讨论共识算法、经济模型以及智能合约的开发

重磅发布 | Ultrain 2020 年技术路线图
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有心的彩民就能花费时间和精力找出来彩票,而很多彩民则没有意识到这个问题,结果不同彩民的盈亏结果有着极大的差别福彩双色球,也就是这个原因所致了幸运飞艇

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关于区块链与币市的行业动态与最新消息

写给自己的第四十六封信
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每天习惯晚睡,经常喜欢发呆,做什么事都没有坚持的动力彩票,今天告诉自己明天要努力,明天起来一如往日的模样,你无法忍受现在的自己福彩双色球,却没有毅力改变。越习惯,一切也就越糟糕,所有的无能为力幸运飞艇,大多是因为你--不曾真正努力!!

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黑客马拉松与经常性的线下见面会或在线趣味游戏

跨文化的交错之旅:Emma受邀出席卡地亚·故宫博物院特展
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有心的彩民就能花费时间和精力找出来彩票,而很多彩民则没有意识到这个问题福彩双色球,结果不同彩民的盈亏结果有着极大的差别幸运飞艇,也就是这个原因所致了

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链上分布式应用的开发工具以及高质量的应用推荐

新版Ultrain浏览器上线,终于可以查Token啦!
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所以,如何既能满足链上商业数据的隐私保护要求彩票,又同时不丧失区块链技术公开透明的特点福彩双色球,是一个区块链技术商业落地中必须解决的核心问题幸运飞艇。基于密码学的零知识证明技术就应运而生了。

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consensus and smart contract development

Ultrain Technology Roadmap in 2020
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The Ultrain main net has been running steadily for a year since it was launched on 2019.4.15. At present, the Ultrain network is composed of nearly 700 nodes, which are distributed in many countries and regions such as China, the East and West Coast of the United States, Australia, South Africa and Germany. The network deployment methods include public cloud networks (Alibaba Cloud, Amazon Cloud, Microsoft Cloud, Kingsoft Cloud), enterprise intranet, enterprise private network, open Internet and home broadband network.

On the basis of technical stability and shaping, Ultrain’s main task in 2020 is to realize the commercial implementation of blockchain technology. In the second half of 2019, we spent a lot of energy exploring and designing business models with our many business partners, and we have a full understanding of the advantages and disadvantages of blockchain technology in business competition:”Blockchain Business and Technology Status and Development Trend Outlook”. On this basis, we have determined the business model that we hope to be empowered by Ultrain technology in 2020: in a fully competitive industry, establish a mutual trust franchise business model at low cost.

In order to achieve this goal, Ultrain’s technology needs to be further upgraded from the following aspects in 2020:

Compliance with business compliance requirements: In recent months, various ministries and commissions have issued normative guidelines related to blockchain technology, such as the “Financial Distributed Ledger Technical Security Specification” issued by the Central Bank. These specifications will become the basic threshold for the application of enterprises in the future. In order to meet the requirements of these specifications and achieve commercial compliance, Ultrain needs to conduct further research and development in many aspects;

Consensus innovation: The franchise business model has two characteristics, one is that there are many franchisees, and the other is that the geographical distribution of franchisees is very scattered. This mainly brings a variety of technical challenges, including the different network environments of franchisees, and the need for users to automatically adapt to different networks without perception. There are many network nodes, and the online time of franchisees is not fixed. How to maintain the stability of the blockchain network in the face of a dynamic network. As an open network, how to ensure the security of the network; these aspects are the technical challenges we need to solve this year;

Blockchain privacy protection: In the business environment, privacy protection is the bottom line requirement for system operation. The “Personal Financial Information Protection Technical Specification” issued by the central bank at the beginning of this year can be used as a reference. Ultrain has a deep accumulation of blockchain privacy protection solutions. This year we will form a commercial solution to export and provide services;

The above are the three technical routes of Ultrain in 2020. We have further divided this technical route:

The above is the technology roadmap of Ultrain in 2020, which contains a number of world-leading technological breakthroughs. We will further publish the technical implementation details at each step and share our progress with you. Hope that Ultrain's breakthrough in technology can contribute to the commercial landing of blockchain technology.

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Industry dynamics and latest news about blockchain and currency

Ultrain Monthly Report(03/16–04/12)
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Ultrain Monthly Report(03/16–04/12)

Following is the monthly report on the progress of the project from Mar. 16th -Apr. 12th, which contains two items: project development progress and community dynamic update. It is for the community members to check. Thank you for your attention.

Technology Update from Ultrain (3/16–4/12)
Ultrain’s Core Technology

According to the Central Bank’s “Financial Distributed Ledger Technical Security Specification” compliance check and improve the node code;

The node code adds national secret algorithm support to the transaction account;

Establish an on-chain data table to support miners’ daily reward data on-chain storage;

Optimize the historical data query code and improve the browser query response speed;

Calculate the Merkel tree hash of the world state change data to provide world state data verification.

Ultrain’s Ecosystem

A new version of the user relationship diagram, store settings and other functions are launched on the backstage of the merchant, which completes the development of funds management, product management, store opening help and other pages, and is scheduled to go online at the end of April;

The new version of the Hyper-physical APP is launched, optimizing the rich text display on the product detail page, optimizing the homepage effect and other functions;

Optimize the merchant entry process, complete function development such as shop reward activities and shop package purchase, and plan to go online after passing the test in early May.

Ultrain Developer Kit

U3 SDK adds national secret algorithm support;

Optimize the Ultrain One wallet wealth page to support reading on the miner reward data chain;

Optimize Ultrain One wallet transfer code to improve transfer response speed.

Ultrain’s Latest Community & Event Update

Ultrain overseas ambassadors synchronized the development of the blockchain industry around the world

In March, due to multiple factors, the global financial market was in crisis. But at the same time, in this special period, emerging technologies such as blockchain have also accelerated. Ultrain’s overseas ambassadors conducted a survey to provide you with an in-depth understanding of the development of the blockchain industry around the world.

Ultrain wished community members a happy April Fools’ Day!

Ultrain launched the technology roadmap of 2020

The Ultrain mainnet has been running steadily for a year since it was launched on 2019.4.15. On the basis of technical stability and shaping, Ultrain ’s main task in 2020 is to achieve the commercial implementation of blockchain technology, and it has clarified the business model that hopes to be empowered by Ultrain technology in 2020: in a fully competitive industry To establish a mutual trust franchise business model through low cost.

In order to achieve this goal, Ultrian’s technology needs to be further upgraded from the following aspects in 2020: 1. Compliance with business compliance requirements; 2. Consensus innovation; 3. Blockchain privacy protection. We have further divided the technical route.

The above is the progress report of Ultrain from Mar 16th to Apr 12th, looking forward to more exciting contents after that!

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hacker marathon and regular meetup or online game

Ultrain Monthly Report(5/11–6/7)
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Following is the monthly report on the progress of the project from May. 11th -Jun.7th, which contains two items: project development progress and community dynamic update. It is for the community members to check. Thank you for your attention.

Technology Update from Ultrain (5/11–6/7)

Ultrain’s Core Technology

• Ultrain infrastructure

Complete the development of the Windows version of the family mining machine software, and implement the Windows 10 environment automation deployment tool to complete the internal test;

Node software adds on-chain data compression and encrypted storage, and increases data distributed storage mechanism support;

Improve the certificate system management tool to support encrypted authentication communication between nodes and between the client and the server.

Ultrain’s Ecosystem

New functions of exporting merchant orders, customizing reward rules, intelligent display of user data and other functions have been released on the S.I.R platform and updated versions have been released;

The S.I.R system completes the product video, custom sharing copy and other function development, and enters the test stage;

Complete the construction and development of the blockchain enterprise service platform and data upload, and complete the development of related systems such as new marketing activities for blockchain games.

Ultrain Developer Kit

Complete TypeScript refactoring for UltrainOne to improve code readability and maintainability.

Ultrain’s Latest Community & Event Update

Ultrain fully introduced its own blockchain certificate management system

Currently, the mainstream blockchain technology in China is called an open license chain. The license chain refers to the owners of all the nodes that make up the license chain. Their identities are authenticated, and they can only join the blockchain network after being authorized by the license. In this scenario, the network is open to authorized organizations or institutions, and there is a collaborative relationship between the participants on the chain, with an access mechanism. As a complete solution, the PKI/CA system can provide identity authentication certificates for each participant in the license chain to realize access control. It can be said that the certificate mechanism is the cornerstone of the permission chain network security.

Recently, Ultrain technical experts wrote an article, which describes the Ultrain certificate management system in detail after describing the basic concepts of PKI/CA as necessary.

Ultrain has completed development of many new functions

Ultrain independently developed a one-stop user growth technology service platform based on a small program store. The super-item system has completed iterations. It has a variety of powerful tool libraries to support the needs of merchant stores in multiple scenarios: SMS and subscription notifications, merchandise Fission posters, user relationship management … In the future, there will also be functions such as social dynamics and interaction, live broadcast playback, etc.

At present, Superphysical is engaged in store exploration and nugget activities, inviting merchants from all walks of life to open stores, and you will receive a reward for opening a store. Permanently receive 1% of the order transaction amount as a reward.

Ultrain is working closely with multiple business partners

Recently, Ultrain has helped a blockchain game to complete the construction of its marketing system, and has also completed the construction and development of a blockchain enterprise service center and data upload. In addition, there are many business partners in close negotiation and cooperation.

The above is the progress report of Ultrain from May 11th to Jun 7th, looking forward to more exciting contents after that!

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Dapp develop tools and high-quality application recommendations

How to build an end-to-end DApp on Ultrain - 2
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Step2:Write DApp

There are two Dapps to be written, one is MiningDapp, the other is UDapp. We use the Javascript SDK U3.js to write the DApps. To be simple, we create the two DApps in one project.

Written by DApp

In WebStorm, create a new project -> Node.js Express App-> Template select Pug (Jade); modify the project name to CarbonDApp;

Click ‘Create’ to create a project

Import project dependent class library

Copy all the directories in node_modules in CarbonProject to the node_modules directory of CarbonDApp, and repeat the directory skipping without copying;
Copy the CarbonDApp/node_modules/u3.js/dist/u3.js file to the CarbonDApp/public/javascripts directory.

Modify the DApp server port

Since the default 3000 port is already occupied, you need to modify the server port of the DApp.

Open the bin/www file and find var port = normalizePort(process.env.PORT || '3000'); change 3000 to 3001

Create an account information browsing page

Create an index.html page in the public directory and add the following code to the page:

<html> <head> <meta charset="UTF-8"> <title>test</title> <link rel="stylesheet" href="/stylesheets/style.css"> <script src="./javascripts/u3.js"></script> <script> let u3 = U3.createU3({ httpEndpoint: 'http://127.0.0.1:8888', httpEndpoint_history: 'http://127.0.0.1:3000', broadcast: true, debug: false, sign: true, logger: { log: console.log, error: console.error, debug: console.log }, chainId:'2616bfbc21e11d60d10cb798f00893c2befba10e2338b7277bb3865d2e658f58', symbol: 'UGAS' }); async function getBalanceInfo() { let SYMBOL = 'CARB'; let account = 'ben'; const ben_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: account }); document.getElementById("carbon_balance").innerHTML = '账户余额:'+ben_balance; const bob_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: 'bob' }); document.getElementById("bob_balance").innerHTML = '账户余额:'+ bob_balance; const tom_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: 'tom' }); document.getElementById("tom_balance").innerHTML = '账户余额:'+tom_balance; const tony_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: 'tony' }); document.getElementById("tony_balance").innerHTML = '账户余额:'+tom_balance; const jerry_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: 'jerry' }); document.getElementById("jerry_balance").innerHTML = '账户余额:'+tom_balance; const jack_balance = await u3.getCurrencyBalance({ code:'ben', symbol: SYMBOL, account: 'jack' }); document.getElementById("jack_balance").innerHTML = '账户余额:'+tom_balance; } getBalanceInfo(); //transfer(); </script> </head> <body> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>CarbonCoin发行方</h1> <p>账户:ben</p> <p>描述:进行CarbonCoin发行的发行方,持有所有未分配的CarbonCoin</p> <p id="carbon_balance"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备1</h1> <p>账户:bob</p> <p>描述:通过节能产生CarbonCoin的节能设备1</p> <p id="bob_balance"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备2</h1> <p>账户:tom</p> <p>描述:通过节能产生CarbonCoin的节能设备2</p> <p id="tom_balance"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>航空公司C</h1> <p>账户:tony</p> <p>描述:大型航空公司,化石能源使用大户</p> <p id="tony_balance"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>汽车制造商D</h1> <p>账户:jerry</p> <p>描述:大型汽车制造商,化石能源使用大户</p> <p id="jerry_balance"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>CarbonCoin销毁账户</h1> <p>账户:jack</p> <p>描述:用于CarbonCoin销毁的账户,持有所有销毁的CarbonCoin</p> <p id="jack_balance"></p> </div> </body> </html> Start the DApp service, test the page
In the npm interface, double click the start button

After the server is successfully started, visit http://127.0.0.1:3001/index.html and the following page appears:

It can be seen that the issuer ben account holds 10 million of all CARB Tokens issued; other accounts have not yet held CARB Token;

Create a mining.html page

Mining.html page, energy-saving device 1 and energy-saving device 2 send the calorie value generated in the first 30 seconds to the energy smart contract every 30 seconds, and redeem CarbonCoin;

Create a mining.html page in the public directory, enter the following code:

<html> <head> <meta charset="UTF-8"> <title>test</title> <link rel="stylesheet" href="/stylesheets/style.css"> <script src="./javascripts/u3.js"></script> <script> let u3_bob = U3.createU3({ httpEndpoint: 'http://127.0.0.1:8888', httpEndpoint_history: 'http://127.0.0.1:3000', broadcast: true, debug: false, sign: true, logger: { log: console.log, error: console.error, debug: console.log }, chainId:'2616bfbc21e11d60d10cb798f00893c2befba10e2338b7277bb3865d2e658f58', keyProvider: '5JoQtsKQuH8hC9MyvfJAqo6qmKLm8ePYNucs7tPu2YxG12trzBt',//bob's private_key symbol: 'CARB' }); let u3_tom = U3.createU3({ httpEndpoint: 'http://127.0.0.1:8888', httpEndpoint_history: 'http://127.0.0.1:3000', broadcast: true, debug: false, sign: true, logger: { log: console.log, error: console.error, debug: console.log }, chainId:'2616bfbc21e11d60d10cb798f00893c2befba10e2338b7277bb3865d2e658f58', keyProvider: '5KXYYEWSFRWfNVrMPaVcxiRTjD9PzHjBSzxhA9MeQKHPMxWP8kU',//tom's private_key symbol: 'CARB' }); function wait(ms = 0) { return new Promise(res => setTimeout(res, ms)); } function randomFrom(lowerValue,upperValue) { return Math.floor(Math.random() * (upperValue - lowerValue + 1) + lowerValue); } async function mining() { let owner_account = 'ben'; const tr_bob = await u3_bob.contract(owner_account); const tr_tom = await u3_tom.contract(owner_account); // let amount = U3.format.UDecimalPad(2000,4); let heat_bob = randomFrom(15000,20000); let heat_tom = randomFrom(15000,20000); await tr_bob.recordHeat(heat_bob,{ authorization: [`bob@active`] }); await tr_tom.recordHeat(heat_tom,{ authorization: [`tom@active`] }); var d=new Date(); var t=d.toLocaleTimeString(); document.getElementById("bob_log").innerHTML = 'time :'+t+', heat value :'+ heat_bob; document.getElementById("tom_log").innerHTML = 'time :'+t+', heat value :'+ heat_tom; } mining(); var int=self.setInterval("mining()",30*1000); </script> </head> <body> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备1</h1> <p>账户:bob</p> <p>描述:通过节能产生CarbonCoin的节能设备1</p> <p id="bob_log"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备2</h1> <p>账户:tom</p> <p>描述:通过节能产生CarbonCoin的节能设备2</p> <p id="tom_log"></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <button onclick="int=window.clearInterval(int)">stop</button> </div> </body> </html>

Go to http://127.0.0.1:3001/mining.html and the following page appears:

There are two things to note here.

When sending data to the energy smart contract, you need to hold the private key of the account before you can sign and send it. In order to simplify the programming, the private key is directly written to the webpage. In the actual program, the private key needs to be protected and hidden.

To simplify the writing, the Bob and tom DApp programs are written directly to a page. Actually, they should be two DApp program instances, which are running on two devices respectively.

Now our energy-saving equipment can already send data to the smart contract, and after the energy smart contract receives the data, it will pass the data to the operator server, and the operator server will call the energy smart contract again to exchange carboncoin. So we need to establish EnergyServer;

Step3: EnergyServer

Establish event monitor and handle events

In this section, we will deal with the above calorific value data upload event.

1.1 Establish listener event server code

In the bin directory of the CarbonDApp project, create a new file msgBroker.js and enter the following code.

const { createU3 , format} = require('u3.js/src'); const http = require('http'); const port = 3002; let u3 = createU3({ httpEndpoint: 'http://127.0.0.1:8888', httpEndpoint_history: 'http://127.0.0.1:3000', broadcast: true, debug: false, sign: true, logger: { log: console.log, error: console.error, debug: console.log }, chainId:'2616bfbc21e11d60d10cb798f00893c2befba10e2338b7277bb3865d2e658f58', keyProvider:'5JbedY3jGfNK7HcLXcqGqSYrmX2n8wQWqZAuq6K7Gcf4Dj62UfL',//ben's private key symbol: 'UGAS' }); let server = http.createServer((request, response) => { const { headers, method, url } = request; console.log(method); console.log(url); let body = []; request.on('error', (err) => { console.error(err); }).on('data', (chunk) => { body.push(chunk); }).on('end', () => { body = Buffer.concat(body).toString(); console.log("received msg:", body); if (body != null && body.trim()!="") { var obj = JSON.parse(body); let heatValue = JSON.parse(obj[1]).heat.split(",")[0]; let account = JSON.parse(obj[1]).heat.split(",")[1]; exchangeCarbonCoin(account,heatValue); } response.on('error', (err) => { console.error(err); }); response.statusCode = 200; response.setHeader('Content-Type', 'application/json'); response.write("ok"); response.end(); }); }); server.keepAliveTimeout = 0; server.timeout = 0; server.listen(port, function () { console.log((new Date()) + " Server is listening on port " + port); }); function wait(ms = 0) { return new Promise(res => setTimeout(res, ms)); } async function exchangeCarbonCoin(account,heat) { let SYMBOL = 'CARB'; let code = 'ben'; const tr = await u3.contract(code); let heatValue = format.DecimalPad(heat,4); const result = await tr.exchangeCarbonCoin('ben', account, heatValue+' ' + SYMBOL, 'test', { authorization: [`ben@active`] }); let tx = await u3.getTxByTxId(result.transaction_id); while (!tx.irreversible) { await wait(1000); tx = await u3.getTxByTxId(result.transaction_id); if (tx.irreversible) { console.log(tx); break; } } }

The code establishes a service on port 3002. After the energy-saving device uploads its calorific value, the smart contract will send the energy-saving device to the service to upload the calorific value data. The service calls the exchangeCarbonCoin method of the energy smart contract to exchange the CarbonCoin.

1.2 Establish a listener event server startup script

Open the CarbonDApp/package.json file and add the following code to the scripts property: "event": "node ./bin/msgBroker"

1.3 Start the listening server

Refresh the npm window with the ‘event’ option

Double-click event to complete server startup

1.4 Register event monitoring mechanism on the chain

Query the internal network address of the machine through the ifconfig command, for example: 10.20.8.32

In the CarbonProject/test directory, create the registerEvent.js file; enter the following code in the file

const U3Utils = require('u3-utils/dist/es5'); const { createU3, format, listener } = require('u3.js/src'); const config = require('../config'); const chai = require('chai'); require('chai') .use(require('chai-as-promised')) .should(); const should = chai.should(); const expect = chai.expect; const assert = chai.assert; describe('Test cases', function() { it('event register', async () => { let account = 'ben'; const u3 = createU3(config); await u3.registerEvent(account, 'http:// 10.20.8.32:3002'); U3Utils.wait(1000); }); it('event unregister', async () => { let account = 'ben'; const u3 = createU3(config); await u3.unregisterEvent(account, ' http:// 10.20.8.32:3002'); U3Utils.wait(1000); }); });

Note that the registered address is modified to be the internal network address of the machine, and 127.0.0.1 cannot be used.
Run the event register test case to complete the event registration;

1.5 Test calorie value for CarbonCoin function

Visit http://127.0.0.1:3001/mining.html page, every 30 seconds, both bob and tom will randomly send a random value between 15000 and 20000 as the calorific value to convert the smart contract to CarbonCoin;
Visit and refresh the http://127.0.0.1:3001/index.html page, you can find that the CarbonCoin account of bob and tom is increasing every 30 seconds;

Step4:Improve DApp functionality

Add transfer function

After the energy-saving equipment acquires CarbonCoin, it can sell CarbonCoin to the enterprise, such as airlines, etc. The simple embodiment is that the equipment account can be transferred to the corporate company account;

Open the /CarbonDApp/index.html page and add the code

1.1 U3 object used when establishing the transfer

let u3_bob = U3.createU3({ keyProvider:'5JoQtsKQuH8hC9MyvfJAqo6qmKLm8ePYNucs7tPu2YxG12trzBt',//bob's private key }) let u3_tom = U3.createU3({ keyProvider:'5KXYYEWSFRWfNVrMPaVcxiRTjD9PzHjBSzxhA9MeQKHPMxWP8kU',//tom's private key })

1.2 Add the js code of the transfer to call the corresponding smart contract method

async function sendCoin(from,to){ let SYMBOL = 'CARB'; let code = 'ben'; let coins = U3.format.DecimalPad(this.randomFrom(100,500),4); if (from == 'bob'){ const tr = await u3_bob.contract(code); const result = await tr.transfer(from, to, coins + ' ' + SYMBOL, 'sendCoin', { authorization: [`bob@active`] }); let tx = await u3_bob.getTxByTxId(result.transaction_id); while (!tx.irreversible) { await wait(1000); tx = await u3_bob.getTxByTxId(result.transaction_id); if (tx.irreversible) { alert("bob send coin success:"+ coins); break; } } } else if (from == 'tom'){ const tr = await u3_tom.contract(code); const result = await tr.transfer(from, to, coins + ' ' + SYMBOL, 'sendCoin', { authorization: [`tom@active`] }); let tx = await u3_tom.getTxByTxId(result.transaction_id); while (!tx.irreversible) { await wait(1000); tx = await u3_tom.getTxByTxId(result.transaction_id); if (tx.irreversible) { alert("tom send coin success:"+ coins); break; } } } }

1.3 Add a call to the sendcoin() method on the page, update the following code

<div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备1</h1> <p>账户:bob</p> <p>描述:通过节能产生CarbonCoin的节能设备1</p> <p id="bob_balance"></p> <p><a href="#" OnClick="sendCoin('bob','tony')">给航空公司C转账</a></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>节能设备2</h1> <p>账户:tom</p> <p>描述:通过节能产生CarbonCoin的节能设备2</p> <p id="tom_balance"></p> <p><a href="#" OnClick="sendCoin('tom','jerry')">给汽车制造商D转账</a></p> </div>

1.4 Access the page and test the function

Visit: http://127.0.0.1:3001/index.html, click the "Transfer to the airline C" button, wait for a period of time (up to about 10 seconds, confirm the time for the Ultrain transaction), the following prompt appears, indicating the transfer success.

Add a company to convert CarbonCoin to a charity point function

By converting CarbonCoin into charitable points, the company makes its own contribution to reducing carbon emissions and enhances its reputation:

Open the /CarbonDApp/index.html page and add the code

2.1 U3 object used when establishing point redemption

let u3_tony = U3.createU3({ keyProvider:'5KbHvFfDXovPvo2ACNd23yAE9kJF7Mxaws7srp6VapjMr7TrHZB',//tony's private key }) let u3_jerry = U3.createU3({ keyProvider:'5JFz7EbcsCNHrDLuf9VpHtnLdepL4CcAEXu7AtSUYfcoiszursr',//jerry's private key })

2.2 Add the redeemed js code to call the corresponding smart contract method

async function exchangeScore(account){ let SYMBOL = 'CARB'; let code = 'ben'; let to = 'jack'; let coins = U3.format.DecimalPad(this.randomFrom(10,50),4); if (account == 'tony'){ const tr = await u3_tony.contract(code); const result = await tr.exchangeScore(account, to, coins + ' ' + SYMBOL, 'sendCoin', { authorization: [`tony@active`] }); let tx = await u3_tony.getTxByTxId(result.transaction_id); while (!tx.irreversible) { await wait(1000); tx = await u3_tony.getTxByTxId(result.transaction_id); if (tx.irreversible) { alert("tony buy score success:"+ coins); break; } } } else if (account == 'jerry'){ const tr = await u3_jerry.contract(code); const result = await tr.exchangeScore(account, to, coins + ' ' + SYMBOL, 'sendCoin', { authorization: [`jerry@active`] }); let tx = await u3_jerry.getTxByTxId(result.transaction_id); while (!tx.irreversible) { await wait(1000); tx = await u3_jerry.getTxByTxId(result.transaction_id); if (tx.irreversible) { alert("jerry buy score success:"+ coins); break; } } } }

2.3 Add a call to the exchangeScore() method on the page, update the following code

<div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>航空公司C</h1> <p>账户:tony</p> <p>描述:大型航空公司,化石能源使用大户</p> <p id="tony_balance"></p> <p><a href="#" OnClick="exchangeScore('tony');return false;">购买公益积分</a></p> </div> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>汽车制造商D</h1> <p>账户:jerry</p> <p>描述:大型汽车制造商,化石能源使用大户</p> <p id="jerry_balance"></p> <p><a href="#" OnClick="exchangeScore('jerry');return false;">购买公益积分</a></p> </div>

2.4 Access the page and test the function

Visit: http://127.0.0.1:3001/index.html, click the "Buy Charity Points" button, wait for a period of time (up to about 10 seconds, confirm the time for the Ultrain transaction), the following prompt appears, indicating that the points are successfully redeemed. At the same time, you can see the number of CarbonCoins destroyed in the CarbonCoin destruction account at the bottom of the page.

Query the public welfare points exchange history

By enquiring the redemption history of charity points, we can establish a ranking of corporate charity points.

3.1 Creating a page

In the CarbonDApp/public/ directory, create a new leaderboard.html and enter the following code:

<html> <head> <meta charset="UTF-8"> <title>leaderboard</title> <link rel="stylesheet" href="/stylesheets/style.css"> <script src="./javascripts/u3.js"></script> <script> let u3 = U3.createU3({ httpEndpoint: 'http://127.0.0.1:8888', httpEndpoint_history: 'http://127.0.0.1:3000', broadcast: true, debug: false, sign: true, logger: { log: console.log, error: console.error, debug: console.log }, chainId:'2616bfbc21e11d60d10cb798f00893c2befba10e2338b7277bb3865d2e658f58', symbol: 'UGAS' }); function wait(ms = 0) { return new Promise(res => setTimeout(res, ms)); } async function getLeaderboard() { let owner_account = 'ben'; const tr = await u3.contract(owner_account); const result = await u3.getAllTxs(1,10000000,{"actions.name":"exchangeScore"},{_id:-1}); //console.log(result); let content = ''; for ( let i = 0 ;i< result.results.length;i++){ content = content + '<tr><td>'+ result.results[i].actions[0].data.from+":"+result.results[i].actions[0].data.quantity +'</td></tr>'; } document.getElementById("leaderboard").innerHTML = content; } getLeaderboard(); </script> </head> <body> <div style="padding:8px;border:1px solid #96c2f1;background:#eff7ff"> <h1>leaderboard</h1> <table id="leaderboard"> </table> </div> </body> </html>

We use the u3.getAllTxs(1,10000000,{"actions.name":"exchangeScore"},{_id:-1}); method to query all redemption transactions and print their specific data to the page.

3.2 Run page

Visit http://127.0.0.1:3001/leaderboard.html and you can see the following page:

Here is a history of all points redemption.

Summary

This tutorial system describes how to write an end-to-end web version of the DApp application. Although it has been simplified in the process of writing, it generally describes the overall picture of DApp application development, developers can do the basis of this framework. Enrich and improve your DApp application.

About developing DApp on iOS and Android, you can integrate u3.js into the corresponding hybrid Native development framework, and the principle is the same as the web version DApp.

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