initial public commit

tools/subscriptions/client.go

@@ -0,0 +1,141 @@
+package subscriptions
+
+import (
+	"sync"
+
+	"github.com/pocketbase/pocketbase/tools/security"
+)
+
+// Message defines a client's channel data.
+type Message struct {
+	Name string
+	Data string
+}
+
+// Client is an interface for a generic subscription client.
+type Client interface {
+	// Id Returns the unique id of the client.
+	Id() string
+
+	// Channel returns the client's communication channel.
+	Channel() chan Message
+
+	// Subscriptions returns all subscriptions to which the client has subscribed to.
+	Subscriptions() map[string]struct{}
+
+	// Subscribe subscribes the client to the provided subscriptions list.
+	Subscribe(subs ...string)
+
+	// Unsubscribe unsubscribes the client from the provided subscriptions list.
+	Unsubscribe(subs ...string)
+
+	// HasSubscription checks if the client is subscribed to `sub`.
+	HasSubscription(sub string) bool
+
+	// Set stores any value to the client's context.
+	Set(key string, value any)
+
+	// Get retrieves the key value from the client's context.
+	Get(key string) any
+}
+
+// ensures that DefaultClient satisfies the Client interface
+var _ Client = (*DefaultClient)(nil)
+
+// DefaultClient defines a generic subscription client.
+type DefaultClient struct {
+	mux           sync.RWMutex
+	id            string
+	store         map[string]any
+	channel       chan Message
+	subscriptions map[string]struct{}
+}
+
+// NewDefaultClient creates and returns a new DefaultClient instance.
+func NewDefaultClient() *DefaultClient {
+	return &DefaultClient{
+		id:            security.RandomString(40),
+		store:         map[string]any{},
+		channel:       make(chan Message),
+		subscriptions: make(map[string]struct{}),
+	}
+}
+
+// Id implements the Client.Id interface method.
+func (c *DefaultClient) Id() string {
+	return c.id
+}
+
+// Channel implements the Client.Channel interface method.
+func (c *DefaultClient) Channel() chan Message {
+	return c.channel
+}
+
+// Subscriptions implements the Client.Subscriptions interface method.
+func (c *DefaultClient) Subscriptions() map[string]struct{} {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	return c.subscriptions
+}
+
+// Subscribe implements the Client.Subscribe interface method.
+//
+// Empty subscriptions (aka. "") are ignored.
+func (c *DefaultClient) Subscribe(subs ...string) {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	for _, s := range subs {
+		if s == "" {
+			continue // skip empty
+		}
+
+		c.subscriptions[s] = struct{}{}
+	}
+}
+
+// Unsubscribe implements the Client.Unsubscribe interface method.
+//
+// If subs is not set, this method removes all registered client's subscriptions.
+func (c *DefaultClient) Unsubscribe(subs ...string) {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	if len(subs) > 0 {
+		for _, s := range subs {
+			delete(c.subscriptions, s)
+		}
+	} else {
+		// unsubsribe all
+		for s := range c.subscriptions {
+			delete(c.subscriptions, s)
+		}
+	}
+}
+
+// HasSubscription implements the Client.HasSubscription interface method.
+func (c *DefaultClient) HasSubscription(sub string) bool {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	_, ok := c.subscriptions[sub]
+
+	return ok
+}
+
+// Get implements the Client.Get interface method.
+func (c *DefaultClient) Get(key string) any {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	return c.store[key]
+}
+
+// Set implements the Client.Set interface method.
+func (c *DefaultClient) Set(key string, value any) {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	c.store[key] = value
+}