這篇文章告訴大家了php與ethereum客戶端互動的相關知識點,有著一定的參考價值,對此有需要的朋友可以跟著學習下。
php與ethereum rpc server通訊
一、Json RPC
{ "method": "", "params": [], "id": idNumber }
二、建構一個Json RPC客戶端
#
<?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 = '' : $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('Method name has no scalar value'); } // check if (is_array($params)) { // no keys $params = $params[0]; } else { throw new Exception('Params must be given as array'); } // sets notification or request task if ($this->notification) { $currentId = NULL; } else { $currentId = $this->id; } // prepares the request $request = array( 'method' => $method, 'params' => $params, 'id' => $currentId ); $request = json_encode($request); $this->debug && $this->debug.='***** Request *****'."\n".$request."\n".'***** End Of request *****'."\n\n"; // performs the HTTP POST $opts = array ('http' => array ( 'method' => 'POST', 'header' => 'Content-type: application/json', 'content' => $request )); $context = stream_context_create($opts); if ($fp = fopen($this->url, 'r', false, $context)) { $response = ''; while($row = fgets($fp)) { $response.= trim($row)."\n"; } $this->debug && $this->debug.='***** Server response *****'."\n".$response.'***** End of server response *****'."\n"; $response = json_decode($response,true); } else { throw new Exception('Unable to connect to '.$this->url); } // debug output if ($this->debug) { echo nl2br($debug); } // final checks and return if (!$this->notification) { // check if ($response['id'] != $currentId) { throw new Exception('Incorrect response id (request id: '.$currentId.', response id: '.$response['id'].')'); } if (!is_null($response['error'])) { throw new Exception('Request error: '. var_export($response['error'], true)); } return $response['result']; } else { return true; } } } ?>
三、呼叫RPC的兩類方法
{ "method": "eth_accounts", "params": [], "id": 1 }
##RPC Server自帶方法的列表
調用自帶方法比較簡單,參考上述鏈接,大部分都有示例.
合約方法調用json格式
調用合約方法必須使用自帶方法中的eth_call. 而合約方法名稱和合約方法參數列表則使用params進行體現, 例如: 我們要調用合約中的balanceOf方法, 則json資料應該如何構造呢?
#首先看看getBalanace的函數實作:
function balanceOf(address _owner) public view returns (uint256 balance)
提煉出函數原型:
balanceOf(address)
在geth控制台下執行指令:
web3.sha3("balanceOf(address)").substring(0, 10)
得到函數hash "0x70a08231"
假設待查詢的位址address _owner = "0x38aabef4cd283ccd5091298dedc85027c5ec 則去掉前面的"0x", 並在左邊補24個零(一般地址長度為42位, 去掉'0x'後為40位),構成64位十六進位參數.
最終得到的參數為"0x70a0823100000000000000000000000038aabef4cd283ccd5091298dedc88d2 .
則得到最終的json資料為:
{ "method": "eth_call", "params": [{"from": "0x38aabef4cd283ccd5091298dedc88d27c5ec5750", "to": "0xaeab4084194B2a425096fb583Fbcd67385210ac3", "data": "0x70a0823100000000000000000000000038aabef4cd283ccd5091298dedc88d27c5ec5750"}, "latest"], "id": 1 }
把以上json資料以post方式發送給伺服器,就可以調用合約方法"balanceOf", 查詢給定的地址中的代幣餘額.
調用合約中的其他方法也要新遵循上面的方式, 我們再分析一下transfer方法, 加深印象:
#首先, 看看程式碼中的函數實作:
function transfer(address _to, uint256 _value) public returns (bool)
其次, 提煉出函數原型:
transfer(address,uint256) //注意逗号后面不能有空格
再次, 在控制台運行sha3函數:
web3.sha3("transfer(address,uint256)").substring(0, 10)
#得到函數hash "0xa9059cbb"
第一個參數假設address _to = "0x38aabef4cd283ccd5091298dedc88d27c5ec5750", 則去"0x", 補零到dc88d27c5ec5750", 則去"0x", 補零到dc64
二個參數假設uint256 _value = 43776, 則化為十六進位"0xab00"後, 去"0x", 補零到64位.
"0xa9059cbb000000000000 27c5ec57500000000000000000000000000000000000000000000000000000000000ab00"
建立json資料:
{ "method": "eth_call", "params": [{"from": "0x38aabef4cd283ccd5091298dedc88d27c5ec5750", "to": "0xaeab4084194B2a425096fb583Fbcd67385210ac3", "data": "0xa9059cbb00000000000000000000000038aabef4cd283ccd5091298dedc88d27c5ec5750000000000000000000000000000000000000000000000000000000000000ab00"}, "latest"], "id": 1 }
#to 合約位址
data 上述運算所得到的十六進位數
把以上的步驟轉換成程式碼.
<?php require './jsonRPCClient.php'; //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 $client = null; //布署合约的账户地址 const COINBASE = '0x38aabef4cd283ccd5091298dedc88d27c5ec5750'; //合约地址 const CONTRACT = '0xaeab4084194B2a425096fb583Fbcd67385210ac3'; public static function __callStatic($method, $params) { $params = count($params) < 1 ? [] : $params[0]; try { if (is_null(self::$client)) { self::$client = new jsonRPCClient('http://127.0.0.1:8545', true); } } catch (\Exception $e) { echo $e->getMessage(); } return call_user_func([self::$client, $method], $params); } public static function getBalance($address) { $method_hash = '0x70a08231'; $method_param1_hex = str_pad(substr($address, 2), 64, '0', STR_PAD_LEFT); $data = $method_hash . $method_param1_hex; $params = ['from' => $address, 'to' => self::CONTRACT, 'data' => $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 = '0xa9059cbb'; $method_param1_hex =str_pad(substr($to, 2), 64, '0', STR_PAD_LEFT); $method_param2_hex = str_pad(strval(bc_dechex($value)), 64, '0', STR_PAD_LEFT); $data = $method_hash . $method_param1_hex . $method_param2_hex; $params = ['from' => self::COINBASE, 'to' => self::CONTRACT, 'data' => $data]; return self::eth_sendTransaction([$params]); } }
transfer函數的value單位很小, 是10 ^ -18, 所以如果你想轉1000個,其實是要乘於10的18次方, 這裡的18是decimals.
#由於第1點, 應該使用bcpow代替pow函數.
######不能使用php自帶的dechex函數. 因為dechex要求整數不能大於PHP_INT_MAX, 而這個數在32位元機上為4294967295 。由於第1 點, 所有的數都要乘於10的18次方, 所以得到的數要遠大於PHP_INT_MAX. 建議自己實現10進制轉16進制,如果你不知道如何實現,參考上述代碼。 ############在運行某些合約方法, 例如transfer時, 要先unlock用戶.############發送交易之後, 一定要在伺服器端啟動挖礦, 這樣交易才會真的寫入到區塊, 比如你調用transfer之後,卻發現對方沒有到賬,先別吃驚,啟動挖礦試試。如果想啟用自動挖碼, 在geth --rpc ...最後加上--mine.################測試:#########<?php var_dump(EthereumRPCClient::personal_newAccount(['password'])); var_dump(EthereumRPCClient::personal_unlockAccount([EthereumRPCClient::COINBASE, "password", 3600]); var_dump(EthereumRPCClient::getBalance("0x...."));
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