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package broadcast
import "sync"
// Client subscribes to a given topic and consumes or publish messages to it.
type Client struct {
upstream chan *Message
broker Broker
mu sync.Mutex
topics []string
patterns []string
}
// Channel returns incoming messages channel.
func (c *Client) Channel() chan *Message {
return c.upstream
}
// Publish message into associated topic or topics.
func (c *Client) Publish(msg ...*Message) error {
return c.broker.Publish(msg...)
}
// Subscribe client to specific topics.
func (c *Client) Subscribe(topics ...string) error {
c.mu.Lock()
defer c.mu.Unlock()
newTopics := make([]string, 0)
for _, topic := range topics {
found := false
for _, e := range c.topics {
if e == topic {
found = true
break
}
}
if !found {
newTopics = append(newTopics, topic)
}
}
if len(newTopics) == 0 {
return nil
}
c.topics = append(c.topics, newTopics...)
return c.broker.Subscribe(c.upstream, newTopics...)
}
// SubscribePattern subscribe client to the specific topic pattern.
func (c *Client) SubscribePattern(pattern string) error {
c.mu.Lock()
defer c.mu.Unlock()
for _, g := range c.patterns {
if g == pattern {
return nil
}
}
c.patterns = append(c.patterns, pattern)
return c.broker.SubscribePattern(c.upstream, pattern)
}
// Unsubscribe client from specific topics
func (c *Client) Unsubscribe(topics ...string) error {
c.mu.Lock()
defer c.mu.Unlock()
dropTopics := make([]string, 0)
for _, topic := range topics {
for i, e := range c.topics {
if e == topic {
c.topics = append(c.topics[:i], c.topics[i+1:]...)
dropTopics = append(dropTopics, topic)
}
}
}
if len(dropTopics) == 0 {
return nil
}
return c.broker.Unsubscribe(c.upstream, dropTopics...)
}
// UnsubscribePattern client from topic pattern.
func (c *Client) UnsubscribePattern(pattern string) error {
c.mu.Lock()
defer c.mu.Unlock()
for i := range c.patterns {
if c.patterns[i] == pattern {
c.patterns = append(c.patterns[:i], c.patterns[i+1:]...)
return c.broker.UnsubscribePattern(c.upstream, pattern)
}
}
return nil
}
// Topics return all the topics client subscribed to.
func (c *Client) Topics() []string {
c.mu.Lock()
defer c.mu.Unlock()
return c.topics
}
// Patterns return all the patterns client subscribed to.
func (c *Client) Patterns() []string {
c.mu.Lock()
defer c.mu.Unlock()
return c.patterns
}
// Close the client and consumption.
func (c *Client) Close() (err error) {
c.mu.Lock()
defer c.mu.Unlock()
if len(c.topics) != 0 {
err = c.broker.Unsubscribe(c.upstream, c.topics...)
}
close(c.upstream)
return err
}
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