Node.js Mongoose Library find data in mongodb using promises
Example
Setup
First, install the necessary packages with:
npm install express cors mongoose
Code
Then, add dependencies to server.js, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB:
var express = require('express');
var cors = require('cors'); // We will use CORS to enable cross origin domain requests.
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var app = express();
var schemaName = new Schema({
request: String,
time: Number
}, {
collection: 'collectionName'
});
var Model = mongoose.model('Model', schemaName);
mongoose.connect('mongodb://localhost:27017/dbName');
var port = process.env.PORT || 8080;
app.listen(port, function() {
console.log('Node.js listening on port ' + port);
});
app.use(function(err, req, res, next) {
console.error(err.stack);
res.status(500).send('Something broke!');
});
app.use(function(req, res, next) {
res.status(404).send('Sorry cant find that!');
});
Now add Express.js routes that we will use to query the data:
app.get('/find/:query', cors(), function(req, res, next) {
var query = req.params.query;
Model.find({
'request': query
})
.exec() //remember to add exec, queries have a .then attribute but aren't promises
.then(function(result) {
if (result) {
res.json(result)
} else {
next() //pass to 404 handler
}
})
.catch(next) //pass to error handler
})
Assume that the following documents are in the collection in the model:
{
"_id" : ObjectId("578abe97522ad414b8eeb55a"),
"request" : "JavaScript is Awesome",
"time" : 1468710551
}
{
"_id" : ObjectId("578abe9b522ad414b8eeb55b"),
"request" : "JavaScript is Awesome",
"time" : 1468710555
}
{
"_id" : ObjectId("578abea0522ad414b8eeb55c"),
"request" : "JavaScript is Awesome",
"time" : 1468710560
}
And the goal is to find and display all the documents containing "JavaScript is Awesome" under the "request" key.
For this, start MongoDB and run server.js with node server.js:
Usage
To use this to find data, go to the following URL in a browser:
http://localhost:8080/find/<query>
Where <query> is the search query.
Example:
http://localhost:8080/find/JavaScript%20is%20Awesome
Output:
[{
_id: "578abe97522ad414b8eeb55a",
request: "JavaScript is Awesome",
time: 1468710551,
__v: 0
},
{
_id: "578abe9b522ad414b8eeb55b",
request: "JavaScript is Awesome",
time: 1468710555,
__v: 0
},
{
_id: "578abea0522ad414b8eeb55c",
request: "JavaScript is Awesome",
time: 1468710560,
__v: 0
}]
