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Python Ethereum Smart Contract

Github - Ethereum/web3.py: A Python Interface For Interacting With The Ethereum Blockchain And Ecosystem.

Github - Ethereum/web3.py: A Python Interface For Interacting With The Ethereum Blockchain And Ecosystem.

Read more in the documentation on ReadTheDocs . View the change log on Github . import jsonimport web3from web3 import Web3, HTTPProvider, TestRPCProviderfrom solc import compile_sourcefrom web3.contract import ConciseContract# Solidity source codecontract_source_code = '''pragma solidity ^0.4.0;contract Greeter { string public greeting; function Greeter() { greeting = 'Hello'; } function setGreeting(string _greeting) public { greeting = _greeting; } function greet() constant returns (string) { return greeting; }}'''compiled_sol = compile_source(contract_source_code) # Compiled source codecontract_interface = compiled_sol[':Greeter']# web3.py instancew3 = Web3(TestRPCProvider())# Instantiate and deploy contractcontract = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])# Get transaction hash from deployed contracttx_hash = contract.deploy(transaction={'from': w3.eth.accounts[0], 'gas': 410000})# Get tx receipt to get contract addresstx_receipt = w3.eth.getTransactionReceipt(tx_hash)contract_address = tx_receipt['contractAddress']# Contract instance in concise modeabi = contract_interface['abi']contract_instance = w3.eth.contract(address=contract_address, abi=abi,ContractFactoryClass=ConciseContract)# Getters + Setters for web3.eth.contract objectprint('Contract value: {}'.format(contract_instance.greet()))contract_instance.setGreeting('Nihao', transact={'from': w3.eth.accounts[0]})print('Setting value to: Nihao')print('Contract value: {}'.format(contract_instance.greet())) virtualenv venv. venv/bin/activatepip install -e .[tester] -r requirements-dev.txt For different environments, you can set up multiple virtualenv. For example, if you want to create a venvdocs, then you do the following: virtualenv venvdocs. venvdocs/bin/activa Continue reading >>

The Python Ethereum Ecosystem

The Python Ethereum Ecosystem

Given the recent influx of new users to the Ethereum ecosystem it feels appropriate to give an update on the state of Ethereum tools for Python developers. The following tools sit at the top of the python stack, exposing high level interfaces and abstractions for application development and interaction with the Ethereum blockchain. Populus is a smart contract development framework. It can be used as a command line tool to compile and deploy your contracts as well as a python library for high level scripting and automation. The framework also includes tools that make testing your smart contracts simple and painless. Web3.py is a python library inspired by the original Javascript based web3 library. This library exposes a standard and familiar way to interact with the JSON-RPC interface exposed by Ethereum nodes. In addition, it exposes a number of common utilities such as Ethereum currency denomination conversions, a contract class for interacting with smart contracts, and encoding/decoding utilities. Eth-TestRPC: This is the Python implementation of the TestRPC server (not to be confused with the Javascript implementation). This can be run as either a command line tool or programmatically from your code to create a transient Ethereum blockchain that can be used for testing. PyEthApp: PyEthApp sits on top of the PyEthereum library as a full Ethereum node written in python. It has atrophied a bit in the last year due to a lack of active maintenance and development. While I do not believe that this application can be run as a viable full Ethereum node, there is work being done now to fix this. These lower level tools attempt to do one thing well. They are likely to prevent you from re-inventing the wheel as you develop your Ethereum applications. Ethereum Utils: This libr Continue reading >>

Tutorial: Controlling Ethereum With Python

Tutorial: Controlling Ethereum With Python

Get the directory solc installed to: $ which solc Copy this directory, and use it in the geth console like > admin.setSolc("/usr/local/bin/solc") Confirm that the compiler has been successfully installed by running > eth.getCompilers() There are two common ways to interface with an Ethereum network: through the command line, and with the Wallet GUI app (also called Mist). Well be using the command line for coding, but you might find it helpful to use the Wallet app to explore whats going on in your Ethereum network and make sure that everything is running as expected. The Wallet is designed to provide easy usability out-of-the-box, and installers can be found here . Some notes: The Wallet app will look for a geth.ipc file in the default directory, and if it doesnt find one will start the loooong process of syncing with the main Ethereum network. If you dont want this on the main network, be sure to run an Ethereum node from the command line ahead of time. By default, an etherbase account is created. This is an externally owned account, not a wallet contract- i.e. it is not visible on the blockchain. To get enough ether to create a transaction, start CPU mining (Menu> ) or use a faucet like this one to request test Ether be sent to your account (this is play money, as youre on the test network). Ill be using a virtual environment running Python 2.7.12, and install the required packages for interfacing with Ethereum: NOTE: Due to changes in how Geth handles RPC calls, the pip version of ethjsonrpc (v0.3.0) does not currently work, and . Ive made a working fork and here for this demo, it is sufficient but necessary to be able to run the example in README.md. You can clone my fork and set it up by running $ python setup.py install From here on, well use the dollar sign to Continue reading >>

Github - Ethereum/py-solc: Python Wrapper Around The Solc Solidity Compiler.

Github - Ethereum/py-solc: Python Wrapper Around The Solc Solidity Compiler.

Python wrapper around the solc Solidity compiler. If nothing happens, download GitHub Desktop and try again. If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. Python wrapper around the solc Solidity compiler. This library requires the solc executable to be present. Only versions >=0.4.2 are supported and tested though this library may workwith other versions. Or you can install tox to run the full test suite. Pandoc is required for transforming the markdown README to the proper format torender correctly on pypi. bumpversion $$VERSION_PART_TO_BUMP$$git push && git push --tagsmake release The version format for this repo is {major}.{minor}.{patch} for stable, and{major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta). To issue the next version in line, use bumpversion and specify which part to bump,like bumpversion minor or bumpversion devnum. If you are in a beta version, bumpversion stage will switch to a stable. To issue an unstable version when the current version is stable, specify thenew version explicitly, like bumpversion --new-version 4.0.0-alpha.1 devnum >>> from solc import compile_standard>>> compile_standard({... 'language': 'Solidity',... 'sources': {'Foo.sol': 'content': "...."},... }){ 'contracts': {...}, 'sources': {...}, 'errors': {...},}>>> compile_standard({... 'language': 'Solidity',... 'sources': {'Foo.sol': 'urls': ["/path/to/my/sources/Foo.sol"]},... }, allow_paths="/path/to/my/sources"){ 'contracts': {...}, 'sources': {...}, 'errors': {...},} >>> from solc import compile_source, compile_files, link_code>>> compile_source("contract Foo { function Foo() {} }"){ 'Foo': { 'abi': [{'in Continue reading >>

Build Your First Ethereum Smart Contract With Soliditytutorial

Build Your First Ethereum Smart Contract With Soliditytutorial

Finance & Tech Nerd, Investor, Blockchain & Crypto Enthusiast, Wannabe Polymath, Master of Discipline in Training, Laissez Faire. Talk Is Cheap. Build Your First Ethereum Smart Contract with Solidity Tutorial So you wanna build a smart contract? Perhaps you want to understand how they work, maybe you want to build your own Dapp, maybe you want to launch the very first billion dollar ICO (sarcasm)... Regardless of your intentions, learning how smart contracts work is invaluable. The Ethereum platform possesses enormous potential to create Dapps that could change the way we interact on the web in the decades to come. While Ethereum deploys smart contracts that work much like a standard blockchain transaction, they yield a conditional statement that must be met before a function(s) is executed. Smart contracts can be used for voting, crowdfunding, blind auctions, multi-signature wallets and MUCH more. Bob has his own scrap metal depot business in the United States, Eric is his iron scrap supplier. Eric is based out of China. Bob and Eric have a GREAT business relationship. They trust each other and have been doing business for a long time. Both have booming businesses, and Bob in particular sells out of iron scrap on a routine basis. Bob deploys a contract where once his iron scrap inventory reaches a certain range, he automatically sends an order out to Eric for X lbs of iron scrap at Y ether per ton. Eric agrees to the arrangement and accepts Bobs payment in ether right away. Eric gets to work right away and starts fulfilling Bobs order. Eric can exchange his ether at a local exchange online for Yuan for a tiny fee and itll be processed instantaneously. Whether Eric decides to hold ether or convert to Yuan is his choice, but either way he can now put this capital to wor Continue reading >>

Github - Adamyala/your_first_decentralized_application_python: An Up To Date And Bare Minimum Tutorial On Deploying Smart Contracts With Python

Github - Adamyala/your_first_decentralized_application_python: An Up To Date And Bare Minimum Tutorial On Deploying Smart Contracts With Python

An up to date and bare minimum tutorial on deploying smart contracts with python If nothing happens, download GitHub Desktop and try again. If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. Your_First_Decentralized_Application_Python This code borrows heavily from llSourcell's turtorial which in turn borrows heavily from maheshmurthy's tutorial. Please head over to each and toss a star on the repositories. Both of them created a wonderful tutorials to learn from. We will be building a decentralized voting application! The functionality of this repo is nearly identical to llSourcell's but the entire implementation is done in python! Create and activate a virtual environment Install dependencies with pip install -r requirements.txt Install the ganache-cli command line tool with npm install -g ganache-cli What does this cli do? It runs an ethereum node locally. Normally we'd have to download a lot of blockchain transactions and run a test ethereum node locally. This tool lets us run a small local node for easy peasey development. This tool used to be called the testrpc. Uh... This tool isn't python... True, but I have found the JavaScript tooling for testrpc to be fantastic and easy to use. If you don't want to bother with npm or just want to try out a full python stack, try out eth-testrpc . It's pip installable but not as maintained as ganache-cli. Open up two tabs. In the first tab run ganache-cli. This will start a block chain locally that we can play with. In the second tab activate your virtual environment and run main.py. This will start our little flask app in debug mode, deploying our contract in the process. After the pyth Continue reading >>

Ethereum Smart Contracts In Python: A Comprehensive(ish) Guide

Ethereum Smart Contracts In Python: A Comprehensive(ish) Guide

Astrophysicist, cofounder of @sempo. Were reinventing disaster response to make it efficient, systematic and transparent. Ethereum Smart Contracts in Python: a comprehensive(ish) guide Its one thing to get a basic smart contract up on Ethereum just google ERC20 Token Tutorial youll find plenty of information on how to do it. Interacting with a contract programmatically is another thing entirely, and if youre a Python coder, then tutorials are scarce. Fortunately for us, Version 4 of Web3.py has just been released, which means its now easier than ever to run a python script and watch as magical things happen on the blockchain. Spooky. A big shout out Piper Merriam , Jason Carver and all the others whove worked so on hard on Web3.py to make life easy for the rest of us at Sempo were using Ethereum to make Disaster Response more transparent, and its only really possible thanks to Web3.py. First we get set up, making sure we have the relevant python libraries installed and so-forth. Python libraries everywhere, but what are theyfor? There are plenty of python libraries related to Ethereum out there, but there are two that come up a lot when people talk about Ethereum: Web3.py and Pyethereum. At first glance its not obvious which one you should use for what. A Python implementation of the Ethereum Virtual Machine (EVM). The EVM, in turn is the part of the Ethereum protocol that actually runs the code in Smart Contracts and determines their outputs. So if you wanted to run an Ethereum node in Python, Pyethereum is a good place to start. Even if youre perfectly happy running your Smart Contracts without running your own node, Pyethereum is still a good library to have around it contains a bunch of functions that do useful things like calculate a users address from their priva Continue reading >>

Pyethereum - Are There Any Implementations Of Smart Contracts In Python? - Ethereum Stack Exchange

Pyethereum - Are There Any Implementations Of Smart Contracts In Python? - Ethereum Stack Exchange

Are there any implementations of smart contracts in Python? pythereum and pythapp - your question tags - are Python implementations of Ethereum's core library and command line client respectively. They are orthogonal to the language in which smart contracts are written. So the short answer to your question is: no. Having said that, have a look at Serpent: Is it possible to do that though? iivri andre Nov 16 '16 at 22:26 See the other answer from eth. In theory you could write a smart contract in any language you like, but you'd also need to write a compiler. Richard Horrocks Nov 17 '16 at 7:49 Ethereum smart contracts need to compile to EVM (Ethereum Virtual Machine) bytecode. There are no Python to EVM compilers, and for some of the challenges, see What is the merit of creating new smart contract languages like Solidity instead of using other languages? The options are to use a Python-like language Serpent or a recent (Nov 2016) experimental language named Viper . See this for additional information on Viper and Serpent, including their differences. Continue reading >>

Remix: Develop Smart Contracts For The Ethereum Blockchain

Remix: Develop Smart Contracts For The Ethereum Blockchain

Remix is a Solidity IDE thats used to write, compile and debug Solidity code. Solidity is a high-level, contract-oriented programming language for writing smart contracts. It was influenced by popular languages such as C++, Python and JavaScript. IDE stands for Integrated Development Environment and is an application with a set of tools designed to help programmers execute different tasks related to software development such as writing, compiling, executing and debugging code. Before you begin using Remix to develop smart contracts, make sure youre familiar with some basic concepts. In particular, give these articles about blockchain and Ethereum a read. A smart contract is a trust-less agreement between two parties that makes use of blockchain technology, to enforce the parties to adhere to the terms, rather than relying on the traditional ways such as trusting a middleman or using laws to handle disputes. Using the Ethereum blockchain, you can create smart contracts with the Solidity language (among others). Ethereum is not the only platform that can be used to create smart contacts, but its the most popular choice, as it was designed from the start to support building them. Dapp stands for decentralized application and is a web3 application that can have a front-end written in traditional languages such as JavaScript, HTML, CSS and a smart contract (as back-end code) which runs on the blockchain. So you can simply think of a Dapp as the front end plus the associated blockchain smart contract(s). Unlike the smart contract deployed on the blockchain itself, the front end of a Dapp can be either hosted on a centralized server like a CDN or on decentralized storage like Swarm . You can access the Remix IDE in different ways: online, via a web browser like Chrome, from a Continue reading >>

Solidity Solidity 0.4.24 Documentation

Solidity Solidity 0.4.24 Documentation

Solidity is a contract-oriented, high-level language for implementing smart contracts.It was influenced by C++, Python and JavaScriptand is designed to target the Ethereum Virtual Machine (EVM). Solidity is statically typed, supports inheritance, libraries and complexuser-defined types among other features. As you will see, it is possible to create contracts for voting,crowdfunding, blind auctions, multi-signature wallets and more. The best way to try out Solidity right now is using Remix (it can take a while to load, please be patient). Remix is a web browserbased IDE that allows you to write Solidity smart contracts, then deployand run the smart contracts. Since software is written by humans, it can have bugs. Thus, alsosmart contracts should be created following well-known best-practices insoftware development. This includes code review, testing, audits and correctness proofs.Also note that users are sometimes more confident in code than its authors.Finally, blockchains have their own things to watch out for, so please takea look at the section Security Considerations . This documentation is translated into several languages by community volunteers, but the English version stands as a reference. Plugin for the Vim editor providing compile checking. Specialized web IDE that also provides shell access to a complete Ethereum environment. Solidity grammar for the ANTLR 4 parser generator On the next pages, we will first see a simple smart contract writtenin Solidity followed by the basics about blockchains and the Ethereum Virtual Machine . The next section will explain several features of Solidity by givinguseful example contracts Remember that you can always try out the contracts in your browser ! The last and most extensive section will cover all aspects of Solidity Continue reading >>

Would It Be Difficult To Learn Ethereum Smart Contract Programming With Very Little Python Experience?

Would It Be Difficult To Learn Ethereum Smart Contract Programming With Very Little Python Experience?

If you understand the basics of any object oriented programming language, then I would say you have the qualifications to start learning Solidity (Ethereums high level programming language). I would suggest heading over to Create a cryptocurrency contract in Ethereum to give programming in it a shot. Its fairly straightforward! Answered Jul 12, 2018 Author has 388 answers and 46.7k answer views Use Ethereum, Solidity, and Smart Contracts to build production-ready apps based on the blockchain Smart Contracts? They're here. The Ethereum Blockchain? Covered. Solidity? Yep! There can be no understating it: Ethereum and Blockchain technology is the most disruptive force in years. Companies cannot hire developers who understand blockchain technologies fast enough, but there are a tiny number of resources published to help you truly understand what blockchains are used for, let alone build apps with them. That's the purpose of this course: to be the best resource online for learning about Ethereum, blockchains, and how to build apps with this new technology. The development community is still figuring out the best way to use Ethereum in the creation of new and exciting apps. I spent a tremendous amount of time to research and create best practice for interfacing with Ethereum from Javascript. I can't overstate it enough; this course will show you the best and most easily repeatable patterns for creating production-ready apps with Ethereum. The Ethereum tech ecosystem is in constant change. Don't be fooled by other courses that mention how you'll learn a dozen different libraries! Every library that you'll use with Ethereum breaks and is deprecated on a near-weekly basis! Instead, this course will teach you how to assemble your own boilerplate package to develop, compile, and Continue reading >>

Dominik Harz

Dominik Harz

Interact with Ethereum contracts from python with web3py In Ethereum and other blockchains there are still a lot of proof of concept implementation and developers trying out how to cope with the new concepts. As part of the dInvest dInvest post series I was also looking into Ethereum and trying to implement a hedge fund in a blockchain. In a previous post I discussed how to get a quantitative framework in python up and running. In this post I will write how to integrate python programs with Ethereum smart contracts. For one reason or another you might be also faced with the issue, that although Ethereum offers a Turing-complete language not everything is actually doable there. Lets say you have created one of the simple tutorial contracts in Ethereum and now want to look at something more advanced. I personally liked the Hitchhikers Guide to Smart Contracts by Manuel Aroz to get started with more complex code, setup testrpc, and truffle. Take a look at it. dInvest is composed of one smart contract that is responsible for making investments, verifying investmentcriteria and distribution of returns. The contract exposes public functions to create new investments andfor withdrawal which will act as main functions of a hedge fund. Users of the hedge fund are identifiedby their Ethereum address which is equivalent for the public key. Suggestion of investment strategies andstrategy execution are done in different agents that also have Ethereum addresses. These agents are set bythe contract creator only.When a user is creating an investment it is possible to specify a list of industry sectors identified by atwo digit number based on the Standard Industrial Classification codes. These sectors will be identifiedas a black list when making the investments. Therefore user have th Continue reading >>

Smartbtc Sees The Need For Centralized Python-based Smart Contracts

Smartbtc Sees The Need For Centralized Python-based Smart Contracts

Smartbtc Sees the Need for Centralized Python-Based Smart Contracts Just recently the startup Smartbtc announced the execution of a bitcoin-based smart contract written in the Python codebase. The team intended to grow their Twitter following by creating a contract that paid 0.011 BTC after it accrued 1,000 followers in sixty days. After the goal was met, Smartbtcs Python contract executed on February 19. Also read: United Bitcoin May Be the Most Controversial Fork to Date Python Based Contracts Tethered to BTC Payouts Smartbtc is a platform that facilitates smart contracts tethered to BTC chain payouts, and contracts are written entirely in Python code. The contracts programming considers the agreement fulfilled after the def contract() Python method returns True. One thing to note is Smartbtc is a centralized service and contracts are executed periodically until it is fulfilled or it expires. Even though the contracts rely on a level of trust and Smartbtcs servers, the developer believes a centralized type of contract infrastructure tied to BTC payments will still be needed. Smartbtcs creator thinks existing financial institutions and average users will gravitate towards these types of maintained agreements as opposed to a system thats entirely decentralized. Even smart contracts written in Ethereums Solidity codebase require a level of trust in the autonomous nature alongside putting faith in codebase audits. The application fees are calculated by the agreement period and execution interval which can be anywhere between 1-2 percent. If the contract obligation is not fulfilled the owner will be charged 0.5 percent of the arrangement cost and the rest of the sum is returned back to the originator. If the smart contract is fulfilled the promisee will get the specified Continue reading >>

Creating Decentralized Smart Contracts Using Python

Creating Decentralized Smart Contracts Using Python

Creating decentralized smart contracts using Python Creating decentralized smart contracts using Python Bitcoin has been gaining popularity in the recent years due to its market value. But more importantly, the underlying technology is gaining the attention among the developers. Many developer communities inspired by bitcoin have created their own platform to use the underlying technology widely known as "blockchain" to achieve decentralization. Ethereum is one such platform that has created a blockchain platform which allows developers to develop their own decentralized applications (dApps) in the ethereum network by coding the logic in the execulatable contracts called "smart contracts". Although ethereum has gained a huge fame due to its smart contract implementation to create decentralized applications, it imposes developer to write the logic in an ethereum's domain-specific language called Solidity. In addition to coding in a new language, it mandates the developer to set up a new develop environment. NEO blockchain platform provides a convenient way to develop smart contracts in general purpose programming language. NEO achieves this by providing compilers to compile code written in most of the languages to bytecode that can be executed in NEO virtual machine. Currently, NEO allows compilation of python smart contracts through neo-python project. This is the first blockchain project to provide such a freedom to the developer. NEO project provides plenty of benefits over other blockchain platforms out there. It plans to achieve smart economy by creating a strong digital identity. It achieves faster transaction rate which is the key to scale any platform. NEO is being referred to as the "New Ethereum" due to its increasing popularity. I plan on conducting a worksho Continue reading >>

How To Use Python To Test Your Ethereum Smart Contracts

How To Use Python To Test Your Ethereum Smart Contracts

I recently started working on Ethereum Blockchain development. Most of thetools, including the solidity language are biased towards javascript. While I managed to get started using truffle when it came to testing, I found that javascript tests were (IMO) unnecessarily too long. I have always been more comfortable with python than JS. I liked and have usedpy.test in my previous projects. So when I had an option to test my smartcontracts using py.test, I definitely was gonna give it a try. That is when I came across populus. Turns out it aims to be truffle forpythonistas (my words, not the official tagline, but they can use it.) Initially it was a personal project - which was officially adopted by ethereumorganization (on github) adding credibility to the excellent work done so far. You can read the official documentation here As I mentioned earlier, I came for the chance to use py.test for testing thesmart contracts. Writing the tests (along with web3.py) was quite easy. Running the tests in not populus test (like truffle test). As I mentionedearlier, it is via py.test. So it is py.test / .. and this is where I ran into a glitch. Turns out there is a known issue and a solution One thing I liked about using py.test was that I did not require to explicitly start testrpc For truffle test testrpc or geth is required to be run explicitly. Else you get the following error: $ truffle testCould not connect to your Ethereum client. Please check that your Ethereum client: - is running - is accepting RPC connections (i.e., "--rpc" option is used in geth) - is accessible over the network - is properly configured in your Truffle configuration file (truffle.js) Im not saying that there is anything is wrong in that, just that it is nice toomit a step. One more Continue reading >>

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