write_logger

Version 0.0.4 — Colored console logging and daily file logging for Flutter apps, with optional encryption and automatic retention cleanup.

Features

• Console logs with ANSI colors and a box border per entry (enableConsole: kDebugMode by default)
• Daily log files (log_yyyy-MM-dd.txt) with the same box layout
• Optional pluggable encryption for file message contents (AppEncryptionAdapter sample in example) — level / timestamp / tag stay plaintext
• Automatic deletion of logs older than N days
• All log levels written (no min-level filter)
• Tags for categorizing events — any string (e.g. cURL, Login cURL, Auth); no special colors or handling
• Extensible sinks (addSink)

Getting started

dependencies:
  write_logger: ^0.0.4
  # or path / git:
  # write_logger:
  #   path: ../write_logger

Source: github.com/fakeeh-tech/WriteLogger

See CHANGELOG.md for release notes.

See the full demo in example/: every log level, sample cURL, open file, and in-app viewer.

cd example
flutter run

Use a terminal so ANSI colors show up.

Usage

import 'package:flutter/foundation.dart';
import 'package:write_logger/write_logger.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await WriteLogger.init(
    WriteLoggerConfig(
      enableConsole: kDebugMode, // optional, default: kDebugMode
      retentionDays: 7,         // optional
      enableFile: true,         // optional
      // encryption: AppEncryptionAdapter(), // optional — see example sample
    ),
  );

  await WriteLogger.i('App started', tag: 'Bootstrap');
  await WriteLogger.w('Slow network');
  await WriteLogger.e('Failed', error: Exception('boom'));
}

Minimal init

All config fields have defaults:

await WriteLogger.init();

enableConsole defaults to kDebugMode (on in debug, off in release/profile). Colors are always applied when the console sink is active.

Log a cURL from your app

Build the cURL string in your HTTP layer (Dio interceptor, etc.), then pass it in. Color comes from the level only — the tag is a plain label for filtering:

final curl = "curl -X POST "
    "-H 'Content-Type: application/json' "
    "-H 'Authorization: ***' "
    "--data '{\"id\":1}' "
    "'https://api.example.com/v1/items'";

await WriteLogger.d(curl, tag: 'cURL');
// or a more specific label:
await WriteLogger.d(curl, tag: 'Login cURL');

Tip	Detail
Level	Prefer debug for routine requests; error when the call fails
Tag	Any string — e.g. cURL, Login cURL, HTTP. No special color or logic
Color	From the level only (e.g. WriteLogger.d → blue). Tag does not affect color
Secrets	Redact Authorization, cookies, and API keys before logging

Custom encryption

Implement EncryptionAdapter in the host app and pass it to init. A full copy-paste sample lives in example/lib/app_encryption_adapter.dart.

import 'dart:convert';

import 'package:write_logger/write_logger.dart';

/// Sample only — replace with real AES / keystore crypto in production.
class AppEncryptionAdapter implements EncryptionAdapter {
  static const _prefix = 'WL1:';

  @override
  Future<String> encrypt(String plainText) async {
    final bytes = utf8.encode(plainText);
    return '$_prefix${base64Encode(bytes)}';
  }

  @override
  Future<String> decrypt(String cipherText) async {
    if (!cipherText.startsWith(_prefix)) return cipherText;
    final encoded = cipherText.substring(_prefix.length);
    return utf8.decode(base64Decode(encoded));
  }
}

await WriteLogger.init(
  WriteLoggerConfig(encryption: AppEncryptionAdapter()),
);

Omit encryption (or pass null) for plain-text files.

When encryption is on, only the message body (plus error / stack) is encrypted. Level, timestamp, and tag stay readable so you can scan the file for [cURL], [Login cURL], [Auth], etc. without decrypting:

┌───────────────────────────────────
│ [DEBUG] [2026-08-10 11:54:00] [Login cURL] WL1:aGVsbG8...
└───────────────────────────────────

Log layout

Console and file use the same boxed layout:

┌───────────────────────────────────
│ [INFO] [2026-08-10 11:54:00] [BLOC TRANSITION] SplashBloc → ...
└───────────────────────────────────

Levels

Helper	Level	Typical console color
WriteLogger.t	trace	gray
WriteLogger.d	debug	blue
WriteLogger.i	info	cyan
WriteLogger.w	warning	yellow
WriteLogger.e	error	red
WriteLogger.security	security	magenta
WriteLogger.performance	performance	green
WriteLogger.validate	validate	green
WriteLogger.delete	delete	yellow

Or:

await WriteLogger.log('custom', level: WriteLogLevel.security);

Get today's file path

final path = await WriteLogger.getLogFilePath();
// null on web, or when file logging is disabled

if (WriteLogger.supportsFileLogging) {
  // mobile / desktop file logs available
}

Opening or sharing the file (OS viewer, share sheet) belongs in the host app. The example shows openLogFile() via open_filex and an in-app viewer.

Web (console-only)

On Flutter web, dart:io is unavailable. The package still compiles and logs to the console (debug mode); file sink, retention, and getLogFilePath() are skipped / return null even if enableFile: true.

Config reference

Field	Default	Notes
enableConsole	kDebugMode	Colored print output
retentionDays	7	Delete older daily files
enableFile	true	Daily files on disk
encryption	null	Encrypts message body only; tag/level/ts stay plaintext
directoryPath	documents dir	Override for tests
fileNamePrefix	log_	log_2026-08-06.txt

ANSI colors are always on for console output.

Pass host-app values (e.g. Remote Config retention days) into WriteLoggerConfig — this package does not depend on Firebase.

Example app

The example/ project demonstrates:

• Every log helper and WriteLogger.log() for all WriteLogLevel values
• Log sample cURL — app-provided curl string with any tag (demo uses cURL)
• Open file — open today’s log with the OS default app (open_filex)
• View in app — read and display log contents in a screen
• Encryption sample — AppEncryptionAdapter

License

MIT. See LICENSE.

Additional information

Designed for Flutter apps that need durable, optionally encrypted device logs plus colored console output during development. On web, logging is console-only.

Current package version: 0.0.4.