txmlconnector

Go adapter around the proprietary Win32 TXmlConnector.dll. The adapter exposes the connector over gRPC so native Linux and macOS applications do not depend on Win32 calls or Wine themselves.

Architecture

Linux/macOS/Windows application
        |
        | gRPC (XML command + broadcast XML stream)
        v
server package (platform-neutral lifecycle and transport)
        |
        | connector.Connector
        v
Win32 adapter (windows/amd64 only, pure Go syscall/stdcall)
        |
        v
TXmlConnector.dll

The important boundary is the small connector.Connector interface:

type Connector interface {
    Start(MessageHandler) error
    SendCommand(context.Context, string) (string, error)
    Close() error
}

This keeps the vendor DLL, its memory ownership and Win32 ABI out of gRPC and business code. It also makes the server testable on Linux/macOS with a fake adapter. Calls into the DLL are serialized because the vendor documents the library as not thread-safe. The callback copies the XML and frees DLL-owned memory before publishing it to buffered subscribers.

The Win32 executable no longer needs CGO or MinGW. On Linux, run that executable under Wine and keep Linux clients native. A direct Linux wrapper around the DLL is not possible because the vendor distributes a Win32 binary, not an ELF shared library.

Build and test

go test ./...
go vet ./...
make server_build     # produces bin/server.exe, CGO_ENABLED=0

Run the server on Windows:

$env:TC_DLL_PATH = "C:\path\to\txmlconnector64-6.47.2.26.4.dll"
$env:TC_LISTEN_ADDR = ":50051"
.\bin\server.exe

Run the same adapter on Linux/macOS using Wine:

export TC_DLL_PATH=/absolute/path/to/txmlconnector64-6.47.2.26.4.dll
make server

Or build and run the container:

make build
docker run --rm -p 50051:50051 kmlebedev/txmlconnector:local server

Native Go client

The client connects over gRPC and is platform-independent:

export TC_TARGET=localhost:50051
export TC_LOGIN=...
export TC_PASSWORD=...
export TC_HOST=...
export TC_PORT=...
make client

Configuration:

Variable	Purpose	Default
TC_DLL_PATH	Explicit DLL path	version-derived file name
TC_DLL_VER	DLL version used in the derived name	6.43.2.24.0
TC_DLL_LOG_DIR	Directory for DLL logs	logs
TC_DLL_LOG_LEVEL	Native DLL log level (1-3)	2
TC_LISTEN_ADDR	gRPC listen address	:50051
TC_SUBSCRIBER_BUFFER	Per-client XML burst buffer on the server	8192
TC_TARGET	Client gRPC target	localhost:50051
TC_LOG_LEVEL	Go application log level	info

Compatibility notes

• The protobuf service and existing Go client fields remain compatible.
• server.TxmlSendCommand, server.Messages and server.Done remain available on windows/amd64 as deprecated migration shims. New code should depend on connector.Connector explicitly.
• Every gRPC stream receives its own copy of each XML message. Slow subscribers are disconnected with ResourceExhausted rather than blocking the vendor callback and all other clients.
• The Go client reads the gRPC stream into an internal FIFO before decoding XML. This keeps application handlers and temporary database stalls from blocking transport reads while preserving message order.

References

• TRANSAQ XML Connector documentation
• gRPC