Initial capabilities support for custom implementations

lavalink.go

@@ -23,6 +23,8 @@ type Lavalink struct {
 	nodes   []*Node
 	players map[string]*Player
 
+	capabilities map[string]interface{}
+
 	BestNodeFunc func([]*Node) (*Node, error)
 }
 
@@ -133,3 +135,12 @@ func (lavalink *Lavalink) GetPlayer(guild string) (*Player, error) {
 
 	return p, nil
 }
+
+// Add capabilities mappings to the client, letting the server know what we support
+func (lavalink *Lavalink) AddCapability(key string, i interface{}) {
+	if lavalink.capabilities == nil {
+		lavalink.capabilities = make(map[string]interface{})
+	}
+
+	lavalink.capabilities[key] = i
+}

node.go

@@ -6,6 +6,7 @@ import (
 	"github.com/valyala/fastjson"
 	"net/http"
 	"strconv"
+	"strings"
 
 	"github.com/gorilla/websocket"
 )
@@ -71,6 +72,22 @@ func (node *Node) open() error {
 	header.Set("Num-Shards", node.manager.shards)
 	header.Set("User-Id", node.manager.userID)
 
+	if node.manager.capabilities != nil {
+		v := make([]string, 0)
+
+		for k, vals := range node.manager.capabilities {
+			b, err := json.Marshal(vals)
+
+			if err != nil {
+				continue
+			}
+
+			v = append(v, k+"="+string(b))
+		}
+
+		header.Set("Capabilities", strings.Join(v, ";"))
+	}
+
 	ws, resp, err := websocket.DefaultDialer.Dial(node.config.WebSocket, header)
 
 	if err != nil {