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Server Transport

As mentioned in USB Connection, a USB device can only be exclusively accessed by one program at a time. This means if multiple ADB clients want to access the same device, only one of them can succeed.

Google ADB solves this problem by starting a server (also called "host") to manage the USB devices, and all ADB clients connect to the server, instead of the device directly. The server forwards ADB commands to devices for those clients.

The protocol between ADB Client and Server is different from the protocol between ADB Server and Daemon. AdbServerClient class is a TypeScript re-implementation of Google ADB Client. It connects to Google ADB Server using TCP sockets, and can create AdbServerTransports for each device.

Installation​

This class is included in the core package:

npm i @yume-chan/adb

To support different runtime environments, AdbServerClient uses an AdbServerConnector implementation to create those TCP sockets. Currently, there is no built-in connector for Web platforms, as TCP sockets are not supported there. Tango provides a Node.js implementation using its net module, and also accepts custom connector implementations for other runtime environments.

Overview​

Here are the overall steps to create an Adb instance from AdbServerClient:

  1. Creates an AdbServerClient.ServerConnector that works on the target runtime environment.
  2. Creates an AdbServerClient instance with the connector.
  3. Queries the device list and selects an already authenticated device.
  4. Creates an AdbServerTransport instance for the selected device.
  5. Creates an Adb instance with the transport object.