accounts

Documentation

Overview

Package accounts implements high level Ethereum account management.

Index

• Constants
• Variables
• func NewAuthNeededError(needed string) error
• func TextAndHash(data []byte) ([]byte, string)
• func TextHash(data []byte) []byte
• type Account
• type AuthNeededError
  • func (err *AuthNeededError) Error() string
• type Backend
• type DerivationPath
  • func ParseDerivationPath(path string) (DerivationPath, error)
  • func (path DerivationPath) String() string
• type Manager
  • func NewManager(backends ...Backend) *Manager
  • func (am *Manager) Backends(kind reflect.Type) []Backend
  • func (am *Manager) Close() error
  • func (am *Manager) Find(account Account) (Wallet, error)
  • func (am *Manager) Subscribe(sink chan<- WalletEvent) event.Subscription
  • func (am *Manager) Wallet(url string) (Wallet, error)
  • func (am *Manager) Wallets() []Wallet
• type URL
  • func (u URL) Cmp(url URL) int
  • func (u URL) MarshalJSON() ([]byte, error)
  • func (u URL) String() string
  • func (u URL) TerminalString() string
  • func (u *URL) UnmarshalJSON(input []byte) error
• type Wallet
• type WalletEvent
• type WalletEventType

Constants

const (
	MimetypeTextWithValidator = "text/validator"
	MimetypeTypedData         = "data/typed"
	MimetypeClique            = "application/x-clique-header"
	MimetypeTextPlain         = "text/plain"
)

Variables

var DefaultBaseDerivationPath = DerivationPath{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0, 0}

DefaultBaseDerivationPath is the base path from which custom derivation endpoints are incremented. As such, the first account will be at m/44'/60'/0'/0/0, the second at m/44'/60'/0'/0/1, etc.

var DefaultLedgerBaseDerivationPath = DerivationPath{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0}

DefaultLedgerBaseDerivationPath is the base path from which custom derivation endpoints are incremented. As such, the first account will be at m/44'/60'/0'/0, the second at m/44'/60'/0'/1, etc.

var DefaultRootDerivationPath = DerivationPath{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0}

DefaultRootDerivationPath is the root path to which custom derivation endpoints are appended. As such, the first account will be at m/44'/60'/0'/0, the second at m/44'/60'/0'/1, etc.

var ErrInvalidPassphrase = errors.New("invalid passphrase")

ErrInvalidPassphrase is returned when a decryption operation receives a bad passphrase.

var ErrNotSupported = errors.New("not supported")

ErrNotSupported is returned when an operation is requested from an account backend that it does not support.

var ErrUnknownAccount = errors.New("unknown account")

ErrUnknownAccount is returned for any requested operation for which no backend provides the specified account.

var ErrUnknownWallet = errors.New("unknown wallet")

ErrUnknownWallet is returned for any requested operation for which no backend provides the specified wallet.

var ErrWalletAlreadyOpen = errors.New("wallet already open")

ErrWalletAlreadyOpen is returned if a wallet is attempted to be opened the second time.

var ErrWalletClosed = errors.New("wallet closed")

ErrWalletClosed is returned if a wallet is attempted to be opened the secodn time.

Functions

func NewAuthNeededError

func NewAuthNeededError(needed string) error

NewAuthNeededError creates a new authentication error with the extra details about the needed fields set.

func TextAndHash

func TextAndHash(data []byte) ([]byte, string)

TextAndHash is a helper function that calculates a hash for the given message that can be safely used to calculate a signature from.

The hash is calulcated as

keccak256("\x19Ethereum Signed Message:\n"${message length}${message}).

This gives context to the signed message and prevents signing of transactions.

func TextHash

func TextHash(data []byte) []byte

TextHash is a helper function that calculates a hash for the given message that can be safely used to calculate a signature from.

The hash is calulcated as

keccak256("\x19Ethereum Signed Message:\n"${message length}${message}).

This gives context to the signed message and prevents signing of transactions.

Types

type Account

type Account struct {
	Address common.Address `json:"address"` // Ethereum account address derived from the key
	URL     URL            `json:"url"`     // Optional resource locator within a backend
}

Account represents an Ethereum account located at a specific location defined by the optional URL field.

type AuthNeededError

type AuthNeededError struct {
	Needed string // Extra authentication the user needs to provide
}

AuthNeededError is returned by backends for signing requests where the user is required to provide further authentication before signing can succeed.

This usually means either that a password needs to be supplied, or perhaps a one time PIN code displayed by some hardware device.

func (*AuthNeededError) Error

func (err *AuthNeededError) Error() string

Error implements the standard error interface.

type Backend

type Backend interface {
	// Wallets retrieves the list of wallets the backend is currently aware of.
	//
	// The returned wallets are not opened by default. For software HD wallets this
	// means that no base seeds are decrypted, and for hardware wallets that no actual
	// connection is established.
	//
	// The resulting wallet list will be sorted alphabetically based on its internal
	// URL assigned by the backend. Since wallets (especially hardware) may come and
	// go, the same wallet might appear at a different positions in the list during
	// subsequent retrievals.
	Wallets() []Wallet

	// Subscribe creates an async subscription to receive notifications when the
	// backend detects the arrival or departure of a wallet.
	Subscribe(sink chan<- WalletEvent) event.Subscription
}

Backend is a "wallet provider" that may contain a batch of accounts they can sign transactions with and upon request, do so.

type DerivationPath

type DerivationPath []uint32

DerivationPath represents the computer friendly version of a hierarchical deterministic wallet account derivaion path.

The BIP-32 spec https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki defines derivation paths to be of the form:

m / purpose' / coin_type' / account' / change / address_index

The BIP-44 spec https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki defines that the `purpose` be 44' (or 0x8000002C) for crypto currencies, and SLIP-44 https://github.com/satoshilabs/slips/blob/master/slip-0044.md assigns the `coin_type` 60' (or 0x8000003C) to Ethereum.

The root path for Ethereum is m/44'/60'/0'/0 according to the specification from https://github.com/ethereum/EIPs/issues/84, albeit it's not set in stone yet whether accounts should increment the last component or the children of that. We will go with the simpler approach of incrementing the last component.

func ParseDerivationPath

func ParseDerivationPath(path string) (DerivationPath, error)

ParseDerivationPath converts a user specified derivation path string to the internal binary representation.

Full derivation paths need to start with the `m/` prefix, relative derivation paths (which will get appended to the default root path) must not have prefixes in front of the first element. Whitespace is ignored.

func (DerivationPath) String

func (path DerivationPath) String() string

String implements the stringer interface, converting a binary derivation path to its canonical representation.

type Manager

type Manager struct {
	// contains filtered or unexported fields
}

Manager is an overarching account manager that can communicate with various backends for signing transactions.

func NewManager

func NewManager(backends ...Backend) *Manager

NewManager creates a generic account manager to sign transaction via various supported backends.

func (*Manager) Backends

func (am *Manager) Backends(kind reflect.Type) []Backend

Backends retrieves the backend(s) with the given type from the account manager.

func (*Manager) Close

func (am *Manager) Close() error

Close terminates the account manager's internal notification processes.

func (*Manager) Find

func (am *Manager) Find(account Account) (Wallet, error)

Find attempts to locate the wallet corresponding to a specific account. Since accounts can be dynamically added to and removed from wallets, this method has a linear runtime in the number of wallets.

func (*Manager) Subscribe

func (am *Manager) Subscribe(sink chan<- WalletEvent) event.Subscription

Subscribe creates an async subscription to receive notifications when the manager detects the arrival or departure of a wallet from any of its backends.

func (*Manager) Wallet

func (am *Manager) Wallet(url string) (Wallet, error)

Wallet retrieves the wallet associated with a particular URL.

func (*Manager) Wallets

func (am *Manager) Wallets() []Wallet

Wallets returns all signer accounts registered under this account manager.

type URL

type URL struct {
	Scheme string // Protocol scheme to identify a capable account backend
	Path   string // Path for the backend to identify a unique entity
}

URL represents the canonical identification URL of a wallet or account.

It is a simplified version of url.URL, with the important limitations (which are considered features here) that it contains value-copyable components only, as well as that it doesn't do any URL encoding/decoding of special characters.

The former is important to allow an account to be copied without leaving live references to the original version, whereas the latter is important to ensure one single canonical form opposed to many allowed ones by the RFC 3986 spec.

As such, these URLs should not be used outside of the scope of an Ethereum wallet or account.

func (URL) Cmp

func (u URL) Cmp(url URL) int

Cmp compares x and y and returns:

-1 if x <  y
 0 if x == y
+1 if x >  y

func (URL) MarshalJSON

func (u URL) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaller interface.

func (URL) String

func (u URL) String() string

String implements the stringer interface.

func (URL) TerminalString

func (u URL) TerminalString() string

TerminalString implements the log.TerminalStringer interface.

func (*URL) UnmarshalJSON

func (u *URL) UnmarshalJSON(input []byte) error

UnmarshalJSON parses url.

type Wallet

type Wallet interface {
	// URL retrieves the canonical path under which this wallet is reachable. It is
	// user by upper layers to define a sorting order over all wallets from multiple
	// backends.
	URL() URL

	// Status returns a textual status to aid the user in the current state of the
	// wallet. It also returns an error indicating any failure the wallet might have
	// encountered.
	Status() (string, error)

	// Open initializes access to a wallet instance. It is not meant to unlock or
	// decrypt account keys, rather simply to establish a connection to hardware
	// wallets and/or to access derivation seeds.
	//
	// The passphrase parameter may or may not be used by the implementation of a
	// particular wallet instance. The reason there is no passwordless open method
	// is to strive towards a uniform wallet handling, oblivious to the different
	// backend providers.
	//
	// Please note, if you open a wallet, you must close it to release any allocated
	// resources (especially important when working with hardware wallets).
	Open(passphrase string) error

	// Close releases any resources held by an open wallet instance.
	Close() error

	// Accounts retrieves the list of signing accounts the wallet is currently aware
	// of. For hierarchical deterministic wallets, the list will not be exhaustive,
	// rather only contain the accounts explicitly pinned during account derivation.
	Accounts() []Account

	// Contains returns whether an account is part of this particular wallet or not.
	Contains(account Account) bool

	// Derive attempts to explicitly derive a hierarchical deterministic account at
	// the specified derivation path. If requested, the derived account will be added
	// to the wallet's tracked account list.
	Derive(path DerivationPath, pin bool) (Account, error)

	// SelfDerive sets a base account derivation path from which the wallet attempts
	// to discover non zero accounts and automatically add them to list of tracked
	// accounts.
	//
	// Note, self derivaton will increment the last component of the specified path
	// opposed to decending into a child path to allow discovering accounts starting
	// from non zero components.
	//
	// You can disable automatic account discovery by calling SelfDerive with a nil
	// chain state reader.
	SelfDerive(base DerivationPath, chain ethereum.ChainStateReader)

	// SignData requests the wallet to sign the hash of the given data
	// It looks up the account specified either solely via its address contained within,
	// or optionally with the aid of any location metadata from the embedded URL field.
	//
	// If the wallet requires additional authentication to sign the request (e.g.
	// a password to decrypt the account, or a PIN code o verify the transaction),
	// an AuthNeededError instance will be returned, containing infos for the user
	// about which fields or actions are needed. The user may retry by providing
	// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock
	// the account in a keystore).
	SignData(account Account, mimeType string, data []byte) ([]byte, error)

	// SignDataWithPassphrase is identical to SignData, but also takes a password
	// NOTE: there's an chance that an erroneous call might mistake the two strings, and
	// supply password in the mimetype field, or vice versa. Thus, an implementation
	// should never echo the mimetype or return the mimetype in the error-response
	SignDataWithPassphrase(account Account, passphrase, mimeType string, data []byte) ([]byte, error)

	// Signtext requests the wallet to sign the hash of a given piece of data, prefixed
	// by the Ethereum prefix scheme
	// It looks up the account specified either solely via its address contained within,
	// or optionally with the aid of any location metadata from the embedded URL field.
	//
	// If the wallet requires additional authentication to sign the request (e.g.
	// a password to decrypt the account, or a PIN code o verify the transaction),
	// an AuthNeededError instance will be returned, containing infos for the user
	// about which fields or actions are needed. The user may retry by providing
	// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock
	// the account in a keystore).
	SignText(account Account, text []byte) ([]byte, error)

	// SignTextWithPassphrase is identical to Signtext, but also takes a password
	SignTextWithPassphrase(account Account, passphrase string, hash []byte) ([]byte, error)

	// SignTx requests the wallet to sign the given transaction.
	//
	// It looks up the account specified either solely via its address contained within,
	// or optionally with the aid of any location metadata from the embedded URL field.
	//
	// If the wallet requires additional authentication to sign the request (e.g.
	// a password to decrypt the account, or a PIN code to verify the transaction),
	// an AuthNeededError instance will be returned, containing infos for the user
	// about which fields or actions are needed. The user may retry by providing
	// the needed details via SignTxWithPassphrase, or by other means (e.g. unlock
	// the account in a keystore).
	SignTx(account Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error)

	// SignTxWithPassphrase is identical to SignTx, but also takes a password
	SignTxWithPassphrase(account Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error)
}

Wallet represents a software or hardware wallet that might contain one or more accounts (derived from the same seed).

type WalletEvent

type WalletEvent struct {
	Wallet Wallet          // Wallet instance arrived or departed
	Kind   WalletEventType // Event type that happened in the system
}

WalletEvent is an event fired by an account backend when a wallet arrival or departure is detected.

type WalletEventType

type WalletEventType int

WalletEventType represents the different event types that can be fired by the wallet subscription subsystem.

const (
	// WalletArrived is fired when a new wallet is detected either via USB or via
	// a filesystem event in the keystore.
	WalletArrived WalletEventType = iota

	// WalletOpened is fired when a wallet is successfully opened with the purpose
	// of starting any background processes such as automatic key derivation.
	WalletOpened

	// WalletDropped
	WalletDropped
)