ya-webadb/libraries/adb

@yume-chan/adb

TypeScript implementation of Android Debug Bridge (ADB) protocol.

WARNING: The public API is UNSTABLE. If you have any questions, please open an issue.

• Compatibility
  • Basic usage
  • Use without bundlers
• Connection
  • Backend
    • connect
    • read
    • write
• Authentication
  • AdbCredentialStore
    • generateKey
    • iterateKeys
    • Implementations
  • AdbAuthenticator
• Stream multiplex
  • Backend
• Commands
  • childProcess
  • usb
  • tcpip
  • sync
    • LIST
    • LIS2
    • STAT
    • LST2
    • STA2
    • RECV
    • RCV2
    • SEND
    • SND2
• Useful links

Compatibility

Here is a list of features, their used APIs, and their compatibilities. If you don't use an optional feature, you can ignore its requirement.

Some features can be polyfilled to support older runtimes, but this library doesn't ship with any polyfills.

Each backend may have different requirements.

Basic usage

	Chrome	Edge	Firefox	Internet Explorer	Safari	Node.js
@yume-chan/struct1	67	79	68	No	14	8.32, 11
Streams	67	79	No	No	14.1	16.5
Overall	67	79	No	No	14.1	16.5

¹ uint64 and string used.

² TextEncoder and TextDecoder are only available in util module. Need to be assigned to globalThis.

Use without bundlers

	Chrome	Edge	Firefox	Internet Explorer	Safari	Node.js
Top-level await1	89	89	89	No	15	14.8

Connection

This library doesn't tie to a specific transportation method.

Instead, a Backend is responsible for transferring data in its own way (USB, WebSocket, etc).

Backend

connect

Establishes a connection with the device.

If a backend doesn't have extra steps to establish the connection, it can omit the connect method implementation.

read

read(length: number): ArrayBuffer | Promise<ArrayBuffer>

Reads the specified amount of data from the underlying connection.

The returned ArrayBuffer may have more or less data than the length parameter specified, if there is some residual data in the connection buffer. The client will automatically call read again with the same length.

write

write(buffer: ArrayBuffer): void | Promise<void>

Writes data to the underlying connection.

Authentication

For how does ADB authentication work, see https://chensi.moe/blog/2020/09/30/webadb-part2-connection/#auth.

In this library, authentication comes in two parts:

• AdbCredentialStore: because JavaScript has no unified method to generate, store and iterate crypto keys, an implementation of AdbCredentialStore is required for the two built-in authenticators.
• AdbAuthenticator: can be used to implement custom authentication modes.

Custom AdbCredentialStores and AdbAuthenticators can be specified in the Adb#connect method.

AdbCredentialStore

generateKey

generateKey(): ArrayBuffer | Promise<ArrayBuffer>

Generate and store a RSA private key with modulus length 2048 and public exponent 65537.

The returned ArrayBuffer is the private key in PKCS #8 format.

iterateKeys

iterateKeys(): Iterator<ArrayBuffer> | AsyncIterator<ArrayBuffer>

Synchronously or asynchronously iterate through all stored RSA private keys.

Each call to iterateKeys must return a different iterator that iterate through all stored keys.

Implementations

The @yume-chan/adb-backend-webusb package contains a AdbWebCredentialStore implementation using Web Crypto API to generating keys and Web Storage API to storing keys.

AdbAuthenticator

An AdbAuthenticator generates AUTH responses for each AUTH request from server.

This package contains AdbSignatureAuthenticator and AdbPublicKeyAuthenticator, the two basic modes.

Stream multiplex

ADB commands are all based on streams. Multiple streams can send and receive at the same time in one connection.

1. Client sends an OPEN packet to create a stream.
2. Server responds with OKAY or FAIL.
3. Client and server read/write on the stream.
4. Client/server sends a CLSE to close the stream.

The Backend is responsible for reading and writing data from underlying source.

Backend

Commands

childProcess

Spawns child process on server. ADB has two shell modes:

	Legacy mode	Shell Protocol
Feature flag	-	shell_v2
Implementation	AdbLegacyShell	AdbShellProtocol
Splitting stdout and stderr	No	Yes
Returning exit code	No	Yes
Resizing window	No	Yes

The Adb#childProcess#shell and Adb#childProcess#spawn methods accepts a list of implementations, and will use the first supported one.

usb

Disable ADB over WiFi.

tcpip

Enable ADB over WiFi.

sync

Client and server will communicate with another protocol on the opened stream.

LIST

Request server to list the content of a folder.

LIS2

Version 2 of the LIST command, contains more information.

Supported on devices with ls_v2 feature.

STAT

Request server to return the information of a file.

If path is a symbolic link, the returned information is about the link itself.

So it's actually the lstat system call.

LST2

Version 2 of the STAT command, contains more information.

Supported on devices with stat_v2 feature.

STA2

Basically identical to LST2, but if path is a symbolic link, the information is about the file it refers to.

Supported on devices with stat_v2 feature.

RECV

Request server to send the content of a file.

RCV2

(Not Implemented)

Version 2 of the RECV command.

Supported on devices with sendrecv_v2 feature.

SEND

(Not Implemented)

Send a file onto server's file system.

SND2

(Not Implemented)

Version 2 of the SEND command.

Supported on devices with sendrecv_v2 feature.

Useful links

• ADB protocol overview
• ADB commands