Google Forms onFormSubmit Trigger Generator

// Google Forms onFormSubmit trigger → Slack
//
// Generated by https://routeforms.com/tools/google-forms-on-submit-trigger-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, select installOnFormSubmit and click Run.
//   4. When Google asks, click Advanced → Go to ... (unsafe) → Allow.
//      You're authorising your own script — read it before running.
//   5. Submit a test response to verify end-to-end.

const DESTINATION_URL = "PASTE_YOUR_WEBHOOK_URL_HERE";
const TEST_MODE = false;

function installOnFormSubmit() {
  var form = FormApp.getActiveForm();
  if (!form) {
    throw new Error(
      "No active form. Open this script from inside the Google Form: " +
        "Form → three-dot menu → Apps Script."
    );
  }
  // Remove any existing onFormSubmit triggers 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]);
    }
  }
  ScriptApp.newTrigger("onFormSubmit")
    .forForm(form)
    .onFormSubmit()
    .create();
  Logger.log("\u2713 onFormSubmit trigger installed for form: " + form.getTitle());
}

function collectResponse(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();
    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 buildSlackPayload(data) {
  var formTitle = (data._meta && data._meta.formTitle) || "Google Form";
  var lines = [];
  for (var k in data) {
    if (k === "_meta" || k.charAt(0) === "_") continue;
    var v = data[k];
    var rendered = (v === null || v === undefined)
      ? "\u2014"
      : (typeof v === "object" ? JSON.stringify(v) : String(v));
    if (rendered.length > 500) rendered = rendered.slice(0, 500) + "\u2026";
    lines.push("*" + k + ":* " + rendered);
  }
  return {
    text: "New response from " + formTitle,
    blocks: [
      { type: "section", text: { type: "mrkdwn", text: ":inbox_tray: *New form response*" } },
      { type: "section", text: { type: "mrkdwn", text: "*Form:* " + formTitle + "\n*Submitted:* " + new Date().toLocaleString() } },
      { type: "divider" },
      { type: "section", text: { type: "mrkdwn", text: lines.join("\n") || "_(no fields)_" } }
    ]
  };
}

function onFormSubmit(e) {
  try {
    var data = collectResponse(e);
    var payload = buildSlackPayload(data);

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

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

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