Php sendgrid发送多个收据电子邮件

您好，我在sendgrid的发送多回执电子邮件api中遇到问题 实际上api接受这个数组

<?php

  $url = 'https://api.sendgrid.com/';
    $user = 'abc';
    $pass = 'xyx';
  $params = array(
'api_user'  => $user,
'api_key'   => $pass,
'x-smtpapi' => json_encode($json_string),
'to'        => "$to",
'subject'   => "$subject",
'html'      => "$messaget",
'from'      => "site.com<contact@site.com>",
 );


  $request =  $url.'api/mail.send.json';

 // Generate curl request
   $session = curl_init($request);
    // Tell curl to use HTTP POST
  curl_setopt ($session, CURLOPT_POST, true);
  // Tell curl that this is the body of the POST
    curl_setopt ($session, CURLOPT_POSTFIELDS, $params);
  // Tell curl not to return headers, but do return the response
      curl_setopt($session, CURLOPT_HEADER, false);
    // Tell PHP not to use SSLv3 (instead opting for TLS)
    curl_setopt($session, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1_2);
     curl_setopt($session, CURLOPT_RETURNTRANSFER, true);

     // obtain response
       $response = curl_exec($session);
      curl_close($session);
          ?>

当我将json_字符串保持为

 $json_string = array(
'to' => array(
'email1','email2'
  ),
 'category' => 'test_category'
);

它发送邮件，但问题是我通过mysql从我的数据库中获取电子邮件。我如何将电子邮件直接放入使用循环和 将回迁的电子邮件存储到变量$emailfinallist中，并将该变量传递到$json_字符串数组，但该dosent有效

---

如何将电子邮件直接放入该数组中

看起来您传递的是字符串，而不是“to”参数中的变量：

<?php

  $url = 'https://api.sendgrid.com/';
    $user = 'abc';
    $pass = 'xyx';
  $params = array(
'api_user'  => $user,
'api_key'   => $pass,
'x-smtpapi' => json_encode($json_string),
'to'        => "$to",
'subject'   => "$subject",
'html'      => "$messaget",
'from'      => "site.com<contact@site.com>",
 );


  $request =  $url.'api/mail.send.json';

 // Generate curl request
   $session = curl_init($request);
    // Tell curl to use HTTP POST
  curl_setopt ($session, CURLOPT_POST, true);
  // Tell curl that this is the body of the POST
    curl_setopt ($session, CURLOPT_POSTFIELDS, $params);
  // Tell curl not to return headers, but do return the response
      curl_setopt($session, CURLOPT_HEADER, false);
    // Tell PHP not to use SSLv3 (instead opting for TLS)
    curl_setopt($session, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1_2);
     curl_setopt($session, CURLOPT_RETURNTRANSFER, true);

     // obtain response
       $response = curl_exec($session);
      curl_close($session);
          ?>

'to'=>数组（$emailfinallist”）

应该是

'to'=>$emailfinallist

对于'subject'和'html'参数，您也在做同样的事情