Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
App.jsconst http = require('http'); const server = http.createServer((req, res)=>{ console.log(req); }); server.listen(3000);Run it with command: node App.jsWe can see what is inside a request object by opening a browser and navigating to localhost:3000There is lots of information which will get printed on console window. We will see some important properties.Identifying the url from where request came, request method type and headers in request is important.Headers will give us information on host and browser type , accepted response by host etc. Request method can be of any http method type like GET, POST, PUT, DELETE etc.const http = require('http'); const ... Read More
Simple http server in node.js will register an event loop which will keep on listening for http requests.Execution of file containing code for creation of server will work as shown below −node App.js => Start executing script => Code parsing, Register events and functions => event loop=> keeps on running as long as event are registered.This is the single threaded event driven approach of the node.js. For accessing and updating of values in database also works using the event driven approach. Even though it’s a single threaded, it can handle multiple requests at a time due to its speed of ... Read More
The mostly used core modules of Node.js are −http − used to launch a simple server, send requestshttps − used to launch a ssl secured http serverpath − used to handle path based on operating systemfs − It’s a file system handling moduleos − its used for os related operationsLets build a simple http server using Node.js −Create a javascript file App.js (name it as you like) in an editor like visual studio code .App.jsconst http = require(‘http’); function reqListener(req, res){ console.log(‘Hello’); } const server = http.createServer(reqListener); server.listen(3000);ExplainationWe used const keyword instead of var or let to import a ... Read More
To display an image inside SVG circle, use the element and set the clipping path. The element is used to define a clipping path. Image in SVG is set using the element.ExampleYou can try to run the following code to learn how to display an image inside SVG circle in HTML5Live Demo HTML5 SVG Image
Yes, use getSiblingDB(). Let us add some documents to the database −> use customer_tracker-990; switched to db customer_tracker-990 > db.demo1.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea4697ca7e81adc6a0b3954") } > db.demo1.insertOne({"Name":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea46980a7e81adc6a0b3955") } > db.demo1.insertOne({"Name":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea46984a7e81adc6a0b3956") }Display all documents from a collection with the help of find() method −> db.getSiblingDB("customer_tracker-990").demo1.find();This will produce the following output −{ "_id" : ObjectId("5ea4697ca7e81adc6a0b3954"), "Name" : "Chris" } { "_id" : ObjectId("5ea46980a7e81adc6a0b3955"), "Name" : "David" } { "_id" : ObjectId("5ea46984a7e81adc6a0b3956"), "Name" : "Bob" }Read More
To limit the number of documents in a collection, set capped − true. Set the size there itself. Let us create a collection with documents −> db.createCollection( "demo683", { capped: true, size: 5 ,max:4} ) { "ok" : 1 } > db.demo683.insertOne({Value:100}); { "acknowledged" : true, "insertedId" : ObjectId("5ea468afa7e81adc6a0b394e") } > db.demo683.insertOne({Value:500}); { "acknowledged" : true, "insertedId" : ObjectId("5ea468b0a7e81adc6a0b394f") } > db.demo683.insertOne({Value:1000}); { "acknowledged" : true, "insertedId" : ObjectId("5ea468b1a7e81adc6a0b3950") } > db.demo683.insertOne({Value:400}); { "acknowledged" : true, "insertedId" : ObjectId("5ea468b2a7e81adc6a0b3951") } > db.demo683.insertOne({Value:800}); { "acknowledged" : true, "insertedId" : ObjectId("5ea468b3a7e81adc6a0b3952") } ... Read More
Yes, you can skip some documents using skip() in MongoDB. Use limit() to display how many documents you want to display after skipping some. Let us create a collection with documents −> db.demo682.insertOne({FirstName:"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea462a804263e90dac94402") } > db.demo682.insertOne({FirstName:"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea462ac04263e90dac94403") } > db.demo682.insertOne({FirstName:"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea462af04263e90dac94404") } > db.demo682.insertOne({FirstName:"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea462b304263e90dac94405") } > db.demo682.insertOne({FirstName:"Adam"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea462ba04263e90dac94406") } > db.demo682.insertOne({FirstName:"Chris"}); { "acknowledged" : true, "insertedId" ... Read More
To get the topmost document, use find() along with limit(). To fetch only a single document, consider using limit(1). Let us create a collection with documents −> db.demo681.insertOne({_id:101, Name:"Chris"}); { "acknowledged" : true, "insertedId" : 101 } > db.demo681.insertOne({_id:102, Name:"Bob"}); { "acknowledged" : true, "insertedId" : 102 } > db.demo681.insertOne({_id:103, Name:"David"}); { "acknowledged" : true, "insertedId" : 103 } > db.demo681.insertOne({_id:104, Name:"Bob"}); { "acknowledged" : true, "insertedId" : 104 } > db.demo681.insertOne({_id:105, Name:"Sam"}); { "acknowledged" : true, "insertedId" : 105 }Display all documents from a collection with the help of find() method −> db.demo681.find();This will produce the following output −{ ... Read More
The $and performs a logical AND operation on an array of one or more expressions. Let us create a collection with documents −> db.demo680.insertOne({Values:40}); { "acknowledged" : true, "insertedId" : ObjectId("5ea4461b04263e90dac943fe") } > db.demo680.insertOne({Values:70}); { "acknowledged" : true, "insertedId" : ObjectId("5ea4461e04263e90dac943ff") } > db.demo680.insertOne({Values:[80, 30]}); { "acknowledged" : true, "insertedId" : ObjectId("5ea4462a04263e90dac94400") } > db.demo680.insertOne({Values:20}); { "acknowledged" : true, "insertedId" : ObjectId("5ea4463304263e90dac94401") }Display all documents from a collection with the help of find() method −> db.demo680.find();This will produce the following output −{ "_id" : ObjectId("5ea4461b04263e90dac943fe"), "Values" : 40 } { "_id" : ... Read More
Let us create a collection with documents −> db.demo677.insertOne({Value:10}); { "acknowledged" : true, "insertedId" : ObjectId("5ea421f404263e90dac943f8") } > db.demo677.insertOne({Value:50}); { "acknowledged" : true, "insertedId" : ObjectId("5ea421f704263e90dac943f9") } > db.demo677.insertOne({Value:20}); { "acknowledged" : true, "insertedId" : ObjectId("5ea421fa04263e90dac943fa") } > db.demo677.insertOne({Value:20}); { "acknowledged" : true, "insertedId" : ObjectId("5ea421fe04263e90dac943fb") }Display all documents from a collection with the help of find() method −> db.demo677.find();This will produce the following output −{ "_id" : ObjectId("5ea421f404263e90dac943f8"), "Value" : 10 } { "_id" : ObjectId("5ea421f704263e90dac943f9"), "Value" : 50 } { "_id" : ObjectId("5ea421fa04263e90dac943fa"), "Value" : 20 } { "_id" : ... Read More