-tedious-azure-sql-oh-my/
I am new to Node.js and express.
I use following function to upload image to s3.
function defaultContentType(req, file, cb) {
setImmediate(function () {
var ct = file.contentType || file.mimetype || 'application/octet-stream'
cb(null, ct);
});
}
module.exports = async function (fileName, file) {
aws.config.update({
secretAccessKey: process.env.AWSSecretKey,
accessKeyId: process.env.AWSAccessKeyId,
contentType: defaultContentType,
});
var s3bucket = new aws.S3({
params: {
Bucket: process.env.S3_Bucket_Name,
}
});
var params = {
Key: fileName,
Body: file
};
var fileData = await s3bucket.upload(params, function (err, data) {
if (err) {
throw err;
} else {
return data;
}
});
return fileData;
}
before uploading the image, I resize it using
request(req.file.location, async function (err, response, body) {
var fileInstance = await sharp(body);
var resizeFile = await fileInstance.resize({
height: 150,
fit: 'inside'
});
var data = await s3Upload('mobile_' + req.file.key, resizeFile);
req.mobile = data.Location;
next();
});
The problem I have is;
The image does get resized and saved to s3.
But "s3Upload" function does not return the file location.
Seems like it take some time to complete the operation. Before it get completed, undefined value get return.
Can anyone suggest a way to fix this?
Modified method
module.exports = function (fileName, file, finishCallback) {
// more code
s3bucket.upload(params, function (err, data) {
if (err) {
throw err;
} else {
finishCallback(data);
}
});
}
modified the upload method as
s3Upload('mobile_' + req.file.key, resizeFile, (data) => {
req.mobile = data.Location;
next();
});
This seems to be working as expected.
I am not really sure this is the correct way to do things.
Is there a way to do this correctly?
I am trying to use a simple suite of functions built utilizing the Tedious library to access a Microsoft SQL Server. Here is my "tools" file:
'use strict';
const tedious = require('tedious');
const q = require('q');
var Connection = tedious.Connection;
var Request = tedious.Request;
module.exports = {
connectSQL : function(config) {
var connection = new Connection(config);
connection.on('connect', function(err) {
if (err) {
console.log('FAIL ON CONNECT');
console.log(err);
} else {
try {
/* ----- */
return connection;
} catch (err) {
console.log(err);
return;
}
}
});
connection.on('error', function(err) {
if (err) {
console.log('FAIL ON ERROR');
console.log(err);
} else {
console.log("Error called with no err object.");
}
});
},
executeSQL: function(connection, requestString) {
var results = [];
var request = new Request( requestString , function(err, data) {
if (err) {
console.log(err);
} else {
console.log( data );
}
});
request.on('row', function(row) {
//console.log(row);
results.push( row );
});
request.on('requestCompleted', function(){
console.log('Finished');
return results;
});
connection.execSql(request);
}
}
I call these functions as follows in my server file.
const sqlTools = require('./sqlTools.js');
var connection = sqlTools.connectSQL(config);
sqlTools.executeSQL(connection, "select * from dbo.test");
However, I get the error "TypeError: Cannot read property 'execSql' of undefined", even if I make the program sleep for 10 seconds before calling my function sqlTools.executeSQL (obviously not ideal).
I was able to get this to work by calling the request within the sqlTools.connectSQL function (at the "/* ----- */"), but I want to re-use the Tedious connection to make multiple calls. Any suggestions? Thanks!
~~~~~~~EDIT~~~~~~~~~~
With help from akinjide I was able to implement callbacks that allow me to make a single call to my SQL database. However, I am struggling to implement promises to make subsequent calls. I changed my "tools" file as such:
'use strict';
const tedious = require('tedious');
const q = require('q');
var Connection = tedious.Connection;
var Request = tedious.Request;
module.exports = {
connectSQL: function(config) {
var deferred = q.defer();
var connection = new Connection(config);
connection.on('connect', function(err) {
if (err) {
deferred.reject( err );
} else {
deferred.resolve( connection );
}
});
connection.on('error', function(err) {
deferred.reject(err);
});
return deferred.promise;
},
executeSQL: function(connection, requestString, callback) {
var results = [];
const request = new Request(requestString, function(err) {
callback(err);
});
request.on('row', function(row) {
results.push(row);
});
request.on('requestCompleted', function() {
console.log('request completed!');
callback(null, results);
});
connection.execSql(request);
}
}
and I call this code like this...
var promise = sqlTools.connectSQL(config);
promise.then(function (connection) {
sqlTools.executeSQL(connection, "select * from dbo.test", function(err, results) {
if (err) {
console.log(err);
}
console.log(results);
});
}).catch(function (err) {
console.log(err);
}).then(function (connection) {
sqlTools.executeSQL(connection, "select * from dbo.test2", function(err, results) {
if (err) {
console.log(err);
}
console.log(results);
});
}).catch(function(err) {
console.log(err);
});
This returns the first call's results correctly, but unfortunately returns this error "TypeError: Cannot read property 'execSql' of undefined" for the second call as it is not recognizing the connection the second time around. Any suggestions?
A better approach would be to pass a node.js callback style function as an argument to connectSQL.
return keyword won't work within an asynchronous program.
'use strict';
const tedious = require('tedious');
const Connection = tedious.Connection;
const Request = tedious.Request;
module.exports = {
connectSQL: function(config, callback) {
const connection = new Connection(config);
connection.on('connect', function(err) {
if (err) {
callback(err);
} else {
callback(null, connection);
}
});
connection.on('error', function (err) {
callback(err);
});
},
executeSQL: function(connection, requestString, callback) {
let results = [];
const request = new Request(requestString, function(err) {
callback(err);
});
request.on('row', function(row) {
results.push(row);
});
request.on('requestCompleted', function(){
console.log('Finished');
callback(null, results);
});
connection.execSql(request);
}
}
Then you can require, use sqlTools.connectSQL passing two parameters config and function(err, connection) {}
const sqlTools = require('./sqlTools');
sqlTools.connectSQL(config, function(err, connection) {
if (err) {
console.log('FAIL ON CONNECT');
console.log(err);
}
sqlTools.executeSQL(connection, "select * from dbo.test", function (err, results) {
if (err) {
console.log(err);
}
console.log(results);
});
});
I'm newer with Node.js and Express.js.
I want to upload first a image into the server (directory: uploads/spots), and then (synchronous) upload the rest of form data in MongoDB.
I'm using REST (Method Post)
app.route('/spots').post(users.requiresLogin, spots.create);
and I'm using Multer for updating the image into the server, and works.
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));
Is working, but is asynchronous , and returns the response to frontend before that the image will be upload into the server.
My question is how to do this but synchronous and how to return the response to the frontend after that the image was uploaded.
Thank you!
spots.server.routes.js
'use strict';
module.exports = function(app) {
var gm = require('gm');
var multer = require('multer');
var users = require('../controllers/users.server.controller.js');
var spots = require('../controllers/spots.server.controller.js');
//Upload image
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin, spots.create);
app.route('/spots/:spotId')
.get(spots.read)
.put(users.requiresLogin, spots.update)
.delete(users.requiresLogin, spots.hasAuthorization, spots.delete);
// Finish by binding the Spot middleware
app.param('spotId', spots.spotByID);
};
spots.server.controller.js (create method)
'use strict';
/**
* Module dependencies.
*/
var mongoose = require('mongoose'),
errorHandler = require('./errors.server.controller.js'),
Spot = mongoose.model('Spot'),
_ = require('lodash'),
fs = require('fs');
/**
* Create a Spot
*/
exports.create = function(req, res) {
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if(req.files.file)
spot.image=req.files.file.name;
else
spot.image='default.jpg';
spot.save(function(err) {
if (err) {
fs.unlinkSync('public/uploads/spots/'+spot.image);
fs.unlinkSync('public/uploads/spots/850x850/'+spot.image);
fs.unlinkSync('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.'+spot.municipality, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.province, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.community, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.country, {spot:spot, user:req.user});
res.jsonp(spot);
}
});
};
/**
* Spot authorization middleware
*/
exports.hasAuthorization = function(req, res, next) {
if (req.spot.user.id !== req.user.id) {
return res.status(403).send('User is not authorized');
}
next();
};
The solution is not use onFileUploadStart method and use a function with callback in the controller.
routes
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin,multer({ dest: './public/uploads/spots'}), spots.create);
controller
exports.create = function(req, res) {
if (req.files.file)
exports.uploadImage(req.files.file,callback);
else
callback();
function callback(){
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if (req.files.file)
spot.image = req.files.file.name;
else
spot.image = 'default.jpg';
spot.save(function (err) {
if (err) {
fs.unlink('public/uploads/spots/850x850/'+spot.image);
fs.unlink('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.' + spot.municipality, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.province, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.community, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.country, {spot: spot, user: req.user});
req.spot = spot;
Feedback.subscribeSpot(req);
Notify.getLocalSubscriptors(spot.municipality,spot.province,spot.community,spot.country,function(subscriptions){
Notify.create(req,null,spot,null,null,null,subscriptions,'spots/'+spot._id,false,'SPOT_CREATED', function(){
res.jsonp(spot);
});
});
}
});
}
};
exports.uploadImage = function(file, fn){
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
if(fn)fn();
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
};