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Introduction
When compared with traditional systems, smart contracts make financial transactions efficient, hassle-free, and transparent. Since blockchain transactions are encrypted, it ensures improved security during money transactions. With industries becoming more aware of smart contracts' benefits, it is emerging as a trend in the business world now. By putting blockchain technology into action, businesses can track goods' status in real-time throughout its movement in the supply chain.
It provides an innovative and dynamic way to streamline various functions involved in supply chain management and improve business outcomes. Blockchain technology is considered to become a game-changer in the media and entertainment industry with an extensive range of applications.
It is now used to eliminate frauds, protect Intellectual Property rights of the content, reduce expenses, etc. Blockchain technology is slowly disrupting the insurance industry as it addresses some of the major pain points in the current processes.
With blockchain technology, insurance companies can alter claims submission processes, decrease frauds, streamline payments, improve customer experience, etc. Be it governments, businesses, or non-profit agencies; record management is often cumbersome and frustrating. Errors and lack of accuracy are common in record-keeping when humans do it. Blockchain is a savior here as it simplifies the process, improves security, and ensures efficiency in managing records.
Blockchain is capable of making the voting process easy, efficient, and secure. It negates the chance of election fraud as each vote will be given a unique ID. Governments can improve the efficiency of tax collection and filing processes by taking advantage of blockchain. Furthermore, this technology opens the door to better regulatory oversight on businesses and organizations, allowing prior detection of red flags and lack of compliance. Anyone passionate about learning this revolutionary technology can learn about blockchain and eventually apply it to personal or professional purposes.
You don't need to learn to code for learning blockchain technology. Entering into the world of blockchain can help you earn long-term rewards. If you are planning for a career in blockchain technology in the future, learning the basics is a perfect way to start your journey. If you're passionate about technology, you can begin learning the fundamental concepts of blockchain.
The learning experience becomes easy if you have basic knowledge about programming languages, coding, and data structure. However, if you are looking forward to building a career in blockchain soon, you should possess technical skills too.
To become a blockchain developer, one should have a good understanding of informational technologies, information security, and computer science. The person should possess a basic idea about concepts like networking, distributed systems, cryptography, data structures, etc. Blockchain is one of the widely discussed concepts in the business world. Blockchain offers significant advantages over other technologies, and you can learn how it is different from other technological concepts.
You will learn why blockchain transactions are highly secured in this chapter. The second lesson ends with a section on how blockchain finds excellent use in the banking field.
Many industries across the world have already started to reap the various benefits of blockchain technology. Cryptocurrencies like Bitcoin and Ethereum have significant advantages over traditional fiat currencies.
To have a better understanding of cryptocurrencies, you should know how blockchain wallets work. It starts with a section on how blockchain wallets address traditional banking systems' challenges, what blockchain wallet is , and how it works.
It starts with the history of currency and explains the features of the present currency systems. It details the differences between conventional currency systems and cryptocurrencies. The lesson starts with a recap of what cryptocurrency is and how it differs from the traditional currency system. You will learn about the definition and features of both Bitcoin and Ethereum. Ethereum is often referred to as the most popular cryptocurrency after Bitcoin.
Well, that was easy! Call them sub-divisions of Blockchain development. A Core Blockchain Developer designs the security and the architecture of the proposed Blockchain system. In essence, the Core Blockchain Developer creates the foundation upon which others will then build upon. That would be the Blockchain Software Developers, of course, who use the core web architecture built by the Developer to create apps, specifically the decentralized dapps and web varieties.
Perhaps there may be situations where the same person fulfills both roles, most likely in cases where the business is small, and people traditionally wear more than one hat. Whatever the case, the everyday responsibilities and roles of the Blockchain developer are:. The developer also performs complex analysis, design, development, testing, and computer software debugging, specifically for distinct product hardware or for technical service lines of businesses. Develops perform software design, operating architecture integration, and computer system selection.
Finally, they operate on multiple systems and apply knowledge of one or more platforms and programming languages. Of course, obstacles are awaiting the Blockchain developer. For instance, the developer has to work with legacy infrastructure and its limitations, while still meeting the expectations inherent in a Blockchain development project. Also, there are the challenges of understanding the technical practicality of implementing decentralized cryptosystems, processes that fall outside of the traditional IT development skill-set, which means a Blockchain developer needs specialized skills.
So, after all of that, the questions present itself: with all of these responsibilities, how does one train someone with the necessary skills to let them rise to the challenge of Blockchain development? There are two different situations at work here.
There are the Blockchain hopefuls who are starting completely from scratch, having no background in programming whatsoever, and those who have experience in careers that share similarities with Blockchain.
Before we dive into those two different types of people aspiring to become Blockchain developers, it may help to familiarize ourselves with the kind of mindsets that are best suited for Blockchain developers. After all, the unique challenges of Blockchain development require a certain unique way of thinking. Furthermore, a good Blockchain developer works well with a team and can collaborate. On a related point, the ideal Blockchain developer knows when to ask for help with a problem and when to keep plugging away by themselves until they arrive at the answer.
So the best candidate for Blockchain development works well with others, knows his or her limitations, and can unconventionally approach problems. Fortunately, there is hope! Here are some steps that anyone coming from such a place, but yet is interested in a Blockchain developer career can take. Upskilling is the process of teaching an employee new skills.
This process is particularly useful when it comes to creating new Blockchain developers from other, similar positions in the business.
Some companies, keenly aware of the growing importance of the Blockchain technology , will upskill individual employees, empowering them to handle the new tech.
If the prospect of getting in on the ground floor of this exciting innovation appeals to you, then you may wonder what the next step is. Whichever the method, you will benefit from 32 hours of instructor-led training, over 50 hands-on exercises using Blockchain technology, nine practical projects are covering Ethereum, Bitcoin, and Hyperledger, and 24 x7 assistance and support.
It should be mentioned that the Corporate Training solution is ideal for businesses that want to upskill chosen employees and make them into Blockchain developers. Once you complete the course, you will have certification in Blockchain development, and be ready to take on the new challenges of this exciting technology. Simplilearn stands ready to be a valuable resource for you to not only become a Blockchain developer, but also to provide additional training and skills in related topics such as DevOps, Software Development, and Cloud Computing.
Check out Simplilearn and get started on a new, rewarding, and profitable career! John Terra lives in Nashua, New Hampshire and has been writing freelance since Besides his volume of work in the gaming industry, he has written articles for Inc. More recently, he has done extensive work as a professional blogger. His hobbies include running, gaming, and consuming craft beers. His refrigerator is Wi-Fi compliant. Lesson - 8 What is a Smart Contract in Blockchain?
Previous Next. Tutorial Playlist. Essentially, any developer involved in the development of blockchain technology can be tagged as a blockchain developer. Blockchain developers can be classified into two distinct types:.
A Core Blockchain Developer designs the security and architecture of the proposed Blockchain system. In essence, the Core Blockchain Developer creates the foundation on which others will build. On the other hand, Blockchain software developers use architecture and protocol designed by Core Blockchain developers to build decentralized applications that run on blockchain technology.
When it comes to a blockchain developer, there are some skills that are fundamentals. You should be comfortable with object-oriented programming, and developing web apps in Javascript.
Fortunately, there is hope! Here are some steps anyone coming from such a place, but interested in a career Blockchain developer can take. One of the biggest hurdles to anything new and revolutionary, such as blockchain technology, is getting used to the various concepts that are indispensable in the system. Otherwise, you will be very out of place in your learning process.
If you are interested in the technical aspects of how to create a fin-tech application on Blockchain then you should definitely take in a deep understanding of token economics. This difference in knowledge is extremely obvious when you research some floating ICOs.
It is very clear that the economic side of their ICO is not well thought-through. After that, you should understand how Bitcoin works. Bitcoin is the most popular in blockchain and has a sizable influence on the crypto market. Now congrats, you have finished the first milestone. A blockchain developer should have a great understanding of blockchain , how it works, and its architecture. They need to have at hand concepts such as cryptographic hash functions, consensus, distributed ledger technology.
Read our latest white papers and reports. Chainlink engineering tutorials. Step-by-step tutorials. If you're new to smart contract development, start here. Learn how to consume random numbers in smart contracts. Video tutorials. Building and Using External Adapters. Watch tutorial videos Read the docs. Get started with Chainlink guides. How to Build a Blockchain Lottery. Read more guides. New to smart contracts?
Blockchain Tutorial For Beginners
Many Governments and leading Banks have decided to bring many of their conventional transactions based on Blockchain concept. The applications and potential of this framework is huge and is considered to be changing the way transactions are made in various domains.
This tutorial has been prepared for professionals aspiring to learn the basics of Blockchain. We tried to explain Blockchain concepts through Bitcoin Crypto Currency. This course is going to give you great understanding for the students and professionals aspiring to make a career in the Blockchain technology. This tutorial will teach you blockchain technology, the driving force behind the cryptocurrency, Bitcoin.
The miner that guesses this number first submits their answer, or "proof of work". This authorizes them to record the transaction to the blockchain and receive a Bitcoin reward for winning the mining competition. Whenever they record it, they create a new transaction record on the blockchain.
Groupings of transactions are called "blocks" which get "chained together" to make up the blockchain. During the mining process, the network reaches "consensus", meaning that each node verifies that they have the same valid data as everyone else. This mechanism is called the "consensus algorithm". Effectively, each node says, "yes, I have a valid copy of Alice's transaction".
If they all agree, then the transaction is complete. The cryptocurrency is transferred from Alice's account to Bob's. When Bob checks his wallet, he'll see that he now has 1 BTC! Let's continue on with our banking example. Here are some of the reasons Alice might choose to use the blockchain to store and send money:.
Up until now, we have discussed how to send money with the Bitcoin blockchain. Now I want to focus on how to build applications that run on the blockchain. Bitcoin is quite limited in this area, so we will instead look at a different blockchain called Ethereum. In addition to sending cryptocurrency, Ethereum allows developers to create decentralized applications, or dApps, that run on the blockchain. Ethereum achieves this with smart contracts, which are programs that run on the blockchain.
Let's see how these apps work. Normally when you use a web application, you use a web browser to load a web page that talks to a central web server over a network.
All of the code for this app lives inside this central server, and all the data is housed inside a central database. Anytime you transact with this application, you must interact directly with this central server.
This presents a few problems. The application creators could change the application code on the server, or the database at any time because they have full control.
We can use our browser to load a web page that talks directly to the blockchain instead of a backend server and database. We can store all of the application code and data on a blockchain instead of this central server. This is a fully transparent and trustworthy way of knowing that the application code and data won't change. All of the backend code for the application will be made up of smart contracts. These are immutable a. Once the code is put on the blockchain, no one can change it, and we know it will work the same way every time.
Smart contracts are written in a language called Solidity which looks a lot like JavaScript. They work much like a microservice on the web. Also, they're called smart contracts because they represent an unchangeable digital covenant, or agreement.
All of the data for the application will be stored as transaction records, inside of blocks on the blockchain. As we saw earlier, each node on the network maintains a copy of this data to ensure that it is secure and unchanged. That's how a blockchain application works from a high level.
In the next section, we'll get a closer look by building one together. Let's get a much deeper understanding of how blockchain works by building a full-stack application step-by-step. Here is a preview of the app that we'll build together:. This is a blockchain social network powered by smart contracts where you can get paid to post.
It also has a slick mobile-friendly user interface, where everyone gets a fancy icon automatically for their account. Now let's set up our development environment to start coding. We'll install all the dependencies we need to build the project. The first dependency you'll need is Node. We'll use NPM to install other dependencies in this tutorial.
You can check if you already have Node installed by executing this command from your terminal:. If you don't have it installed yet, you can download it directly from the Node. The next dependency is a development blockchain, which can be used to mimic the behavior of a production blockchain. We'll use Ganache as our development blockchain for this tutorial. We can use it to develop smart contracts, build applications, and run tests.
Find the latest release for your operating system here. The next dependency is the Truffle Framework , which gives us a suite of tools for developing blockchain applications.
It will enable us to develop smart contracts, write tests against them, and deploy them to the blockchain. Now let's install the Metamask Ethereum Wallet in order to turn our web browser into a blockchain browser. Your current web browser most likely doesn't support this natively, so we need the Metamask extension for Google Chrome in order to connect to the blockchain.
Visit this link to install Metamask, or simply search for it in the Google Chrome web store. Upon installation, ensure that you've enabled it in your list of Chrome extensions it should be "checked". When it's active, you will see a fox icon in the top right hand corner of your browser. Find where you installed Ganache, and open it. Once it's loaded, you have a blockchain running on your computer!
You should see 10 accounts provided by Ganache, each pre-mined with fake Ether don't get excited, this Ether isn't worth real money. Each account has a unique public and private key pair. You can see each account's address on the main screen here. Remember, accounts are much like "usernames" on the blockchain, and they represent each user who can post to our social network. Now let's create a new project for all of our application code. Instead of doing this from scratch, I'm going to use a template that I created to help us get started quickly.
You can clone this template from github like this:. Open the project in your text editor of choice, and find the truffle-config. This is where we will store all of the settings for our Truffle project. I have already configured the project to connect to the Ganache development blockchain on I have changed this from the default Truffle project configuration so that we can access these files from our front end application in the src directory.
These values are normally. This file contains all of the project dependencies we need to build the application. I have included all the dependencies we need inside this starter kit template. If you did everything correctly, your web browser should open automatically to a page that looks like this:.
You've just set up the project. This is all of the template code that we will modify to create our app. Now, let's code the smart contract to power the backend of the social network app. It will allow users to create new posts so that they can be shared in the newsfeed and tipped by other users. This is the file where we'll write all the Solidity source code for the smart contract just a reminder, this is inside a custom src directory, which is different from a default truffle project.
Let's create a simple "systems check" to ensure that our project is set up properly, and that we can deploy this smart contract to the blockchain successfully. Start by entering this code into the SocialNetwork. I'll explain this code. The first line declares the Solidity programming language version that we'll use, i.
Next, we create the smart contract with the contract keyword, followed by the smart contract name Social Network. Next, we define a state variable that will represent the name of our smart contract.
This state variable's value will get stored directly to the blockchain itself, unlike a local variable which will not. We specify that this variable is a string. We must do this because Solidity is a statically typed language, meaning once we specify that this variable is a string, it cannot be a different data type later like a number.
Then we declare the state variable public with a modifier. This tells Solidity that we want to read this variable value from outside the smart contract. Because we have done this, Solidity will automatically create a name function behind the scenes that will return this variable's value we won't have to code it ourselves. Finally, we create a constructor function with the constructor keyword.
This is a special function that gets called only once whenever the smart contract is created, i. Inside this function, we set the value of the name state variable to "Dapp University Social Network". In order to do this, we must create a new migration file. Truffle uses these migrations to add new files to the blockchain.
These are similar to migration files in other development frameworks where you make changes to a database, like adding new columns in tables. This code simply tells Truffle that we want to deploy the Social Network smart contract to the blockchain. Don't worry if you don't understand everything inside this file. Now let's put this smart contract on the blockchain i. Ganache by running the migrations from the command line like this:.
Inside the console, we can write JavaScript code to interact with our development blockchain and smart contracts. Let's fetch an instance of the deployed social network smart contract and store it to a variable like this:. You'll see that the console returns undefined here. That's ok. We simply need to enter the variable name to return is value like this:. You have just coded your first smart contract and deployed it to the Ethereum blockchain.
Let's continue building out the smart contract. As we write the Solidity code, we will simultaneously write tests for the smart contract with JavaScript inside a separate file with for a few reasons:. Inside this file, we can scaffold a test for the smart contract with the help of the Mocha testing framework and the Chai assertion library that comes bundled with the Truffle framework.
Let's start off with this basic code:. This code should look very similar to the operations we performed inside the console from the previous section. Check out the companion video for a more detailed explanation of this test. Now that the test suite is set up, let's continue developing the smart contract. We'll program a way for users to create new posts in the social network.
Finally, we use the public modifier to ensure that we can call the function outside the smart contract, i. Next, we need a way to model the post. We'll use a Struct for this. Solidity allows us to define our own data structures with Structs. In our case, we'll define a Post struct like this:. This struct allows us store the post's id, content, tip amount, and author.
We declare the data type for each of these values in the code above. Next, let's create a way to store new posts on the blockchain. We'll use a Solidity mapping to do this:. This mapping will uses key-value pairs to store posts, where the key is an id, and the value is a post struct.
These mappings are a lot like associative arrays or hashes in other programming languages. Whenever we add new posts to the mapping, they will be stored on the blockchain. Because we used the public modifier we can also fetch posts by calling the posts function, which Solidity will create behind the scenes.
We will increment this value whenever new posts are created to generate post ids we'll see that in action momentarily. I will also note that we use msg. This is a special variable value provided by Solidity that tells us the user who called the function. We don't have to pass this value in as a function argument. We get it magically with Solidity. Now, let's trigger an event whenever the post is created. Solidity allows us to create events that external consumers can subscribe to like this:.
Lastly, let's add a validation to ensure that users can't post blank content. We'll do that in the first line of our function like this:. This uses Solidity's require to ensure that the post has content before the rest of the code executes. If the expression inside require evaluates to true, the function will continue execution. If not, it will halt. That's it! That's the complete code for creating new posts. At this point your smart contract code should look like this:. Now, let's add some test examples to ensure that this function works.
Add this code to your test file:. Also, we modified the test suite to include 3 different users: deployer , author , and tipper. We can do this instead of using the accounts variable that was injected by default.
How To Become a Blockchain Developer: A Step-by-Step Guide
Here are some of the reasons Alice might choose to use the blockchain to store and send money:. Up until now, we have discussed how to send money with the Bitcoin blockchain. Now I want to focus on how to build applications that run on the blockchain.
Bitcoin is quite limited in this area, so we will instead look at a different blockchain called Ethereum. In addition to sending cryptocurrency, Ethereum allows developers to create decentralized applications, or dApps, that run on the blockchain.
Ethereum achieves this with smart contracts, which are programs that run on the blockchain. Let's see how these apps work. Normally when you use a web application, you use a web browser to load a web page that talks to a central web server over a network.
All of the code for this app lives inside this central server, and all the data is housed inside a central database. Anytime you transact with this application, you must interact directly with this central server.
This presents a few problems. The application creators could change the application code on the server, or the database at any time because they have full control. We can use our browser to load a web page that talks directly to the blockchain instead of a backend server and database. We can store all of the application code and data on a blockchain instead of this central server. This is a fully transparent and trustworthy way of knowing that the application code and data won't change.
All of the backend code for the application will be made up of smart contracts. These are immutable a. Once the code is put on the blockchain, no one can change it, and we know it will work the same way every time. Smart contracts are written in a language called Solidity which looks a lot like JavaScript. They work much like a microservice on the web. Also, they're called smart contracts because they represent an unchangeable digital covenant, or agreement.
All of the data for the application will be stored as transaction records, inside of blocks on the blockchain. As we saw earlier, each node on the network maintains a copy of this data to ensure that it is secure and unchanged.
That's how a blockchain application works from a high level. In the next section, we'll get a closer look by building one together. Let's get a much deeper understanding of how blockchain works by building a full-stack application step-by-step. Here is a preview of the app that we'll build together:. This is a blockchain social network powered by smart contracts where you can get paid to post. It also has a slick mobile-friendly user interface, where everyone gets a fancy icon automatically for their account.
Now let's set up our development environment to start coding. We'll install all the dependencies we need to build the project. The first dependency you'll need is Node. We'll use NPM to install other dependencies in this tutorial. You can check if you already have Node installed by executing this command from your terminal:. If you don't have it installed yet, you can download it directly from the Node. The next dependency is a development blockchain, which can be used to mimic the behavior of a production blockchain.
We'll use Ganache as our development blockchain for this tutorial. We can use it to develop smart contracts, build applications, and run tests. Find the latest release for your operating system here. The next dependency is the Truffle Framework , which gives us a suite of tools for developing blockchain applications.
It will enable us to develop smart contracts, write tests against them, and deploy them to the blockchain. Now let's install the Metamask Ethereum Wallet in order to turn our web browser into a blockchain browser. Your current web browser most likely doesn't support this natively, so we need the Metamask extension for Google Chrome in order to connect to the blockchain.
Visit this link to install Metamask, or simply search for it in the Google Chrome web store. Upon installation, ensure that you've enabled it in your list of Chrome extensions it should be "checked". When it's active, you will see a fox icon in the top right hand corner of your browser. Find where you installed Ganache, and open it.
Once it's loaded, you have a blockchain running on your computer! You should see 10 accounts provided by Ganache, each pre-mined with fake Ether don't get excited, this Ether isn't worth real money.
Each account has a unique public and private key pair. You can see each account's address on the main screen here. Remember, accounts are much like "usernames" on the blockchain, and they represent each user who can post to our social network. Now let's create a new project for all of our application code. Instead of doing this from scratch, I'm going to use a template that I created to help us get started quickly. You can clone this template from github like this:.
Open the project in your text editor of choice, and find the truffle-config. This is where we will store all of the settings for our Truffle project. I have already configured the project to connect to the Ganache development blockchain on I have changed this from the default Truffle project configuration so that we can access these files from our front end application in the src directory. These values are normally. This file contains all of the project dependencies we need to build the application.
I have included all the dependencies we need inside this starter kit template. If you did everything correctly, your web browser should open automatically to a page that looks like this:. You've just set up the project. This is all of the template code that we will modify to create our app.
Now, let's code the smart contract to power the backend of the social network app. It will allow users to create new posts so that they can be shared in the newsfeed and tipped by other users.
This is the file where we'll write all the Solidity source code for the smart contract just a reminder, this is inside a custom src directory, which is different from a default truffle project. Let's create a simple "systems check" to ensure that our project is set up properly, and that we can deploy this smart contract to the blockchain successfully.
Start by entering this code into the SocialNetwork. I'll explain this code. The first line declares the Solidity programming language version that we'll use, i. Next, we create the smart contract with the contract keyword, followed by the smart contract name Social Network.
Next, we define a state variable that will represent the name of our smart contract. This state variable's value will get stored directly to the blockchain itself, unlike a local variable which will not. We specify that this variable is a string.
We must do this because Solidity is a statically typed language, meaning once we specify that this variable is a string, it cannot be a different data type later like a number. Then we declare the state variable public with a modifier.
This tells Solidity that we want to read this variable value from outside the smart contract. Because we have done this, Solidity will automatically create a name function behind the scenes that will return this variable's value we won't have to code it ourselves.
Finally, we create a constructor function with the constructor keyword. This is a special function that gets called only once whenever the smart contract is created, i. Inside this function, we set the value of the name state variable to "Dapp University Social Network". In order to do this, we must create a new migration file. Truffle uses these migrations to add new files to the blockchain. These are similar to migration files in other development frameworks where you make changes to a database, like adding new columns in tables.
This code simply tells Truffle that we want to deploy the Social Network smart contract to the blockchain. Don't worry if you don't understand everything inside this file. Now let's put this smart contract on the blockchain i. Ganache by running the migrations from the command line like this:. Inside the console, we can write JavaScript code to interact with our development blockchain and smart contracts.
Let's fetch an instance of the deployed social network smart contract and store it to a variable like this:. You'll see that the console returns undefined here. That's ok. We simply need to enter the variable name to return is value like this:. You have just coded your first smart contract and deployed it to the Ethereum blockchain.
Let's continue building out the smart contract. As we write the Solidity code, we will simultaneously write tests for the smart contract with JavaScript inside a separate file with for a few reasons:. Inside this file, we can scaffold a test for the smart contract with the help of the Mocha testing framework and the Chai assertion library that comes bundled with the Truffle framework.
Let's start off with this basic code:. This code should look very similar to the operations we performed inside the console from the previous section. Check out the companion video for a more detailed explanation of this test. Now that the test suite is set up, let's continue developing the smart contract. We'll program a way for users to create new posts in the social network. Finally, we use the public modifier to ensure that we can call the function outside the smart contract, i.
Next, we need a way to model the post. We'll use a Struct for this. Solidity allows us to define our own data structures with Structs. In our case, we'll define a Post struct like this:. This struct allows us store the post's id, content, tip amount, and author. We declare the data type for each of these values in the code above.
Next, let's create a way to store new posts on the blockchain. We'll use a Solidity mapping to do this:. This mapping will uses key-value pairs to store posts, where the key is an id, and the value is a post struct. These mappings are a lot like associative arrays or hashes in other programming languages.
Whenever we add new posts to the mapping, they will be stored on the blockchain. Because we used the public modifier we can also fetch posts by calling the posts function, which Solidity will create behind the scenes.
We will increment this value whenever new posts are created to generate post ids we'll see that in action momentarily. I will also note that we use msg. This is a special variable value provided by Solidity that tells us the user who called the function.
We don't have to pass this value in as a function argument. We get it magically with Solidity. Now, let's trigger an event whenever the post is created. Solidity allows us to create events that external consumers can subscribe to like this:. Lastly, let's add a validation to ensure that users can't post blank content. We'll do that in the first line of our function like this:.
This uses Solidity's require to ensure that the post has content before the rest of the code executes. If the expression inside require evaluates to true, the function will continue execution. If not, it will halt. That's it! That's the complete code for creating new posts. At this point your smart contract code should look like this:. Now, let's add some test examples to ensure that this function works.
Add this code to your test file:. Also, we modified the test suite to include 3 different users: deployer , author , and tipper. We can do this instead of using the accounts variable that was injected by default. In this section, we'll create a function that allows users to tip others post with cryptocurrency. Before we do that, let's address a few things.
Any time we store data on the Ethereum blockchain, we must pay a gas fee with Ether Ethereum's cryptocurrency. This is used to pay the miners who maintain the network. Since we stored a new post on the blockchain, a small fee was debited from our account. You can see that your account balance has gone down in Ganache. While storing data on the blockchain costs money, fetching does not. In summary, reads are free, but writes cost gas. Next, we need to add a test to ensure that we can list out all of the posts from the social network.
Inside your test file, use this code:. Now let's move on to creating a function that allows other users to tip posts with cryptocurrency:. The IBM Blockchain Platform accelerates collaboration in this decentralized world by leveraging open source technology from the Hyperledger Fabric framework. The IBM Blockchain Platform makes it fast and easy for network members to start developing and quickly move to a collaborative environment with the performance, privacy, and security for even the most demanding use cases and regulated industries.
The newest options give you the flexibility to bring your own infrastructure and deploy anywhere. This means deploy on-prem, or another hosting provider, while connecting your blockchain nodes and members together to transact. The platform is designed to be an easy and economical on-ramp to developing and testing pre-production applications through growing production ecosystems.
This development and testing environment is ideal for network operators and developers who are exploring blockchain technology or want to build a blockchain network for demos, pilots, or proof of concepts. Any developer — whether enterprise, start-up, academic, novice, or experienced — can deploy code to a full-function, multi-organization blockchain network with the IBM Blockchain Platform.
Then you can start developing, demoing, and staging your blockchain applications on a simulated multi-organization network. The Free Tier is optimized to give you a view into the operational tooling, and to help you do quick development and testing. It differs from the Standard plans in several ways:. With a Standard plan, you get the ability to add more IBM Blockchain Platform nodes, more resources compute and storage , plus a crash-tolerant, production-level infrastructure that runs in a secure-cloud, Kubernetes-based portable environment.
A locally deployed blockchain based on the Hyperledger Fabric framework can be a terrific simulation. In addition, using the open source technologies locally requires a bit more patience and dexterity with command-line coding.
Conversely, with the IBM Blockchain Platform, you get a scalable, reliable, fully integrated set of operational and governance tools that guide you through network creation, deployment, monitoring, and governance with simple clicks and easy instructions.
In addition, you get direct access to experts who continue to be dedicated and contribute to the open source code base along with the IBM Blockchain Platform tooling we provide.
There are several built-in samples that can help you get started, including commercial paper and FabCar. Once you install the extension, you can create your first smart contract by walking through this tutorial. With the VS Code extension, you can quickly develop, package, and deploy your smart contracts with easy management of multiple workspaces.
Plus, the extension has a built-in local Hyperledger Fabric installation to test your smart contract quickly. In addition, you can easily connect to remote networks, which enables you to deploy your packaged smart contracts to any network in which you participate.
Get involved Close outline. Close Close. Blockchain Cloud Hyperledger Hyperledger Fabric. Business blockchain concepts What is a business blockchain network?
What's beyond the Free Tier?
Learn to Code Blockchain DApps By Building Simple Games
After developer, you should understand how Bitcoin works. Smart contracts are written tutorials a language called Solidity which blockchain a lot like JavaScript. First, we'll tutorials a default state for this developer like this:. After all, the unique challenges of Blockchain development require a certain unique way of thinking. Contact Jobs Email Blockchain Telegram.
Below, you will find a description of the most common technology used for blockchain: DLT Distributed Ledger Technology. Imagine that everybody has a notebook in which anyone can see what is written by others. This is what is provided by distributed ledger technology. Everyone gets information about what is happening within the network.
As you can see from the picture above, all users of the network like for Bitcoin or Ethereum will receive updated information on new blocks. This means that all operations within the network can be tracked. And this is where we come to nodes — the storage of the ledger. A node is a replica containing all the information about the operations performed within the network.
For example, if there are blocks in the blockchain and there are nodes, each node will contain records of all blocks. You may ask, why do we need more than one node? Well, this is why blockchain technology is so popular. As there are many nodes, and each contains information about all transactions within the network, there is no real opportunity for fraud, system failure, or hacks.
This is the reason why all operations within blockchain can be performed without the participation of a third party. For some blockchains Bitcoin, for instance , there exists a special category of nodes called miners.
Basically, miners are nodes that not only store all information about all transactions within the network, but also record the transactions and form them into blocks by performing calculations.
In blockchain technology, data is collected in blocks, and blocks are connected to each other, forming a chain. This describes why the technology is called blockchain. The size of a block and the type of data it can contain fully depends upon the type of blockchain. For Bitcoin, it is transactions, and for Ethereum, it is smart contracts. Usually, any user, even if he or she is not a member of the network, can see the blocks, check their contents, and track orders.
Sometimes, however, they cannot. It all depends on the permission type featured for blockchain. Permission types define whether a blockchain is public or private. In public blockchains, anyone can see all the operations within the network, and in private blockchains, only specified or approved users can get full access to operations within the network. The consensus type implemented in blockchain defines the principles of its performance.
The creation of proof of work consensus the first realized for blockchain in Bitcoin has shown that a decentralized network in which operations can be performed without a third-party intermediary can be created. In this type of consensus, miners solve mathematical tasks to record operations within the network and build blocks. Afterwards, the first solution that has been found and fits the parameters is verified by the other nodes.
The miner who finds the solution gets a reward. This was the first type of consensus algorithm for blockchain, and it was used in Bitcoin and its forks. This type of consensus demands an increase in computational power when the network grows.
Proof of Stake is a type of consensus algorithm that considers a choice of node that forms the next block on the basis of a prescribed algorithm. However, the age of the coins is then decreased to zero days.
There are also other implementations of proof of stake consensus. Its greatest advantage is the fact that it demands less computational power than PoW. According to the principle of Byzantine Fault Tolerance consensus, there is a list of faults that can be tolerated, and decisions on whether or not to verify transactions are made according to the results of voting.
For example, if there is a transaction that has been made, the first node that votes to verify it or not is called a leader, and other nodes should vote, too. This type of consensus considers that there should be a specified number of nodes that have voted for a decision to make it valid for the whole network. No matter what kind of consensus algorithm is used, an authority can change the rules or cancel decisions. The authority in this example is a validator — a node with special rights.
Lesson 11 of 12 By John Terra. Blockchain technology is poised to revolutionize the way the digital world handles data and does business. Initially created as a platform for supporting Bitcoin, Blockchain is demonstrating a level of versatility and security that has made many sectors of business and government take notice and begin putting it to their use. If this prospect intrigues you, and you want to know how to become a Blockchain developer, then read on and find out all you need to know about this exciting and intriguing profession.
The wise yet short answer to this is: a Blockchain developer develops Blockchains! Well, that was easy! Call them sub-divisions of Blockchain development. A Core Blockchain Developer designs the security and the architecture of the proposed Blockchain system.
In essence, the Core Blockchain Developer creates the foundation upon which others will then build upon. That would be the Blockchain Software Developers, of course, who use the core web architecture built by the Developer to create apps, specifically the decentralized dapps and web varieties. Perhaps there may be situations where the same person fulfills both roles, most likely in cases where the business is small, and people traditionally wear more than one hat.
Whatever the case, the everyday responsibilities and roles of the Blockchain developer are:. The developer also performs complex analysis, design, development, testing, and computer software debugging, specifically for distinct product hardware or for technical service lines of businesses. Develops perform software design, operating architecture integration, and computer system selection.
Finally, they operate on multiple systems and apply knowledge of one or more platforms and programming languages. Of course, obstacles are awaiting the Blockchain developer. In addition, using the open source technologies locally requires a bit more patience and dexterity with command-line coding.
Conversely, with the IBM Blockchain Platform, you get a scalable, reliable, fully integrated set of operational and governance tools that guide you through network creation, deployment, monitoring, and governance with simple clicks and easy instructions. In addition, you get direct access to experts who continue to be dedicated and contribute to the open source code base along with the IBM Blockchain Platform tooling we provide.
There are several built-in samples that can help you get started, including commercial paper and FabCar. Once you install the extension, you can create your first smart contract by walking through this tutorial.
With the VS Code extension, you can quickly develop, package, and deploy your smart contracts with easy management of multiple workspaces. Plus, the extension has a built-in local Hyperledger Fabric installation to test your smart contract quickly. In addition, you can easily connect to remote networks, which enables you to deploy your packaged smart contracts to any network in which you participate.
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