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protocol.go
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protocol.go
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package nsq
import (
"encoding/binary"
"errors"
"io"
"regexp"
)
// MagicV1 is the initial identifier sent when connecting for V1 clients
var MagicV1 = []byte(" V1")
// MagicV2 is the initial identifier sent when connecting for V2 clients
var MagicV2 = []byte(" V2")
// frame types
const (
FrameTypeResponse int32 = 0
FrameTypeError int32 = 1
FrameTypeMessage int32 = 2
)
var validTopicNameRegex = regexp.MustCompile(`^[\.a-zA-Z0-9_-]+$`)
var validChannelNameRegex = regexp.MustCompile(`^[\.a-zA-Z0-9_-]+(#ephemeral)?$`)
// IsValidTopicName checks a topic name for correctness
func IsValidTopicName(name string) bool {
if len(name) > 64 || len(name) < 1 {
return false
}
return validTopicNameRegex.MatchString(name)
}
// IsValidChannelName checks a channel name for correctness
func IsValidChannelName(name string) bool {
if len(name) > 64 || len(name) < 1 {
return false
}
return validChannelNameRegex.MatchString(name)
}
// ReadResponse is a client-side utility function to read from the supplied Reader
// according to the NSQ protocol spec:
//
// [x][x][x][x][x][x][x][x]...
// | (int32) || (binary)
// | 4-byte || N-byte
// ------------------------...
// size data
func ReadResponse(r io.Reader) ([]byte, error) {
var msgSize int32
// message size
err := binary.Read(r, binary.BigEndian, &msgSize)
if err != nil {
return nil, err
}
// message binary data
buf := make([]byte, msgSize)
_, err = io.ReadFull(r, buf)
if err != nil {
return nil, err
}
return buf, nil
}
// UnpackResponse is a client-side utility function that unpacks serialized data
// according to NSQ protocol spec:
//
// [x][x][x][x][x][x][x][x]...
// | (int32) || (binary)
// | 4-byte || N-byte
// ------------------------...
// frame ID data
//
// Returns a triplicate of: frame type, data ([]byte), error
func UnpackResponse(response []byte) (int32, []byte, error) {
if len(response) < 4 {
return -1, nil, errors.New("length of response is too small")
}
return int32(binary.BigEndian.Uint32(response)), response[4:], nil
}
// ReadUnpackedResponse reads and parses data from the underlying
// TCP connection according to the NSQ TCP protocol spec and
// returns the frameType, data or error
func ReadUnpackedResponse(r io.Reader) (int32, []byte, error) {
resp, err := ReadResponse(r)
if err != nil {
return -1, nil, err
}
return UnpackResponse(resp)
}