微信小程序 出现47001 data format error原因解决办法

 public function sendmessage(){
 $data=$_POST=json_decode(file_get_contents('php://input'), TRUE);
 $access_token=$this->getAccessToken();
 $request_url='https://api.weixin.qq.com/cgi-bin/message/wxopen/template/send?access_token='.$access_token;
 $request_data=array(
  'touser'=>$data['touser'],//接收者（用户）的 openid
  'template_id'=>$data['template_id'],//所需下发的模板消息的id
  'page'=>$data['page'],//点击模板卡片后的跳转页面
  'form_id'=>$data['form_id'],//表单提交场景下，为 submit 事件带上的 formId；支付场景下，为本次支付的 prepay_id
  'data'=>$data['data'],//"keyword1": {"value": "339208499", "color": "#173177"}
  'emphasis_keyword'=>$data['emphasis_keyword']//模板需要放大的关键词，不填则默认无放大
 );
 $return=json_decode(https_request($request_url,$request_data,'json'),true);
 $this->response($return,'json');
 }

function https_request($url,$data,$type){
 if($type=='json'){//json $_POST=json_decode(file_get_contents('php://input'), TRUE);
 $headers = array("Content-type: application/json;charset=UTF-8","Accept: application/json","Cache-Control: no-cache", "Pragma: no-cache");
 $data=json_encode($data);
 }
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, $url);
 curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
 curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
 if (!empty($data)){
 curl_setopt($curl, CURLOPT_POST, 1);
 curl_setopt($curl, CURLOPT_POSTFIELDS,$data);
 }
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers ); 
 $output = curl_exec($curl);
 curl_close($curl);
 return $output;
}