dev_log_client

Client library for dev_log_viewer. Forwards structured log entries from a Flutter/Dart app to the viewer server running on localhost. All logging is a no-op in release builds.

Installation

# pubspec.yaml — add under dependencies (or dev_dependencies)
dev_log_client: ^0.2.2

Or use the one-command setup wizard from the server package:

dart pub global activate dev_log_viewer
dev_log_setup   # run from your project root

Setup

Call LogForwarder.init() once, early in main():

import 'package:dev_log_client/dev_log_client.dart';

void main() {
  LogForwarder.init(project: 'my_app');   // auto-discovers the viewer on ports 8181–8185
  runApp(MyApp());
}

Pass project on iOS/Android. Discovery prefers a server reporting the same project name when more than one is running, but the app is sandboxed on mobile — there's no pubspec.yaml on disk to auto-detect it from the way there is on desktop/CLI targets. Without project, discovery still works (it falls back to picking the lowest port that responds), but it can't tell your project's server apart from someone else's or a stale one — pass it explicitly to be sure.

Three integration options

Option A — Raw LogForwarder (any project)

LogForwarder.send(tag: 'AUTH', message: 'User signed in');
LogForwarder.send(
  tag: 'ERR',
  message: 'Upload failed',
  level: 'error',
  error: e.toString(),
);

Option B — DevLogInterceptor (Dio projects, zero-config API logging)

dio.interceptors.add(DevLogInterceptor());

Every request, response body, status code, and round-trip duration streams to the viewer automatically — unredacted, since this only ever travels to localhost while you're actively debugging. The viewer masks fields like password, pin, token, and authorization by default (click to reveal), so it's safe to glance at or screen-share without exposing credentials, but the Copy button on any entry always copies the real value — handy for pasting a failing request straight to a backend developer.

Option C — AppLog (named tag shortcuts)

AppLog.auth('User signed in: $uid');
AppLog.nav('Pushed /checkout');
AppLog.store('Cart updated');
AppLog.error('PAY', 'Charge failed', error: e, stack: s);
AppLog.log('CUSTOM', 'anything');   // custom tag

Options B and C can be combined — add DevLogInterceptor for automatic API traffic and use AppLog for manual events.

Multiple projects simultaneously

Discovery pings every port in 8181–8185 concurrently (via the side-effect-free /ping endpoint) and prefers a server reporting the same project, picking the most recently started one if more than one matches. So two Flutter apps — or two runs of the same app, old and new — can have viewers open on different ports at once without the older one winning just because it's on a lower port.

For explicit control (e.g. pinning to a port you know is free):

LogForwarder.init(port: 8182);

Platform support

Uses dart:io (HttpClient) — works on Android, iOS, macOS, Linux, and Windows. Not supported on Flutter Web.

Example

A runnable Flutter app demonstrating all three integration options is in example/.

Release safety

All client code is guarded by:

const bool _kDebugMode = !bool.fromEnvironment('dart.vm.product');

No connections are made and no logs are sent in release builds.

Libraries

dev_log_client
Client library for Dev Log Viewer.