Set up sheets flows

# The body of this request is described in `open-sheet` flow. This will be sent as a single stringified JSON object under the key `intercom_data`.

{
  "workspace_id": /* string id_code of the app using the card */,
  "current_canvas": /* Canvas object */,
  "component_id": /* component_id, component which triggered action */,
  "input_values": {
    "component_id": /* value entered in component */,
    ...
  },
  "user": /* Encrypted user object of end-user who triggered action */,
  "context": /* Context object */
}

# As defined by the `open-sheet` flow, the user object that we send as part of the payload to the `sheet` will be encrypted.

# The user is encrypted using AES256-CGM and then Base64 encoded.

# The below example is in Ruby:

intercom_data[:user] = encrypt({ test: "test" }.to_json)
encrypted_user = intercom_data[:user]
decoded_user = Base64.decode64(encrypted.encode('utf-8'))

secret = "<OAUTH_CLIENT_SECRET>"
key = Digest::SHA256.digest(secret)
decipher = ::OpenSSL::Cipher.new('aes-256-gcm')

GCM_IV_LENGTH = 12
GCM_AUTH_TAG_LENGTH = 16

decipher.decrypt
decipher.key = key
decipher.iv = decoded_user[0, GCM_IV_LENGTH]
decipher.auth_tag = decoded_user[(decoded_user.length - GCM_AUTH_TAG_LENGTH), GCM_AUTH_TAG_LENGTH]
ciphertext = decoded_user[GCM_IV_LENGTH, (decoded_user.length - GCM_AUTH_TAG_LENGTH - GCM_IV_LENGTH)]
decipher.update(ciphertext) + decipher.final
=> "{\"test\":\"test\"}"

/* As defined by the `open-sheet` flow, the user object that we send as part of the payload to the `sheet` will be encrypted.

The user is encrypted using AES256-CGM and then Base64 encoded.

The below example is in PHP: */

<?php
$encodedUser = "<USER-FROM-REQUEST>";

$decodedUser = base64_decode($encodedUser);

$secret = "<THIS-IS-A-SECRET>";
$key = openssl_digest($secret, 'sha256', TRUE);

$ivlen = 12;
$taglen = 16;

$iv = substr($decodedUser, 0, $ivlen);
$tag = substr($decodedUser, strlen($decodedUser) - $taglen, $taglen);

$cipherLen = strlen($decodedUser) - $taglen - $ivlen;
$cipherText = substr($decodedUser, $ivlen, $cipherLen);

$decryptedUser = openssl_decrypt($cipherText, 'aes-256-gcm', $key, OPENSSL_RAW_DATA, $iv, $tag);
?>

/* As defined by the `open-sheet` flow, the user object that we send as part of the payload to the `sheet` will be encrypted.

The user is encrypted using AES256-CGM and then Base64 encoded.

The below example is in Java: */

String encodedUser = "<USER-FROM-REQUEST>";
byte[] decodedUser = Base64.getDecoder().decode(encodedUser.replaceAll("\n", "").getBytes());
String secret = "<THIS-IS-A-SECRET>";

MessageDigest sha256MessageDigest = MessageDigest.getInstance("SHA-256");
sha256MessageDigest.update(secret.getBytes());
byte[] keyBytes = sha256MessageDigest.digest();

int ivlen = 12;
byte[] iv = Arrays.copyOfRange(decodedUser, 0, ivlen);
byte[] cipherText = Arrays.copyOfRange(decodedUser, ivlen, decodedUser.length);

Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding", "SunJCE");
GCMParameterSpec spec = new GCMParameterSpec(128, iv);
SecretKey key = new SecretKeySpec(keyBytes, "AES");
cipher.init(Cipher.DECRYPT_MODE, key, spec);

byte[] res = cipher.doFinal(cipherText);
String decryptedUser = new String(res);

/* As defined by the `open-sheet` flow, the user object that we send as part of the payload to the `sheet` will be encrypted.

The user is encrypted using AES256-CGM and then Base64 encoded.

The below example is in Node.js: */

const masterkey = 'your-master-key';

// base64 decoding
const bData = Buffer.from(decoded, 'base64');

// convert data to buffers
const ivlen = 12;
const iv = bData.slice(0, ivlen);

const taglen = 16;
const tag = bData.slice(bData.length - taglen, bData.length);

const cipherLen = bData.length - taglen;
const cipherText = bData.slice(ivlen, cipherLen);

let hash = crypto.createHash('sha256').update(masterkey);
let key = Buffer.from(hash.digest("binary"), "binary");//buffer from binary string.

// AES 256 GCM Mode
const decipher = crypto.createDecipheriv('aes-256-gcm', key, iv);
decipher.setAuthTag(tag);

// encrypt the given text
let decrypted = decipher.update(cipherText, 'binary', 'utf8');
decrypted += decipher.final('utf8');

console.log(decrypted);

<!DOCTYPE html>
<html>
<head>
  <title>Sheet 1</title>
  <script src="https://s3.amazonaws.com/intercom-sheets.com/messenger-sheet-library.latest.js"></script>
</head>
<body>
  <button id="done">Done</button>

  <script>
    const done = document.querySelector('#done');
    done.addEventListener('click', () => {
      INTERCOM_MESSENGER_SHEET_LIBRARY.submitSheet({ super: "secret" });
    });
  </script>
</body>
</html>

# When a **Sheet** is submitted, Intercom POSTs a request to the messenger-app's submit-sheet URL with the following payload.

{
  "workspace_id": /* string id_code of the app using the card */,
  "current_canvas": /* Canvas object */,
  "sheet_values": {
    "key": /* value */,
    ...
  },
  "user": /* User object of end-user who triggered action */,
  "context": /* Context object */
}

{
  "canvas": /* Canvas object */,
  "event": { "type": "completed" } //App Completion Tracking (optional)
}

# The app completion event is recorded by Intercom.

# Closes the sheet immediately. The Messenger will not be aware of any actions the end-user may have taken in the sheet and the card that triggered the sheet will not be updated.

INTERCOM_MESSENGER_SHEET_LIBRARY.closeSheet()

# Closes the sheet and triggers a request to the submit sheet webhook (see Submit-sheet flow). This allows the third party developer to perform any side-effects and update the card that triggered the sheet if required.

INTERCOM_MESSENGER_SHEET_LIBRARY.submitSheet(sheetValues)

# Set the `title` of the sheet in the Messenger. Title is an optional param which will default to `document.title`. The Messenger will call this method automatically when the script loads.

INTERCOM_MESSENGER_SHEET_LIBRARY.setTitle(title)