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sdmg15/tinyblockchain-cli.php

Forked from vgrovestine/tinyblockchain-cli.php
Created December 29, 2017 04:46
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Revisions

  1. @vgrovestine vgrovestine revised this gist Dec 19, 2017. No changes.
  2. @vgrovestine vgrovestine created this gist Dec 19, 2017.
    99 changes: 99 additions & 0 deletions tinyblockchain-cli.php
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,99 @@
    <?php
    class Block {
    private $ts;
    private $nonce = 0;
    private $data;
    private $prev_hash;
    protected $hash;
    private $hash_algorithm;
    private $hash_prefix;

    protected function __construct($hash_algorithm, $hash_prefix, $prev_hash, $data) {
    $this->ts = microtime();
    $this->data = $data;
    $this->prev_hash = $prev_hash;
    $this->hash_algorithm = $hash_algorithm;
    $this->hash_prefix = $hash_prefix;
    $payload = $this->ts . $this->data . $this->prev_hash . $this->nonce;
    $this->hash = hash($this->hash_algorithm, $payload);
    if(!empty($this->prev_hash)) {
    while(!$this->is_valid_hash($this->hash)) {
    $this->nonce++;
    $payload = $this->ts . $this->data . $this->prev_hash . $this->nonce;
    $this->hash = hash($this->hash_algorithm, $payload);
    }
    }
    return $this;
    }

    private function is_valid_hash($hash) {
    if(strlen($this->hash_prefix) == 0) {
    return true;
    }
    else if(substr($hash, 0, strlen($this->hash_prefix)) === $this->hash_prefix) {
    return true;
    }
    return false;
    }

    }


    class Blockchain extends Block {
    private $hash_algorithm;
    private $hash_prefix;
    private $chain;

    public function __construct($hash_algorithm = '', $hash_prefix = '') {
    $this->is_valid_hash_algorithm($hash_algorithm) or die('Invalid hash algorithm: "' . $hash_algorithm . '" is not supported on this system.' . "\n");
    $this->hash_algorithm = $hash_algorithm;
    $this->is_valid_hash_prefix($hash_prefix) or die('Invalid hash prefix: "' . $hash_prefix . '" is not a hexadecimal string, or blank.' . "\n");
    $this->hash_prefix = $hash_prefix;
    $this->chain = array();
    $this->genesis();
    return $this;
    }

    private function genesis() {
    $this->chain[] = new Block($this->hash_algorithm, $this->hash_prefix, false, '**Genesis**');
    return $this->last();
    }

    public function grow($data) {
    $this->chain[] = new Block($this->hash_algorithm, $this->hash_prefix, $this->last()->hash, $data);
    return $this->last();
    }

    private function last() {
    return $this->chain[count($this->chain)-1];
    }

    private function is_valid_hash_algorithm($algorithm) {
    if(in_array($algorithm, hash_algos())) {
    return true;
    }
    return false;
    }

    private function is_valid_hash_prefix($prefix) {
    if(empty($prefix) or preg_match('/^[a-f0-9]*$/i', $prefix)) {
    return true;
    }
    return false;
    }

    public function dumpraw() {
    print_r($this->chain);
    }

    }


    // Now, let's build a tiny blockchain...
    $tinyblockchain = new Blockchain('sha256', '999');
    $tinyblockchain->grow("one potatoe");
    $tinyblockchain->grow("Two potatoes");
    $tinyblockchain->grow("Three Potatoes");
    $tinyblockchain->grow("FOUR!");
    $tinyblockchain->dumpraw();
    ?>