Initial upload

fcast/connection.go

@@ -0,0 +1,78 @@
+package fcast
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"errors"
+	"log"
+	"net"
+	"strconv"
+)
+
+type Connection struct {
+	net.Conn
+}
+
+func Connect(host string) (*Connection, error) {
+	conn, err := net.Dial("tcp", host+":"+strconv.Itoa(DefaultPort))
+	return &Connection{conn}, err
+}
+
+func (c *Connection) ListenForMessages(em *EventManager) error {
+
+	c.addPingHandlerIfNotSet(em)
+
+	for {
+
+		var (
+			bodyLenBuf = make([]byte, 4)
+			opCodeBuf  [1]byte
+			// bodyBuf's size depends on bodyLen's value
+		)
+
+		_, err := c.Read(bodyLenBuf)
+		bodyBuf := make([]byte, binary.LittleEndian.Uint32(bodyLenBuf)-1)
+		_, err = c.Read(opCodeBuf[:])
+		_, err = c.Read(bodyBuf)
+
+		if err != nil {
+			if errors.Is(err, net.ErrClosed) {
+				return nil
+			}
+			return err
+		}
+
+		rawMsg, err := DeserializeRaw(bodyLenBuf, opCodeBuf[:], bodyBuf)
+		if err != nil {
+			return err
+		}
+
+		err = em.dispatchMessage(rawMsg)
+		if err != nil {
+			return err
+		}
+
+	}
+
+	return nil
+
+}
+
+func (c *Connection) addPingHandlerIfNotSet(em *EventManager) {
+	if em.codes[Ping].handler == nil {
+		em.SetHandler(PingMessage{}, func(message Message) {
+			err := c.SendMessage(PongMessage{})
+			if err != nil {
+				log.Println("[ERROR} fcast: error in default pong responder:", err)
+			}
+		})
+	}
+}
+
+func (c *Connection) SendMessage(message Message) error {
+	body, _ := json.Marshal(message)
+	rawMessage := NewMessage(message.getOpCode(), body)
+	serialized := SerializeRaw(rawMessage)
+	_, err := c.Write(serialized)
+	return err
+}