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70 lines
1.3 KiB
70 lines
1.3 KiB
6 years ago
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package echo
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import (
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"encoding/binary"
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"errors"
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"io"
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"net"
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"github.com/gansidui/gotcp"
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)
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type EchoPacket struct {
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buff []byte
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}
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func (this *EchoPacket) Serialize() []byte {
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return this.buff
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}
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func (this *EchoPacket) GetLength() uint32 {
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return binary.BigEndian.Uint32(this.buff[0:4])
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}
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func (this *EchoPacket) GetBody() []byte {
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return this.buff[4:]
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}
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func NewEchoPacket(buff []byte, hasLengthField bool) *EchoPacket {
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p := &EchoPacket{}
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if hasLengthField {
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p.buff = buff
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} else {
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p.buff = make([]byte, 4+len(buff))
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binary.BigEndian.PutUint32(p.buff[0:4], uint32(len(buff)))
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copy(p.buff[4:], buff)
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}
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return p
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}
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type EchoProtocol struct {
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}
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func (this *EchoProtocol) ReadPacket(conn *net.TCPConn) (gotcp.Packet, error) {
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var (
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lengthBytes []byte = make([]byte, 4)
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length uint32
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)
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// read length
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if _, err := io.ReadFull(conn, lengthBytes); err != nil {
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return nil, err
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}
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if length = binary.BigEndian.Uint32(lengthBytes); length > 1024 {
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return nil, errors.New("the size of packet is larger than the limit")
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}
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buff := make([]byte, 4+length)
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copy(buff[0:4], lengthBytes)
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// read body ( buff = lengthBytes + body )
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if _, err := io.ReadFull(conn, buff[4:]); err != nil {
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return nil, err
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}
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return NewEchoPacket(buff, true), nil
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}
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