fix: try to get clsid from server list and reg

opcserver.go

@@ -6,6 +6,7 @@ import (
 	"unsafe"
 
 	"github.com/huskar-t/opcda/com"
+	"golang.org/x/sys/windows/registry"
 
 	"golang.org/x/sys/windows"
 )
@@ -32,15 +33,23 @@ func Connect(progID, node string) (opcServer *OPCServer, err error) {
 	if !com.IsLocal(node) {
 		location = com.CLSCTX_REMOTE_SERVER
 	}
-	iCatInfo, err := com.MakeCOMObjectEx(node, location, &com.CLSID_OpcServerList, &com.IID_IOPCServerList2)
-	if err != nil {
-		return nil, err
-	}
-	defer iCatInfo.Release()
-	sl := &com.IOPCServerList2{IUnknown: iCatInfo}
-	clsid, err := sl.CLSIDFromProgID(progID)
-	if err != nil {
-		return nil, err
+	var clsid *windows.GUID
+	if location == com.CLSCTX_LOCAL_SERVER {
+		id, err := windows.GUIDFromString(progID)
+		if err != nil {
+			return nil, err
+		}
+		clsid = &id
+	} else {
+		// try get clsid from server list
+		clsid, err = getClsIDFromServerList(progID, node, location)
+		if err != nil {
+			// try get clsid from windows reg
+			clsid, err = getClsIDFromReg(progID, node)
+			if err != nil {
+				return nil, err
+			}
+		}
 	}
 	iUnknownServer, err := com.MakeCOMObjectEx(node, location, clsid, &com.IID_IOPCServer)
 	if err != nil {
@@ -115,6 +124,46 @@ func Connect(progID, node string) (opcServer *OPCServer, err error) {
 	return opcServer, nil
 }
 
+func getClsIDFromServerList(progID, node string, location com.CLSCTX) (*windows.GUID, error) {
+	iCatInfo, err := com.MakeCOMObjectEx(node, location, &com.CLSID_OpcServerList, &com.IID_IOPCServerList2)
+	if err != nil {
+		return nil, err
+	}
+	defer iCatInfo.Release()
+	sl := &com.IOPCServerList2{IUnknown: iCatInfo}
+	clsid, err := sl.CLSIDFromProgID(progID)
+	if err != nil {
+		return nil, err
+	}
+	return clsid, nil
+}
+
+func getClsIDFromReg(progID, node string) (*windows.GUID, error) {
+	var clsid windows.GUID
+	var err error
+	hKey, err := registry.OpenRemoteKey(node, registry.CLASSES_ROOT)
+	if err != nil {
+		return nil, err
+	}
+	defer hKey.Close()
+	hProgIDKey, err := registry.OpenKey(hKey, progID, registry.READ)
+	if err != nil {
+		return nil, err
+	}
+	defer hProgIDKey.Close()
+	hClsidKey, err := registry.OpenKey(hProgIDKey, "CLSID", registry.READ)
+	if err != nil {
+		return nil, err
+	}
+	defer hClsidKey.Close()
+	clsidStr, _, err := hClsidKey.GetStringValue("")
+	if err != nil {
+		return nil, err
+	}
+	clsid, err = windows.GUIDFromString(clsidStr)
+	return &clsid, err
+}
+
 type ServerInfo struct {
 	ProgID       string
 	ClsStr       string

opcserver_test.go

@@ -1,11 +1,13 @@
 package opcda
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
 	"github.com/huskar-t/opcda/com"
 	"github.com/stretchr/testify/assert"
+	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc"
 	"golang.org/x/sys/windows/svc/mgr"
 )
@@ -356,3 +358,121 @@ func TestOPCServer_RegisterServerShutDown(t *testing.T) {
 	}
 	<-done
 }
+
+func Test_getClsIDFromReg(t *testing.T) {
+	id, err := windows.GUIDFromString(TestProgID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	localNode, err := windows.ComputerName()
+	if err != nil {
+		t.Fatal(err)
+	}
+	type args struct {
+		progID string
+		node   string
+	}
+
+	tests := []struct {
+		name    string
+		args    args
+		want    *windows.GUID
+		wantErr assert.ErrorAssertionFunc
+	}{
+		{
+			name: "normal",
+			args: args{
+				progID: TestProgID,
+				node:   localNode,
+			},
+			want:    &id,
+			wantErr: assert.NoError,
+		},
+		{
+			name: "wrong node",
+			args: args{
+				progID: TestProgID,
+				node:   "wrong",
+			},
+			want:    nil,
+			wantErr: assert.Error,
+		},
+		{
+			name: "wrong progID",
+			args: args{
+				progID: "wrong",
+				node:   localNode,
+			},
+			want:    nil,
+			wantErr: assert.Error,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := getClsIDFromReg(tt.args.progID, tt.args.node)
+			if !tt.wantErr(t, err, fmt.Sprintf("getClsIDFromReg(%v, %v)", tt.args.progID, tt.args.node)) {
+				return
+			}
+			assert.Equalf(t, tt.want, got, "getClsIDFromReg(%v, %v)", tt.args.progID, tt.args.node)
+		})
+	}
+}
+
+func Test_getClsIDFromServerList(t *testing.T) {
+	id, err := windows.GUIDFromString(TestProgID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	type args struct {
+		progID   string
+		node     string
+		location com.CLSCTX
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    *windows.GUID
+		wantErr assert.ErrorAssertionFunc
+	}{
+		{
+			name: "Test with valid progID and node",
+			args: args{
+				progID:   TestProgID,
+				node:     TestHost,
+				location: com.CLSCTX_LOCAL_SERVER,
+			},
+			want:    &id,
+			wantErr: assert.NoError,
+		},
+		{
+			name: "Test with invalid progID",
+			args: args{
+				progID:   "InvalidProgID",
+				node:     TestHost,
+				location: com.CLSCTX_LOCAL_SERVER,
+			},
+			want:    nil,
+			wantErr: assert.Error,
+		},
+		{
+			name: "Test with invalid node",
+			args: args{
+				progID:   TestProgID,
+				node:     "InvalidNode",
+				location: com.CLSCTX_LOCAL_SERVER,
+			},
+			want:    nil,
+			wantErr: assert.Error,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := getClsIDFromServerList(tt.args.progID, tt.args.node, tt.args.location)
+			if !tt.wantErr(t, err, fmt.Sprintf("getClsIDFromServerList(%v, %v, %v)", tt.args.progID, tt.args.node, tt.args.location)) {
+				return
+			}
+			assert.Equalf(t, tt.want, got, "getClsIDFromServerList(%v, %v, %v)", tt.args.progID, tt.args.node, tt.args.location)
+		})
+	}
+}