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Editor to share with you how to write custom data into the block chain, I believe that most people do not know much about it, so share this article for your reference. I hope you will learn a lot after reading this article. Let's learn about it!

Practical example 5.5.1. Data is written to the block chain

Make a transaction and write data to the block chain

Let Web3 = require ("web3"); let fs = require ("fs"); let web3 = new Web3 ("http://localhost:8545");let log = {time: (new Date). GetTime (), type:" info ", msg:" Web3 testworthy activities! "}; let str = JSON.stringify (log); console.log (str); let data = Buffer.from (str) .toString ('hex'); data =' 0x examples / / write data to the transaction let coinbase = "0x5c18a33df2cc41a1beddc91133b8422e89f041b7" console.log (coinbase) let user1 = "0xc2b9e316f246d35052118e51b55c75bfe99d247e"; web3.eth.personal.unlockAccount (coinbase, "chen1980"); let address = web3.eth.sendTransaction ({from:coinbase, to:user1, value:'0x00', data:data}, function (error, hash) {console.log (hash);})

Running the above program will generate a transaction, write down the hash value, and then start mining.

> miner.start (); null# stops after a period of time > miner.stop (); true

And then check that this is better than the deal.

Let Web3 = require ("web3"); let fs = require ("fs"); let web3 = new Web3 ("http://localhost:8545");let address =" 0xb15681eb4bdb6b9670d305fb341ebbc95d45c2ede0ea5034ef432b74f30b1b4f "; / / get data web3.eth.getTransaction (address) .then (console.log) from the transaction address; web3.eth.getTransaction (address,function (error, result) {/ / console.log (result); inputData = result.input) Res_str = Buffer.from (inputData.replace ('0x records'), 'hex') .toString (); res_json = JSON.parse (res_str); console.log (res_json);})

Result output

{blockHash: '0x78dacc2af60900d2e4cae90b71e27446e6e883df36c53f21cbc9e071f7a586f4', blockNumber: 1258, from: '0x5c18a33DF2cc41a1bedDC91133b8422e89f041B7', gas: 90000, gasPrice: '18000000000', hash: '0xb15681eb4bdb6b9670d305fb341ebbc95d45c2ede0ea5034ef432b74f30b1b4f', input: '0x7b2274696d65223a313531383933313435323537372c2274797065223a22696e666f222c226d7367223a22576562332054657374212121227d', nonce: 4, to: '0xc2b9e316F246d35052118E51B55C75BfE99d247e', transactionIndex: 0, value: '0', v: '0x41', r: '0x7fcd86c7fd975a0e98bd0e61a99da950b0155cd6c4581fefa4defbdcd404a930', s: '0x16f14ce1fbfadb9d59f343f8ac235cdd73dcedec5db1025ef91206b8bb17a827' }{ time: 1518931452577, type: 'info', msg: 'Web3 Test!!!'}

{time: 1518931452577, type: 'info', msg:' Web3 testworthy entries'} is the data stored in the chunk chain.

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