redcon/append.go

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package redcon
import (
"strconv"
"strings"
)
// Kind is the kind of command
type Kind int
const (
// Redis is returned for Redis protocol commands
Redis Kind = iota
// Tile38 is returnd for Tile38 native protocol commands
Tile38
// Telnet is returnd for plain telnet commands
Telnet
)
var errInvalidMessage = &errProtocol{"invalid message"}
// ReadNextCommand reads the next command from the provided packet. It's
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// possible that the packet contains multiple commands, or zero commands
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// when the packet is incomplete.
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// 'argsbuf' is an optional reusable buffer and it can be nil.
// 'complete' indicates that a command was read. false means no more commands.
// 'args' are the output arguments for the command.
// 'kind' is the type of command that was read.
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// 'leftover' is any remaining unused bytes which belong to the next command.
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// 'err' is returned when a protocol error was encountered.
func ReadNextCommand(packet []byte, argsbuf [][]byte) (
complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
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args = argsbuf[:0]
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if len(packet) > 0 {
if packet[0] != '*' {
if packet[0] == '$' {
return readTile38Command(packet, args)
}
return readTelnetCommand(packet, args)
}
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// standard redis command
for s, i := 1, 1; i < len(packet); i++ {
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if packet[i] == '\n' {
if packet[i-1] != '\r' {
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return false, args[:0], Redis, packet, errInvalidMultiBulkLength
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}
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count, ok := parseInt(packet[s : i-1])
if !ok || count < 0 {
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return false, args[:0], Redis, packet, errInvalidMultiBulkLength
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}
i++
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if count == 0 {
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return true, args[:0], Redis, packet[i:], nil
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}
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nextArg:
for j := 0; j < count; j++ {
if i == len(packet) {
break
}
if packet[i] != '$' {
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return false, args[:0], Redis, packet,
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&errProtocol{"expected '$', got '" +
string(packet[i]) + "'"}
}
for s := i + 1; i < len(packet); i++ {
if packet[i] == '\n' {
if packet[i-1] != '\r' {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
n, ok := parseInt(packet[s : i-1])
if !ok || count <= 0 {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
i++
if len(packet)-i >= n+2 {
if packet[i+n] != '\r' || packet[i+n+1] != '\n' {
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return false, args[:0], Redis, packet, errInvalidBulkLength
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}
args = append(args, packet[i:i+n])
i += n + 2
if j == count-1 {
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// done reading
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return true, args, Redis, packet[i:], nil
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}
continue nextArg
}
break
}
}
break
}
break
}
}
}
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return false, args[:0], Redis, packet, nil
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}
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func readTile38Command(packet []byte, argsbuf [][]byte) (
complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
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for i := 1; i < len(packet); i++ {
if packet[i] == ' ' {
n, ok := parseInt(packet[1:i])
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if !ok || n < 0 {
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return false, args[:0], Tile38, packet, errInvalidMessage
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}
i++
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if len(packet) >= i+n+2 {
if packet[i+n] != '\r' || packet[i+n+1] != '\n' {
return false, args[:0], Tile38, packet, errInvalidMessage
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}
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line := packet[i : i+n]
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reading:
for len(line) != 0 {
if line[0] == '{' {
// The native protocol cannot understand json boundaries so it assumes that
// a json element must be at the end of the line.
args = append(args, line)
break
}
if line[0] == '"' && line[len(line)-1] == '"' {
if len(args) > 0 &&
strings.ToLower(string(args[0])) == "set" &&
strings.ToLower(string(args[len(args)-1])) == "string" {
// Setting a string value that is contained inside double quotes.
// This is only because of the boundary issues of the native protocol.
args = append(args, line[1:len(line)-1])
break
}
}
i := 0
for ; i < len(line); i++ {
if line[i] == ' ' {
value := line[:i]
if len(value) > 0 {
args = append(args, value)
}
line = line[i+1:]
continue reading
}
}
args = append(args, line)
break
}
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return true, args, Tile38, packet[i+n+2:], nil
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}
break
}
}
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return false, args[:0], Tile38, packet, nil
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}
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func readTelnetCommand(packet []byte, argsbuf [][]byte) (
complete bool, args [][]byte, kind Kind, leftover []byte, err error,
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) {
// just a plain text command
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for i := 0; i < len(packet); i++ {
if packet[i] == '\n' {
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var line []byte
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if i > 0 && packet[i-1] == '\r' {
line = packet[:i-1]
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} else {
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line = packet[:i]
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}
var quote bool
var quotech byte
var escape bool
outer:
for {
nline := make([]byte, 0, len(line))
for i := 0; i < len(line); i++ {
c := line[i]
if !quote {
if c == ' ' {
if len(nline) > 0 {
args = append(args, nline)
}
line = line[i+1:]
continue outer
}
if c == '"' || c == '\'' {
if i != 0 {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
quotech = c
quote = true
line = line[i+1:]
continue outer
}
} else {
if escape {
escape = false
switch c {
case 'n':
c = '\n'
case 'r':
c = '\r'
case 't':
c = '\t'
}
} else if c == quotech {
quote = false
quotech = 0
args = append(args, nline)
line = line[i+1:]
if len(line) > 0 && line[0] != ' ' {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
continue outer
} else if c == '\\' {
escape = true
continue
}
}
nline = append(nline, c)
}
if quote {
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return false, args[:0], Telnet, packet, errUnbalancedQuotes
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}
if len(line) > 0 {
args = append(args, line)
}
break
}
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return true, args, Telnet, packet[i+1:], nil
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}
}
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return false, args[:0], Telnet, packet, nil
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}
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// appendPrefix will append a "$3\r\n" style redis prefix for a message.
func appendPrefix(b []byte, c byte, n int64) []byte {
if n >= 0 && n <= 9 {
return append(b, c, byte('0'+n), '\r', '\n')
}
b = append(b, c)
b = strconv.AppendInt(b, n, 10)
return append(b, '\r', '\n')
}
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// AppendUint appends a Redis protocol uint64 to the input bytes.
func AppendUint(b []byte, n uint64) []byte {
b = append(b, ':')
b = strconv.AppendUint(b, n, 10)
return append(b, '\r', '\n')
}
// AppendInt appends a Redis protocol int64 to the input bytes.
func AppendInt(b []byte, n int64) []byte {
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return appendPrefix(b, ':', n)
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}
// AppendArray appends a Redis protocol array to the input bytes.
func AppendArray(b []byte, n int) []byte {
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return appendPrefix(b, '*', int64(n))
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}
// AppendBulk appends a Redis protocol bulk byte slice to the input bytes.
func AppendBulk(b []byte, bulk []byte) []byte {
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b = appendPrefix(b, '$', int64(len(bulk)))
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b = append(b, bulk...)
return append(b, '\r', '\n')
}
// AppendBulkString appends a Redis protocol bulk string to the input bytes.
func AppendBulkString(b []byte, bulk string) []byte {
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b = appendPrefix(b, '$', int64(len(bulk)))
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b = append(b, bulk...)
return append(b, '\r', '\n')
}
// AppendString appends a Redis protocol string to the input bytes.
func AppendString(b []byte, s string) []byte {
b = append(b, '+')
b = append(b, stripNewlines(s)...)
return append(b, '\r', '\n')
}
// AppendError appends a Redis protocol error to the input bytes.
func AppendError(b []byte, s string) []byte {
b = append(b, '-')
b = append(b, stripNewlines(s)...)
return append(b, '\r', '\n')
}
// AppendOK appends a Redis protocol OK to the input bytes.
func AppendOK(b []byte) []byte {
return append(b, '+', 'O', 'K', '\r', '\n')
}
func stripNewlines(s string) string {
for i := 0; i < len(s); i++ {
if s[i] == '\r' || s[i] == '\n' {
s = strings.Replace(s, "\r", " ", -1)
s = strings.Replace(s, "\n", " ", -1)
break
}
}
return s
}
// AppendTile38 appends a Tile38 message to the input bytes.
func AppendTile38(b []byte, data []byte) []byte {
b = append(b, '$')
b = strconv.AppendInt(b, int64(len(data)), 10)
b = append(b, ' ')
b = append(b, data...)
return append(b, '\r', '\n')
}
// AppendNull appends a Redis protocol null to the input bytes.
func AppendNull(b []byte) []byte {
return append(b, '$', '-', '1', '\r', '\n')
}