Crate opc_da_client 

opc-da-client

Backend-agnostic OPC DA client library for Rust — async, trait-based, with RAII COM guard.

Quick Start

use opc_da_client::{ComGuard, OpcDaWrapper, OpcProvider};

let _guard = ComGuard::new()?;
let client = OpcDaWrapper::default();
let servers = client.list_servers("localhost").await?;

Feature Flags

Flag	Default	Effect
opc-da-backend	✅	Native OPC DA backend via windows-rs
test-support	❌	Enables MockOpcProvider via mockall

Platform

Windows only — OPC DA is built on COM/DCOM.

Macros

try_from_native

Helper macro for instantiating native COM structs from safe types.

Structs

ComConnector

Real COM-backed server connector implementation.

ComGuard

Drop guard for COM thread initialization.

MockOpcProvider

Async trait for OPC DA operations.

OpcDaWrapper

Concrete OpcProvider implementation for Windows OPC DA.

TagValue

A single tag’s read result.

WriteResult

Result of a single write operation.

Enums

OpcValue

Typed value to write to an OPC DA tag.

Traits

OpcProvider

Async trait for OPC DA operations.

Functions

format_hresult

Format a COM HRESULT for user-facing error messages.

friendly_com_hint

Maps known COM/DCOM error codes to actionable user hints.