google_sheets_logger 1.0.2

A lightweight, serverless error tracking system for Flutter Web that routes crashes and API failures directly into a Google Sheet using Google Apps Script.

Google Sheets Logger

A lightweight, serverless error tracking system for Flutter Web that routes crashes and API failures directly into a Google Sheet using Google Apps Script. No backend server required.

Features

• 🚀 Serverless - No backend server needed, uses Google Apps Script
• 🌐 Flutter Web Optimized - Uses text/plain content-type to bypass CORS preflight
• 🌍 Auto IP Detection - Automatically captures client IP via ipify
• 🛡️ Error Resilient - Silently fails if logging fails (never crashes your app)
• 🔧 Zero Config Backend - Just deploy a Google Apps Script
• 📱 Cross-platform - Works on Flutter Web, iOS, Android, and Desktop

Getting Started

1. Add Dependency

dependencies:
  google_sheets_logger: ^1.0.0

2. Create a Google Apps Script

1. Go to script.google.com
2. Create a new project
3. Paste this code:

function doPost(e) {
  const sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  const data = JSON.parse(e.postData.contents);
  
  const row = [
    new Date(),                    // Timestamp
    data.projectName,              // Project name
    data.environment,              // Environment (dev/staging/prod)
    data.ipAddress,                // Client IP
    data.errorType,                // Error type (e.g., "API_ERROR", "CRASH")
    data.endpoint || '',           // API endpoint (if applicable)
    data.errorCode || '',          // Error code (if applicable)
    data.errorMessage,             // Error message
    data.stackTrace || ''          // Stack trace
  ];
  
  sheet.appendRow(row);
  
  return ContentService.createTextOutput(JSON.stringify({success: true}))
    .setMimeType(ContentService.MimeType.JSON);
}

4. Deploy → New Deployment → Web App
   • Execute as: Me
   • Who has access: Anyone
   • Copy the Web App URL (ends with /exec)

3. Initialize in main.dart

import 'package:flutter/material.dart';
import 'package:google_sheets_logger/google_sheets_logger.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  // Initialize BEFORE runApp()
  await GoogleSheetsLogger.initialize(
    scriptUrl: 'https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec',
    projectName: 'My Flutter App',
    environment: 'production', // or 'development', 'staging'
  );
  
  runApp(const MyApp());
}

4. Log Errors Manually

try {
  final response = await http.get(Uri.parse('https://api.example.com/data'));
  if (response.statusCode != 200) {
    throw Exception('API returned ${response.statusCode}');
  }
} catch (e, stackTrace) {
  await GoogleSheetsLogger.logError(
    errorMessage: e.toString(),
    errorType: 'API_ERROR',
    endpoint: 'https://api.example.com/data',
    errorCode: 'HTTP_${response?.statusCode}',
    stackTrace: stackTrace.toString(),
  );
  
  // Show user-friendly error
  ScaffoldMessenger.of(context).showSnackBar(
    SnackBar(content: Text('Failed to load data. Please try again.')),
  );
}

5. Catch Uncaught Flutter Errors (Optional)

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  await GoogleSheetsLogger.initialize(
    scriptUrl: 'https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec',
    projectName: 'My Flutter App',
    environment: 'production',
  );
  
  // Catch Flutter framework errors
  FlutterError.onError = (FlutterErrorDetails details) async {
    await GoogleSheetsLogger.logError(
      errorMessage: details.exceptionAsString(),
      errorType: 'FLUTTER_FRAMEWORK_ERROR',
      stackTrace: details.stack?.toString(),
    );
    FlutterError.presentError(details);
  };
  
  // Catch Dart async errors
  PlatformDispatcher.instance.onError = (error, stack) async {
    await GoogleSheetsLogger.logError(
      errorMessage: error.toString(),
      errorType: 'DART_ASYNC_ERROR',
      stackTrace: stack.toString(),
    );
    return true;
  };
  
  runApp(const MyApp());
}

API Reference

GoogleSheetsLogger.initialize()

Initializes the logger. Must be called before runApp().

static Future<void> initialize({
  required String scriptUrl,      // Your Google Apps Script Web App URL
  required String projectName,    // Your project/app name
  required String environment,    // 'development' | 'staging' | 'production'
}) async

Parameters:

Parameter	Type	Required	Description
scriptUrl	String	Yes	Google Apps Script Web App URL (ends with /exec)
projectName	String	Yes	Your project/app name for identification
environment	String	Yes	Environment name (e.g., 'production', 'staging', 'development')

GoogleSheetsLogger.logError()

Manually log an error to Google Sheets.

static Future<void> logError({
  required String errorMessage,   // Human-readable error message
  required String errorType,      // Error category (e.g., 'API_ERROR', 'CRASH')
  String? endpoint,               // API endpoint that failed (optional)
  String? errorCode,              // Error code (e.g., 'HTTP_500', 'TIMEOUT')
  String? stackTrace,             // Stack trace string (optional)
}) async

Parameters:

Parameter	Type	Required	Description
errorMessage	String	Yes	The error message to log
errorType	String	Yes	Category/type of error
endpoint	String?	No	API endpoint URL if applicable
errorCode	String?	No	HTTP status code or custom error code
stackTrace	String?	No	Stack trace as string

Suggested Error Types:

Type	Use Case
API_ERROR	HTTP API failures
NETWORK_ERROR	Network connectivity issues
PARSE_ERROR	JSON parsing failures
AUTH_ERROR	Authentication/authorization failures
VALIDATION_ERROR	Input validation failures
FLUTTER_FRAMEWORK_ERROR	Flutter framework errors
DART_ASYNC_ERROR	Uncaught Dart async errors
CRASH	App crashes
CUSTOM	Custom error types

Google Sheets Output Format

The Google Sheet will receive rows with these columns:

Column	Description
A	Timestamp (auto-generated)
B	Project Name
C	Environment
D	Client IP Address
E	Error Type
F	API Endpoint
G	Error Code
H	Error Message
I	Stack Trace

Complete Example: main.dart

import 'package:flutter/material.dart';
import 'package:google_sheets_logger/google_sheets_logger.dart';
import 'package:flutter/foundation.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  // Initialize logger BEFORE runApp
  await GoogleSheetsLogger.initialize(
    scriptUrl: const String.fromEnvironment('GOOGLE_SCRIPT_URL'),
    projectName: const String.fromEnvironment('PROJECT_NAME', defaultValue: 'MyApp'),
    environment: const String.fromEnvironment('ENVIRONMENT', defaultValue: 'development'),
  );
  
  // Global error handlers (optional but recommended)
  FlutterError.onError = (details) async {
    await GoogleSheetsLogger.logError(
      errorMessage: details.exceptionAsString(),
      errorType: 'FLUTTER_FRAMEWORK_ERROR',
      stackTrace: details.stack?.toString(),
    );
    FlutterError.presentError(details);
  };
  
  PlatformDispatcher.instance.onError = (error, stack) async {
    await GoogleSheetsLogger.logError(
      errorMessage: error.toString(),
      errorType: 'DART_ASYNC_ERROR',
      stackTrace: stack.toString(),
    );
    return true;
  };
  
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Google Sheets Logger Demo',
      theme: ThemeData(primarySwatch: Colors.blue),
      home: const HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  String _status = 'Ready';
  
  Future<void> _testApiError() async {
    setState(() => _status = 'Testing API error...');
    
    try {
      // This will fail - invalid URL
      await http.get(Uri.parse('https://httpstat.us/500'));
    } catch (e, stack) {
      await GoogleSheetsLogger.logError(
        errorMessage: e.toString(),
        errorType: 'API_ERROR',
        endpoint: 'https://httpstat.us/500',
        errorCode: 'HTTP_500',
        stackTrace: stack.toString(),
      );
      setState(() => _status = 'Error logged! Check your Google Sheet.');
    }
  }
  
  Future<void> _testCrash() async {
    await GoogleSheetsLogger.logError(
      errorMessage: 'Test crash from button press',
      errorType: 'CRASH',
      stackTrace: StackTrace.current.toString(),
    );
    setState(() => _status = 'Test crash logged!');
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Google Sheets Logger Demo')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(_status, style: const TextStyle(fontSize: 18)),
            const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _testApiError,
              child: const Text('Test API Error'),
            ),
            const SizedBox(height: 10),
            ElevatedButton(
              onPressed: _testCrash,
              child: const Text('Test Manual Crash Log'),
            ),
          ],
        ),
      ),
    );
  }
}

Environment Variables (Recommended)

Use --dart-define for sensitive configuration:

flutter run --dart-define=GOOGLE_SCRIPT_URL=https://script.google.com/macros/s/XXX/exec \
            --dart-define=PROJECT_NAME=MyApp \
            --dart-define=ENVIRONMENT=production

await GoogleSheetsLogger.initialize(
  scriptUrl: const String.fromEnvironment('GOOGLE_SCRIPT_URL'),
  projectName: const String.fromEnvironment('PROJECT_NAME'),
  environment: const String.fromEnvironment('ENVIRONMENT'),
);

Google Apps Script Setup Details

Sheet Setup

1. Create a new Google Sheet
2. Add headers in row 1:

   Timestamp | Project | Environment | IP Address | Error Type | Endpoint | Error Code | Message | Stack Trace
   

3. Open Extensions → Apps Script
4. Paste the doPost function from Quick Start
5. Deploy as Web App (Anyone, Execute as Me)

CORS Note

The library uses Content-Type: text/plain to avoid CORS preflight requests on Flutter Web. The Apps Script handles JSON parsing from e.postData.contents.

Security (Optional)

Add a secret token validation in Apps Script for production:

function doPost(e) {
  const secret = e.parameter.secret;
  if (secret !== PropertiesService.getScriptProperties().getProperty('SECRET')) {
    return ContentService.createTextOutput('Unauthorized').setMimeType(ContentService.MimeType.TEXT);
  }
  // ... rest of code
}

Error Handling Behavior

Scenario	Behavior
Not initialized	Logs debug message, returns silently
Network error	Catches silently, logs to debug console
CORS error	Catches silently (text/plain bypasses preflight)
Apps Script error	Catches silently, logs to debug console
App crash	Never crashes your app - fails silently

Troubleshooting

Issue	Solution
"Not initialized" error	Call initialize() before runApp()
Errors not appearing in Sheet	Check Apps Script execution logs (Extensions → Apps Script → Executions)
CORS errors	Ensure Apps Script is deployed as "Anyone" access
IP shows "Unknown IP"	ipify.org may be blocked; check network
Sheet not updating	Check Apps Script execution transcript for errors

License

MIT License - See LICENSE file for details.