Tutorial by Examples: c

Introduction to regular expressions in Kotlin

This post shows how to use most of the functions in the Regex class, work with null safely related to the Regex functions, and how raw strings makes it easier to write and read regex patterns. The RegEx class To work with regular expressions in Kotlin, you need to use the Regex(pattern: String) cl...

Kotlin • Regex

Fast Asymmetric File Encryption

Asymmetric encryption is often regarded as preferable to Symmetric encryption for transferring messages to other parties. This is mainly because it negates many of the risks related to the exchange of a shared key and ensures that whilst anyone with the public key can encrypt a message for the inten...

C# Language • Cryptography (System.Security.Cryptography)

Shopify local development with Theme Kit

Shopify themes can also be developed locally. Follow the steps below to setup local development environment: Install Shopify Theme Kit Get API Access Use a new theme or Configure an existing theme with theme kit Explanation of the above steps are as follows: Install Shopify Theme Kit A...

Shopify • Getting started with Shopify

Simple HttpClient AuthToken Interceptor (Angular 4.3+)

import { Injectable } from '@angular/core'; import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http'; import { UserService } from '../services/user.service'; import { Observable } from 'rxjs/Observable'; @Injectable() export class AuthHeaderInterceptor imple...

Angular 2 • Http Interceptor

Finding an object's class

To find whether an object was constructed by a certain constructor or one inheriting from it, you can use the instanceof command: //We want this function to take the sum of the numbers passed to it //It can be called as sum(1, 2, 3) or sum([1, 2, 3]) and should give 6 function sum(...arguments) {...

JavaScript • Datatypes in Javascript

Implementing policy deny rules

It is occasionally desirable to deny a certain Permission to some ProtectionDomain, regardless of any other permissions that domain accrues. This example demonstrates just one of all the possible approaches for satisfying this kind of requirement. It introduces a "negative" permission clas...

Java Language • SecurityManager

Place the user's pin in the map.

Note, if you are not familiar with the google maps api, you may read the precedent example (basics) in order to understand this little example. First, initialize the map. You may add an map's element in your HTML code and a bite of CSS like this: <!DOCTYPE html> <html> <h...

google-maps-api-3 • Getting started with google-maps-api-3

Faster multiplication or division by powers of 2

Shifting bits left (right) is equivalent to multiplying (dividing) by 2. It's the same in base 10: if we "left-shift" 13 by 2 places, we get 1300, or 13 * (10 ** 2). And if we take 12345 and "right-shift" by 3 places and then remove the decimal part, we get 12, or Math.floor(1234...

JavaScript • Bitwise Operators - Real World Examples (snippets)

Running Thread Safe Code from an Asynchronous Task

Sometimes you'll need to execute synchronous code from within an asynchronous task. To do this, simply schedule a synchronous task from within the asynchronous block. Bukkit.getScheduler().runTaskTimerAsynchronously(VoidFlame.getPlugin(), () -> { Bukkit.getScheduler().runTask(VoidFlame.ge...

bukkit • Scheduler Programming

Create association with new/custom file types via Info.plist

<key>CFBundleDocumentTypes</key> <array> <dict> <key>CFBundleTypeIconFile</key> <string>Icon file for associated file</string> <key>CFBundleTypeName</key> <string>My file format</string>...

osx • File association

Spring Boot and Spring Data Elasticsearch integration

In this example we are going to implement spring-data-elasticsearch project to store POJO in elasticsearch. We will see a sample maven project which does the followings: Insert a Greeting(id, username, message) item on elasticsearch. Get All Greeting items which have been inserted. Update a Gr...

spring-boot • Spring Boot + Spring Data Elasticsearch

Spring boot and spring data elasticsearch integration

In this example we are going to see a maven based spring boot application which integrates spring-data-elasticsearch. Here, we will do the followings and see the respective code segments. Insert a Greeting(id, username, message) item on elasticsearch. Get all items from elasticsearch Update a s...

spring-boot • Spring Boot + Spring Data Elasticsearch

Organizing new invoice numbers

Incrementing an invoice number and saving its value is a frequent task. Using CustomDocumentProperties (CDPs) is a good method to store such numbers in a relatively safe way within the same work book, but avoiding to show related cell values simply in an unprotected work sheet. Additional hint: A...

excel-vba • CustomDocumentProperties in practice

Secure express.js 3 Application

The configuration to make a secure connection using express.js (Since version 3): var fs = require('fs'); var http = require('http'); var https = require('https'); var privateKey = fs.readFileSync('sslcert/server.key', 'utf8'); var certificate = fs.readFileSync('sslcert/server.crt', 'utf8'); ...

Node.js • Securing Node.js applications

Docker and docker-compose

First of all, we will need to create our Dockerfile. A good example can be found on this blog by Nick Janetakis. This code contains the script that will be executed on our docker machine at the moment of start.For this reason, we are installing all the required libraries and ends with the start of ...

Ruby on Rails • Rails on docker

Carefully Closing a Scanner

it can happen that you use a scanner with the System.in as parameter for the constructor, then you need to be aware that closing the scanner will close the InputStream too giving as next that every try to read the input on that (Or any other scanner object) will throw an java.util.NoSuchElementExcep...

Java Language • Scanner

Delete local branches that have been deleted on the remote

To remote tracking between local and deleted remote branches use git fetch -p you can then use git branch -vv to see which branches are no longer being tracked. Branches that are no longer being tracked will be in the form below, containing 'gone' branch 12345e6 [origin/bran...

Git • Tidying up your local and remote repository

Convert blocking method to asynchonous

The following method will take a second or two depending on your connection to retrieve a web page and count the text length. Whatever thread calls it will block for that period of time. Also it rethrows an exception which is useful later on. public static long blockingGetWebPageLength(String urlS...

Java Language • CompletableFuture

Create and push tag(s) in GIT

Create a tag: To create a tag on your current branch: git tag < tagname > This will create a local tag with the current state of the branch you are on. To create a tag with some commit: git tag tag-name commit-identifier This will create a local tag with the commit-identifier...

Git • Git Tagging

Simple Example of CompletableFuture

In the example below, the calculateShippingPrice method calculates shipping cost, which takes some processing time. In a real world example, this would e.g. be contacting another server which returns the price based on the weight of the product and the shipping method. By modeling this in an async ...

Java Language • CompletableFuture