nearby_service/README.md

Nearby Service

Connecting phones in a P2P network

Nearby Service Flutter Plugin is used to create connections in a P2P network. With this plugin you can easily create any kind of information sharing application without Internet connection.

Table of Contents

• About
  • Android
  • IOS
• Setup
  • Android
  • IOS
• Usage
• Features
• Contributing
• License

About

A peer-to-peer (P2P) network is a decentralized network architecture in which each participant, called a peer, can act as both a client and a server. This means that peer-to-peer networks can exchange resources such as files, data or services directly with each other without needing a central authority or server.

Android

For Android, Wi-fi Direct is used as a P2P network.

It is implemented through the android.net.wifi.p2p module. It requires permissions for ACCESS_FINE_LOCATION and NEARBY_WIFI_DEVICES (for Android 13+).

It is also important that you need Wi-fi enabled on your device to use it.

To check permissions and Wi-fi status, the nearby_service plugin includes a set of methods:

• checkWifiService() (Android only): returns true if Wi-fi is enabled
• requestPermissions() (Android only): requests permissions for location and nearby devices and returns true if granted
• openServicesSettings(): opens Wi-fi settings for Android and general settings for iOS

IOS

For IOS, the P2P connection is implemented through the Multipeer Connectivity framework.

This framework automatically selects the best network technology depending on the situation - using Wi-Fi if both devices are on the same network, or using peer-to-peer Wi-Fi or Bluetooth otherwise.

The module will work even with Wi-fi turned off (via Bluetooth), but you can still use openServicesSettings() from the nearby_service plugin to open the settings and prompt the user to turn Wi-fi on.

Setup

Android

All necessary Android permissions are already in the AndroidManifest.xml of the plugin so you don't need to add anything to work with p2p network.

Note that if you want to use the plugin to send files, you need to add

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> 
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 

to your AndroidManifest.xml. If you are using an external package to work with the device's file system, follow that package's documentation about managing with permissions.

IOS

For IOS, you need to add the following values to Info.plist:

<key>NSBonjourServices</key>
  <array>
    <string>_mp-connection._tcp</string>
  </array>
<key>UIRequiresPersistentWiFi</key>
<true/>
<key>NSLocalNetworkUsageDescription</key>
<string>[Your description here]</string>

• NSBonjourServices

  For the nearby_service plugin, you should add the value <string>_mp-connection._tcp</string>. This key is required for Multipeer Connectivity. It defines the Bonjour services that your application will look for. Bonjour is Apple's implementation of zero-configuration networking, which allows devices on a LAN to discover each other and establish connections without requiring manual configuration.

• UIRequiresPersistentWiFi

  This key is not strictly required for Multipeer Connectivity to work. This key is used to indicate that your application requires a persistent Wi-Fi connection even when the screen is off. This can be useful for maintaining a network connection for continuous data transfer.

• NSLocalNetworkUsageDescription

  This key is needed to inform users why your application will use the local network. You must provide a string value that explains why your application needs LAN access.

Note that if you want to use the plugin to send files, you also need to follow the instructions of the filesystem management package you are using.

Usage