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config.go
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config.go
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package websocket
import (
"math/rand"
"net/http"
"time"
"github.com/iris-contrib/go.uuid" // a stable version of go.uuid to avoid the problems we had with go modules.
)
const (
// DefaultWebsocketWriteTimeout 0, no timeout
DefaultWebsocketWriteTimeout = 0
// DefaultWebsocketReadTimeout 0, no timeout
DefaultWebsocketReadTimeout = 0
// DefaultWebsocketPongTimeout 60 * time.Second
DefaultWebsocketPongTimeout = 60 * time.Second
// DefaultWebsocketPingPeriod (DefaultPongTimeout * 9) / 10
DefaultWebsocketPingPeriod = (DefaultWebsocketPongTimeout * 9) / 10
// DefaultWebsocketMaxMessageSize 1024
DefaultWebsocketMaxMessageSize = 1024
// DefaultWebsocketReadBufferSize 4096
DefaultWebsocketReadBufferSize = 4096
// DefaultWebsocketWriterBufferSize 4096
DefaultWebsocketWriterBufferSize = 4096
// DefaultEvtMessageKey is the default prefix of the underline websocket events
// that are being established under the hoods.
//
// Defaults to "go-websocket-message:".
// Last character of the prefix should be ':'.
DefaultEvtMessageKey = "go-websocket-message:"
)
var (
// DefaultIDGenerator returns a random unique for a new connection.
// Used when config.IDGenerator is nil.
DefaultIDGenerator = func(w http.ResponseWriter, r *http.Request) string {
id, err := uuid.NewV4()
if err != nil {
return randomString(64)
}
return id.String()
}
)
// Config the websocket server configuration
// all of these are optional.
type Config struct {
// IDGenerator used to create (and later on, set)
// an ID for each incoming websocket connections (clients).
// The request is an input parameter which you can use to generate the ID (from headers for example).
// If empty then the ID is generated by DefaultIDGenerator: uuid or,if failed, a randomString(64)
IDGenerator func(w http.ResponseWriter, r *http.Request) string
// EvtMessagePrefix is the prefix of the underline websocket events that are being established under the hoods.
// This prefix is visible only to the javascript side (code) and it has nothing to do
// with the message that the end-user receives.
// Do not change it unless it is absolutely necessary.
//
// If empty then defaults to []byte("go-websocket-message:").
EvtMessagePrefix []byte
// Error is the function that will be fired if any client couldn't upgrade the HTTP connection
// to a websocket connection, a handshake error.
Error func(w http.ResponseWriter, r *http.Request, status int, reason error)
// CheckOrigin a function that is called right before the handshake,
// if returns false then that client is not allowed to connect with the websocket server.
CheckOrigin func(r *http.Request) bool
// HandshakeTimeout specifies the duration for the handshake to complete.
HandshakeTimeout time.Duration
// WriteTimeout time allowed to write a message to the connection.
// 0 means no timeout.
// Default value is 0
WriteTimeout time.Duration
// ReadTimeout time allowed to read a message from the connection.
// 0 means no timeout.
// Default value is 0
ReadTimeout time.Duration
// PongTimeout allowed to read the next pong message from the connection.
// Default value is 60 * time.Second
PongTimeout time.Duration
// PingPeriod send ping messages to the connection within this period. Must be less than PongTimeout.
// Default value is 60 *time.Second
PingPeriod time.Duration
// MaxMessageSize max message size allowed from connection.
// Default value is 1024
MaxMessageSize int64
// BinaryMessages set it to true in order to denotes binary data messages instead of utf-8 text
// compatible if you wanna use the Connection's EmitMessage to send a custom binary data to the client, like a native server-client communication.
// Default value is false
BinaryMessages bool
// ReadBufferSize is the buffer size for the connection reader.
// Default value is 4096
ReadBufferSize int
// WriteBufferSize is the buffer size for the connection writer.
// Default value is 4096
WriteBufferSize int
// EnableCompression specify if the server should attempt to negotiate per
// message compression (RFC 7692). Setting this value to true does not
// guarantee that compression will be supported. Currently only "no context
// takeover" modes are supported.
//
// Defaults to false and it should be remain as it is, unless special requirements.
EnableCompression bool
// Subprotocols specifies the server's supported protocols in order of
// preference. If this field is set, then the Upgrade method negotiates a
// subprotocol by selecting the first match in this list with a protocol
// requested by the client.
Subprotocols []string
}
// Validate validates the configuration
func (c Config) Validate() Config {
// 0 means no timeout.
if c.WriteTimeout < 0 {
c.WriteTimeout = DefaultWebsocketWriteTimeout
}
if c.ReadTimeout < 0 {
c.ReadTimeout = DefaultWebsocketReadTimeout
}
if c.PongTimeout < 0 {
c.PongTimeout = DefaultWebsocketPongTimeout
}
if c.PingPeriod <= 0 {
c.PingPeriod = DefaultWebsocketPingPeriod
}
if c.MaxMessageSize <= 0 {
c.MaxMessageSize = DefaultWebsocketMaxMessageSize
}
if c.ReadBufferSize <= 0 {
c.ReadBufferSize = DefaultWebsocketReadBufferSize
}
if c.WriteBufferSize <= 0 {
c.WriteBufferSize = DefaultWebsocketWriterBufferSize
}
if c.Error == nil {
c.Error = func(w http.ResponseWriter, r *http.Request, status int, reason error) {
//empty
}
}
if c.CheckOrigin == nil {
c.CheckOrigin = func(r *http.Request) bool {
// allow all connections by default
return true
}
}
if len(c.EvtMessagePrefix) == 0 {
c.EvtMessagePrefix = []byte(DefaultEvtMessageKey)
}
if c.IDGenerator == nil {
c.IDGenerator = DefaultIDGenerator
}
return c
}
const (
letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
)
var src = rand.NewSource(time.Now().UnixNano())
// random takes a parameter (int) and returns random slice of byte
// ex: var randomstrbytes []byte; randomstrbytes = utils.Random(32)
func random(n int) []byte {
b := make([]byte, n)
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = src.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return b
}
// randomString accepts a number(10 for example) and returns a random string using simple but fairly safe random algorithm
func randomString(n int) string {
return string(random(n))
}