?php
class JSSDK {
 private $appId;
 private $appSecret;

 public function __construct($appId, $appSecret) {
 $this->appId = $appId;
 $this->appSecret = $appSecret;
 }

 public function getSignPackage() {
 $jsapiTicket = $this->getJsApiTicket();

 // 注意 URL 一定要動態獲取，不能 hardcode.
 $protocol = (!empty($_SERVER['HTTPS'])  $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
 $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

 $timestamp = time();
 $nonceStr = $this->createNonceStr();

 // 這里參數的順序要按照 key 值 ASCII 碼升序排序
 $string = "jsapi_ticket=$jsapiTicketnoncestr=$nonceStrtimestamp=$timestampurl=$url";

 $signature = sha1($string);

 $signPackage = array(
  "appId"  => $this->appId,
  "nonceStr" => $nonceStr,
  "timestamp" => $timestamp,
  "url"  => $url,
  "signature" => $signature,
  "rawString" => $string
 );
 return $signPackage; 
 }

 private function createNonceStr($length = 16) {
 $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 $str = "";
 for ($i = 0; $i  $length; $i++) {
  $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
 }
 return $str;
 }

 private function getJsApiTicket() {
 
  $accessToken = $this->getAccessToken();
  
  // 如果是企業號用以下 URL 獲取 ticket
  // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
  $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapiaccess_token=$accessToken";
  $res = json_decode($this->httpGet($url));
  
  $ticket = $res->ticket;
  
 return $ticket;
 }

 private function getAccessToken() {
 // access_token 應該全局存儲與更新，以下代碼以寫入到文件中做示例
 // 如果是企業號用以下URL獲取access_token
 // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appIdcorpsecret=$this->appSecret";
  $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credentialappid=$this->appIdsecret=$this->appSecret";
  $res = json_decode($this->httpGet($url));
  $access_token = $res->access_token;
  
 return $access_token;
 }

 private function httpGet($url) {
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
 curl_setopt($curl, CURLOPT_TIMEOUT, 500);
 curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
 curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
 curl_setopt($curl, CURLOPT_URL, $url);

 $res = curl_exec($curl);
 curl_close($curl);

 return $res;
 }
}