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package centrifuge
import (
"encoding/json"
"fmt"
"strings"
"sync"
)
// Disconnect allows to configure how client will be disconnected from server.
// The important note that Disconnect serialized to JSON must be less than 127 bytes
// due to WebSocket protocol limitations (because at moment we send Disconnect inside
// reason field of WebSocket close handshake).
// Note that due to performance reasons we cache Disconnect text representation
// for Close Frame on first send to client so changing field values inside existing
// Disconnect instance won't be reflected in WebSocket/Sockjs Close frames.
type Disconnect struct {
// Code is disconnect code.
Code uint32 `json:"code,omitempty"`
// Reason is a short description of disconnect.
Reason string `json:"reason"`
// Reconnect gives client an advice to reconnect after disconnect or not.
Reconnect bool `json:"reconnect"`
closeTextOnce sync.Once
cachedCloseText string
}
var _ error = (*Disconnect)(nil)
// String representation.
func (d *Disconnect) String() string {
return fmt.Sprintf("code: %d, reason: %s, reconnect: %t", d.Code, d.Reason, d.Reconnect)
}
// Error representation.
func (d *Disconnect) Error() string {
return fmt.Sprintf("disconnected: code: %d, reason: %s, reconnect: %t", d.Code, d.Reason, d.Reconnect)
}
// CloseText allows to build disconnect advice sent inside Close frame.
// At moment we don't encode Code here to not duplicate information
// since it is sent separately as Code of WebSocket/SockJS Close Frame.
func (d *Disconnect) CloseText() string {
d.closeTextOnce.Do(func() {
buf := strings.Builder{}
buf.WriteString(`{"reason":`)
reason, _ := json.Marshal(d.Reason)
buf.Write(reason)
buf.WriteString(`,"reconnect":`)
if d.Reconnect {
buf.WriteString("true")
} else {
buf.WriteString("false")
}
buf.WriteString(`}`)
d.cachedCloseText = buf.String()
})
return d.cachedCloseText
}
// Some predefined disconnect structures used by library internally. Though
// it's always possible to create Disconnect with any field values on the fly.
// Library users supposed to use codes in range 4000-4999 for custom disconnects.
var (
// DisconnectNormal is clean disconnect when client cleanly closed connection.
DisconnectNormal = &Disconnect{
Code: 3000,
Reason: "normal",
Reconnect: true,
}
// DisconnectShutdown sent when node is going to shut down.
DisconnectShutdown = &Disconnect{
Code: 3001,
Reason: "shutdown",
Reconnect: true,
}
// DisconnectInvalidToken sent when client came with invalid token.
DisconnectInvalidToken = &Disconnect{
Code: 3002,
Reason: "invalid token",
Reconnect: false,
}
// DisconnectBadRequest sent when client uses malformed protocol
// frames or wrong order of commands.
DisconnectBadRequest = &Disconnect{
Code: 3003,
Reason: "bad request",
Reconnect: false,
}
// DisconnectServerError sent when internal error occurred on server.
DisconnectServerError = &Disconnect{
Code: 3004,
Reason: "internal server error",
Reconnect: true,
}
// DisconnectExpired sent when client connection expired.
DisconnectExpired = &Disconnect{
Code: 3005,
Reason: "expired",
Reconnect: true,
}
// DisconnectSubExpired sent when client subscription expired.
DisconnectSubExpired = &Disconnect{
Code: 3006,
Reason: "subscription expired",
Reconnect: true,
}
// DisconnectStale sent to close connection that did not become
// authenticated in configured interval after dialing.
DisconnectStale = &Disconnect{
Code: 3007,
Reason: "stale",
Reconnect: false,
}
// DisconnectSlow sent when client can't read messages fast enough.
DisconnectSlow = &Disconnect{
Code: 3008,
Reason: "slow",
Reconnect: true,
}
// DisconnectWriteError sent when an error occurred while writing to
// client connection.
DisconnectWriteError = &Disconnect{
Code: 3009,
Reason: "write error",
Reconnect: true,
}
// DisconnectInsufficientState sent when server detects wrong client
// position in channel Publication stream. Disconnect allows client
// to restore missed publications on reconnect.
DisconnectInsufficientState = &Disconnect{
Code: 3010,
Reason: "insufficient state",
Reconnect: true,
}
// DisconnectForceReconnect sent when server disconnects connection.
DisconnectForceReconnect = &Disconnect{
Code: 3011,
Reason: "force reconnect",
Reconnect: true,
}
// DisconnectForceNoReconnect sent when server disconnects connection
// and asks it to not reconnect again.
DisconnectForceNoReconnect = &Disconnect{
Code: 3012,
Reason: "force disconnect",
Reconnect: false,
}
// DisconnectConnectionLimit can be sent when client connection exceeds a
// configured connection limit (per user ID or due to other rule).
DisconnectConnectionLimit = &Disconnect{
Code: 3013,
Reason: "connection limit",
Reconnect: false,
}
)
|
