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How to Write a Smart Contract with Python on Ontology? Part 4: Native API

Reading time4 min
Views1.7K
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Earlier, I have introduced the Ontology Smart Contract in
Part 1: Blockchain & Block API and
Part 2: Storage API
Part 3: Runtime API
Today, let’s talk about how to invoke an Ontology native smart contract through the Native API. One of the most typical functions of invoking native contract is asset transfer.
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Total votes 5: ↑5 and ↓0+5
Comments0

How to Write a Smart Contract with Python on Ontology? Part 3: Runtime API

Reading time3 min
Views1.3K
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Introduction


Earlier, I have introduced the Ontology Smart Contract in
Part 1: Blockchain & Block API and
Part 2: Storage API
Now when you have an idea about how to call the relevant API for persistent storage when developing Python smart contract on Ontology, let’s go on to Runtime API (Contract Execution API). The Runtime API has 8 related APIs that provide common interfaces for contract execution and help developers get, convert, and validate data. Here’s a brief description of these 8 APIs:
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How to Write a Smart Contract with Python on Ontology? Part 2: Storage API

Reading time3 min
Views1.3K
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This is an official tutorial published earlier on Ontology Medium blog
Excited to publish it for Habr readers. Feel free to ask any related questions and suggest a better format for tutorial materials

Foreword


Earlier, in Part 1, we introduced the Blockchain & Block API of Ontology’s smart contract. Today we will discuss how to use the second module: Storage API. The Storage API has five related APIs that enable addition, deletion, and changes to persistent storage in blockchain smart contracts. Here’s a brief description of the five APIs:
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How to Write a Smart Contract with Python on Ontology? Part 1: the Blockchain & Block API

Reading time5 min
Views3K
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This is an official tutorial published earlier on Ontology Medium blog
Excited to publish it for Habr readers. Feel free to ask any related questions and suggest a better format for tutorial materials

Foreword


In this article, we will begin to introduce the smart contract API of Ontology. The Ontology’s smart contract API is divided into 7 modules:


In this article, we will introduce the Blockchain & Block API, which is the most basic part of the Ontology smart contract system. The Blockchain API supports basic blockchain query operations, such as obtaining the current block height, whereas the Block API supports basic block query operations, such as querying the number of transactions for a given block.

Let’s get started!

First, create a new contract in SmartX and then follow the instructions below.

1. How to Use Blockchain API


References to smart contract functions are identical to Python’s references. Developers can introduce the appropriate functions as needed. For example, the following statement introduces GetHeight, the function to get the current block height, and GetHeader, the function to get the block header.
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Total votes 20: ↑18 and ↓2+16
Comments0

Blockchain RSA-based random

Reading time5 min
Views1.9K
There’s a problem we needed to address in the course of developing our games. It’s complicated to generate a random number in a distributed network. Almost all blockchains have already faced this issue. Indeed, in networks where there is no trust between anyone, the creation of a random number solves a wide range of problems.

In this article, we explain how we solved this problem for our games. The first of these was Waves Xmas Tree.



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Total votes 13: ↑13 and ↓0+13
Comments0

The Data Structures of the Plasma Cash Blockchain's State

Reading time7 min
Views1.5K


Hello, dear Habr users! This article is about Web 3.0 — the decentralized Internet. Web 3.0 introduces the concept of decentralization as the foundation of the modern Internet. Many computer systems and networks require security and decentralization features to meet their needs. A distributed registry using blockchain technology provides efficient solutions for decentralization.
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Total votes 9: ↑9 and ↓0+9
Comments0

How to make possible micro-payments in your app

Reading time8 min
Views5.2K

This week I spent coding my very first public pet-app based on Telegram chat bot which acts as a Bitcoin wallet and allows to send and receive tips between Telegram users and other so-called “Lightning Apps”. I assume that you are familiar with Bitcoin & Telegram in general, i’ll try to post short and without deep jump into details. More resources about Bitcoin can be found here and Telegram is simply an instant messenger that allows you to create your custom apps (chat-bots) using their platform.


What are the key points of such app?


  • Allows to rate other users ideas and answers with real value instead of
    ‘virtual likes’. This brings online conversation to completely new level
  • Real example of working micro-payment app which can act with other entities
    over internet using open protocol
  • All the modules are open-source projects and can be easy re-used and adjusted
    for your own project. App does not relay on third-party commercial services.
    Even it falls under e-commerce field, which is currently almost closed, the app
    is based on open solutions.

What are the use-cases?


something like this…

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Total votes 12: ↑11 and ↓1+10
Comments0

Version 12 Launches Today! (And It’s a Big Jump for Wolfram Language and Mathematica)

Reading time47 min
Views3.1K


Quick links


The Road to Version 12
First, Some Math
The Calculus of Uncertainty
Classic Math, Elementary and Advanced
More with Polygons
Computing with Polyhedra
Euclid-Style Geometry Made Computable
Going Super-Symbolic with Axiomatic Theories
The n-Body Problem
Language Extensions & Conveniences
More Machine Learning Superfunctions
The Latest in Neural Networks
Computing with Images
Speech Recognition & More with Audio
Natural Language Processing
Computational Chemistry
Geographic Computing Extended
Lots of Little Visualization Enhancements
Tightening Knowledgebase Integration
Integrating Big Data from External Databases
RDF, SPARQL and All That
Numerical Optimization
Nonlinear Finite Element Analysis
New, Sophisticated Compiler
Calling Python & Other Languages
More for the Wolfram “Super Shell”
Puppeting a Web Browser
Standalone Microcontrollers
Calling the Wolfram Language from Python & Other Places
Linking to the Unity Universe
Simulated Environments for Machine Learning
Blockchain (and CryptoKitty) Computation
And Ordinary Crypto as Well
Connecting to Financial Data Feeds
Software Engineering & Platform Updates
And a Lot Else…

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Total votes 9: ↑9 and ↓0+9
Comments0

WavesKit — PHP framework for working with Waves Platform

Reading time3 min
Views2.2K

I like PHP for development speed and excellent portability. It's great to have such a tool in your pocket, always ready to solve problems.


For me it was quite sad that there was no Waves Platform SDK for PHP when i first met this nice blockchain. Well, I had to write such kit.

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Total votes 12: ↑8 and ↓4+4
Comments0

Bitcoin (BTC)’s Low Volatility Will Lead to the Next Crypto Bull Run

Reading time3 min
Views1.2K
Curiosity has taken over the crypto space. Every enthusiast and potential trader wants to know when the next crypto bull run will start. The digital currency reached an all-time high in December 2017 and since then, it has been stuck in a crypto winter.

As well all know, Bitcoin, is the highest rising digital asset of all time. This is partly because of Bitcoin’s speculative nature, unlimited potential, and its built-in difficulty adjustment designed to throw off the elements of supply and demand to create a balance. This increases the Bitcoin price against the USD in return. It is a major reason why the leading digital currency can potentially initiate the next crypto bull run.

Bitcoin (BTC) Price Today – BTC / USD
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Total votes 9: ↑6 and ↓3+3
Comments0

«Non-Blockchain Games Involving Money Must Die»

Reading time4 min
Views1.7K


Dmitry Pichulin, known under the nick «deemru», won the game Fhloston Paradise, developed by Tradisys on the Waves blockchain.

The winner of Fhloston Paradise was supposed to be the player paying the very last stake during a 60-block period, before any other player could pay their stake and reset the counter to zero. The winner would collect all stakes paid by other players.

Dmitry's winning recipe was the bot Patrollo, which he created. The bot paid just eight 1 WAVES stakes for Dmitry and eventually won him 4,700 WAVES ($13,100). In this interview, Dmitry discusses his bot and prospects of blockchain games.

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Total votes 21: ↑17 and ↓4+13
Comments0

Crystal Blockchain Analytics: Investigating the Hacks and Theft Cases

Reading time8 min
Views2.7K
In this report, Bitfury shares analysis completed by its Crystal Blockchain Analytics engineering team on the movement of bitcoin from the Zaif exchange, Bithumb exchange and Electrum wallets.

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Total votes 15: ↑13 and ↓2+11
Comments0

Bitcoin for Starbucks Coffee Poses Significant Tax Filing Issues

Reading time2 min
Views952
A while ago, Starbucks announced that it was entering into a partnership with the United States cryptocurrency-based platform, Bakkt. Two days ago, new details about the partnership revealed that Starbucks, the United States coffee giant, may start accepting Bitcoin Bakkt payments because of the equity deal. The news was initially reported by The Block, a cryptocurrency news outlet.

Bitcoin Bakkt Payments On Starbucks


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In August last year, Starbucks became one of the founding partners of Bakkt. Now, the coffee giant will install the Bitcoin Bakkt software that will allow customers make payments for their products in Bitcoin. The report from The Block stated that even if the payments will be made in cryptocurrencies, no Bitcoin will be left on the chain. They will be converted into fiat instantly.

Bitcoin (BTC) Price Today – BTC / USD

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The entire cryptocurrency industry has been waiting for the release of Bakkt which is currently in its final stages. The platform is expected to support the massive adoption of cryptocurrencies around the globe. The platform will most likely be launched this year. Among other things, it is going to provide issuance for physically-delivered Bitcoin futures contracts. Right now, the main thing that is holding the platform back is regulatory approval from the CFTC. As soon as the United States Commodities Futures Trading Commission gives its approval, the platform will go live. This is expected to happen later this year.
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Total votes 8: ↑6 and ↓2+4
Comments0

Cryptocurrency market valuation to hit $1 trillion this year -Cryptocurrency Predictions 2019

Reading time2 min
Views797
Cryptocurrency market valuation to hit $1 trillion this year. The market cap of cryptocurrency seems to just increase. Even though some of the individual ones are falling but cumulatively, the market cap seems to increase year-on-year.

According to the CEO of Kraken, Jesse Powell, cryptocurrencies would see accelerated growth. They would be able to pull back from the bottom to new highs.

According to him, there are many businesses revolving around cryptocurrencies now. Also, there are many people in the know-how of cryptocurrency is no
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Total votes 24: ↑21 and ↓3+18
Comments1

Factors of the Bitcoin’s value

Reading time8 min
Views1.1K

Introduction


In the modern world, new technologies become important factors of the development of financial sphere of world economy. Emergency of such cryptocurrency as Bitcoin is connected with both great opportunities and certain risks for the users of this cryptocurrency. The aim of the present work is to determine the main factors which affect the price of Bitcoin.
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Total votes 11: ↑9 and ↓2+7
Comments1

The authoritative guide to Blockchain Sharding

Reading time12 min
Views1.3K

Hi, I'm one of the developers of the sharded blockchain Near Protocol, and in this article want to talk about what blockchain sharding is, how it is implemented, and what problems exist in blockchain sharding designs.


It is well-known that Ethereum, the most used general purpose blockchain at the time of this writing, can only process less than 20 transactions per second on the main chain. This limitation, coupled with the popularity of the network, leads to high gas prices (the cost of executing a transaction on the network) and long confirmation times; despite the fact that at the time of this writing a new block is produced approximately every 10–20 seconds the average time it actually takes for a transaction to be added to the blockchain is 1.2 minutes, according to ETH Gas Station. Low throughput, high prices, and high latency all make Ethereum not suitable to run services that need to scale with adoption.

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Total votes 15: ↑14 and ↓1+13
Comments0
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