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Custom Transport

ADB is a stream multiplexing protocol. Invoking an command opens a new logical stream, also called an ADB Socket. Adb class relies on an AdbTransport implementation to open and manage those ADB Sockets.

While there might not be any other transports that can create ADB Sockets directly, it's still useful to allow custom transports for other purposes. For example, a mock transport that returns fixed data can be used in tests, and a WebSocket transport can wrap a built-in transport and allow multiple clients to access the device over the Internet.

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The difference between a custom transport and a custom Daemon Transport connection or Server Transport connector is that, the former handles raw request and response data for ADB commands, while the latter always has those data in an encoded format.

For example, to write a unit test for an ADB command, a custom transport only needs to return the expected response data, but a Daemon Transport connection must encode that response using Daemon protocol, which then gets decoded by Daemon Transport.

Overview​

To implement a custom transport, you need to create two class:

  • An AdbSocket implementation that sends and receives raw data.
  • An AdbTransport implementation that creates new AdbSockets when requested.