feat: add cors support

optionally control cross origin requests by origin and
method

cmd/beacon/main.go

@@ -267,7 +267,7 @@ func main() {
 	}()
 
 	// ── HTTP server ──────────────────────────────────────────────────────────
-	r := router.New(h, reader, []*ingest.Worker{broker1, broker2}, maxConnsPerIP)
+	r := router.New(h, reader, []*ingest.Worker{broker1, broker2}, maxConnsPerIP, cfg.CORS)
 
 	srv := &http.Server{
 		Addr:    addr,

config.yaml.example

@@ -75,6 +75,18 @@ packets:
 websocket:
   max_connections_per_ip: 5 # default: 5
 
+# CORS configuration.
+# Controls which origins, methods and headers are allowed for cross-origin requests.
+# Defaults to allowing all origins with GET/HEAD/OPTIONS if omitted — appropriate
+# for a public read-only API. Restrict allowed_origins if you expose write endpoints.
+#cors:
+#  allowed_origins:
+#    - "https://app.example.com"
+#  allowed_methods: [GET, HEAD, OPTIONS, POST]
+#  allowed_headers: [Accept, Authorization, Content-Type]
+#  allow_credentials: false
+#  max_age: 300
+
 # Redis caching layer.
 # If REDIS_ADDR is not set, caching is disabled and all reads go directly to PostgreSQL.
 # TTLs are specified as duration strings e.g. "30m", "1h", "2h".

go.mod

@@ -19,6 +19,7 @@ require (
 	filippo.io/edwards25519 v1.2.0 // indirect
 	github.com/KyleBanks/depth v1.2.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/go-chi/cors v1.2.2 // indirect
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
 	github.com/go-openapi/jsonreference v0.20.0 // indirect
 	github.com/go-openapi/spec v0.20.6 // indirect

go.sum

@@ -14,6 +14,8 @@ github.com/eclipse/paho.mqtt.golang v1.5.1 h1:/VSOv3oDLlpqR2Epjn1Q7b2bSTplJIeV2I
 github.com/eclipse/paho.mqtt.golang v1.5.1/go.mod h1:1/yJCneuyOoCOzKSsOTUc0AJfpsItBGWvYpBLimhArU=
 github.com/go-chi/chi/v5 v5.2.2 h1:CMwsvRVTbXVytCk1Wd72Zy1LAsAh9GxMmSNWLHCG618=
 github.com/go-chi/chi/v5 v5.2.2/go.mod h1:L2yAIGWB3H+phAw1NxKwWM+7eUH/lU8pOMm5hHcoops=
+github.com/go-chi/cors v1.2.2 h1:Jmey33TE+b+rB7fT8MUy1u0I4L+NARQlK6LhzKPSyQE=
+github.com/go-chi/cors v1.2.2/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
 github.com/go-openapi/jsonpointer v0.19.3/go.mod h1:Pl9vOtqEWErmShwVjC8pYs9cog34VGT37dQOVbmoatg=
 github.com/go-openapi/jsonpointer v0.19.5 h1:gZr+CIYByUqjcgeLXnQu2gHYQC9o73G2XUeOFYEICuY=
 github.com/go-openapi/jsonpointer v0.19.5/go.mod h1:Pl9vOtqEWErmShwVjC8pYs9cog34VGT37dQOVbmoatg=

internal/api/router/router.go

@@ -12,10 +12,12 @@ import (
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
+	"github.com/go-chi/cors"
 
 	"github.com/MeshCore-Beacon/beacon-server/internal/api"
 	"github.com/MeshCore-Beacon/beacon-server/internal/api/handlers"
 	mw "github.com/MeshCore-Beacon/beacon-server/internal/api/middleware"
+	"github.com/MeshCore-Beacon/beacon-server/internal/config"
 	"github.com/MeshCore-Beacon/beacon-server/internal/hub"
 	"github.com/MeshCore-Beacon/beacon-server/internal/ingest"
 	"github.com/MeshCore-Beacon/beacon-server/internal/ws"
@@ -39,9 +41,34 @@ import (
 //
 // The private group is stubbed and ready for the auth middleware drop-in
 // described in Future Features → Admin authentication.
-func New(h *hub.Hub, reader api.Reader, workers []*ingest.Worker, maxConnsPerIP int) http.Handler {
+func New(h *hub.Hub, reader api.Reader, workers []*ingest.Worker, maxConnsPerIP int, corsCfg config.CORSConfig) http.Handler {
 	r := chi.NewRouter()
 
+	// ── CORS ─────────────────────────────────────────────────────────────────
+	allowedOrigins := corsCfg.AllowedOrigins
+	if len(allowedOrigins) == 0 {
+		allowedOrigins = []string{"*"}
+	}
+	allowedMethods := corsCfg.AllowedMethods
+	if len(allowedMethods) == 0 {
+		allowedMethods = []string{"GET", "HEAD", "OPTIONS"}
+	}
+	allowedHeaders := corsCfg.AllowedHeaders
+	if len(allowedHeaders) == 0 {
+		allowedHeaders = []string{"Accept", "Authorization", "Content-Type"}
+	}
+	maxAge := corsCfg.MaxAge
+	if maxAge == 0 {
+		maxAge = 300
+	}
+	r.Use(cors.Handler(cors.Options{
+		AllowedOrigins:   allowedOrigins,
+		AllowedMethods:   allowedMethods,
+		AllowedHeaders:   allowedHeaders,
+		AllowCredentials: corsCfg.AllowCredentials,
+		MaxAge:           maxAge,
+	}))
+
 	// ── Global middleware ────────────────────────────────────────────────────
 	r.Use(middleware.RequestID)
 	r.Use(middleware.RealIP)

internal/config/config.go

@@ -23,6 +23,33 @@ type Config struct {
 	Ingest      IngestFilterConfig    `yaml:"ingest"`
 	Scopes      []ScopeConfig         `yaml:"scopes"`
 	Cache       CacheConfig           `yaml:"cache"`
+	CORS        CORSConfig            `yaml:"cors"`
+}
+
+// CORSConfig controls Cross-Origin Resource Sharing behaviour.
+// If omitted, Beacon defaults to allowing all origins, which is appropriate
+// for a public read-only API. Operators exposing write endpoints should
+// restrict AllowedOrigins to known frontends.
+type CORSConfig struct {
+	// AllowedOrigins is the list of origins permitted to make cross-origin
+	// requests. Use ["*"] to allow all origins (default if omitted).
+	AllowedOrigins []string `yaml:"allowed_origins"`
+
+	// AllowedMethods is the list of HTTP methods allowed in CORS requests.
+	// Defaults to [GET, HEAD, OPTIONS] if omitted.
+	AllowedMethods []string `yaml:"allowed_methods"`
+
+	// AllowedHeaders is the list of request headers allowed in CORS requests.
+	// Defaults to [Accept, Authorization, Content-Type] if omitted.
+	AllowedHeaders []string `yaml:"allowed_headers"`
+
+	// AllowCredentials indicates whether the request can include user
+	// credentials (cookies, HTTP authentication). Defaults to false.
+	AllowCredentials bool `yaml:"allow_credentials"`
+
+	// MaxAge is the number of seconds the browser may cache a preflight
+	// response. Defaults to 300 if omitted.
+	MaxAge int `yaml:"max_age"`
 }
 
 // CacheConfig controls Redis caching behaviour.