cmd/geth, node: allow configuring JSON-RPC on custom path prefix (#22184)

This change allows users to set a custom path prefix on which to mount the http-rpc
or ws-rpc handlers via the new flags --http.rpcprefix and --ws.rpcprefix.

Fixes #21826

Co-authored-by: Felix Lange <fjl@twurst.com>

node/node_test.go

@@ -390,7 +390,7 @@ func TestLifecycleTerminationGuarantee(t *testing.T) {
 }
 
 // Tests whether a handler can be successfully mounted on the canonical HTTP server
-// on the given path
+// on the given prefix
 func TestRegisterHandler_Successful(t *testing.T) {
 	node := createNode(t, 7878, 7979)
 
@@ -483,7 +483,112 @@ func TestWebsocketHTTPOnSeparatePort_WSRequest(t *testing.T) {
 	if !checkRPC(node.HTTPEndpoint()) {
 		t.Fatalf("http request failed")
 	}
+}
 
+type rpcPrefixTest struct {
+	httpPrefix, wsPrefix string
+	// These lists paths on which JSON-RPC should be served / not served.
+	wantHTTP   []string
+	wantNoHTTP []string
+	wantWS     []string
+	wantNoWS   []string
+}
+
+func TestNodeRPCPrefix(t *testing.T) {
+	t.Parallel()
+
+	tests := []rpcPrefixTest{
+		// both off
+		{
+			httpPrefix: "", wsPrefix: "",
+			wantHTTP:   []string{"/", "/?p=1"},
+			wantNoHTTP: []string{"/test", "/test?p=1"},
+			wantWS:     []string{"/", "/?p=1"},
+			wantNoWS:   []string{"/test", "/test?p=1"},
+		},
+		// only http prefix
+		{
+			httpPrefix: "/testprefix", wsPrefix: "",
+			wantHTTP:   []string{"/testprefix", "/testprefix?p=1", "/testprefix/x", "/testprefix/x?p=1"},
+			wantNoHTTP: []string{"/", "/?p=1", "/test", "/test?p=1"},
+			wantWS:     []string{"/", "/?p=1"},
+			wantNoWS:   []string{"/testprefix", "/testprefix?p=1", "/test", "/test?p=1"},
+		},
+		// only ws prefix
+		{
+			httpPrefix: "", wsPrefix: "/testprefix",
+			wantHTTP:   []string{"/", "/?p=1"},
+			wantNoHTTP: []string{"/testprefix", "/testprefix?p=1", "/test", "/test?p=1"},
+			wantWS:     []string{"/testprefix", "/testprefix?p=1", "/testprefix/x", "/testprefix/x?p=1"},
+			wantNoWS:   []string{"/", "/?p=1", "/test", "/test?p=1"},
+		},
+		// both set
+		{
+			httpPrefix: "/testprefix", wsPrefix: "/testprefix",
+			wantHTTP:   []string{"/testprefix", "/testprefix?p=1", "/testprefix/x", "/testprefix/x?p=1"},
+			wantNoHTTP: []string{"/", "/?p=1", "/test", "/test?p=1"},
+			wantWS:     []string{"/testprefix", "/testprefix?p=1", "/testprefix/x", "/testprefix/x?p=1"},
+			wantNoWS:   []string{"/", "/?p=1", "/test", "/test?p=1"},
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		name := fmt.Sprintf("http=%s ws=%s", test.httpPrefix, test.wsPrefix)
+		t.Run(name, func(t *testing.T) {
+			cfg := &Config{
+				HTTPHost:       "127.0.0.1",
+				HTTPPathPrefix: test.httpPrefix,
+				WSHost:         "127.0.0.1",
+				WSPathPrefix:   test.wsPrefix,
+			}
+			node, err := New(cfg)
+			if err != nil {
+				t.Fatal("can't create node:", err)
+			}
+			defer node.Close()
+			if err := node.Start(); err != nil {
+				t.Fatal("can't start node:", err)
+			}
+			test.check(t, node)
+		})
+	}
+}
+
+func (test rpcPrefixTest) check(t *testing.T, node *Node) {
+	t.Helper()
+	httpBase := "http://" + node.http.listenAddr()
+	wsBase := "ws://" + node.http.listenAddr()
+
+	if node.WSEndpoint() != wsBase+test.wsPrefix {
+		t.Errorf("Error: node has wrong WSEndpoint %q", node.WSEndpoint())
+	}
+
+	for _, path := range test.wantHTTP {
+		resp := rpcRequest(t, httpBase+path)
+		if resp.StatusCode != 200 {
+			t.Errorf("Error: %s: bad status code %d, want 200", path, resp.StatusCode)
+		}
+	}
+	for _, path := range test.wantNoHTTP {
+		resp := rpcRequest(t, httpBase+path)
+		if resp.StatusCode != 404 {
+			t.Errorf("Error: %s: bad status code %d, want 404", path, resp.StatusCode)
+		}
+	}
+	for _, path := range test.wantWS {
+		err := wsRequest(t, wsBase+path, "")
+		if err != nil {
+			t.Errorf("Error: %s: WebSocket connection failed: %v", path, err)
+		}
+	}
+	for _, path := range test.wantNoWS {
+		err := wsRequest(t, wsBase+path, "")
+		if err == nil {
+			t.Errorf("Error: %s: WebSocket connection succeeded for path in wantNoWS", path)
+		}
+
+	}
 }
 
 func createNode(t *testing.T, httpPort, wsPort int) *Node {