Refactor TrackerRegistration Read to io.Reader interface

[rbdr/mobius] / hotline / tracker.go

diff --git a/hotline/tracker.go b/hotline/tracker.go
index bd7aa00da966d52b21f1a2b872d3153e78348884..a56059fa2f04ba3b19596070ba7ca970fd35b224 100644 (file)
--- a/hotline/tracker.go
+++ b/hotline/tracker.go
@@ -4,49 +4,49 @@ import (
        "bufio"
        "encoding/binary"
        "fmt"
-       "github.com/jhalter/mobius/concat"
+       "io"
        "net"
+       "slices"
        "strconv"
        "time"
 )
 
 // TrackerRegistration represents the payload a Hotline server sends to a Tracker to register
 type TrackerRegistration struct {
-       Port        [2]byte // Server listening port number
+       Port        [2]byte // Server's listening TCP port number
        UserCount   int     // Number of users connected to this particular server
-       PassID      []byte  // Random number generated by the server
+       PassID      [4]byte // Random number generated by the server
        Name        string  // Server name
        Description string  // Description of the server
 }
 
-// TODO: reimplement as io.Reader
-func (tr *TrackerRegistration) Read() []byte {
+// Read implements io.Reader to write tracker registration payload bytes to slice
+func (tr *TrackerRegistration) Read(p []byte) (int, error) {
        userCount := make([]byte, 2)
        binary.BigEndian.PutUint16(userCount, uint16(tr.UserCount))
 
-       return concat.Slices(
-               []byte{0x00, 0x01},
+       return copy(p, slices.Concat(
+               []byte{0x00, 0x01}, // Magic number, always 1
                tr.Port[:],
                userCount,
-               []byte{0x00, 0x00},
-               tr.PassID,
+               []byte{0x00, 0x00}, // Magic number, always 0
+               tr.PassID[:],
                []byte{uint8(len(tr.Name))},
                []byte(tr.Name),
                []byte{uint8(len(tr.Description))},
                []byte(tr.Description),
-       )
+       )[:]), io.EOF
 }
 
 func register(tracker string, tr *TrackerRegistration) error {
        conn, err := net.Dial("udp", tracker)
        if err != nil {
-               return err
+               return fmt.Errorf("failed to dial tracker: %w", err)
        }
+       defer conn.Close()
 
-       b := tr.Read()
-
-       if _, err := conn.Write(b); err != nil {
-               return err
+       if _, err := io.Copy(conn, tr); err != nil {
+               return fmt.Errorf("failed to write to connection: %w", err)
        }
 
        return nil