In Part 1 to 4, we went through solidity to develop smart contract in Remix, setup development environment, created unit testing methods for smart contract, created a front-end application with Node.js to interact with smart contracts. Now, we will deploy smart contract using truffle and infura. Also, will deploy Node.js application to Heroku.
Creating Web App for Smart Contract [Full Stack Ethereum Dapp Part-4]
In Part-3, we created unit test methods for smart contract. Now, we will create a simple webpage to interact with the smart contract. The goal is to create a page with a textbox to enter name, buttons to save name and to get message.
Unit Testing On Smart Contract with Truffle [Full Stack Ethereum Dapp Part-3]
In Part-2, we deployed our smart contract on local private Ethereum blockchain. Now, we will test out our Solidity smart contracts behaviour with unit testing with Truffle which uses Chai and Mocha frameworks. In web development lifecycle, unit testing is needed to do to ensure the code is working the way as it is expected. So let’s start it by creating a test file by running following command:
Setup Dev Environment with a Local Blockchain and Deploy Smart Contract [Full Stack Ethereum Dapp Part-2]
In Part-1, we made Hello World contract in Remix. As we have to write code in the files and manage in repository for development perspective so in this blog post, we will setup our development environment, a private Ethereum blockchain on local machine and deploy our smart contract on the blockchain. I am using Ubuntu 18 for writing this post. But can be setup on Windows and MAC machines.
Hello World Smart Contract In Solidity [Full Stack Ethereum Dapp Part-1]
In this tutorial series, we are going to build a simple Hello World Dapp (decentralized application) on Ethereum with Solidity, Truffle & Web3 tech stack. After this, we will deploy it to test network (Infura and Heroku). This dapp will simply store and retrieve user input text on Ethereum.
In part one, we’ll write a smart contract in Solidity using Remix. Let’s build a simple ‘Hello World’ application (The best way to learn new technologies). It is assumed you know the basics of Blockchain and its terminology. Here is quick intro of some terms:
JavaScript Async/Await: Serial, Parallel and Complex Flow
If you have experience on ASP.NET MVC then probably you are familiar with async/await keywords in C#. The same thing is now in JavaScript. Before that, Callbacks and Promises are used for asynchronous code. Async/await is built on top of promises and non blocking. The power of Async/await provides asynchronous code look like synchronous code. In this article, we will go through serial/chain and parallel flow and implement a complex flow using Async/Await.
Read Also: JavaScript Promises: Understanding Error Handling with Example
Introducing HISAAB – Online Tool To Track Expenses With Your Voice
It’s time to welcome HISAAB, a simple online speech recognition app, for tracking your expenses with your voice i.e. no need to type. It will help you to note your expenses and calculate the total amount quickly. It allows you to Copy, Email, Save or Print the data. It supports English and Hindi languages.
Visual Studio Code: Debugging ES6 Mocha tests with Babel
In my post, I explained how to test server side REST APIs in Node.js using Mocha, Sinon and Chai. I used ES6 test methods for this and Babel is used to execute it. As test methods are executed at development end, so NO need to transpile ES6 to ES5 first and then debug the converted files. You can directly debug ES6 code with Babel.
API Versioning, Express Routers and Node.js
Do you want to set up an API versioning in Node.js and Express environment? This tutorial explains the different ways to do REST API versioning step by step. We will implement the following routing for the versioning:
GET /api/v1.0/
POST /api/v1.0/
GET /api/v2.0/
POST /api/v2.0/
Node.js: Traversing A Directory Recursively with Limited Depth
In this post, we will implement to get all files recursively in a directory using Node.js. Also, will restrict it to traverse directory with limited recursively depth.
Before we get started, consider the following directory structure(For simplicity, the name is according to their depth level i.e. folder 1, sub folder 1.1, sub sub folder 1.1.1…etc):
1 > 1.1 > 1.1.1> 1.1.1.1 > 1.1.1.1.1 2 > 2.1 > 2.1.1 > 2.2
Each directory has txt file with same directory name(means 1.1 will have 1.1.txt file).
WordPress: Disable 404 Redirect to Homepage
If you don’t know what 404 error is, It is an error displayed on when a user requests a web page that couldn’t be found on their server (i.e. the requested webpage is not available). In this case, If you are redirecting (302 redirects) to home page then it is confusing for end user. Definitely, you should avoid 302 redirecting for non-existent URL. Probably you don’t want to send a low quality signal to Google and other engines if they are testing how 404’s are being handled by requesting a noexist page. The best solution is to create custom 404 page having search box saying “Did you mean …?”
In this post, we will see how to prevent 404 Redirect to Homepage in WordPress.
ASP.NET MVC: Display Total and Avg in Table footer in Razor Views
There are various cases in which you may want to display results from aggregate functions (Sum, Avg, Count, Min, Max) performed over the columns in the grid in their footer. This post explains how to display aggregate functions in ASP.NET MVC Razor views.
Used Environment for this post: VS 2015 Update 3, ASP.NET MVC 5
For ASP.NET Web Forms, Read following post:
Displaying Total in ASP.NET Gridview Footer Row Without using Template Field
Best Free WordPress Quiz Plugins: WP Quiz vs Quiz And Survey Master vs WP Pro Quiz
Do you want to conduct a Quiz on your WordPress website to increase user engagement and looking for best free WordPress plugins? In this article, we will compare the following best 3 plugins:
HTTP to HTTPS Migration, WordPress and SEO
Before I start this article, I would like to ask one question to you, How many HTTPS links do you see in first page of Google search result? Generally, I get more than 50% for my search queries and major top links belong to HTTPS. It is self explanatory how important HTTPS and SSL is. As SSL is mandatory for safely processing transaction e-commerce website, but here I am not going to talk about security and safety, my concern is SEO. The web is moving toward using HTTPS encryption by default and it is encouraged by Google with announcement HTTPS as a ranking signal in 2014. Chrome and Firefox browsers started to display warning for HTTP (Non secure) websites. So you decided to move on HTTPS. Hold a minute and see the challenges. you will get many examples on Google saying huge drop in traffic after moving HTTPS if not implemented properly. So you must aware of the challenges. In this post, we will move a WordPress website to HTTPS, Setup free SSL and update dependencies to meet SEO guidelines. It is assumed Apache server is used in Ubuntu server.
Azure Functions + Cognitive Services: Automate Image Moderation
Generally, User submitted images (profile pictures, social media posts, and business documents) are needed to be moderated to protect business and quality. If a large number of images are submitted in an application then manual moderation is time consuming and is not instantaneous. This post explains how to automate image moderation using Azure functions and Cognitive Services. Automated moderation applies machine learning and AI to cost-effectively moderate at scale, without human involvement.