Files
Joseph Doherty
238748bc98
Phase 3 PR 67 -- OPC UA Client IReadable + IWritable via Session.ReadAsync/WriteAsync. Adds IReadable + IWritable capabilities to OpcUaClientDriver, routing reads/writes through the session's non-obsolete ReadAsync(RequestHeader, maxAge, TimestampsToReturn, ReadValueIdCollection, ct) and WriteAsync(RequestHeader, WriteValueCollection, ct) overloads (the sync and BeginXxx/EndXxx patterns are all [Obsolete] in SDK 1.5.378). Serializes on the shared Gate from PR 66 so reads + writes + future subscribe + probe don't race on the single session. NodeId parsing: fullReferences use OPC UA's standard serialized NodeId form -- ns=2;s=Demo.Counter, i=2253, ns=4;g=... for GUID, ns=3;b=... for opaque. TryParseNodeId calls NodeId.Parse with the session's MessageContext which honours the server-negotiated namespace URI table. Malformed input surfaces as BadNodeIdInvalid (0x80330000) WITHOUT a wire round-trip -- saves a request for a fault the driver can detect locally. Cascading-quality implementation per driver-specs.md \u00A78: upstream StatusCode, SourceTimestamp, and ServerTimestamp pass through VERBATIM. Bad codes from the remote server stay as the same Bad code (not translated to generic BadInternalError) so downstream clients can distinguish 'upstream value unavailable' from 'local driver bug'. SourceTimestamp is preserved verbatim (null on MinValue guard) so staleness is visible; ServerTimestamp falls back to DateTime.UtcNow if the upstream omitted it, never overwriting a non-zero value. Wire-level exceptions in the Read batch -- transport / timeout / session-dropped -- fan out BadCommunicationError (0x80050000) across every tag in the batch, not BadInternalError, so operators distinguish network reachability from driver faults. Write-side same pattern: successful WriteAsync maps each upstream StatusCode.Code verbatim into the local WriteResult.StatusCode; transport-layer failure fans out BadCommunicationError across the whole batch. WriteValue carries AttributeId=Value + DataValue wrapping Variant(writeValue) -- the SDK handles the type-to-Variant mapping for common CLR types (bool, int, float, string, etc.) so the driver doesn't need a per-type switch. Name disambiguation: the SDK has its own Opc.Ua.WriteRequest type which collides with ZB.MOM.WW.OtOpcUa.Core.Abstractions.WriteRequest; method signature uses the fully-qualified Core.Abstractions.WriteRequest. Unit tests (OpcUaClientReadWriteTests, 2 facts): ReadAsync_without_initialize_throws_InvalidOperationException + WriteAsync_without_initialize_throws_InvalidOperationException -- pre-init calls hit RequireSession and fail uniformly. Wire-level round-trip coverage against a live remote server lands in a follow-up PR once we scaffold an in-process OPC UA server fixture (the existing Server project in the solution is a candidate host). 7/7 OpcUaClient.Tests pass (5 scaffold + 2 read/write). dotnet build clean. Scope: ITagDiscovery (browse) + ISubscribable + IHostConnectivityProbe remain deferred to PRs 68-69 which also need namespace-index remapping and reference-counted MonitoredItem forwarding per driver-specs.md \u00A78.