adding preflight caching and options response. (lavanet#1094)

protocol/chainlib/common.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/middleware/favicon"
 	common "github.com/lavanet/lava/protocol/common"
 	"github.com/lavanet/lava/protocol/metrics"
 	"github.com/lavanet/lava/utils"
@@ -280,3 +281,27 @@ func GetRelayTimeout(chainMessage ChainMessage, chainParser ChainParser, timeout
 	// Set relay timout, increase it every time we fail a relay on timeout
 	return extraRelayTimeout + time.Duration(timeouts+1)*relayTimeAddition + common.AverageWorldLatency
 }
+
+// setup a common preflight and cors configuration allowing wild cards and preflight caching.
+func createAndSetupBaseAppListener() *fiber.App {
+	app := fiber.New(fiber.Config{})
+	app.Use(favicon.New())
+	app.Use(func(c *fiber.Ctx) error {
+		// we set up wild card by default.
+		c.Set("Access-Control-Allow-Origin", "*")
+		// set up all allowed methods.
+		c.Set("Access-Control-Allow-Methods", "GET,POST,PUT,DELETE,OPTIONS")
+
+		// Handle preflight requests directly
+		if c.Method() == "OPTIONS" {
+			// Cache preflight request for 24 hours (in seconds)
+			c.Set("Access-Control-Max-Age", "86400")
+			return c.SendStatus(fiber.StatusNoContent)
+		}
+		if c.Method() == "DELETE" {
+			return c.SendStatus(fiber.StatusNoContent)
+		}
+		return c.Next()
+	})
+	return app
+}

protocol/chainlib/grpcproxy/grpcproxy.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net/http"
 
+	"github.com/gofiber/fiber/v2"
 	"github.com/improbable-eng/grpc-web/go/grpcweb"
 	"github.com/lavanet/lava/utils"
 	"golang.org/x/net/http2"
@@ -23,8 +24,18 @@ func NewGRPCProxy(cb ProxyCallBack, healthCheckPath string) (*grpc.Server, *http
 		// Set CORS headers
 		resp.Header().Set("Access-Control-Allow-Origin", "*")
 		resp.Header().Set("Access-Control-Allow-Headers", "Content-Type,x-grpc-web")
+		resp.Header().Set("Access-Control-Allow-Methods", "GET,POST,PUT,DELETE,OPTIONS")
+
+		if req.Method == http.MethodOptions {
+			// Cache preflight request for 24 hours (in seconds)
+			resp.Header().Set("Access-Control-Max-Age", "86400")
+			resp.WriteHeader(fiber.StatusNoContent)
+			_, _ = resp.Write(make([]byte, 0))
+			return
+		}
+
 		if req.URL.Path == healthCheckPath && req.Method == http.MethodGet {
-			resp.WriteHeader(200)
+			resp.WriteHeader(fiber.StatusOK)
 			_, _ = resp.Write(make([]byte, 0))
 			return
 		}

protocol/chainlib/jsonRPC.go

@@ -10,7 +10,6 @@ import (
 	"time"
 
 	"github.com/gofiber/fiber/v2"
-	"github.com/gofiber/fiber/v2/middleware/favicon"
 	"github.com/gofiber/websocket/v2"
 	"github.com/lavanet/lava/protocol/chainlib/chainproxy/rpcInterfaceMessages"
 	"github.com/lavanet/lava/protocol/common"
@@ -296,9 +295,7 @@ func (apil *JsonRPCChainListener) Serve(ctx context.Context) {
 	}
 	test_mode := common.IsTestMode(ctx)
 	// Setup HTTP Server
-	app := fiber.New(fiber.Config{})
-
-	app.Use(favicon.New())
+	app := createAndSetupBaseAppListener()
 
 	app.Use("/ws", func(c *fiber.Ctx) error {
 		// IsWebSocketUpgrade returns true if the client

protocol/chainlib/rest.go

@@ -23,7 +23,6 @@ import (
 	pairingtypes "github.com/lavanet/lava/x/pairing/types"
 
 	"github.com/gofiber/fiber/v2"
-	"github.com/gofiber/fiber/v2/middleware/favicon"
 	"github.com/lavanet/lava/protocol/common"
 	"github.com/lavanet/lava/protocol/metrics"
 	spectypes "github.com/lavanet/lava/x/spec/types"
@@ -255,9 +254,7 @@ func (apil *RestChainListener) Serve(ctx context.Context) {
 	}
 
 	// Setup HTTP Server
-	app := fiber.New(fiber.Config{})
-
-	app.Use(favicon.New())
+	app := createAndSetupBaseAppListener()
 
 	chainID := apil.endpoint.ChainID
 	apiInterface := apil.endpoint.ApiInterface

protocol/chainlib/tendermintRPC.go

@@ -13,7 +13,6 @@ import (
 	"time"
 
 	"github.com/gofiber/fiber/v2"
-	"github.com/gofiber/fiber/v2/middleware/favicon"
 	"github.com/gofiber/websocket/v2"
 	"github.com/lavanet/lava/protocol/chainlib/chainproxy"
 	"github.com/lavanet/lava/protocol/chainlib/chainproxy/rpcInterfaceMessages"
@@ -326,12 +325,10 @@ func (apil *TendermintRpcChainListener) Serve(ctx context.Context) {
 	}
 
 	// Setup HTTP Server
-	app := fiber.New(fiber.Config{})
+	app := createAndSetupBaseAppListener()
 	chainID := apil.endpoint.ChainID
 	apiInterface := apil.endpoint.ApiInterface
 
-	app.Use(favicon.New())
-
 	app.Use("/ws", func(c *fiber.Ctx) error {
 		// IsWebSocketUpgrade returns true if the client
 		// requested upgrade to the WebSocket protocol.