🎉 live server seems to be working now

This commit is contained in:
2026-05-14 14:29:57 +02:00
commit d72e439fd9
181 changed files with 47406 additions and 0 deletions

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// ABOUTME: mDNS service discovery for Sendspin Protocol
// ABOUTME: Handles both advertisement (server-initiated) and browsing (client-initiated)
package discovery
import (
"context"
"fmt"
"io"
"log"
"net"
"strings"
"time"
"github.com/hashicorp/mdns"
)
// silentLogger discards hashicorp/mdns internal logs (e.g. "[INFO] mdns: Closing client")
var silentLogger = log.New(io.Discard, "", 0)
type Config struct {
ServiceName string
Port int
ServerMode bool // If true, advertise as _sendspin-server._tcp, otherwise _sendspin._tcp
}
type Manager struct {
config Config
ctx context.Context
cancel context.CancelFunc
servers chan *ServerInfo
clients chan *ClientInfo
}
type ServerInfo struct {
Name string
Host string
Port int
}
// ClientInfo describes a discovered client (player) advertised via
// _sendspin._tcp.local.
type ClientInfo struct {
Instance string // fully-qualified mDNS instance name (stable dedupe key)
Name string // friendly name from TXT "name=" or falls back to Instance
Host string // IPv4 address as a string
Port int
Path string // WebSocket path from TXT "path=" (default "/sendspin")
}
// clientInfoFromEntry converts an mdns.ServiceEntry into a ClientInfo.
// Returns nil when the entry lacks a usable IPv4 address or port, or when
// the entry does not belong to the _sendspin._tcp service (hashicorp/mdns
// is promiscuous and forwards any multicast response received during the
// query window, not just matches to the queried service).
func clientInfoFromEntry(entry *mdns.ServiceEntry) *ClientInfo {
if entry == nil || entry.AddrV4 == nil || entry.Port == 0 {
return nil
}
if !strings.Contains(entry.Name, "._sendspin._tcp.") {
return nil
}
txt := parseTXT(entry.InfoFields)
path := txt["path"]
if path == "" {
path = "/sendspin"
}
name := txt["name"]
if name == "" {
name = entry.Name
}
return &ClientInfo{
Instance: entry.Name,
Name: name,
Host: entry.AddrV4.String(),
Port: entry.Port,
Path: path,
}
}
func NewManager(config Config) *Manager {
ctx, cancel := context.WithCancel(context.Background())
return &Manager{
config: config,
ctx: ctx,
cancel: cancel,
servers: make(chan *ServerInfo, 10),
clients: make(chan *ClientInfo, 10),
}
}
func (m *Manager) Advertise() error {
ips, err := getLocalIPs()
if err != nil {
return fmt.Errorf("failed to get local IPs: %w", err)
}
serviceType := "_sendspin._tcp"
if m.config.ServerMode {
serviceType = "_sendspin-server._tcp"
}
service, err := mdns.NewMDNSService(
m.config.ServiceName,
serviceType,
"",
"",
m.config.Port,
ips,
[]string{"path=/sendspin"},
)
if err != nil {
return fmt.Errorf("failed to create service: %w", err)
}
server, err := mdns.NewServer(&mdns.Config{Zone: service, Logger: silentLogger})
if err != nil {
return fmt.Errorf("failed to create mdns server: %w", err)
}
log.Printf("Advertising mDNS service: %s on port %d (type: %s)", m.config.ServiceName, m.config.Port, serviceType)
go func() {
<-m.ctx.Done()
server.Shutdown()
}()
return nil
}
func (m *Manager) Browse() error {
go m.browseLoop()
return nil
}
func (m *Manager) browseLoop() {
for {
select {
case <-m.ctx.Done():
return
default:
}
entries := make(chan *mdns.ServiceEntry, 10)
go func() {
for entry := range entries {
// hashicorp/mdns is promiscuous: any multicast response arriving
// on the socket during the query window is forwarded, regardless
// of whether it matches Service. Filter by instance-name suffix
// so we don't dial Google Cast, ADB, etc.
if !strings.Contains(entry.Name, "._sendspin-server._tcp.") {
continue
}
if entry.AddrV4 == nil || entry.Port == 0 {
continue
}
server := &ServerInfo{
Name: entry.Name,
Host: entry.AddrV4.String(),
Port: entry.Port,
}
log.Printf("Discovered server: %s at %s:%d", server.Name, server.Host, server.Port)
select {
case m.servers <- server:
case <-m.ctx.Done():
return
}
}
}()
params := &mdns.QueryParam{
Service: "_sendspin-server._tcp",
Domain: "local",
Timeout: 3 * time.Second,
Entries: entries,
Logger: silentLogger,
}
mdns.Query(params)
close(entries)
}
}
func (m *Manager) Servers() <-chan *ServerInfo {
return m.servers
}
func (m *Manager) Stop() {
m.cancel()
}
// BrowseClients searches for Sendspin clients advertising _sendspin._tcp.
func (m *Manager) BrowseClients() error {
go m.browseClientsLoop()
return nil
}
func (m *Manager) Clients() <-chan *ClientInfo {
return m.clients
}
func (m *Manager) browseClientsLoop() {
for {
select {
case <-m.ctx.Done():
return
default:
}
entries := make(chan *mdns.ServiceEntry, 10)
go func() {
for entry := range entries {
info := clientInfoFromEntry(entry)
if info == nil {
continue
}
log.Printf("Discovered client: %s at %s:%d%s",
info.Name, info.Host, info.Port, info.Path)
select {
case m.clients <- info:
case <-m.ctx.Done():
return
}
}
}()
params := &mdns.QueryParam{
Service: "_sendspin._tcp",
Domain: "local",
Timeout: 3 * time.Second,
Entries: entries,
Logger: silentLogger,
}
if err := mdns.Query(params); err != nil {
log.Printf("mdns query error: %v", err)
}
close(entries)
}
}
func getLocalIPs() ([]net.IP, error) {
var ips []net.IP
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
}
for _, iface := range ifaces {
if iface.Flags&net.FlagUp == 0 || iface.Flags&net.FlagLoopback != 0 {
continue
}
addrs, err := iface.Addrs()
if err != nil {
continue
}
for _, addr := range addrs {
if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
if ipnet.IP.To4() != nil {
ips = append(ips, ipnet.IP)
}
}
}
}
return ips, nil
}

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// ABOUTME: Tests for mDNS discovery
// ABOUTME: Tests service advertisement and discovery
package discovery
import (
"net"
"testing"
"github.com/hashicorp/mdns"
)
func TestNewManager(t *testing.T) {
config := Config{
ServiceName: "Test Player",
Port: 8927,
}
mgr := NewManager(config)
if mgr == nil {
t.Fatal("expected manager to be created")
}
}
func TestClientInfoFromEntry(t *testing.T) {
tests := []struct {
name string
entry *mdns.ServiceEntry
want *ClientInfo
}{
{
name: "full entry with path and name",
entry: &mdns.ServiceEntry{
Name: "living-room._sendspin._tcp.local.",
Host: "living-room.local.",
AddrV4: net.ParseIP("192.168.1.42"),
Port: 8928,
InfoFields: []string{"path=/sendspin", "name=Living Room"},
},
want: &ClientInfo{
Instance: "living-room._sendspin._tcp.local.",
Name: "Living Room",
Host: "192.168.1.42",
Port: 8928,
Path: "/sendspin",
},
},
{
name: "missing path defaults to /sendspin",
entry: &mdns.ServiceEntry{
Name: "kitchen._sendspin._tcp.local.",
AddrV4: net.ParseIP("192.168.1.43"),
Port: 8928,
InfoFields: []string{"name=Kitchen"},
},
want: &ClientInfo{
Instance: "kitchen._sendspin._tcp.local.",
Name: "Kitchen",
Host: "192.168.1.43",
Port: 8928,
Path: "/sendspin",
},
},
{
name: "missing name falls back to entry.Name",
entry: &mdns.ServiceEntry{
Name: "bedroom._sendspin._tcp.local.",
AddrV4: net.ParseIP("192.168.1.44"),
Port: 8928,
InfoFields: []string{"path=/sendspin"},
},
want: &ClientInfo{
Instance: "bedroom._sendspin._tcp.local.",
Name: "bedroom._sendspin._tcp.local.",
Host: "192.168.1.44",
Port: 8928,
Path: "/sendspin",
},
},
{
name: "no IPv4 address returns nil",
entry: &mdns.ServiceEntry{
Name: "ipv6-only._sendspin._tcp.local.",
Port: 8928,
InfoFields: []string{"path=/sendspin"},
},
want: nil,
},
{
name: "zero port returns nil",
entry: &mdns.ServiceEntry{
Name: "bad._sendspin._tcp.local.",
AddrV4: net.ParseIP("192.168.1.45"),
Port: 0,
InfoFields: []string{"path=/sendspin"},
},
want: nil,
},
{
// hashicorp/mdns is promiscuous and forwards any multicast
// response, not just matches to the queried service. Entries
// for other services must be filtered out or the server would
// dial Google Cast, ADB, etc. as if they were sendspin clients.
name: "non-sendspin service is filtered out",
entry: &mdns.ServiceEntry{
Name: "SHIELD._googlecast._tcp.local.",
AddrV4: net.ParseIP("192.168.1.50"),
Port: 8009,
InfoFields: []string{},
},
want: nil,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got := clientInfoFromEntry(tt.entry)
if (got == nil) != (tt.want == nil) {
t.Fatalf("clientInfoFromEntry nil-ness mismatch: got %+v, want %+v", got, tt.want)
}
if got == nil {
return
}
if *got != *tt.want {
t.Errorf("clientInfoFromEntry = %+v, want %+v", got, tt.want)
}
})
}
}
func TestManagerExposesClientsChannel(t *testing.T) {
mgr := NewManager(Config{ServiceName: "Test", Port: 8928})
ch := mgr.Clients()
if ch == nil {
t.Fatal("Clients() returned nil channel")
}
// channel must be receive-only or bidirectional — just confirm we can select on it
select {
case <-ch:
t.Fatal("unexpected value on empty clients channel")
default:
}
}

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// ABOUTME: Pure TXT record parsing for mDNS service entries
// ABOUTME: Converts []string of "key=value" entries to map[string]string
package discovery
import "strings"
// parseTXT converts an mDNS TXT record slice (each element "key=value")
// into a map. Empty strings are ignored. Keys without '=' are stored
// with an empty value. When a key appears multiple times, the last
// occurrence wins.
func parseTXT(fields []string) map[string]string {
out := make(map[string]string, len(fields))
for _, f := range fields {
if f == "" {
continue
}
if idx := strings.Index(f, "="); idx >= 0 {
out[f[:idx]] = f[idx+1:]
} else {
out[f] = ""
}
}
return out
}

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// ABOUTME: Tests for TXT record parsing
// ABOUTME: Pure parser, no mDNS dependency
package discovery
import (
"reflect"
"testing"
)
func TestParseTXT(t *testing.T) {
tests := []struct {
name string
fields []string
want map[string]string
}{
{
name: "empty",
fields: nil,
want: map[string]string{},
},
{
name: "single key",
fields: []string{"path=/sendspin"},
want: map[string]string{"path": "/sendspin"},
},
{
name: "multiple keys",
fields: []string{"path=/sendspin", "name=Living Room"},
want: map[string]string{"path": "/sendspin", "name": "Living Room"},
},
{
name: "key without value",
fields: []string{"flag"},
want: map[string]string{"flag": ""},
},
{
name: "value contains equals",
fields: []string{"token=abc=def=ghi"},
want: map[string]string{"token": "abc=def=ghi"},
},
{
name: "empty string ignored",
fields: []string{"", "path=/sendspin"},
want: map[string]string{"path": "/sendspin"},
},
{
name: "duplicate key: last wins",
fields: []string{"path=/old", "path=/new"},
want: map[string]string{"path": "/new"},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got := parseTXT(tt.fields)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("parseTXT(%v) = %v, want %v", tt.fields, got, tt.want)
}
})
}
}