## Sending Email

Mail service -- e.g. Mailgun, Sendgrid, etc.

### submit.php Example (uses Mailgun)

    <?php require_once 'vendor/autoload.php';

    $loader = new \Twig\Loader\FilesystemLoader('./templates');
    $twig = new \Twig\Environment($loader, [
        'cache' => './compilation_cache',
        'debug' => true,
        'auto_reload' => true
    ]);
    $requestTime = new DateTime();
    $requestTime->setTimestamp($_SERVER['REQUEST_TIME']);
    $requestTimeHuman = $requestTime->format('Y-m-d\TH:i:s');

    $echocontent = $twig->render('form-response-template.html',
         [
         'getparams' => $_GET,
         'postparams' => $_POST,
         'httpheaders' => getallheaders(),
         'httpmethod' => $_SERVER['REQUEST_METHOD'],
         'serverinfo' => $_SERVER,
         'requesttime' => $requestTimeHuman,
         'httpreferer' => $_SERVER['HTTP_REFERER']
         ]);
    ?>

    <?php

    require 'vendor/autoload.php';
    use Mailgun\Mailgun;

    $mailto = filter_var($_POST['__mailto'], FILTER_VALIDATE_EMAIL);
    $mailkey = '';
    if (preg_match('/^csci(e|s)12\-(spring|summer|fall)-\d{4}-[a-z]+[0-9]+$/',$_POST['__mailkey'])) {
       $mailkey = $_POST['__mailkey'];
    }

    // only send if POST and if __mailto and if __mailkey exist

    if (strcmp($_SERVER['REQUEST_METHOD'],'POST') == 0 && $mailto && $mailkey ) {
      error_log("FormSubmit | MAILGUN | $mailkey | $mailto |");
      // First, instantiate the SDK with your API credentials
      $MG_API_KEY = getenv('MG_API_KEY');
      $MG_DOMAIN = getenv('MG_DOMAIN');
      $MG_FROM = getenv('MG_FROM');

      $mg = Mailgun::create($MG_API_KEY); // For US servers
      $domain = $MG_DOMAIN;

      // Now, compose and send your message.
      // $mg->messages()->send($domain, $params);
      $mg->messages()->send($domain, [
        'from'    => $MG_FROM,
        'to'      => $mailto,
        'subject' => 'Form Submission',
        'html'    => $echocontent
      ]);
    }

    echo($echocontent);
    ?>

### form_response_template.html

This is a PHP "Twig" template.

    <DOCTYPE html>
    <html lang="en">
      <head><title>Form Submission</title>
        <style>
          body, * { font-family: helvetica, sans-serif; }
          body { margin: 1rem 5%; }
          h2 { margin-top: 1.5rem; }
          table, td, th, tr { border-collapse: collapse; }
          table td, table th { border-collapse: collapse; vertical-align: top; padding: 0.5rem; border: thin solid #101010; }
          table thead tr { color: #ffffff;  background-color: rgb(100,100,100); font-size: larger;}
          table tbody tr:nth-child(even) { background-color: rgb(240,240,240); }
          table tbody tr th { text-align: left; }
          footer { margin-top: 4rem; padding: 0.5rem; background-color: rgb(240,240,240); border-top: thin solid black; }
          footer p { margin-top: 0.5em; margin-bottom: 0.5em; }
        </style>
      </head>

      <body>
        <h1>Form Submission</h1>
        {% if getparams %}
        <h2>GET Parameters</h2>
        <table>
          <thead>
            <tr><th>Name</th><th>Value</th></tr>
          </thead>
          <tbody>
          {% for key, value in getparams %}
          <tr>
            <th>{{ key }}</th>
            <td>
              {% if value is iterable %}
              {% for v in value %}
                {{ v }}{% if not(loop.last) %},<br/>{% endif %}
              {% endfor %}
              {% else %}
                {{ value }}
              {% endif %}
            </td>
          </tr>
          {% endfor %}
          </tbody>
        </table>
        {% endif %}

        {% if postparams %}
        <h2>POST Parameters</h2>
        <table>
          <thead>
            <tr><th>Name</th><th>Value</th></tr>
          </thead>
          <tbody>
          {% for key, value in postparams %}
          <tr>
            <th>{{ key }}</th>
            <td>
              {% if value is iterable %}
              {% for v in value %}
                {{ v }}{% if not(loop.last) %},<br/>{% endif %}
              {% endfor %}
              {% else %}
                {{ value }}
              {% endif %}
            </td>
          </tr>
          {% endfor %}
          </tbody>
        </table>
        {% endif %}

        {% if serverinfo %}
        <h2>Request Information</h2>
        <table>
          <thead>
            <tr><th>Name</th><th>Value</th></tr>
          </thead>
          <tbody>
            <tr><th>Request Time</th><td>{{ requesttime }}</td></tr>
            <tr><th>Remote Address</th><td>{{ serverinfo['REMOTE_ADDR'] }}</td></tr>
            <tr><th>HTTP Referrer</th><td><a href="{{ httpreferer }}">{{ httpreferer }}</a></td></tr>
            <tr><th>HTTP Method</th><td>{{ httpmethod }}</td></tr>
          </tbody>
        </table>
        {% endif %}

        <footer>
          <p>This form submission tool is only for use by current students in <a href="https://cscie12.dce.harvard.edu/">CSCI E-12</a> and <a href="https://cscis12.dce.harvard.edu/">CSCI S-12</a> courses.</p><p>David Heitmeyer | <a href="https://extension.harvard.edu/">Harvard Extension School</a> | <a href="https://summer.harvard.edu/">Harvard Summer School</a></footer>
      </body>
     </html>