node, cmd: remove dead geth-forked httpServer (erigontech#21724)

`node/rpcstack.go` carried a geth-forked `httpServer` (plus
`httpConfig`/`wsConfig`/`rpcHandler`, `checkPath`, and a package-local
`isWebsocket`) that is never constructed outside tests — `newHTTPServer`
has no non-test callers. Erigon's actual HTTP/WS serving lives in
`cmd/rpcdaemon/cli` (`createHandler` + `node.StartHTTPEndpoint`). This
removes the dead closure and its never-wired configuration:

- `node/rpcstack.go`: drop `httpServer` and friends (−331 lines). The
live exports (`NewHTTPHandlerStack`, `NewWSConnectionLimiter`,
`RegisterApisFromWhitelist`, and the CORS/vhost/gzip/admission
middleware) are untouched.
- `cmd/utils/flags.go`: drop `--http.rpcprefix` / `--ws.rpcprefix` flag
definitions — never registered with any command.
- `node/nodecfg/config.go`: drop the corresponding `HTTPPathPrefix` /
`WSPathPrefix` fields — never read.

Tests previously used the dead `httpServer` as a harness around live
middleware; they are rewritten to target the live constructors directly:

- CORS/vhosts/allowlist tests now run `httptest.Server` around
`NewHTTPHandlerStack`.
- WebSocket origin and connection-limit tests use
`rpc.Server.WebsocketHandler` + `NewWSConnectionLimiter`.
- `TestHTTP2H2C` now exercises the production `StartHTTPEndpoint` h2c
path (x/net h2c) instead of the dead server's `http.Protocols` wiring,
so h2c support is finally asserted on a server erigon actually runs.
- `TestIsWebsocket` moves to `cmd/rpcdaemon/cli`, which has the live
(previously untested) `isWebsocket` copy.
- `Test_checkPath` is deleted along with `checkPath`.

Supersedes erigontech#21714: the WS status-code bug fixed there lives in the
removed, unreachable `httpServer.ServeHTTP`. The corresponding upstream
fix is ethereum/go-ethereum#35111, which remains correct in geth where
this code is live.

Pure dead-code removal, no behavior change — per the repo TDD guidance
the rewritten existing tests are the safety net. Verified locally: `make
lint` (twice) clean, `go test ./node/ ./cmd/rpcdaemon/cli/` green, `make
erigon integration` builds.

Possible follow-up (out of scope here): most of the geth-inherited
HTTP/WS block in `nodecfg.Config` (`HTTPHost`, `HTTPPort`, `HTTPCors`,
`HTTPModules`, `WSHost`, `WSPort`, `WSOrigins`, `WSModules`,
`WSExposeAll`) also has no non-test readers.

Author: yperbasis

cmd/rpcdaemon/cli/config_test.go

@@ -17,12 +17,28 @@
 package cli
 
 import (
+	"net/http"
 	"net/url"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
+// TestIsWebsocket tests if an incoming websocket upgrade request is detected properly.
+func TestIsWebsocket(t *testing.T) {
+	r, _ := http.NewRequest("GET", "/", nil)
+
+	require.False(t, isWebsocket(r))
+	r.Header.Set("upgrade", "websocket")
+	require.False(t, isWebsocket(r))
+	r.Header.Set("connection", "upgrade")
+	require.True(t, isWebsocket(r))
+	r.Header.Set("connection", "upgrade,keep-alive")
+	require.True(t, isWebsocket(r))
+	r.Header.Set("connection", " UPGRADE,keep-alive")
+	require.True(t, isWebsocket(r))
+}
+
 func TestParseSocketUrl(t *testing.T) {
 	t.Run("sock", func(t *testing.T) {
 		socketUrl, err := url.Parse("unix:///some/file/path.sock")

cmd/utils/flags.go

@@ -470,11 +470,6 @@ var (
 		Value: 200,
 	}
 
-	HTTPPathPrefixFlag = cli.StringFlag{
-		Name:  "http.rpcprefix",
-		Usage: "HTTP path prefix on which JSON-RPC is served. Use '/' to serve on all paths.",
-		Value: "",
-	}
 	TLSFlag = cli.BoolFlag{
 		Name:  "tls",
 		Usage: "Enable TLS handshake",
@@ -518,11 +513,6 @@ var (
 		Usage: "Origins from which to accept websockets requests",
 		Value: "",
 	}
-	WSPathPrefixFlag = cli.StringFlag{
-		Name:  "ws.rpcprefix",
-		Usage: "HTTP path prefix on which JSON-RPC is served. Use '/' to serve on all paths.",
-		Value: "",
-	}
 	WSSubscribeLogsChannelSize = cli.IntFlag{
 		Name:  "ws.api.subscribelogs.channelsize",
 		Usage: "Size of the channel used for websocket logs subscriptions",

node/nodecfg/config.go

@@ -113,9 +113,6 @@ type Config struct {
 	// interface.
 	HTTPTimeouts rpccfg.HTTPTimeouts
 
-	// HTTPPathPrefix specifies a path prefix on which http-rpc is to be served.
-	HTTPPathPrefix string `toml:",omitempty"`
-
 	// WSHost is the host interface on which to start the websocket RPC server. If
 	// this field is empty, no websocket API endpoint will be started.
 	WSHost string
@@ -125,9 +122,6 @@ type Config struct {
 	// ephemeral nodes).
 	WSPort int `toml:",omitempty"`
 
-	// WSPathPrefix specifies a path prefix on which ws-rpc is to be served.
-	WSPathPrefix string `toml:",omitempty"`
-
 	// WSOrigins is the list of domain to accept websocket requests from. Please be
 	// aware that the server can only act upon the HTTP request the client sends and
 	// cannot verify the validity of the request header.