Crash Reporting / Error Capture for Flutter

error_capture.dart

///
/// Flutter Captured Error Reporting
/// Created by Simon Lightfoot
/// 
/// Copyright (C) DevAngels Limited 2018
/// License: APACHE 2.0 - https://www.apache.org/licenses/LICENSE-2.0
///
import 'dart:async';
import 'dart:io';
import 'dart:ui' as ui show window;

import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
import 'package:package_info/package_info.dart';
import 'package:device_info/device_info.dart';
import 'package:system_info/system_info.dart';
import 'package:connectivity/connectivity.dart';
import 'package:sentry/sentry.dart';

const int MEGABYTE = 1024 * 1024;

typedef Future<Null> ErrorReporter(Object error, StackTrace stackTrace);
typedef Widget ErrorReportingWidget(ErrorReporter reporter);


bool get _isInDebugMode {
	bool inDebugMode = false;
	assert(inDebugMode = true);
	return inDebugMode;
}

///
/// Example:
///     void main() => runCapturedApp((reporter) => new AppComponent(reporter), dsn: '<YOUR-DSN>');
///
/// During your app lifecycle you can use the Reporter parameter to report a exception, like this:
///     try {
///         throw new AssertionError();
///     } catch (exception, stackTrace) {
///         errorReporter(exception, stackTrace);
///     }
///
runCapturedApp(ErrorReportingWidget app, {@required String dsn}) {
	final SentryClient sentry = SentryClient(dsn: dsn);
	FlutterError.onError = (FlutterErrorDetails details) {
		if (_isInDebugMode) {
			// In development mode simply print to console.
			FlutterError.dumpErrorToConsole(details);
		} else {
			// In production mode report to the application zone to report to Sentry.
			Zone.current.handleUncaughtError(details.exception, details.stack);
		}
	};
	runZoned(() {
		runApp(app((error, stackTrace) => reportError(sentry, error, stackTrace)));
	}, onError: (Object error, StackTrace stackTrace) async {
		await reportError(sentry, error, stackTrace);
	});
}

Future<Null> reportError(SentryClient sentry, Object error, StackTrace stackTrace) async {
	print('Caught error: $error');

	if (_isInDebugMode) {
		print(stackTrace);
		print('In dev mode. Not sending report to Sentry.io.');
		return;
	}

	print('Reporting to Sentry.io...');

	final PackageInfo info = await PackageInfo.fromPlatform();

	Map<String, dynamic> extra = {};
	if (defaultTargetPlatform == TargetPlatform.android) {
		extra['device_info'] = await DeviceInfoPlugin.channel.invokeMethod('getAndroidDeviceInfo');
	}
	else if (defaultTargetPlatform == TargetPlatform.iOS) {
		extra['device_info'] = await DeviceInfoPlugin.channel.invokeMethod('getIosDeviceInfo');
	}

	String mode = _isInDebugMode ? 'checked' : 'release';

	Map<String, String> tags = {};
	tags['platform'] = defaultTargetPlatform.toString().substring('TargetPlatform.'.length);
	tags['package_name'] = info.packageName;
	tags['build_number'] = info.buildNumber;
	tags['version'] = info.version;
	tags['mode'] = mode;
	tags['locale'] = ui.window.locale.toString();

	ConnectivityResult connectivity = await (Connectivity().checkConnectivity());
	tags['connectivity'] = connectivity.toString().substring('ConnectivityResult.'.length);

	Map<String, dynamic> uiValues = {};
	uiValues['locale'] = ui.window.locale.toString();
	uiValues['pixel_ratio'] = ui.window.devicePixelRatio;
	uiValues['default_route'] = ui.window.defaultRouteName;
	uiValues['physical_size'] = [ui.window.physicalSize.width, ui.window.physicalSize.height];
	uiValues['text_scale_factor'] = ui.window.textScaleFactor;
	uiValues['view_insets'] = [ui.window.viewInsets.left, ui.window.viewInsets.top, ui.window.viewInsets.right, ui.window.viewInsets.bottom];
	uiValues['padding'] = [ui.window.padding.left, ui.window.padding.top, ui.window.padding.right, ui.window.padding.bottom];
	if (WidgetsBinding.instance != null) {
		// Removed the widget tree as it posts too much information.
		/*
		if (WidgetsBinding.instance.renderViewElement != null) {
			uiValues['render_view'] = WidgetsBinding.instance.renderViewElement.toStringDeep();
		} else {
			uiValues['render_view'] = '<no tree currently mounted>';
		}
		*/
	}
	extra['ui'] = uiValues;

	Map<String, dynamic> memory = {};
	memory['phys_total'] = '${SysInfo.getTotalPhysicalMemory() ~/ MEGABYTE}MB';
	memory['phys_free'] = '${SysInfo.getFreePhysicalMemory() ~/ MEGABYTE}MB';
	memory['virt_total'] = '${SysInfo.getTotalVirtualMemory() ~/ MEGABYTE}MB';
	memory['virt_free'] = '${SysInfo.getFreeVirtualMemory() ~/ MEGABYTE}MB';
	extra['memory'] = memory;

	extra['dart_version'] = Platform.version;

	final Event event = Event(
		loggerName: '',
		exception: error,
		stackTrace: stackTrace,
		release: '${info.version}_${info.buildNumber}',
		environment: 'qa',
		tags: tags,
		extra: extra,
	);

	try {
		final SentryResponse response = await sentry.capture(event: event);
		if (response.isSuccessful) {
			print('Success! Event ID: ${response.eventId}');
		} else {
			print('Failed to report to Sentry.io: ${response.error}');
		}
	}
	catch (e, stackTrace) {
		print('Exception whilst reporting to Sentry.io\n' + stackTrace.toString());
	}
}

void main() => runCapturedApp((reporter) => new AppComponent(reporter), dsn: '');

I do not understand how can I integrate this with the existing app, can you please throw some light on it?

@devashish-patel

runCapturedApp basically replaces runApp that you have in main.dart. So it shouldn't be a problem to add to the existing app.

When I execute this line of code:

final SentryResponse response = await sentry.capture(event: event);

I got the following exception:

_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>

When I execute this line of code:

final SentryResponse response = await sentry.capture(event: event);

I got the following exception:

_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>

It's caused by the deviceInfo part of the code.
I solved it naively but the solution definitely works for me, My Fix.