Blockchain and smart contract technology in PHP

With the gradual popularization and development of blockchain technology, more and more application scenarios have emerged, including the application of blockchain technology and smart contract technology in the field of PHP language. This article will start with the basic knowledge of blockchain and smart contracts in PHP, and give an in-depth explanation of its implementation methods and application scenarios based on actual cases.

1. Basic knowledge of blockchain and smart contracts

1. Basic knowledge of blockchain

Blockchain is composed of blocks. , each block contains a certain amount of transaction information and the hash value of the previous block. The blocks composed in this way are connected through hash pointers, forming an untamperable distributed database and becoming a blockchain. This distributed database not only has high reliability and security, but also enables decentralized data storage and sharing.

2. Basic knowledge of smart contracts

A smart contract is an automated contract, a piece of programming code that can be executed automatically without the need for third-party intervention. terms in the contract. Through smart contracts, some more complex logical calculations and automated execution of rules can be realized.

2. Implementation method of blockchain technology in PHP

As a powerful scripting language, PHP can be used in many fields such as Web development, data processing, and application development. In blockchain technology, PHP can realize its functions through some open source tools and frameworks.

Commonly used PHP blockchain technology implementation methods are as follows:

1. Use third-party blockchain API to achieve

By using third-party blockchain API can quickly integrate blockchain technology into PHP applications to complete operations such as real-time query or writing transaction information. Currently, the more popular third-party blockchain API services include: Blockchain API, Bitcore, BlockCypher, etc.

The following code implements querying the balance of a Bitcoin address:

$api_url = 'https://blockchain.info/rawaddr/1M8s2S5bgAzSSzVTeL7zruvMPLvzSkEAuv';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $api_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$res = curl_exec($ch);
curl_close($ch);

$json = json_decode($res);

echo 'The balance is: ' . $json->final_balance / 100000000;

2. Using PHP framework to implement

Using some PHP frameworks, it can be implemented more conveniently Functions of blockchain technology. For example, a simple blockchain application can be quickly implemented using the Laravel framework and CryptoPHP package.

The following code implements a simple blockchain application based on the Laravel framework and CryptoPHP package:

use CryptoPHPBlockchainBlock;

// 创建区块链
$blockchain = new Blockchain();

// 添加创世块并加入区块链
$blockchain->addBlock(new Block('First Block'));

// 添加第二个块并加入到区块链中
$blockchain->addBlock(new Block('Second Block'));

// 输出区块链内容
var_dump($blockchain->get());

3. Implementation method of smart contract technology in PHP

Smart contract technology in There are relatively few applications in PHP, but they can be compiled into bytecode through Solidity, so that contracts can be called in PHP to implement logical calculations.

1. Writing smart contracts with Solidity

Solidity is a smart contract language and the mainstream smart contract development language used on the Ethereum platform. Logical calculations are implemented by writing Solidity contracts, bytecode is generated after compilation, and smart contracts are implemented through PHP calls. Currently, the process of writing and deploying smart contracts using Solidity is relatively cumbersome and requires the use of Solidity development tool chains (such as Remix, Truffle, etc.) for development and testing.

The following is a simple Solidity contract example:

pragma solidity ^0.5.11;

contract HelloWorld {

    string message;
    
    constructor(string memory initialMessage) public {
        message = initialMessage;
    }

    function setMessage(string memory newMessage) public {
        message = newMessage;
    }

    function getMessage() public view returns (string memory) {
        return message;
    }
}

2. PHP calls the smart contract

The smart contract is implemented by using PHP to call the Ethereum RPC interface transfer. Before calling, the Solidity source code needs to be compiled into bytecode, and the Ethereum client and the Ethereum RPC extension of PHP need to be installed in advance.

The following is a simple example of PHP calling a smart contract:

// 创建以太坊客户端实例
$ethClient = new Ethereum('http://localhost:8545');

// 获取智能合约实例
$contractInstance = $ethClient->contract('HelloWorld', '0x123...');

// 调用getMessage函数，获取返回值
$result = $contractInstance->call('getMessage');
echo $result;

4. Application scenarios of blockchain and smart contract technology in PHP

1. Trade Finance Field

Blockchain technology can realize decentralized storage and secure encryption of transaction information, while smart contracts can complete the automated execution of transactions. In the field of trade finance, PHP can be used to develop applications such as online payment, transaction pricing, and transaction clearing based on blockchain and smart contracts.

2. Copyright protection field

Through blockchain technology and smart contract technology, the registration, verification and distribution of copyright protection can be achieved. Copyright information can be encrypted and stored in the blockchain, and operations such as copyright transfer, authorization, and dividends can be automatically performed through smart contracts.

3. Medical field

In the medical field, blockchain technology can be used to achieve decentralization and non-tampering of patient medical records and drug storage, and to achieve patient management through smart contracts. Authorization and payment operations between doctors.

Summary

This article starts from the basic knowledge of blockchain and smart contracts, introduces the implementation methods of blockchain and smart contract technology in PHP, and illustrates their application in trade finance. , copyright protection and application scenarios in the medical field. I hope this article will inspire readers, provide some references and ideas for PHP developers, and promote the development and innovation of the PHP ecosystem.

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