fix: better cors solution

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/google/uuid v1.2.0 // indirect
 	github.com/gorilla/websocket v1.4.2 // indirect
 	github.com/rjeczalik/notify v0.9.1 // indirect
+	github.com/rs/cors v1.8.3 // indirect
 	github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible // indirect
 	github.com/tklauser/go-sysconf v0.3.5 // indirect
 	github.com/tklauser/numcpus v0.2.2 // indirect

go.sum

@@ -23,6 +23,8 @@ github.com/julienschmidt/httprouter v1.2.0 h1:TDTW5Yz1mjftljbcKqRcrYhd4XeOoI98t+
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/rjeczalik/notify v0.9.1 h1:CLCKso/QK1snAlnhNR/CNvNiFU2saUtjV0bx3EwNeCE=
 github.com/rjeczalik/notify v0.9.1/go.mod h1:rKwnCoCGeuQnwBtTSPL9Dad03Vh2n40ePRrjvIXnJho=
+github.com/rs/cors v1.8.3 h1:O+qNyWn7Z+F9M0ILBHgMVPuB1xTOucVd5gtaYyXBpRo=
+github.com/rs/cors v1.8.3/go.mod h1:XyqrcTp5zjWr1wsJ8PIRZssZ8b/WMcMf71DJnit4EMU=
 github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible h1:Bn1aCHHRnjv4Bl16T8rcaFjYSrGrIZvpiGO6P3Q4GpU=
 github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
 github.com/tklauser/go-sysconf v0.3.5 h1:uu3Xl4nkLzQfXNsWn15rPc/HQCJKObbt1dKJeWp3vU4=

main.go

@@ -22,6 +22,7 @@ import (
 	ethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/julienschmidt/httprouter"
+	"github.com/rs/cors"
 	"golang.org/x/exp/maps"
 )
 
@@ -471,14 +472,13 @@ func main() {
 	router.GET("/tranches/stats", state.GetTranchesStats)
 
 	go state.PullForever()
+	handler := cors.Default().Handler(router)
 
-	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), router))
-
+	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), handler))
 }
 
 func writeOK(w http.ResponseWriter, payload interface{}) {
-	w.Header().Set("Access-Control-Allow-Methods", w.Header().Get("Allow"))
-	w.Header().Set("Access-Control-Allow-Origin", "*")
+
 	w.Header().Set("Content-Type", "application/json")
 	buf, err := json.Marshal(payload)
 	if err != nil {