Node.js and Blockchain
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This document discusses using Node.js to build blockchain applications. It begins with explaining key blockchain concepts like hashes, Merkle trees, blocks and immutability. It then discusses consensus algorithms like proof-of-work and incentives. Examples are given of Bitcoin, Ethereum and Hyperledger blockchains. Reasons for using Node.js to build blockchain apps are provided, along with examples like BitcoinJS, EthereumJS, smart contracts with Solidity, the Truffle framework, dApps, MetaMask, and Hyperledger Composer. Finally, Blockstack is mentioned and a demo app link is provided.
Node.js and Blockchain
- 1. O C T O B E R 2 7 , 2 0 1 7 C O N F I D E N T I A L Node.js and Blockchain Building the Web 3.0 with Node.js
- 2. October 27, 2017 Julián Duque Developer and Educator / Community Organizer / Engineer @julian_duque
- 3. October 27, 2017 Julián Duque Not a Crypto Expert / Not here for Crypto Currencies (or ICOs) @julian_duque
- 4. © 2017 NodeSource C O N F I D E N T I A L What is Blockchain? 📦⛓ 4
- 5. © 2017 NodeSource C O N F I D E N T I A L5 Hashes hash(‘😀’) = 2a02ea…7b6 hash(‘😃’) = e36f86…028 hash(‘Hola’) = f688ae…22e hash(‘Hola!’) = 0676dc…06f
- 6. © 2017 NodeSource C O N F I D E N T I A L6 Merkle Trees binary hash tree Image credit: Wikipedia
- 7. © 2017 NodeSource C O N F I D E N T I A L7 Blockchains • Continuously growing, append only, list of records (blocks) • Distributed Ledger Technology (DLT) • Linked and secured using cryptography
- 8. © 2017 NodeSource C O N F I D E N T I A L8 Blockchains Image credit: Wikipedia
- 9. © 2017 NodeSource C O N F I D E N T I A L9 Blockchain Immutability Image credit: edX - Hyperledger Course
- 10. © 2017 NodeSource C O N F I D E N T I A L10 Reaching Consensus Proof of Work • Blocks are added to the ledger gradually • People (nodes) take turns to add blocks • Root checksum must start with a number of zeroes (difficulty, conditions) • Block includes a nonsense (nonce) that can be changed to create new checksums • Difficulty is adjusted to target desired time between blocks (control)
- 11. © 2017 NodeSource C O N F I D E N T I A L11 Reaching Consensus Incentives • Miner (node) who find a new block gets a reward • Reward is used as currency and to pay transaction fees • Miners also get transaction fees along with the reward • Encourage miners to process blocks with transactions (Game theory) • Encourage users to pay transaction fees depending on urgency
- 12. © 2017 NodeSource C O N F I D E N T I A L Public vs Private 12
- 13. C O N F I D E N T I A L© 2017 NodeSource13
- 14. © 2017 NodeSource C O N F I D E N T I A L14 Bitcoin • Crypto Currency (BTC) • Transfer value from address to address (wallet to wallet) • Scripting Language - Turing-Incomplete • Consensus Algorithm: Proof of Work
- 15. C O N F I D E N T I A L© 2017 NodeSource15
- 16. © 2017 NodeSource C O N F I D E N T I A L16 Ethereum • Virtual Machine (EVM) • Usage is metered by transaction fees (gas) • Crypto Currency (ether - ETH) • Transactions manipulate state • EVM is Turing-Complete • Consensus Algorithm: Proof of Work, moving to Proof of Stake
- 17. C O N F I D E N T I A L© 2017 NodeSource17
- 18. C O N F I D E N T I A L© 2017 NodeSource18 Hyperledger • Umbrella of Open Source projects • Focused on Business / Permissioned Blockchains • No crypto currency • Consensus algorithms: Depending of Project (PoET, PFBT) • Some projects are EVM compatible, others have they own VM
- 19. © 2017 NodeSource C O N F I D E N T I A L Why Node.js? 19
- 20. © 2017 NodeSource C O N F I D E N T I A L20 Why Node.js? • JavaScript: Language of the web • Great for building tools • Great as API / Frontend layer
- 21. © 2017 NodeSource C O N F I D E N T I A L Develop Blockchain Applications 21
- 22. © 2017 NodeSource C O N F I D E N T I A L BitcoinJS 22
- 23. © 2017 NodeSource C O N F I D E N T I A L23 BitcoinJS https://bitcoinjs.org • Create / Interact with Bitcoin wallets • Transactions • Crypto operations
- 24. © 2017 NodeSource C O N F I D E N T I A L EthereumJS 24
- 25. © 2017 NodeSource C O N F I D E N T I A L25 EthereumJS https://ethereumjs.github.io • Collection of libraries and utilities for Ethereum • Always looking for contributors
- 26. © 2017 NodeSource C O N F I D E N T I A L Smart Contracts 26
- 27. © 2017 NodeSource C O N F I D E N T I A L27 Smart Contracts • Applications that can be deployed to the Blockchain (Ethereum / Hyperledger) • Takes care of State in Blockchain • Defines and enforces the rules and penalties around an agreement
- 28. © 2017 NodeSource C O N F I D E N T I A L Solidity 28
- 29. © 2017 NodeSource C O N F I D E N T I A L29 Solidity • High level language to build Smart Contracts for Ethereum • Typed Language • Based on JavaScript • Compiled to EVM
- 30. © 2017 NodeSource C O N F I D E N T I A L30 Solidity pragma solidity ^0.4.11; contract HelloWorld { uint public balance; address public owner; function HelloWorld() public { owner = msg.sender; balance = 0; } function update() public payable isOwner() { balance = msg.value; } modifier isOwner() { require(msg.sender == owner); _; } }
- 31. © 2017 NodeSource C O N F I D E N T I A L31 Solidity $ npm install -g solc
- 32. © 2017 NodeSource C O N F I D E N T I A L32
- 33. © 2017 NodeSource C O N F I D E N T I A L33 Truffle • Framework to build, test and deploy Smart Contracts • Test Smart Contracts with JavaScript • Project generators for ĐApps
- 34. © 2017 NodeSource C O N F I D E N T I A L34 Truffle $ npm install -g truffle
- 35. © 2017 NodeSource C O N F I D E N T I A L ĐApps 35
- 36. © 2017 NodeSource C O N F I D E N T I A L36 ĐApps https://www.stateofthedapps.com • Web 3.0 - Decentralized Applications • Interact with Smart Contracts using backend- less JavaScript Applications • Bitcoin: The first ĐApp
- 37. © 2017 NodeSource C O N F I D E N T I A L MetaMask 37
- 38. © 2017 NodeSource C O N F I D E N T I A L38 MetaMask https://www.metamask.io • Brings Ethereum to your Browser • Perfect for running ĐApps • No need to have a full node running
- 39. © 2017 NodeSource C O N F I D E N T I A L Hyperledger Composer 39
- 40. © 2017 NodeSource C O N F I D E N T I A L40 Hyperledger Composer https://hyperledger.github.io/composer/ • Build private Blockchain Applications and Business Networks • Build Smart Contracts with a model language • Generate REST APIs • Node.js modules (composer-client) to interact with your network
- 41. © 2017 NodeSource C O N F I D E N T I A L41
- 42. © 2017 NodeSource C O N F I D E N T I A L42 Blockstack https://blockstack.org • Build decentralized applications with JavaScript (BlockstackJS) • Virtualchain: An existing Blockchain extension
- 43. © 2017 NodeSource C O N F I D E N T I A L Demo https://julianduque.github.io/simple-vote/ 43
- 44. C O N F I D E N T I A L Thank you! Julián Duque julian@nodesource.com @julian_duque