react-native-tcp-socket

React Native TCP socket API for Android & iOS with client SSL/TLS support. It allows you to create TCP clients and servers sockets, imitating some of Node's net API functionalities (check the available API for more information).

Getting started
- Self-Signed SSL
Compatibility
Usage
API
- TcpSocket
- TcpServer
Maintainers
Acknowledgments
License

Getting started

Install the library using either Yarn:

yarn add react-native-tcp-socket

or npm:

npm install --save react-native-tcp-socket

Using React Native >= 0.60

Linking the package manually is not required anymore with Autolinking.

iOS Platform:

$ cd ios && pod install && cd .. # CocoaPods on iOS needs this extra step
Android Platform:

Modify your android/build.gradle configuration to match minSdkVersion = 21:
```
buildscript {
  ext {
    ...
    minSdkVersion = 21
    ...
  }
```

Self-Signed SSL (only available for React Native > 0.60)

You will need a metro.config.js file in order to use a self-signed SSL certificate. You should already have this file in your root project directory, but if you don't, create it. Inside a module.exports object, create a key called resolver with another object called assetExts. The value of assetExts should be an array of the resource file extensions you want to support.

If you want to support .pem files (plus all the already supported files), your metro.config.js would like like this:

const {getDefaultConfig} = require('metro-config');
const defaultConfig = getDefaultConfig.getDefaultValues(__dirname);

module.exports = {
  resolver: {
    assetExts: [...defaultConfig.resolver.assetExts, 'pem'],
  },
  // ...
};

Using React Native < 0.60

You then need to link the native parts of the library for the platforms you are using. The easiest way to link the library is using the CLI tool by running this command from the root of your project:

$ react-native link react-native-tcp-socket

If you can't or don't want to use the CLI tool, you can also manually link the library using the instructions below (click on the arrow to show them):

Manually link the library on iOS

In XCode, in the project navigator, right click Libraries ➜ Add Files to [your project's name]
Go to node_modules ➜ react-native-tcp-socket and add TcpSockets.xcodeproj
In XCode, in the project navigator, select your project. Add libTcpSockets.a to your project's Build Phases ➜ Link Binary With Libraries
Run your project (Cmd+R)<

Manually link the library on Android

Open up android/app/src/main/java/[...]/MainApplication.java

Add import com.asterinet.react.tcpsocket.TcpSocketPackage; to the imports at the top of the file
Add new TcpSocketPackage() to the list returned by the getPackages() method

Append the following lines to android/settings.gradle:

include ':react-native-tcp-socket'
project(':react-native-tcp-socket').projectDir = new File(rootProject.projectDir, 	'../node_modules/react-native-tcp-socket/android')

Insert the following lines inside the dependencies block in android/app/build.gradle:
```
  compile project(':react-native-tcp-socket')
```

React Native Compatibility

To use this library you need to ensure you are using the correct version of React Native. If you are using a version of React Native that is lower than 0.61 you will need to upgrade before attempting to use this library latest version.

`react-native-tcp-socket` version	Required React Native Version
`4.X.X`, `3.X.X`	`>= 0.61`
`1.2.2`	`>= 0.??`

Usage

Import the library:

import TcpSocket from 'react-native-tcp-socket';
// const net = require('react-native-tcp-socket');

Client

// Create socket
const client = TcpSocket.createConnection(options, () => {
  // Write on the socket
  client.write('Hello server!');

  // Close socket
  client.destroy();
});

client.on('data', function(data) {
  console.log('message was received', data);
});

client.on('error', function(error) {
  console.log(error);
});

client.on('close', function(){
  console.log('Connection closed!');
});

Server

const server = TcpSocket.createServer(function(socket) {
  socket.on('data', (data) => {
    socket.write('Echo server', data);
  });

  socket.on('error', (error) => {
    console.log('An error ocurred with client socket ', error);
  });

  socket.on('close', (error) => {
    console.log('Closed connection with ', socket.address());
  });
}).listen(12345, '0.0.0.0');

server.on('error', (error) => {
  console.log('An error ocurred with the server', error);
});

server.on('close', () => {
  console.log('Server closed connection');
});

SSL Client

const client = TcpSocket.createConnection({
    port: 8443,
    host: "example.com",
    tls: true,
    // tlsCheckValidity: false, // Disable validity checking
    // tlsCert: require('./selfmade.pem') // Self-signed certificate
});

// ...

Note: In order to use self-signed certificates make sure to update your metro.config.js configuration.

API

Here are listed all methods implemented in react-native-tcp-socket, their functionalities are equivalent to those provided by Node's net (more info on #41). However, the methods whose interface differs from Node are shown in bold.

TcpSocket

Methods:
- TcpSocket.createConnection(options[, callback])
- address()
- destroy([error])
- end([data][, encoding][, callback])
- setKeepAlive([enable][, initialDelay]) - initialDelay is ignored
- setNoDelay([noDelay])
- setTimeout(timeout[, callback])
- write(data[, encoding][, callback])

`createConnection()`

createConnection(options[, callback]) creates a TCP connection using the given options.

`createConnection: options`

Required. Available options for creating a socket. It must be an object with the following properties:

Property	Type	iOS	Android	Description
`port`	`<number>`	✅	✅	Required. Port the socket should connect to.
`host`	`<string>`	✅	✅	Host the socket should connect to. IP address in IPv4 format or `'localhost'`. Default: `'localhost'`.
`timeout`	`<number>`	✅	✅	If set, will be used to call `setTimeout(timeout)` after the socket is created, but before it starts the connection.
`localAddress`	`<string>`	✅	✅	Local address the socket should connect from. If not specified, the OS will decide. It is highly recommended to specify a `localAddress` to prevent overload errors and improve performance.
`localPort`	`<number>`	✅	✅	Local port the socket should connect from. If not specified, the OS will decide.
`interface`	`<string>`	❌	✅	Interface the socket should connect from. If not specified, it will use the current active connection. The options are: `'wifi', 'ethernet', 'cellular'`.
`reuseAddress`	`<boolean>`	❌	✅	Enable/disable the reuseAddress socket option. Default: `true`.
`tls`	`<boolean>`	✅	✅	Enable/disable SSL/TLS socket creation. Default: `false`.
`tlsCheckValidity`	`<boolean>`	✅	✅	Enable/disable SSL/TLS certificate validity check. Default: `true`.
`tlsCert`	`<any>`	✅	✅	CA file (.pem format) to trust. If `null`, it will use the device's default SSL trusted list. Useful for self-signed certificates. See example for more info. Default: `null`.

Note: The platforms marked as ❌ use the default value.

TcpServer

Methods:

`listen()`

listen(options[, callback]) creates a TCP server socket using the given options.

`listen: options`

Required. Available options for creating a server socket. It must be an object with the following properties:

Property	Type	iOS	Android	Description
`port`	`<number>`	✅	✅	Required. Port the socket should listen to.
`host`	`<string>`	✅	✅	Host the socket should listen to. IP address in IPv4 format or `'localhost'`. Default: `'0.0.0.0'`.
`reuseAddress`	`<boolean>`	❌	✅	Enable/disable the reuseAddress socket option. Default: `true`.