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author | obscuren <geffobscura@gmail.com> | 2014-06-16 06:51:21 +0800 |
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committer | obscuren <geffobscura@gmail.com> | 2014-06-16 06:51:21 +0800 |
commit | 1fbea2e438d56484ebfa509d7433cc418e17a79b (patch) | |
tree | 464d73f016fefeb36c0511eebcf841b24c410370 /ethwire | |
parent | 8198fd7913ea4066afb5c0cf5e57fa5ec4888fac (diff) | |
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Reworking messaging interface
Diffstat (limited to 'ethwire')
-rw-r--r-- | ethwire/messaging.go | 163 |
1 files changed, 159 insertions, 4 deletions
diff --git a/ethwire/messaging.go b/ethwire/messaging.go index cbcbbb8b7..f13b72353 100644 --- a/ethwire/messaging.go +++ b/ethwire/messaging.go @@ -1,3 +1,5 @@ +// Package ethwire provides low level access to the Ethereum network and allows +// you to broadcast data over the network. package ethwire import ( @@ -9,11 +11,13 @@ import ( "time" ) -// Message: -// [4 bytes token] RLP([TYPE, DATA]) -// Refer to http://wiki.ethereum.org/index.php/Wire_Protocol +// Connection interface describing the methods required to implement the wire protocol. +type Conn interface { + Write(typ MsgType, v ...interface{}) error + Read() *Msg +} -// The magic token which should be the first 4 bytes of every message. +// The magic token which should be the first 4 bytes of every message and can be used as separator between messages. var MagicToken = []byte{34, 64, 8, 145} type MsgType byte @@ -68,6 +72,157 @@ func NewMessage(msgType MsgType, data interface{}) *Msg { } } +type Messages []*Msg + +// The connection object allows you to set up a connection to the Ethereum network. +// The Connection object takes care of all encoding and sending objects properly over +// the network. +type Connection struct { + conn net.Conn + nTimeout time.Duration + pendingMessages Messages +} + +// Create a new connection to the Ethereum network +func New(conn net.Conn) *Connection { + return &Connection{conn: conn, nTimeout: 500} +} + +// Read, reads from the network. It will block until the next message is received. +func (self *Connection) Read() *Msg { + if len(self.pendingMessages) == 0 { + self.readMessages() + } + + ret := self.pendingMessages[0] + self.pendingMessages = self.pendingMessages[1:] + + return ret + +} + +// Write to the Ethereum network specifying the type of the message and +// the data. Data can be of type RlpEncodable or []interface{}. Returns +// nil or if something went wrong an error. +func (self *Connection) Write(typ MsgType, v ...interface{}) error { + var pack []byte + + slice := [][]interface{}{[]interface{}{byte(typ)}} + for _, value := range v { + if encodable, ok := value.(ethutil.RlpEncodable); ok { + slice = append(slice, encodable.RlpValue()) + } else if raw, ok := value.([]interface{}); ok { + slice = append(slice, raw) + } else { + panic(fmt.Sprintf("Unable to 'write' object of type %T", value)) + } + } + + // Encode the type and the (RLP encoded) data for sending over the wire + encoded := ethutil.NewValue(slice).Encode() + payloadLength := ethutil.NumberToBytes(uint32(len(encoded)), 32) + + // Write magic token and payload length (first 8 bytes) + pack = append(MagicToken, payloadLength...) + pack = append(pack, encoded...) + + // Write to the connection + _, err := self.conn.Write(pack) + if err != nil { + return err + } + + return nil +} + +func (self *Connection) readMessage(data []byte) (msg *Msg, remaining []byte, done bool, err error) { + if len(data) == 0 { + return nil, nil, true, nil + } + + if len(data) <= 8 { + return nil, remaining, false, errors.New("Invalid message") + } + + // Check if the received 4 first bytes are the magic token + if bytes.Compare(MagicToken, data[:4]) != 0 { + return nil, nil, false, fmt.Errorf("MagicToken mismatch. Received %v", data[:4]) + } + + messageLength := ethutil.BytesToNumber(data[4:8]) + remaining = data[8+messageLength:] + if int(messageLength) > len(data[8:]) { + return nil, nil, false, fmt.Errorf("message length %d, expected %d", len(data[8:]), messageLength) + } + + message := data[8 : 8+messageLength] + decoder := ethutil.NewValueFromBytes(message) + // Type of message + t := decoder.Get(0).Uint() + // Actual data + d := decoder.SliceFrom(1) + + msg = &Msg{ + Type: MsgType(t), + Data: d, + } + + return +} + +// The basic message reader waits for data on the given connection, decoding +// and doing a few sanity checks such as if there's a data type and +// unmarhals the given data +func (self *Connection) readMessages() (err error) { + // The recovering function in case anything goes horribly wrong + defer func() { + if r := recover(); r != nil { + err = fmt.Errorf("ethwire.ReadMessage error: %v", r) + } + }() + + // Buff for writing network message to + //buff := make([]byte, 1440) + var buff []byte + var totalBytes int + for { + // Give buffering some time + self.conn.SetReadDeadline(time.Now().Add(self.nTimeout * time.Millisecond)) + // Create a new temporarily buffer + b := make([]byte, 1440) + // Wait for a message from this peer + n, _ := self.conn.Read(b) + if err != nil && n == 0 { + if err.Error() != "EOF" { + fmt.Println("err now", err) + return err + } else { + break + } + + // Messages can't be empty + } else if n == 0 { + break + } + + buff = append(buff, b[:n]...) + totalBytes += n + } + + // Reslice buffer + buff = buff[:totalBytes] + msg, remaining, done, err := self.readMessage(buff) + for ; done != true; msg, remaining, done, err = self.readMessage(remaining) { + //log.Println("rx", msg) + + if msg != nil { + self.pendingMessages = append(self.pendingMessages, msg) + } + } + + return +} + func ReadMessage(data []byte) (msg *Msg, remaining []byte, done bool, err error) { if len(data) == 0 { return nil, nil, true, nil |