Google Forms to Slack Apps Script Generator

// Google Forms → Webhook bridge
//
// Generated by https://routeforms.com/tools/google-forms-to-slack-generator
//
// Install (90 seconds):
//   1. In your Google Form, click the three-dot menu → Apps Script.
//   2. Replace the existing function myFunction() {} with the contents of
//      this file, then save (Cmd+S).
//   3. In the function dropdown at the top of the editor, select
//      installFormBridge and click Run.
//   4. When Google asks, click Advanced → Go to ... (unsafe) → Allow.
//      (You're authorising your own script, read it first if you'd like.)
//   5. Submit a test response in your Google Form to verify end-to-end.

const WEBHOOK_URL = "PASTE_YOUR_WEBHOOK_URL_HERE";
const TEST_MODE = false;

function installFormBridge() {
  var form = FormApp.getActiveForm();
  if (!form) {
    throw new Error(
      "No active form. Open this script editor from inside your Google Form: " +
        "Form → three-dot menu → Apps Script."
    );
  }

  // Wipe any existing onFormSubmit trigger so re-running install is safe.
  var existing = ScriptApp.getProjectTriggers();
  for (var i = 0; i < existing.length; i++) {
    if (existing[i].getHandlerFunction() === "onFormSubmit") {
      ScriptApp.deleteTrigger(existing[i]);
    }
  }

  // Create the correct form-submit trigger automatically so you can't pick
  // "On open" by mistake.
  ScriptApp.newTrigger("onFormSubmit").forForm(form).onFormSubmit().create();
  Logger.log("\u2713 Form bridge installed. Submit a test response to verify.");
}

function collectFields(e) {
  var form = FormApp.getActiveForm();
  var response = e.response;
  var itemResponses = response.getItemResponses();
  var data = {};
  for (var i = 0; i < itemResponses.length; i++) {
    var ir = itemResponses[i];
    var title = ir.getItem().getTitle();
    var answer = ir.getResponse();
    // Google Forms checkbox responses arrive as arrays; collapse to a string.
    if (Array.isArray(answer)) answer = answer.join(", ");
    data[title] = answer;
  }
  data._meta = {
    formTitle: form.getTitle(),
    formId: form.getId(),
    responseId: response.getId ? response.getId() : null,
    submittedAt: new Date().toISOString(),
  };
  return data;
}


function onFormSubmit(e) {
  try {
    var data = collectFields(e);
    var payload = data;
    var destinationUrl = WEBHOOK_URL;

    if (TEST_MODE) {
      Logger.log("TEST MODE \u2014 would have POSTed to " + destinationUrl + ":");
      Logger.log(JSON.stringify(payload, null, 2));
      return;
    }

    var res = UrlFetchApp.fetch(destinationUrl, {
      method: "post",
      contentType: "application/json",
      payload: JSON.stringify(payload),
      muteHttpExceptions: true
    });
    var code = res.getResponseCode();
    if (code < 200 || code >= 300) {
      Logger.log("Slack returned " + code + ": " + res.getContentText());
    }
  } catch (err) {
    Logger.log("Form bridge error: " + err);
  }
}

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