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// Copyright 2012 Gary Burd
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
package redis
import (
"context"
"errors"
"time"
)
// Subscription represents a subscribe or unsubscribe notification.
type Subscription struct {
// Kind is "subscribe", "unsubscribe", "psubscribe" or "punsubscribe"
Kind string
// The channel that was changed.
Channel string
// The current number of subscriptions for connection.
Count int
}
// Message represents a message notification.
type Message struct {
// The originating channel.
Channel string
// The matched pattern, if any
Pattern string
// The message data.
Data []byte
}
// Pong represents a pubsub pong notification.
type Pong struct {
Data string
}
// PubSubConn wraps a Conn with convenience methods for subscribers.
type PubSubConn struct {
Conn Conn
}
// Close closes the connection.
func (c PubSubConn) Close() error {
return c.Conn.Close()
}
// Subscribe subscribes the connection to the specified channels.
func (c PubSubConn) Subscribe(channel ...interface{}) error {
if err := c.Conn.Send("SUBSCRIBE", channel...); err != nil {
return err
}
return c.Conn.Flush()
}
// PSubscribe subscribes the connection to the given patterns.
func (c PubSubConn) PSubscribe(channel ...interface{}) error {
if err := c.Conn.Send("PSUBSCRIBE", channel...); err != nil {
return err
}
return c.Conn.Flush()
}
// Unsubscribe unsubscribes the connection from the given channels, or from all
// of them if none is given.
func (c PubSubConn) Unsubscribe(channel ...interface{}) error {
if err := c.Conn.Send("UNSUBSCRIBE", channel...); err != nil {
return err
}
return c.Conn.Flush()
}
// PUnsubscribe unsubscribes the connection from the given patterns, or from all
// of them if none is given.
func (c PubSubConn) PUnsubscribe(channel ...interface{}) error {
if err := c.Conn.Send("PUNSUBSCRIBE", channel...); err != nil {
return err
}
return c.Conn.Flush()
}
// Ping sends a PING to the server with the specified data.
//
// The connection must be subscribed to at least one channel or pattern when
// calling this method.
func (c PubSubConn) Ping(data string) error {
if err := c.Conn.Send("PING", data); err != nil {
return err
}
return c.Conn.Flush()
}
// Receive returns a pushed message as a Subscription, Message, Pong or error.
// The return value is intended to be used directly in a type switch as
// illustrated in the PubSubConn example.
func (c PubSubConn) Receive() interface{} {
return c.receiveInternal(c.Conn.Receive())
}
// ReceiveWithTimeout is like Receive, but it allows the application to
// override the connection's default timeout.
func (c PubSubConn) ReceiveWithTimeout(timeout time.Duration) interface{} {
return c.receiveInternal(ReceiveWithTimeout(c.Conn, timeout))
}
// ReceiveContext is like Receive, but it allows termination of the receive
// via a Context. If the call returns due to closure of the context's Done
// channel the underlying Conn will have been closed.
func (c PubSubConn) ReceiveContext(ctx context.Context) interface{} {
return c.receiveInternal(ReceiveContext(c.Conn, ctx))
}
func (c PubSubConn) receiveInternal(replyArg interface{}, errArg error) interface{} {
reply, err := Values(replyArg, errArg)
if err != nil {
return err
}
var kind string
reply, err = Scan(reply, &kind)
if err != nil {
return err
}
switch kind {
case "message":
var m Message
if _, err := Scan(reply, &m.Channel, &m.Data); err != nil {
return err
}
return m
case "pmessage":
var m Message
if _, err := Scan(reply, &m.Pattern, &m.Channel, &m.Data); err != nil {
return err
}
return m
case "subscribe", "psubscribe", "unsubscribe", "punsubscribe":
s := Subscription{Kind: kind}
if _, err := Scan(reply, &s.Channel, &s.Count); err != nil {
return err
}
return s
case "pong":
var p Pong
if _, err := Scan(reply, &p.Data); err != nil {
return err
}
return p
}
return errors.New("redigo: unknown pubsub notification")
}
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