Iam using ldapjs library for my project with standard LDAP server and iam trying to using search(). Its working right until i want to return results.
So i believe its more my misunderstanding of how javascript works rather than library as its working fine console.log
Secondly iam not sure if iam using nested search() correctly and efficiently.
Any help would be appreciated
function getPhones() {
return new Promise((resolve, reject) => {
let phones = [];
const opts = {
filter: `(objectClass=Phone)`,
scope: 'sub',
// attributes: ['*'],
};
client.search(`cn=${callserver.cn},cn=Modules`, opts, function (err, res) {
if (err) {
console.log('Error in promise', err);
}
res.on('searchEntry', function (entry) {
let newPhone = {};
const opts2 = {
filter: `(objectClass=*)`,
scope: 'sub',
};
client.search(`${entry.object.dn}`, opts2, function (err, res) {
res.on('searchEntry', function (entry2) {
newPhone = entry2.object;
console.log(newPhone); //here its logging just fine with all attributes
});
});
console.log(newPhone);// here newPhone is empty
phones.push(
{ ...entry.object, details: newPhone }
// followMeTo: entry.object.followMeTo,
// telephoneNumber: parseInt(entry.object.telephoneNumber),
);
});
res.on('end', function () {
resolve(phones);
});
res.on('err', function () {
reject('Error');
});
});
}
}
UPDATE 1:
if i try to use as suggested:
client.search(`${entry.object.dn}`, opts, function (err, res) {
res.on('searchEntry', function (entry2) {
phones.push({ ...entry.object, detail: entry2.object });
});
});
in here i cant access phones array, or nothing is pushed into it
so i have to do it this way:
client.search(`${entry.object.dn}`, opts, function (err, res) {
res.on('searchEntry', function (entry2) {
});
phones.push({ ...entry.object, detail: entry2.object });
});
but here i lose access to entry2 :-(
Losing my mind now
I am not familiar with this API, but it looks like your code would be something like this:
function getPhones() {
return new Promise((resolve, reject) => {
let phones = [];
const opts = {
filter: `(objectClass=Phone)`,
scope: "sub"
};
client.search(`cn=${callserver.cn},cn=Modules`, opts, function (err, res) {
if (err) {
console.log("Error in promise", err);
}
res.on("searchEntry", function (entry) {
const opts = {
filter: `(objectClass=*)`,
scope: "sub"
};
client.search(`${entry.object.dn}`, opts, function (err, res) {
res.on("searchEntry", function (entry2) {
phones.push({
...entry.object,
...{
details: entry2.object
}
});
});
});
res.on("end", function () {
resolve(phones);
});
res.on("err", function () {
reject("Error");
});
});
});
});
}
The problem with below code:
client.search(`${entry.object.dn}`, opts2, function (err, res) {
res.on('searchEntry', function (entry2) {
newPhone = entry2.object;
console.log(newPhone); //here its logging just fine with all attributes
});
});
console.log(newPhone);// here newPhone is empty
Is that JS executes client.search() which is an async action, and without waiting for the response continues to execute the console.log(newPhone);.
So the fix here would be to simply push phones into results when the response comes back, within the success callback.
Side note:You can also look into async await if you want to write the code that "looks" synchronous
Related
I am using the package "fcm-node" in order to send notifications to certain device id.
the sendNotification function is as follows:
const FCM = require('fcm-node');
const serverKey = process.env.SERVER_KEY;
const fcm = new FCM(serverKey);
function sendNotification(registrationToken, title, body, type, key) {
const message = {
to: registrationToken,
collapse_key: key,
notification: {
title: title,
body: body,
delivery_receipt_requested: true,
sound: `ping.aiff`
},
data: {
type: type,
my_key: key,
}
};
fcm.send(message, function (err, value) {
if (err) {
console.log(err);
return false;
} else {
console.log(value);
return value;
}
});
};
module.exports = {
sendNotification
};
The api function I use to call this function is as follows:
router.get('/test', async (req, res, next) => {
const promise = new Promise((resolve, reject) => {
let data = sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
console.log(data)
if (data == false) reject(data);
else resolve(data);
});
promise
.then((data) => { return res.status(200).send(data); })
.catch((data) => { return res.status(500).send(data) })
});
When I console.log the "err" and "value" from the sendNotification, I get either of the followings:
{"multicast_id":4488027446433525506,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1652082785265643%557c6f39557c6f39"}]};
{"multicast_id":8241007545302148303,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"InvalidRegistration"}]}
In case it is successful, I made sure that the device is receiving the notification.
The problem is in the api's data. It is always "undefined" and weither send notification is successful or not I get the 200 Ok status.
What seems to be the problem?
You can't return anything from the function (err, value) {} callback of a node-style asynchrnous function.
Your sendNotification() function needs to return a promise. util.promisify() makes the conversion from a node-style asynchronous function to a promise-returning asynchronous function convenient. Note the return, it's important:
const FCM = require('fcm-node');
const serverKey = process.env.SERVER_KEY;
const fcm = new FCM(serverKey);
const { promisify } = require('util');
fcm.sendAsync = promisify(fcm.send);
function sendNotification(registrationToken, title, body, type, key) {
return fcm.sendAsync({
to: registrationToken,
collapse_key: key,
notification: {
title: title,
body: body,
delivery_receipt_requested: true,
sound: `ping.aiff`
},
data: {
type: type,
my_key: key,
}
});
}
module.exports = {
sendNotification
};
Now you can do what you had in mind
router.get('/test', async (req, res, next) => {
try {
const data = await sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
return res.status(200).send(data);
} catch (err) {
return res.status(500).send(err);
}
});
Maybe it will help, at first try to return your response (the promise) in sendNotification, as actually you have a void function, that's why it's always undefined and after in your route
router.get('/test', async (req, res, next) => {
try {
const data = sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
if (data) {
return res.status(200).send(data);
}
} catch(err) {
return res.status(500).send(err);
}
});
I have my function who call the DB to do something :
function callQuery(query) {
db.query(query, (err, res) => {
if (err) {
// Error DB connecion
console.log(err.stack)
} else {
// Send back the results
return(res.rows[0])
}
})
}
My problem is when I call this function by :
const idUser = callQuery("INSERT INTO blablabla RETURNING *")
My data is successfully added in the DB, but idUser came null. It should be res.rows[0]
I am using this tutorial (who instead of setting a variable, call console.log) : https://node-postgres.com/features/connecting
Thank you in advance
I think this is something due to asynchronous
let promisess = new Promise(function(resolve, reject) {
function callQuery(query) {
db.query(query, (err, res) => {
if (err) {
// Error DB connecion
console.log(err.stack)
} else {
// Send back the results
resolve(res.rows[0])
}
})
}
});
promisess.then((res)=> {
your data in res
});
getting undefined all the time "main.js":
var dbAccess = require('../dao/dbAccess');
dbaInstance = new dbAccess();
var wordPool = dbaInstance.getWordPool();
console.log (wordPool);
and "dbAccess.js" contains:
var DatabaseAccess = function() {}
DatabaseAccess.prototype.getWordPool = function () {
RoundWord.find({},'words decoys', function(err, wordPoolFromDB) {
if (err) throw err;
//console.log(wordPoolFromDB); -working ok
return (wordPoolFromDB);
});
}
module.exports = DatabaseAccess;
why is it not working?
DatabaseAccess.prototype.getWordPool is not returning any result.
Since you are using an asynchronous function, you need do one of these things:
a) Take a callback as parameter and invoke the callback with a result
DatabaseAccess.prototype.getWordPool = function (cb) {
RoundWord.find({}, 'words decoys', function(err, results) {
if (err) {
return cb(err, null);
}
cb(null, results);
});
}
The callback convention is: cb(error, results...)
b) Use promises
DatabaseAccess.prototype.getWordPool = function () {
return RoundWord.find({}, 'words decoys', function (err, results) {
if (err) {
throw err; // however you might want to sanitize it
}
return results;
});
}
To consume this result you will need to do it as a promise
databaseAccess.getWordPool()
.catch(function (err) {
// process the error here
})
.then(function (results) {
// something with results
});
It will work if you change to this:
var dbAccess = require('../dao/dbAccess');
dbaInstance = new dbAccess();
dbaInstance.getWordPool(function(wordPool){console.log (wordPool);});
And:
var DatabaseAccess = function() {}
DatabaseAccess.prototype.getWordPool = function (cb) {
RoundWord.find({},'words decoys', function(err, wordPoolFromDB) {
if (err) throw err;
//console.log(wordPoolFromDB); -working ok
cb(wordPoolFromDB);
});
}
module.exports = DatabaseAccess;
If the function is Asynchronous you need to pass a callback to find to get the result:
DatabaseAccess.prototype.getWordPool = function (callback) {
RoundWord.find({},'words decoys', function(err, wordPoolFromDB) {
if (err) throw err;
callback(err, wordPoolFromDB);
});
}
and call it as follows in main:
dbaInstance.getWordPool(function (err, wordPool) {
console.log (wordPool);
// wordPool is only available inside this scope,
//unless assigned to another external variable
});
// cannot access wordPool here
I'm using mongodb for pretty much everything in my node.js application, and now i want create a restful application, so, i did that:
I'm trying to do just the get method, for now:
restApi.js:
var restAPI = {
get: function(method, model, sort, limit, options) {
if (method !== 'get') {
return;
}
model.find(options).sort(sort).limit(3).exec(function (error, result) {
if (error) {
return error;
} else {
return result;
}
});
},
};
And now i can require this in my route:
var restApi = require('restApi');
and use like this:
app.get('/', function(req, res, next) {
var result = restAPI.get('get', Event, 'date', 3, {'isActive': true});
res.render('/', {
result: result
});
});
Is not working, the result is undefined. Why??
How can i transform this in a async function with callback? This is possible?
Thanks! :)
You're not returning anything from restApi.get. If you're using mongoose, you could return a Promise easily enough:
var restAPI = {
get: function(method, model, sort, limit, options) {
if (method !== 'get') {
return;
}
return model.find(options).sort(sort).limit(3).exec();
},
};
Then you can use it like this:
app.get('/', function(req, res, next) {
restAPI.get('get', Event, 'date', 3, {'isActive': true}).then( function ( result ) {
res.render('/', {
result: result
});
}).catch( error ) {
// Render error page and log error
});
});
It is because your model is async. You have to pass callbacks.
Using async way is better because it is not blocking your application while waiting for response.
Example on your case:
restApi.js:
var restAPI = {
get: function(method, model, sort, limit, options, cb) {
if (method !== 'get') {
return cb("Method must be GET");
}
model.find(options).sort(sort).limit(3).exec(function (error, result) {
if (error) {
return cb(error);
} else {
return cb(null, result);
}
});
},
};
And now i can require this in my route:
var restApi = require('restApi');
and use like this:
app.get('/', function(req, res, next) {
restAPI.get('get', Event, 'date', 3, {'isActive': true}, function(err, result){
if(err)
return res.render("Error:" + err)
res.render('/', {
result: result
});
});
});
I've added cb argument to your REST API function so it is called when model async operation is done.
Router handler passes it's callback and prints output when operation is finished.
I'm new to expressJS and i'm wondering what is the best way to requery the database (mongo in my case) to get all the records after one is added.
exports.get = function (db) {
return function (req, res) {
var collection = db.get('notes');
collection.find({}, {}, function (e, docs) {
res.send(docs);
});
};
};
exports.create = function (db) {
return function (req, res) {
var title = req.body.title;
var note = req.body.note;
var collection = db.get('notes');
// Insert/update the note
collection.insert(
{
"title": title,
"note": note
},
function (err, doc) {
// If it failed, return error
if (err) {
res.send("There was a problem adding the information to the database. Error: "+err);
} else {
//res.redirect('/');
//res.json(db.get('notes'));
// WHAT IS THE BEST THING TO DO HERE TO GET ALL THE RECORDS INCLUDING THE ONE I'VE JUST ADDED?
exports.get(db);
}
}
);
}
};
I would replace
exports.get(db);
for
collection.find({}, {}, function (e, docs) {
res.send(docs);
});
The reason is that you are invoking this in the callback, AFTER the record has been inserted
Your exports.get function return a function, a kind of middleware I see.
Repplace
exports.get(db);
by
exports.get(db)();