envoy-header-cert.html

<html>
<head>
  <style>
    body {
      font-size: x-small;
      width: 60em;
      margin: auto auto;
      border-left: 2px solid #288;
      padding: 10px 10px
    }
    div {
      font-family: monospace;
      word-break:break-all;
    }
    p {
      font-size: medium;
    }
    textarea {
      font-family: monospace;
      width: 100%;
      height: 40em;
    }
  </style>
</head>
<body>
<p>Tool to encode PEM certs as envoy XFCC headers.</p>
<textarea id="pem" placeholder="paste PEM certificate"></textarea>

<p>Output:</p>
<div id="output"></div>
<script>
pem.addEventListener("input", () => {
  output.innerText = "-H \"X-Forwarded-Client-Cert: Cert=\\\"" + encodeURIComponent(pem.value) + "\\\"\"";
})
</script>
</body>
</html>