Add btcd notification types and parser.

notifications.go

@@ -0,0 +1,245 @@
+// Copyright (c) 2013 Conformal Systems LLC.
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcws
+
+import (
+	"encoding/json"
+	"errors"
+	"github.com/conformal/btcjson"
+)
+
+var (
+	// ErrNtfnUnexpected describes an error where an unexpected
+	// notification is received when unmarshaling into a concrete
+	// Notification variable.
+	ErrNtfnUnexpected = errors.New("notification unexpected")
+
+	// ErrNtfnNotFound describes an error where a parser does not
+	// handle unmarshaling a notification.
+	ErrNtfnNotFound = errors.New("notification not found")
+)
+
+const (
+	// BlockConnectedNtfnId is the id of the btcd blockconnected
+	// notification.
+	BlockConnectedNtfnId    = "btcd:blockconnected"
+
+	// BlockDisconnectedNtfnId is the id of the btcd blockdisconnected
+	// notification.
+	BlockDisconnectedNtfnId = "btcd:blockdisconnected"
+
+	//TxMinedNtfnId is the id of the btcd txmined notification.
+	TxMinedNtfnId           = "btcd:txmined"
+)
+
+type newNtfnFn func() Notification
+
+func newBlockConnectedNtfn() Notification {
+	return &BlockConnectedNtfn{}
+}
+
+func newBlockDisconnectedNtfn() Notification {
+	return &BlockDisconnectedNtfn{}
+}
+
+func newTxMinedNtfn() Notification {
+	return &TxMinedNtfn{}
+}
+
+var newNtfnFns = map[string]newNtfnFn{
+	BlockConnectedNtfnId:    newBlockConnectedNtfn,
+	BlockDisconnectedNtfnId: newBlockDisconnectedNtfn,
+	TxMinedNtfnId:           newTxMinedNtfn,
+}
+
+// ParseMarshaledNtfn attempts to unmarshal a marshaled notification
+// into the notification described by id.
+func ParseMarshaledNtfn(id string, b []byte) (Notification, error) {
+	if newFn, ok := newNtfnFns[id]; ok {
+		n := newFn()
+		if err := n.UnmarshalJSON(b); err != nil {
+			return nil, err
+		}
+		return n, nil
+	}
+	return nil, ErrNtfnNotFound
+}
+
+// Notification is an interface implemented by all notification types.
+type Notification interface {
+	json.Marshaler
+	json.Unmarshaler
+	Id() interface{}
+}
+
+// BlockConnectedNtfn is a type handling custom marshaling and
+// unmarshaling of blockconnected JSON websocket notifications.
+type BlockConnectedNtfn struct {
+	Hash   string `json:"hash"`
+	Height int32  `json:"height"`
+}
+
+type blockConnectedResult BlockConnectedNtfn
+
+// Enforce that BlockConnectedNtfn satisfies the Notification interface.
+var _ Notification = &BlockConnectedNtfn{}
+
+// NewBlockConnectedNtfn creates a new BlockConnectedNtfn.
+func NewBlockConnectedNtfn(hash string, height int32) *BlockConnectedNtfn {
+	return &BlockConnectedNtfn{
+		Hash:   hash,
+		Height: height,
+	}
+}
+
+// satisifies the Notification interface by returning the id of the
+// notification.
+func (n *BlockConnectedNtfn) Id() interface{} {
+	return BlockConnectedNtfnId
+}
+
+// MarshalJSON returns the JSON encoding of n.  Part of the Notification
+// interface.
+func (n *BlockConnectedNtfn) MarshalJSON() ([]byte, error) {
+	id := n.Id()
+	reply := btcjson.Reply{
+		Result: *n,
+		Id:     &id,
+	}
+	return json.Marshal(reply)
+}
+
+// UnmarshalJSON unmarshals the JSON encoding of n into n.  Part of
+// the Notification interface.
+func (n *BlockConnectedNtfn) UnmarshalJSON(b []byte) error {
+	var ntfn struct {
+		Result blockConnectedResult `json:"result"`
+		Error  *btcjson.Error       `json:"error"`
+		Id     interface{}          `json:"id"`
+	}
+	if err := json.Unmarshal(b, &ntfn); err != nil {
+		return err
+	}
+
+	// Notification IDs must match expected.
+	if n.Id() != ntfn.Id {
+		return ErrNtfnUnexpected
+	}
+
+	*n = BlockConnectedNtfn(ntfn.Result)
+	return nil
+}
+
+// BlockDisconnectedNtfn is a type handling custom marshaling and
+// unmarshaling of blockdisconnected JSON websocket notifications.
+type BlockDisconnectedNtfn struct {
+	Hash   string `json:"hash"`
+	Height int32  `json:"height"`
+}
+
+type blockDisconnectedResult BlockDisconnectedNtfn
+
+// Enforce that BlockDisconnectedNtfn satisfies the Notification interface.
+var _ Notification = &BlockDisconnectedNtfn{}
+
+// NewBlockDisconnectedNtfn creates a new BlockConnectedNtfn.
+func NewBlockDisconnectedNtfn(hash string, height int32) *BlockDisconnectedNtfn {
+	return &BlockDisconnectedNtfn{
+		Hash:   hash,
+		Height: height,
+	}
+}
+
+// Id satisifies the Notification interface by returning the id of the
+// notification.
+func (n *BlockDisconnectedNtfn) Id() interface{} {
+	return BlockDisconnectedNtfnId
+}
+
+// MarshalJSON returns the JSON encoding of n.  Part of the Notification
+// interface.
+func (n *BlockDisconnectedNtfn) MarshalJSON() ([]byte, error) {
+	id := n.Id()
+	reply := btcjson.Reply{
+		Result: *n,
+		Id:     &id,
+	}
+	return json.Marshal(reply)
+}
+
+// UnmarshalJSON unmarshals the JSON encoding of n into n.  Part of
+// the Notification interface.
+func (n *BlockDisconnectedNtfn) UnmarshalJSON(b []byte) error {
+	var ntfn struct {
+		Result blockDisconnectedResult `json:"result"`
+		Error  *btcjson.Error          `json:"error"`
+		Id     interface{}             `json:"id"`
+	}
+	if err := json.Unmarshal(b, &ntfn); err != nil {
+		return err
+	}
+
+	// Notification IDs must match expected.
+	if n.Id() != ntfn.Id {
+		return ErrNtfnUnexpected
+	}
+
+	*n = BlockDisconnectedNtfn(ntfn.Result)
+	return nil
+}
+
+// TxMinedNtfn is a type handling custom marshaling and
+// unmarshaling of txmined JSON websocket notifications.
+type TxMinedNtfn struct {
+	Hash string `json:"hash"`
+}
+
+type txMinedResult TxMinedNtfn
+
+// Enforce that TxMinedNtfn satisfies the Notification interface.
+var _ Notification = &TxMinedNtfn{}
+
+// NewTxMinedNtfn creates a new TxMinedNtfn.
+func NewTxMinedNtfn(hash string) *TxMinedNtfn {
+	return &TxMinedNtfn{Hash: hash}
+}
+
+// Id satisifies the Notification interface by returning the id of the
+// notification.
+func (n *TxMinedNtfn) Id() interface{} {
+	return TxMinedNtfnId
+}
+
+// MarshalJSON returns the JSON encoding of n.  Part of the Notification
+// interface.
+func (n *TxMinedNtfn) MarshalJSON() ([]byte, error) {
+	id := n.Id()
+	reply := btcjson.Reply{
+		Result: n.Hash,
+		Id:     &id,
+	}
+	return json.Marshal(reply)
+}
+
+// UnmarshalJSON unmarshals the JSON encoding of n into n.  Part of
+// the Notification interface.
+func (n *TxMinedNtfn) UnmarshalJSON(b []byte) error {
+	var ntfn struct {
+		Result txMinedResult  `json:"result"`
+		Error  *btcjson.Error `json:"error"`
+		Id     interface{}    `json:"id"`
+	}
+	if err := json.Unmarshal(b, &ntfn); err != nil {
+		return err
+	}
+
+	// Notification IDs must match expected.
+	if n.Id() != ntfn.Id {
+		return ErrNtfnUnexpected
+	}
+
+	*n = TxMinedNtfn(ntfn.Result)
+	return nil
+}