1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308
|
// Copyright 2014 Vic Demuzere
//
// Use of this source code is governed by the MIT license.
package irc
import (
"bytes"
"strings"
)
// Various constants used for formatting IRC messages.
const (
prefix byte = 0x3A // Prefix or last argument
prefixUser byte = 0x21 // Username
prefixHost byte = 0x40 // Hostname
space byte = 0x20 // Separator
maxLength = 510 // Maximum length is 512 - 2 for the line endings.
)
func cutsetFunc(r rune) bool {
// Characters to trim from prefixes/messages.
return r == '\r' || r == '\n' || r == '\x20' || r == '\x00'
}
// Objects implementing the Sender interface are able to send messages to an IRC server.
//
// As there might be a message queue, it is possible that Send returns a nil
// error, but the message is not sent (yet). The error value is only used when
// it is certain that sending the message is impossible.
//
// This interface is not used inside this package, and shouldn't have been
// defined here in the first place. For backwards compatibility only.
type Sender interface {
Send(*Message) error
}
// Prefix represents the prefix (sender) of an IRC message.
// See RFC1459 section 2.3.1.
//
// <servername> | <nick> [ '!' <user> ] [ '@' <host> ]
//
type Prefix struct {
Name string // Nick- or servername
User string // Username
Host string // Hostname
}
// ParsePrefix takes a string and attempts to create a Prefix struct.
func ParsePrefix(raw string) (p *Prefix) {
p = new(Prefix)
user := indexByte(raw, prefixUser)
host := indexByte(raw, prefixHost)
switch {
case user > 0 && host > user:
p.Name = raw[:user]
p.User = raw[user+1 : host]
p.Host = raw[host+1:]
case user > 0:
p.Name = raw[:user]
p.User = raw[user+1:]
case host > 0:
p.Name = raw[:host]
p.Host = raw[host+1:]
default:
p.Name = raw
}
return p
}
// Len calculates the length of the string representation of this prefix.
func (p *Prefix) Len() (length int) {
length = len(p.Name)
if len(p.User) > 0 {
length = length + len(p.User) + 1
}
if len(p.Host) > 0 {
length = length + len(p.Host) + 1
}
return
}
// Bytes returns a []byte representation of this prefix.
func (p *Prefix) Bytes() []byte {
buffer := new(bytes.Buffer)
p.writeTo(buffer)
return buffer.Bytes()
}
// String returns a string representation of this prefix.
func (p *Prefix) String() (s string) {
// Benchmarks revealed that in this case simple string concatenation
// is actually faster than using a ByteBuffer as in (*Message).String()
s = p.Name
if len(p.User) > 0 {
s = s + string(prefixUser) + p.User
}
if len(p.Host) > 0 {
s = s + string(prefixHost) + p.Host
}
return
}
// IsHostmask returns true if this prefix looks like a user hostmask.
func (p *Prefix) IsHostmask() bool {
return len(p.User) > 0 && len(p.Host) > 0
}
// IsServer returns true if this prefix looks like a server name.
func (p *Prefix) IsServer() bool {
return len(p.User) <= 0 && len(p.Host) <= 0 // && indexByte(p.Name, '.') > 0
}
// writeTo is an utility function to write the prefix to the bytes.Buffer in Message.String().
func (p *Prefix) writeTo(buffer *bytes.Buffer) {
buffer.WriteString(p.Name)
if len(p.User) > 0 {
buffer.WriteByte(prefixUser)
buffer.WriteString(p.User)
}
if len(p.Host) > 0 {
buffer.WriteByte(prefixHost)
buffer.WriteString(p.Host)
}
return
}
// Message represents an IRC protocol message.
// See RFC1459 section 2.3.1.
//
// <message> ::= [':' <prefix> <SPACE> ] <command> <params> <crlf>
// <prefix> ::= <servername> | <nick> [ '!' <user> ] [ '@' <host> ]
// <command> ::= <letter> { <letter> } | <number> <number> <number>
// <SPACE> ::= ' ' { ' ' }
// <params> ::= <SPACE> [ ':' <trailing> | <middle> <params> ]
//
// <middle> ::= <Any *non-empty* sequence of octets not including SPACE
// or NUL or CR or LF, the first of which may not be ':'>
// <trailing> ::= <Any, possibly *empty*, sequence of octets not including
// NUL or CR or LF>
//
// <crlf> ::= CR LF
type Message struct {
*Prefix
Command string
Params []string
Trailing string
// When set to true, the trailing prefix (:) will be added even if the trailing message is empty.
EmptyTrailing bool
}
// ParseMessage takes a string and attempts to create a Message struct.
// Returns nil if the Message is invalid.
func ParseMessage(raw string) (m *Message) {
// Ignore empty messages.
if raw = strings.TrimFunc(raw, cutsetFunc); len(raw) < 2 {
return nil
}
i, j := 0, 0
m = new(Message)
if raw[0] == prefix {
// Prefix ends with a space.
i = indexByte(raw, space)
// Prefix string must not be empty if the indicator is present.
if i < 2 {
return nil
}
m.Prefix = ParsePrefix(raw[1:i])
// Skip space at the end of the prefix
i++
}
// Find end of command
j = i + indexByte(raw[i:], space)
// Extract command
if j > i {
m.Command = raw[i:j]
} else {
m.Command = raw[i:]
// We're done here!
return m
}
// Skip space after command
j++
// Find prefix for trailer
i = indexByte(raw[j:], prefix)
if i < 0 {
// There is no trailing argument!
m.Params = strings.Split(raw[j:], string(space))
// We're done here!
return m
}
// Compensate for index on substring
i = i + j
// Check if we need to parse arguments.
if i > j {
m.Params = strings.Split(raw[j:i-1], string(space))
}
m.Trailing = raw[i+1:]
// We need to re-encode the trailing argument even if it was empty.
if len(m.Trailing) <= 0 {
m.EmptyTrailing = true
}
return m
}
// Len calculates the length of the string representation of this message.
func (m *Message) Len() (length int) {
if m.Prefix != nil {
length = m.Prefix.Len() + 2 // Include prefix and trailing space
}
length = length + len(m.Command)
if len(m.Params) > 0 {
length = length + len(m.Params)
for _, param := range m.Params {
length = length + len(param)
}
}
if len(m.Trailing) > 0 || m.EmptyTrailing {
length = length + len(m.Trailing) + 2 // Include prefix and space
}
return
}
// Bytes returns a []byte representation of this message.
//
// As noted in rfc2812 section 2.3, messages should not exceed 512 characters
// in length. This method forces that limit by discarding any characters
// exceeding the length limit.
func (m *Message) Bytes() []byte {
buffer := new(bytes.Buffer)
// Message prefix
if m.Prefix != nil {
buffer.WriteByte(prefix)
m.Prefix.writeTo(buffer)
buffer.WriteByte(space)
}
// Command is required
buffer.WriteString(m.Command)
// Space separated list of arguments
if len(m.Params) > 0 {
buffer.WriteByte(space)
buffer.WriteString(strings.Join(m.Params, string(space)))
}
if len(m.Trailing) > 0 || m.EmptyTrailing {
buffer.WriteByte(space)
buffer.WriteByte(prefix)
buffer.WriteString(m.Trailing)
}
// We need the limit the buffer length.
if buffer.Len() > (maxLength) {
buffer.Truncate(maxLength)
}
return buffer.Bytes()
}
// String returns a string representation of this message.
//
// As noted in rfc2812 section 2.3, messages should not exceed 512 characters
// in length. This method forces that limit by discarding any characters
// exceeding the length limit.
func (m *Message) String() string {
return string(m.Bytes())
}
|