ZaSQaSZH

1<?php
2
3class Blockchain
4{
5    public $lastHash;
6
7    private $db;
8
9    public function __construct()
10    {
11        $this->db = new \PDO('sqlite:blockchain.db');
12        $this->db->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
13
14        $this->db->exec(<<<QUERY
15CREATE TABLE IF NOT EXISTS blocks (
16    id INTEGER PRIMARY KEY,
17    hash VARCHAR(64),
18    block TEXT
19)
20QUERY
21        );
22
23        $this->lastHash = $this->db
24            ->query('SELECT hash FROM blocks ORDER BY id DESC LIMIT 1')
25            ->fetchColumn();
26
27        if (!$this->lastHash) {
28            echo "Blockchain'de blok bulunamadı. Genesis blok oluşturuluyor.";
29            $genesis = newBlock('Genesis Block', '');
30
31            $query = $this->db->prepare('INSERT INTO blocks (hash, block) VALUES (?, ?)');
32            $query->execute([$genesis->hash, json_encode($genesis)]);
33
34            $this->lastHash = $genesis->hash;
35        }
36    }
37}