I am new to node and I have read the data from mongoDB successfully.
But I would like to store the whole data from the Collection into a variable in nodejs as I would like to use them in the index page.
I do not know how to store it.
// Connection URL
var url = 'mongodb://localhost:27017/test';
// Use connect method to connect to the Server
MongoClient.connect(url, function (err, db) {
assert.equal(null, err);
console.log("Connected correctly to server");
seriescollection = db.collection('series');
});
var findseries = function (db, callback) {
var cursor = db.collection('series').find();
cursor.each(function (err, doc) {
assert.equal(err, null);
if (doc != null) {
console.dir(doc);
} else {
callback();
}
});
};
MongoClient.connect(url, function (err, db) {
assert.equal(null, err);
//insertDocument(db, function () {});
findseries(db, function () {
db.close();
});
});
My sample JSON object in MongoDb is
{
"_id" : "b835225ba18",
"title" : "Name",
"imageurl" :"https://promotions.bellaliant.net/files/Images/TMN/Ballers-June2015.jpg",
"namespaceId" : "UNI890"
}
I would like to access all the fields and create a page based on the fields that I have stored. I need to access all the fields and that is my main goal.
This is a pet project I am working on a leisure time to learn MEAN stack a bit.
Thanks a lot for your help!!!!
There's a few issues with this code, but I think what you're looking for is the toArray method:
var findseries = function (db, callback) {
db.collection('series').find().toArray(function(err, allTheThings) {
// Do whatever with the array
// Spit them all out to console
console.log(allTheThings);
// Get the first one
allTheThings[0];
// Iterate over them
allTheThings.forEach(function(thing) {
// This is a single instance of thing
thing;
});
// Return them
callback(null, allTheThings);
}
}
More here: https://docs.mongodb.org/manual/reference/method/cursor.toArray/
And here: https://mongodb.github.io/node-mongodb-native/api-generated/cursor.html#toarray
Related
I want to use an module to get and process data from my MongoDB database. (It should generate an object that represents my Express.js site's navbar)
I thought of doing something like this:
var nav = { Home: "/" };
module.exports = function() {
MongoClient.connect(process.env.MONGO_URL, function(err, db) {
assert.equal(err, null);
fetchData(db, function(articles, categories) {
combine(articles, categories, function(sitemap) {
// I got the data. What now?
console.log("NAV: ", nav);
})
});
});
};
var fetchData = function(db, callback) {
db.collection('articles').find({}).toArray(function(err, result) {
assert.equal(err);
articles = result;
db.collection('categories').find({}).toArray(function(err, result) {
assert.equal(err);
categories = result;
db.close();
callback(articles, categories);
});
});
};
var combine = function(articles, categories, callback) {
categories.forEach(function(category) {
nav[category.title] = {};
articles.forEach(function(article) {
if(article.category == category.name) {
nav[category.title][article.title] = "link";
}
})
});
callback(nav);
};
As of line 6, I do have all data I need.
(An object, currenty like { Home: '/', Uncategorized: { 'Hello world!': 'link' } })
But since I'm in an anonymous function, I don't know how to return that value. I mean, return would just return it the function that called it... And in the end, MongoClient.connect would receive my data.
If I set a variable instead, it would be set as module.exports returned before Node can even query the data from the database, right?
What can I do in order to make this work?
It should result in some kind of function, like
var nav = require('nav');
console.log(nav());
Thanks in advance!
Add another callback:
var nav = { Home: "/" };
module.exports = function(cb) {
MongoClient.connect(process.env.MONGO_URL, function(err, db) {
assert.equal(err, null);
fetchData(db, function(articles, categories) {
combine(articles, categories, function(sitemap) {
cb(sitemap);
})
});
})
});
And then use this way:
var nav = require('nav');
nav(function(sitemap){ console.log(sitemap); });
You can use mongoose module or monk module. These modules have been tested properly .
Just use
npm install mongoose or monk
The suggestion about mongoose is great and you can look into it, however I think you've already done the job with the fetching of the data from the db. You just need to access it in your main node flow.
You can try this:
module.exports.generateNav = function() {
MongoClient.connect(process.env.MONGO_URL, function(err, db) {
assert.equal(err, null);
var output = fetchData(db, function(articles, categories) {
combine(articles, categories, function(sitemap) {
})
});
return (output);
});
};
And then in your main application you can call it in the following way:
var nav = require('nav');
navigation = nav.generateNav();
console.log(navigation);
I am using mongodb driver for nodejs.
I am getting below error while updating a record.
{"name":"MongoError","message":"selector must be a valid JavaScript
object","driver":true}
Here is my script :
MongoClient.connect(url, function (err, db) {
if (err)
{
console.log('Unable to connect to the mongoDB server. Error:', err);
return;
}
var collName = "bank";
var SelectParas = {"name":"ABC"};
var UpdateValues = {"name":"PQR"};
db.collection(collName).update(collName,SelectParas,{$set:UpdateValues},function (err,numUpdated){
if(err)
{
console.log('err');
console.log(err);
return;
}
if(numUpdated)
{
console.log('Updated Successfully %d document(s).', numUpdated);
}
db.close();
});
});
I can write the below line in mongo console & it works.
db.bank.update({"name":"ABC"},{$set:{"name":"PQR"}})
You are passing collecion name i.e. a string as find query of the update. Need not pass collecton name there.
db.collection(collName).update(collName,SelectParas,{$set:UpdateValues},function (err,numUpdated)
// collName need not pass in the update function.
Need to use
db.collection(collName).update(SelectParas,{$set:UpdateValues},function (err,numUpdated) instead.
I have following code to fetch some data from the db (mongo).
function getAllUsers(){
var UsersPromise = Q.defer();
UserSchema.find({}, function(err, data){
if(err){
UsersPromise .reject(err);
}else {
UsersPromise .resolve(data);
}
});
return UsersPromise .promise;
}
Then I modify each of these models. I add certain fields to the model depending on the type of user. (This is working correctly).
function buildUsers(users){
// my code iterates over users and adds
// properties as required.
// Working fine.
return users; // updated users.
}
Now I want to save these updated models back to mongo and this is where it's making me pull my hair.
function saveUsers(users){
// here, the users are received correctly. But the following line to save the users fails.
var SaveUsersPromise = Q.defer();
UserSchema.save(users, function(err, data){
if(err){
SaveUsersPromise .reject(err);
} else {
SaveUsersPromise .resolve(data);
}
});
return SaveUsersPromise .promise;
}
Lastly I call these functions like:
DB.connect()
.then(getAllUsers)
.then(buildUsers)
.then(saveUsers)
.catch(errorHandler);
Everything works correctly untill I call UserSchema.save. What could be the problem?
PS: I am using mongoose.
TIA.
UserSchema.save accepts single instance, you have to loop through users and save each. Mongoose doesn't have bulk inserts implemented yet (see issue #723).
Here's simple implementation using async.eachSeries
function saveUsers(users){
var async = require('async'); // <== npm install async --save
var SaveUsersPromise = Q.defer();
async.eachSeries(users, function(user, done){
UserSchema.save(user, done);
// or
user.save(done); // if user is Mongoose-document object
}, function(err){
if(err){
SaveUsersPromise.reject(err);
} else {
SaveUsersPromise.resolve();
}
});
return SaveUsersPromise.promise;
}
I am creating a CRUD api with express and mongodb. I have a specific route which queries one collection in my mongo db and retrieves whatever documents match the query criteria. My program then loops through these documents and trys to find the latest cross entry in another collection in my db
exports.findLatestCommitforAllRepos = function(req,res,next){
var githubCommitDataCollection = index.db.collection(githubCommitDataCollectionName);
var enabledRepoCollection = index.db.collection(enabledRepoCollectionName);
var latestCommits = [];
enabledRepoCollection.find({enabled:true}).toArray(function(err,repos) {
if (err) { next(err); }
if (repos.length === 0 || repos === 'undefined') {
res.status(404);
res.send("There are no repos being tracked")
}
else {
repos.forEach(function(enabledRepo) {
var repo = enabledRepo.repo;
var userOrOrg = enabledRepo.userOrOrg;
githubCommitDataCollection.find({repo: repo, userOrOrg:userOrOrg}).sort({commitDate: -1}).limit(1).toArray(function(err,commit) {
if (commit.length === 0 || repos === 'undefined') {
res.send("No commit found for repo " + repo);
}
// console.log(commit[0]);
latestCommits.push(commit[0]);
console.log(latestCommits);
});
});
res.setHeader('Content-Type', 'application/json');
res.status(200);
res.json(latestCommits);
res.end();
}
});
}
This results in an empty array being returned.
You can use the async libary especially the async.waterfall() method when you need to run a tasks array of functions in series, each passing their results to the next in the array.
Consider the following example:
// Include the async package
// Make sure you add "async" to your package.json
async = require("async");
exports.findLatestCommitforAllRepos = function(req,res,next){
var latestCommits = [];
async.waterfall([
// Load all documents
function(callback) {
index.db.collection(enabledRepoCollectionName).find({"enabled": true}).toArray(function(err,repos){
if (err) return callback(err);
callback(null, repos);
});
},
// Get count of documents where price is empty
function(reposData, callback) {
async.each(reposData, function(enabledRepo, callback) {
index.db.collection(githubCommitDataCollectionName)
.findOne({repo: enabledRepo.repo, userOrOrg: enabledRepo.userOrOrg})
.sort({commitDate: -1}).limit(1)
.exec(function(err, commit) {
latestCommits.push(commit);
callback();
});
}, callback);
}
], function(err, result) { //This function gets called after the three tasks have called their "task callbacks"
if (err) return next(err);
res.setHeader('Content-Type', 'application/json');
res.status(200);
res.json(latestCommits);
res.end();
});
});
One minor suggestion in code,
use .findOne instead of .find
Means instead of
githubCommitDataCollection.find({repo: repo, userOrOrg:userOrOrg}).sort({commitDate: -1}).limit(1).toArray(function(err,commit) {
use
githubCommitDataCollection.findOne({repo: repo, userOrOrg:userOrOrg}).sort({commitDate: -1}).exec(function(err,commit) {
It will return only one commit and check console.log(commit) value to check what your are getting as result.
Or Please check share existing documents of githubCommitDataCollection
I'm working on a web app with nodejs, express, and mongodb.
In my 'main' file where I listed for API calls, I include a Users class that has methods like Users.authenticate(userObject, callback), and Users.getById(userId, callback).
Sorry for this long code snippet. It's just a snippet of my users class.
function Users (db) {
if (!db) {
return {'message': 'creating an instance of Users requires a database'}
} else {
this.db = db;
return this;
}
}
Users.prototype.authenticate = function (user, callback) {
if (!user.username) {
return {'message': 'Users.authenticate(user, callback) requires user.username'};
} else if (!user.password) {
return {'message': 'Users.authenticate(user, callback) requires user.password'};
} else if (!callback) {
return {'message': 'Users.authenticate(user, callback) requires callback(err, user)'};
}
this.db.collection('users', function (err, collection) {
if (err) {return {'message': 'could not open users collection'}};
/* query for the user argument */
collection.findOne(user, function (err, doc) {
if (!err) {
if (!doc) {
callback({'message': 'user does not exist'}, null);
} else {
callback(null, doc);
}
} else {
callback({'message': 'error finding user'}, null);
}
});
});
};
exports.Users = Users;
That's it
I pass an open DB connection to my Users class, and make a call like the following:
var server = new mongo.Server('localhost', '27017', {auto_reconnect: true});
var db = new mongo.Db('supportdash', server, {"fsync": true});
// open connection to be, init users
db.open(function (err, db) {
var users = new Users(db);
users.authenticate({"username": "admin", "password": "password"}, function (err, user) {
// do something with the error, or user object
});
});
Now for my questions
Should I be passing an open db connection, or should I be passing the info needed (localhost, port, database name) for the Users class to manage its own connection?
I tried to set up testing with jasmine-node, but I ended up with a lot of problems with async database calls. I wanted to add a user, then test that Users.authenticate was working. I used Jasmines runs() and waitsfor() async helpers, but I could not get it to work. I then ran into an issue that took me a while to debug (with a different class), and testing would have saved me a lot of time. Any advice on how I would test my classes that interact with a mongodb database?