Add Internet Connectivity Check

This skill adds internet connectivity checking before executing a Cubit method.

What This Skill Does

Adds the checkInternet parameter to a mix() call to:

• Check device internet connectivity before running the method
• Abort execution if no internet is available
• Optionally show an error dialog or fail silently
• Combine with retry for persistent loading

Instructions

Step 1: Identify the Method

Ask the user which Cubit method needs internet checking, or identify methods that:

• Make network/API calls
• Require internet connectivity to function
• Should not attempt execution without connectivity

Step 2: Add Basic Internet Check

Add checkInternet: checkInternet to the mix() call:

import 'package:bloc_superpowers/bloc_superpowers.dart';

class UserCubit extends Cubit<User> {
  UserCubit() : super(User());

  void loadData() => mix(
    key: this,
    checkInternet: checkInternet,  // Add this line
    () async {
      final user = await api.loadUser();
      emit(user);
    },
  );
}

Step 3: Understand Default Behavior

When internet is unavailable with default settings:

1. Method does not execute
2. Cubit enters failed state (context.isFailed() returns true)
3. ConnectionException is thrown with message "No internet connection"
4. UserExceptionDialog shows the error (if configured)

Note: This only checks device connectivity, not whether your specific server is reachable.

Configuration Options

Default Parameters

checkInternet(
  abortSilently: false,    // If true, don't throw exception
  ifOpenDialog: true,      // If true, show error dialog
  maxRetryDelay: 1.sec,    // Recheck interval when combined with retry
)

Silent Abort (No Error)

For background operations that should quietly skip when offline:

void syncInBackground() => mix(
  key: this,
  checkInternet: checkInternet(abortSilently: true),
  () async {
    await api.syncData();
  },
);

The method returns immediately without executing or throwing. No error dialog appears.

Manual Error Handling (No Dialog)

To handle the error in your widget instead of showing a dialog:

void loadData() => mix(
  key: this,
  checkInternet: checkInternet(ifOpenDialog: false),
  () async {
    final data = await api.getData();
    emit(data);
  },
);

Then in the widget:

Widget build(BuildContext context) {
  if (context.isFailed(UserCubit)) {
    return Column(
      children: [
        const Text('No internet connection'),
        ElevatedButton(
          onPressed: () => context.read<UserCubit>().loadData(),
          child: const Text('Retry'),
        ),
      ],
    );
  }
  // ... rest of widget
}

Retry Until Internet Returns

For critical data that must load eventually:

void loadInitialData() => mix(
  key: this,
  checkInternet: checkInternet,
  retry: retry.unlimited,
  () async {
    final data = await api.getInitialData();
    emit(data);
  },
);

Internet connectivity is rechecked before each retry attempt.

Custom Retry Delay

Control how often to recheck connectivity:

void loadData() => mix(
  key: this,
  checkInternet: checkInternet(maxRetryDelay: 500.millis),
  retry: retry.unlimited(maxDelay: 5.sec),
  () async {
    final data = await api.getData();
    emit(data);
  },
);

Common Patterns

Standard API Call with Internet Check

void fetchProducts() => mix(
  key: this,
  checkInternet: checkInternet,
  () async {
    final products = await api.getProducts();
    emit(state.copyWith(products: products));
  },
);

Background Sync (Silent)

void syncData() => mix(
  key: this,
  checkInternet: checkInternet(abortSilently: true),
  () async {
    await api.sync();
  },
);

Critical Startup Data (Persistent)

void loadAppConfig() => mix(
  key: this,
  checkInternet: checkInternet(maxRetryDelay: 1.sec),
  retry: retry.unlimited,
  () async {
    final config = await api.getConfig();
    emit(config);
  },
);

Internet Check + Retry + Error Handling

void loadData() => mix(
  key: this,
  checkInternet: checkInternet,
  retry: retry(maxRetries: 3),
  catchError: (error, stackTrace) {
    if (error is ConnectionException) {
      throw UserException('Please check your internet connection');
    }
    throw UserException('Failed to load data. Please try again.');
  },
  () async {
    final data = await api.getData();
    emit(data);
  },
);

Behavior Summary

User Preferences

Ask the user:

1. Should it fail silently? (for background operations)
2. Show error dialog or handle manually?
3. Retry until internet returns? (for critical data)