React or Localhsot CORS Error to Solve in Server Side Filters

package com.drvijayy2k2;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import com.product.sr.global.utils.Constants;

/**
 * The Class ContextFilters
 * ******* THIS CONTROLLER IS THE COMMON filter for the API context, this will receive all the request/response ********
 *
 * @author drvijay
 */

@Component
@Order ( 1 )
public class ContextFilters implements Filter, Constants
{


    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
     */
    @Override
    public void init ( FilterConfig arg0 ) throws ServletException
    {
    }

    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#destroy()
     */
    @Override
    public void destroy ()
    {
    }

    /*
     * (non-Javadoc)
     * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
     */
    @Override
    public void doFilter ( ServletRequest request, ServletResponse response, FilterChain chain ) throws IOException, ServletException
    {
        try
        {
            HttpServletRequest req = (HttpServletRequest) request;
            HttpServletResponse res = (HttpServletResponse) response;

            res.setHeader ( "Access-Control-Allow-Origin", "*" );
            res.setHeader ( "Access-Control-Allow-Credentials", "true" );
            res.setHeader ( "Access-Control-Allow-Methods", "ACL, CANCELUPLOAD, CHECKIN, CHECKOUT, COPY, DELETE, GET, HEAD, LOCK, MKCALENDAR, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, REPORT, SEARCH, UNCHECKOUT, UNLOCK, UPDATE, VERSION-CONTROL" );
            res.setHeader ( "Access-Control-Max-Age", "3600" );
            res.setHeader ( "Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Key, Authorization" );

            if ( "OPTIONS".equalsIgnoreCase ( req.getMethod () ) )
            {
                res.setStatus ( HttpServletResponse.SC_OK );
            }
            else
            {
                chain.doFilter ( req, res );
            }

        }
        catch ( Exception e )
        {
            //error
        }
    }

}

Telegram - Broadcast or Send Message through Programming Java Python C# VB

1. Create a bot token through @botfather.
           1.1 Install Telegram
           1.2 Login to telegram
           1.3 on Search window type @botfather and select
           1.4 type one by one until you see Done !, Congratulations , your token
                     /start
                     /newbot
                    drvautobot     (username)
                   
                   Done !, ...
                   token    123456:dsfd..

2. Copy this token and keep it.
   
3. Open telegram and create new channel.
     Ex: autobot
     3.1 open autobot channel window
     3.2 click on top to see administrators , click
     3.3 search @drvautobot (bot username), select
     3.4 assign as administrator

Thats it.
Now use browser or programing with GET method.

browser
https://api.telegram.org/bot/sendMessage?chat_id=@&text=hello

ex: https://api.telegram.org/bot123456:dsfdadsfsdfdsfahgjhgsfd/sendMessage?chat_id=@autobot&text=hello

response 

{"ok":true,"result":{"message_id":2,"chat":{"id":-1001493064021,"title":"Autobot","username":"infovijay","type":"channel"},"date":1566909775,"text":"hello"}}

open your channel window and see the text hello.


Enjoy

Nodejs code to convert string date to another date format.

Sample nodejs code to convert string date to another format.


date.js

var moment = require('moment');
bar ('1980-08-29', 'YYYY-MM-DD', 'DD/MM/YYYY');    //calling method

function bar(date, currentFormat, requiredFormat )
{
    var date = moment(date,currentFormat);
    var train_date = date.format(requiredFormat);
    console.log(train_date);        // 29/08/1980
    return train_date;
}
exports.bar = bar;



//npm install --save
//node date.js

NodeJS - Request Plugin for file attachment MULTIPART/FORM-DATA

package.json

{
  "name": "sample",
  "version": "1.0.0",
  "description": "",
  "main": "apicall.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "dependencies": { 
    "request": "^2.83.0" 
  }
}

apicall.js

var fs = require("fs");

var request = require("request");

var fs = require('fs');

var request = require('request');

request.post({

    url: 'https://url/upload',

    formData: {

keyName1: 'value1',

                keyName2: 'value2',               

               file: fs.createReadStream('d:/temp/30off.jpg')

    },

}, function(error, response, body) {

    console.log(body);

});

steps

npm install
node apicall.js

Nodejs - Decrypt for AES-256-CBC with no padding.

var crypto = require ( 'crypto' );
algorithm  = 'aes-256-cbc';

function decrypt ( key, data )
{
    var sha256 = crypto.createHash ( 'sha256' );
    sha256.update ( key );

    var input      = new Buffer ( data, 'base64' ),
        iv         = Buffer.alloc(16);
        ciphertext = input,
        decipher   = crypto.createDecipheriv( algorithm, sha256.digest (), iv ),
        plaintext  = decipher.update ( ciphertext );
    plaintext += decipher.final ();

    return plaintext
};

var deCodeValue = new Buffer ( "encrypted-content-place-here", 'base64' ).toString ( 'utf-8' );
console.log(deCodeValue);
var p           = decrypt ( 'password', deCodeValue );
console.log ( p );

NodeJs Access Form-Data Property Values

For recent version of NodeJs, You have to install multer plugin.

Package.json

{
  "name": "form-data-nodejs",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "dependencies": {
    "body-parser": "~1.15.1",
    "cookie-parser": "~1.4.3",
    "express": "~4.13.4",
    "multer": "^1.3.0"
  }
}

app.js

const express = require('express')

const app = express()

app.get('/', function (req, res) {

  res.send('Hello World!')

})

app.listen(3000, function () {

  console.log('Example app listening on port 3000!')

})

//let multer = require('multer');

//let upload = multer();

//if let gives error, use var

var multer = require('multer');

var upload = multer();

app.post('/send', upload.fields([]), (req, res) => {

  let formData = req.body;

  console.log('form data', formData.test);

  res.sendStatus(200);

});

>> node install --save

>> node app.js

https://github.com/expressjs/multer

Nodejs nodemailer - Send Email

1. go to cmd prompt in your root project folder 
   Type npm install nodemailer


2. create mail.js

var express = require('express');
var nodemailer = require("nodemailer");
var smtpTransport = require("nodemailer-smtp-transport")
var app = express();

var smtpTransport = nodemailer.createTransport(smtpTransport({
    host : "smpt.gmail.com",
    secureConnection : false,
    port: 587,
    auth : {
        user : "drvijayy2k2@gmail.com",
        pass : "test123"    }
}));
app.get('/send',function(req,res){
    var mailOptions={
        from : "drvijayy2k2@gmail.com",
        to : "drvijayy2k2@gmail.com",
        subject : "Your Subject",
        text : "Your Text",
        html : "HTML GENERATED",
        /*attachments : [
            {   // file on disk as an attachment                //filename: 'a.txt',                path: 'd:/a.txt' // stream this file, use only path property and send the file name in the end, else you may get folder read error            }
        ]*/
    }
    console.log(mailOptions);
    smtpTransport.sendMail(mailOptions, function(error, response){
        if(error){
            console.log(error);
            res.end("error");
        }else{
            console.log(response.response.toString());
            console.log("Message sent: " + response.message);
            res.end("sent");
        }
    });
});

app.listen(3000,function(){
    console.log("Express Started on Port 3000");
});

3. Go to command prompt where the mail.js stored

    Type node mail.js

4. open brower

 http://localhost:3000/send

NodeJs VelocityJs in web app - Template Engine

just create a sample  velocity-text.js  file.

/** * Created by drvijay on 12-10-2016. */
   var context = {
        "name": "velocity"    }

var initialString = "Hello, ${name}!";

var velocityjs = require("velocityjs");
var renderedString = velocityjs.render(initialString,context);
console.log(context);
console.log(initialString);
console.log(renderedString);


// go to cmd type node velocity-text.js

INSTALL

First install velocityjs in your node_modules

npm install velocityjs

Now from your project (where the node_modules mentioned above exists) use browserify

browserify -r velocityjs  > velocity.js

This will create a velocity.js file that you can include in your website directly. If you don't have browserify then do npm install -g browserify

Usage

In your webpage js file first require velocityjs

var velocityjs = require("velocityjs");

Now to get the templated html do

var renderedString = velocityjs.render(initialString,context)

Note that velocity does not care if your initial string was html or not, you need to ensure that

NodeJs VelocityJs in web app - Template Engine

just create a sample  velocity-text.js  file.

/** * Created by drvijay on 12-10-2016. */
   var context = {
        "name": "velocity"    }

var initialString = "Hello, ${name}!";

var velocityjs = require("velocityjs");
var renderedString = velocityjs.render(initialString,context);
console.log(context);
console.log(initialString);
console.log(renderedString);


// go to cmd type node velocity-text.js

INSTALL

First install velocityjs in your node_modules

npm install velocityjs

Now from your project (where the node_modules mentioned above exists) use browserify

browserify -r velocityjs  > velocity.js

This will create a velocity.js file that you can include in your website directly. If you don't have browserify then do npm install -g browserify

Usage

In your webpage js file first require velocityjs

var velocityjs = require("velocityjs");

Now to get the templated html do

var renderedString = velocityjs.render(initialString,context)

Note that velocity does not care if your initial string was html or not, you need to ensure that