Detailed explanation of php and ethereum client interaction php examples

{
  "method": "",
  "params": [],
  "id": idNumber
}

<?php

class jsonRPCClient {
  
  /**
   * Debug state
   *
   * @var boolean
   */
  private $debug;
  
  /**
   * The server URL
   *
   * @var string
   */
  private $url;
  /**
   * The request id
   *
   * @var integer
   */
  private $id;
  /**
   * If true, notifications are performed instead of requests
   *
   * @var boolean
   */
  private $notification = false;
  
  /**
   * Takes the connection parameters
   *
   * @param string $url
   * @param boolean $debug
   */
  public function __construct($url,$debug = false) {
    // server URL
    $this->url = $url;
    // proxy
    empty($proxy) ? $this->proxy = &#39;&#39; : $this->proxy = $proxy;
    // debug state
    empty($debug) ? $this->debug = false : $this->debug = true;
    // message id
    $this->id = 1;
  }
  
  /**
   * Sets the notification state of the object. In this state, notifications are performed, instead of requests.
   *
   * @param boolean $notification
   */
  public function setRPCNotification($notification) {
    empty($notification) ?
              $this->notification = false
              :
              $this->notification = true;
  }
  
  /**
   * Performs a jsonRCP request and gets the results as an array
   *
   * @param string $method
   * @param array $params
   * @return array
   */
  public function __call($method,$params) {
    
    // check
    if (!is_scalar($method)) {
      throw new Exception(&#39;Method name has no scalar value&#39;);
    }
    
    // check
    if (is_array($params)) {
      // no keys
      $params = $params[0];
    } else {
      throw new Exception(&#39;Params must be given as array&#39;);
    }
    
    // sets notification or request task
    if ($this->notification) {
      $currentId = NULL;
    } else {
      $currentId = $this->id;
    }
    
    // prepares the request
    $request = array(
            &#39;method&#39; => $method,
            &#39;params&#39; => $params,
            &#39;id&#39; => $currentId
            );
    $request = json_encode($request);
    $this->debug && $this->debug.=&#39;***** Request *****&#39;."\n".$request."\n".&#39;***** End Of request *****&#39;."\n\n";

    // performs the HTTP POST
    $opts = array (&#39;http&#39; => array (
              &#39;method&#39; => &#39;POST&#39;,
              &#39;header&#39; => &#39;Content-type: application/json&#39;,
              &#39;content&#39; => $request
              ));
    $context = stream_context_create($opts);
    if ($fp = fopen($this->url, &#39;r&#39;, false, $context)) {
      $response = &#39;&#39;;
      while($row = fgets($fp)) {
        $response.= trim($row)."\n";
      }
      $this->debug && $this->debug.=&#39;***** Server response *****&#39;."\n".$response.&#39;***** End of server response *****&#39;."\n";
      $response = json_decode($response,true);
    } else {
      throw new Exception(&#39;Unable to connect to &#39;.$this->url);
    }
    
    // debug output
    if ($this->debug) {
      echo nl2br($debug);
    }
    
    // final checks and return
    if (!$this->notification) {
      // check
      if ($response[&#39;id&#39;] != $currentId) {
        throw new Exception(&#39;Incorrect response id (request id: &#39;.$currentId.&#39;, response id: &#39;.$response[&#39;id&#39;].&#39;)&#39;);
      }
      if (!is_null($response[&#39;error&#39;])) {
        throw new Exception(&#39;Request error: &#39;. var_export($response[&#39;error&#39;], true));
      }
      
      return $response[&#39;result&#39;];
      
    } else {
      return true;
    }
  }
}
?>

{
  "method": "eth_accounts",
  "params": [],
  "id": 1
}

function balanceOf(address _owner) public view returns (uint256 balance)

balanceOf(address)

web3.sha3("balanceOf(address)").substring(0, 10)

{
  "method": "eth_call",
  "params": [{"from": "0x38aabef4cd283ccd5091298dedc88d27c5ec5750", "to": "0xaeab4084194B2a425096fb583Fbcd67385210ac3", "data": "0x70a0823100000000000000000000000038aabef4cd283ccd5091298dedc88d27c5ec5750"}, "latest"],
  "id": 1
}

function transfer(address _to, uint256 _value) public returns (bool)

transfer(address,uint256) //注意逗号后面不能有空格

web3.sha3("transfer(address,uint256)").substring(0, 10)

{
  "method": "eth_call",
  "params": [{"from": "0x38aabef4cd283ccd5091298dedc88d27c5ec5750", "to": "0xaeab4084194B2a425096fb583Fbcd67385210ac3", "data": "0xa9059cbb00000000000000000000000038aabef4cd283ccd5091298dedc88d27c5ec5750000000000000000000000000000000000000000000000000000000000000ab00"}, "latest"],
  "id": 1
}

<?php 

require &#39;./jsonRPCClient.php&#39;;

//php自带的dechex无法把大整型转换为十六进制
function bc_dechex($decimal)
{
  $result = [];

  while ($decimal != 0) {
    $mod = $decimal % 16;
    $decimal = floor($decimal / 16);
    array_push($result, dechex($mod));    
  }

  return join(array_reverse($result));
}

class EthereumRPCClient
{
  public static $client = null;
  
  //布署合约的账户地址
  const COINBASE = &#39;0x38aabef4cd283ccd5091298dedc88d27c5ec5750&#39;;
  
  //合约地址
  const CONTRACT = &#39;0xaeab4084194B2a425096fb583Fbcd67385210ac3&#39;;

  public static function __callStatic($method, $params)
  {
    $params = count($params) < 1 ? [] : $params[0];

    try {
      if (is_null(self::$client)) {
        self::$client = new jsonRPCClient(&#39;http://127.0.0.1:8545&#39;, true);  
      }
    } catch (\Exception $e) {
      echo $e->getMessage();
    }

    return call_user_func([self::$client, $method], $params);

  }

  public static function getBalance($address)
  {
    $method_hash = &#39;0x70a08231&#39;;
    $method_param1_hex = str_pad(substr($address, 2), 64, &#39;0&#39;, STR_PAD_LEFT);
    $data = $method_hash . $method_param1_hex;

    $params = [&#39;from&#39; => $address, &#39;to&#39; => self::CONTRACT, &#39;data&#39; => $data];

    $total_balance = self::eth_call([$params, "latest"]);

    return hexdec($total_balance) / (pow(10, 18));
  }

  public static function transfer($to, $value)
  {
    self::personal_unlockAccount([self::COINBASE, "123456", 3600]);

    $value = bcpow(10, 18) * $value;

    $method_hash = &#39;0xa9059cbb&#39;;
    $method_param1_hex =str_pad(substr($to, 2), 64, &#39;0&#39;, STR_PAD_LEFT);  
    $method_param2_hex = str_pad(strval(bc_dechex($value)), 64, &#39;0&#39;, STR_PAD_LEFT);

    $data = $method_hash . $method_param1_hex . $method_param2_hex;
    $params = [&#39;from&#39; => self::COINBASE, &#39;to&#39; => self::CONTRACT, &#39;data&#39; => $data];

    return self::eth_sendTransaction([$params]);

  }

}