Awesome Solidity

Contributing

Contributors are our favourite people, but we also love you readers too, thank you!

✨ Index ✨

• Getting Started
• Vulnerabilities
• Best practices
• Libraries
• Code Examples
• Tools
• Dapps development

Getting Started

• The Hitchhiker's Guide to Smart Contracts
• Solidity CRUD operations – part1, part2, part3
• Airdrops

• Note of setting up testing environment – A note of how to set up testing environment and avoid annoying errors (on Windows10). Including a few regular tools: testrpc, truffle, mocha.js,truffle flattener, gas-reporter, coveralls, sol-function-profiler, Parity

• Testing tool errors - A list of error messages when running testing tools, and the methods of how to deal with them. Update irregular. Contributions are welcome.

  Concepts

  • Blockchain Oracles, Explained
  • ABI
  • Keccak256
  • A Closer Look At Ethereum Signatures
  • Web 3.0 Explained
  • Random numbers
  • Velocity of Tokens
  • HD Wallet explained

  Tutorials

  • Kauri – Super collection of up-to-date tutorials and tips on How to build on Ethereum
  • CryptoZombies: Learn to Code Ethereum DApps By Building Your Own Game
  • Ethernaut - Smart Contract Hacking Game
  • Hack This Contract Game
  • What's Solidity? – Youtube tutorials
  • Building a fully decentralized User profile app on Ethereum and IPFS
  • Ethereum and Solidity: The Complete Developer's Guide – Udemy course
  • Become a Blockchain Developer with Ethereum and Solidity – Udemy course
  • Creating your own DAO based on Aragon framework
  • Test Driven Development for Solidity

  Short answers to some questions

  • "Indexed" keyword / filtering logs
  • Execution of Fallback function with more 2300 gas

  Typical Business logic

  • Tokens
  • Wallets
  • Crowd sale
  • Distribution/Exchange
  • Vesting/Locking

  News

  • ICO Alert – upcoming ICOs
  • Dappradar – list of new dapps

  Blogs

  • ConsenSys
  • Sarah Baker Mills – Design director @Consensys
  • David Rugendyke – Rocket Pool developer
  • Alex Sherbuck – market news and hacks observation
  • Matthew Di Ferrante – Founder @ ZK Labs
  • Philippe Castonguay
  • Elena Dimitrova – Dev at colony.io
  • Aragon techblog
  • Eric Elliot's blog about blockchain

Vulnerabilities

• Consensys: known attacks (updates are irregular)

• Honey Pots: 1, 2, 3

  Known hacks

  • Integer Overflow (i.e., proxyOverflow Bug) – Found in Multiple ERC20 Smart Contracts
  • The DAO Hack
  • Parity Wallet Hack
  • Parity Wallet Hack II
  • How $800K Evaporated from PoWH Ponzi

Best practices

Security

• Ethereum Smart Contract Security Best Practices (Consensys)
• Exceptions on overflow

Gas spending

• How to write an optimized (gas-cost) smart contract?
• Gas Costs from Yellow paper
• Under-Optimized Smart Contracts Devour Your Money (.pdf)
• public vs external – latter is twice cheaper (496 vs 261)

Common design principles

• Off-Chain Whitelist with On-Chain Verification for Ethereum Smart Contracts
• Library Driven Development in Solidity, and SOLDOC#Libraries
• Reversing Ethereum Smart Contracts – smart contract reverse engineering
• A Crash Course for Mechanism Design

ERCs

• ERC-20 - original token contract for fungible assets [ The Anatomy of ERC20 / Example ]
• ERC-165 - creates a standard method to publish and detect what interfaces a smart contract implements
• ERC-173 - a standard interface for ownership of contracts
• ERC-223 – contracts with safety methods that allow return tokens sent accidentally to the contract address
• ERC-721 - token standard for non-fungible assets [ Walking Through the ERC721 Full Implementation ]
• ERC-725 - proxy contract for key management and execution, to establish a Blockchain identity
• ERC-827 – transfers/approvals with calls
• ERC-875 - for non fungible tokens and simple atomic swaps
• ERC-918 - mineable Token Standard
• ERC Token Standards for Dummies, Like Me – ERC20, ERC223, ERC827, ERC721 short review with major points and concerns

EIPs

• Ethereum Natural Specification Format
• EIP821 – EIP (not ERC) 821. Contracts for Non Fungible Tokens (NFTs)
• A New Advanced Token Standard – Contract defines operators to send tokens on behalf of another address – contract or regular account

Other

• Style Guide – Follow the style guide to make solidity codes layout look pretty
• Upgradable contracts

Libraries

Standard contracts

• OpenZeppelin Contracts – A framework to build secure smart contracts on Ethereum
• OpenZeppelin Base Tokens – Collection of basic token skeletons to extend
• MiniMe Token – The MiniMeToken contract is a standard ERC20 token with extra functionality
• aragonOS – A smart contract framework for building DAOs, Dapps and protocols
• Gnosis MultiSig – Popular multisig deployed by the likes of District0x, Golem, andon, Bancor, and more
• Status.im Crowdsale – Crowdsale contracts from Status
• cryptofin-solidity - A collection of Solidity libraries for building secure and gas-efficient smart contracts on Ethereum.
• Modular Libraries - A group of packages built for use on blockchains utilising the Ethereum Virtual Machine
• DateTime Library - A gas-efficient Solidity date and time library
• Aragon - DAO protocol. Contains aragonOS smart contract framework with focus on upgradeability and governance
• 0x - DEX protocol
• Token Libraries with Proofs - Contains correctness proofs of token contracts wrt. given specifications and high-level properties

Utils

• SafeMath – Safely perform mathematical operations
• Solidity String Utils (use with care)
• Easily Send Many Tokens to Many Addresses
• BytesHelper - library to deal with bytes32

Code and patterns examples

• Bitwise Operations and Bit Manipulation in Solidity, Ethereum
• Upgradable contracts – example
• Solidity Security Exploits: Re-Entrancy, Denial of Service - Gas, Denial of Service - Revert, Force Ether - selfdestruct, Storage Allocation Exploit, Underflow / Overflow, Re-Entrancy Honey Pot, Function Call Honey PotExplanations here
• Not so smart contracts – Another examples of known vulnerabilities
• Changing contract storage from inside of the Library
• Emitting events from the Library
• Chai.js, BDD approach in testing
• Memory vs Storage & How to initialize an array inside a struct
• Multisig contracts – Simpler Ethereum Multisig Contracts
• Self-balancing binary search trees - BST adapted for Solidity and EVM

Tools

Check ConsenSys' Tools List - A great list of frameworks, patterns, and tools from ConsenSys

Testing tools

• Truffle – Truffle is a development environment, testing framework and asset pipeline for Ethereum, aiming to make life as an Ethereum developer easier.
• TestRPC – Fast Ethereum RPC client for testing and development.
• Solhint – Solidity linter that provides security, style guide and best practice rules for smart contract validation.
• Solidity Function Profiler - Analysis report of function signatures, visibility, return values, and modifiers.

Development tools

• pocketh – Toolset, provides a series of cli commands that allow you to quickly operate on a contract
• solc-select – A script to switch between solidity versions, including solc 0.4.x for MacOS
• Web3.js – Ethereum JavaScript API
• ethers.js – Ethereum wallet implementation and utilities in JavaScript (and TypeScript)
• Docker images / Audit repo - Solidity testing environment from us (Blockchain Labs, NZ)
• eth-cli – A collection of CLI tools to help with ethereum learning and development
• 11 Best Ethereum Development Tools
• Solidity Doc generator – from Matt Lough
• Solidity syntax highlighting on Github – howto

Test Ether faucets

• Rinkeby faucet
• Kovan faucet
• Ropsten faucet

Storage

• IPFS - Decentralised storage and file referencing
  • IPFS-Store - IPFS Storage service with added search capability
  • OrbitDB - Decentralised database on top of IPFS
  • JS IPFS API - A client library for the IPFS HTTP API, implemented in JavaScript.
  • TEMPORAL - Easy to use API into IPFS and other distributed/decentralised storage protocols
  • Infura API - Another API to IPFS
• Swarm - Distributed storage platform and content distribution service, a native base layer service of the Ethereum web3 stack
• Filecoin – "DECENTRALIZED MARKET FOR STORAGE". Blockchain on top of IPFS

Online services

• Ethereum gas station
• Ethereum unit converter

Dapps development

Helpful information about Dapps.

• Web3 Design principles – Dapps development
• Blockchain Design Principles
• How to create a DApp using Truffle, Oraclize, ethereum-bridge and Webpack
• Create Blockchain Dapp with Ethereum and VueJS

Design

• Designing for the blockchain
• How to make a user-friendly Ethereum dApp

Private networks

• Local Raiden - Run a local Raiden network in docker containers for demo and testing purposes
• Private networks deployment scripts - Out-of-the-box deployment scripts for private PoA networks
• Parity Demo-PoA Tutorial - Step-by-Step tutorial for building a PoA test chain with 2 nodes with Parity authority round consensus
• Local Ethereum Network - Out-of-the-box deployment scripts for private PoW networks
• Kaleido - Use Kaleido for spinning up a consortium blockchain network. Great for PoCs and testing

React / Redux

• React boilerplate
• React Truffle Box
• Drizzle - Redux library to connect a frontend to a blockchain
• Vortex - A Dapp-ready Redux Store. Smart and Dynamic background data refresh thanks to WebSockets. Works with Truffle and Embark.

APIs / subproviders

Javascript

• Web3.js - Javascript Web3
• Eth.js - Javascript Web3 alternative
• Ethers.js - Javascript Web3 alternative, useful utilities and wallet features
• Web3Wrapper - Typescript Web3 alternative
• Ethereumjs - A collection of utility functions for Ethereum like ethereumjs-util and ethereumjs-tx
• Subproviders - Several useful subproviders to use in conjunction with Web3-provider-engine (including a LedgerSubprovider for adding Ledger hardware wallet support to your dApp)
• web3-webpacked - JS framework to manage web3 injection

Other languages

• elm-ethereum
• purescript-web3
• Web3.py - Python Web3
• Web3.php - PHP Web3
• Ethereum-php - PHP Web3
• Web3j - Java Web3
• web3swift - Swift Web3
• Nethereum - .Net Web3
• Ethereum.rb - Ruby Web3
• Web3.hs - Haskell Web3
• KEthereum - Kotlin Web3
• Pyethereum - The Python core library of the Ethereum project
• Eventeum - A bridge between Ethereum smart contract events and backend microservices, written in Java by Kauri
• Ethereumex - Elixir JSON-RPC client for the Ethereum blockchain
• EthContract - A set of helper methods to help query ETH smart contracts in Elixir