Merge pull request 'Phase 3 PR 64 -- S7 IReadable + IWritable via S7.Net' (#63) from phase-3-pr64-s7-read-write into v2

This commit was merged in pull request #63.
This commit is contained in:
2026-04-19 00:12:59 -04:00
2 changed files with 243 additions and 1 deletions

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@@ -26,8 +26,24 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.S7;
/// </para>
/// </remarks>
public sealed class S7Driver(S7DriverOptions options, string driverInstanceId)
: IDriver, IDisposable, IAsyncDisposable
: IDriver, IReadable, IWritable, IDisposable, IAsyncDisposable
{
/// <summary>OPC UA StatusCode used when the tag name isn't in the driver's tag map.</summary>
private const uint StatusBadNodeIdUnknown = 0x80340000u;
/// <summary>OPC UA StatusCode used when the tag's data type isn't implemented yet.</summary>
private const uint StatusBadNotSupported = 0x803D0000u;
/// <summary>OPC UA StatusCode used when the tag is declared read-only.</summary>
private const uint StatusBadNotWritable = 0x803B0000u;
/// <summary>OPC UA StatusCode used when write fails validation (e.g. out-of-range value).</summary>
private const uint StatusBadInternalError = 0x80020000u;
/// <summary>OPC UA StatusCode used for socket / timeout / protocol-layer faults.</summary>
private const uint StatusBadCommunicationError = 0x80050000u;
/// <summary>OPC UA StatusCode used when S7 returns <c>ErrorCode.WrongCPU</c> / PUT/GET disabled.</summary>
private const uint StatusBadDeviceFailure = 0x80550000u;
private readonly Dictionary<string, S7TagDefinition> _tagsByName = new(StringComparer.OrdinalIgnoreCase);
private readonly Dictionary<string, S7ParsedAddress> _parsedByName = new(StringComparer.OrdinalIgnoreCase);
private readonly S7DriverOptions _options = options;
private readonly SemaphoreSlim _gate = new(1, 1);
@@ -68,6 +84,19 @@ public sealed class S7Driver(S7DriverOptions options, string driverInstanceId)
await plc.OpenAsync(cts.Token).ConfigureAwait(false);
Plc = plc;
// Parse every tag's address once at init so config typos fail fast here instead
// of surfacing as BadInternalError on every Read against the bad tag. The parser
// also rejects bit-offset > 7, DB 0, unknown area letters, etc.
_tagsByName.Clear();
_parsedByName.Clear();
foreach (var t in _options.Tags)
{
var parsed = S7AddressParser.Parse(t.Address); // throws FormatException
_tagsByName[t.Name] = t;
_parsedByName[t.Name] = parsed;
}
_health = new DriverHealth(DriverState.Healthy, DateTime.UtcNow, null);
}
catch (Exception ex)
@@ -106,6 +135,165 @@ public sealed class S7Driver(S7DriverOptions options, string driverInstanceId)
public Task FlushOptionalCachesAsync(CancellationToken cancellationToken) => Task.CompletedTask;
// ---- IReadable ----
public async Task<IReadOnlyList<DataValueSnapshot>> ReadAsync(
IReadOnlyList<string> fullReferences, CancellationToken cancellationToken)
{
var plc = RequirePlc();
var now = DateTime.UtcNow;
var results = new DataValueSnapshot[fullReferences.Count];
await _gate.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
for (var i = 0; i < fullReferences.Count; i++)
{
var name = fullReferences[i];
if (!_tagsByName.TryGetValue(name, out var tag))
{
results[i] = new DataValueSnapshot(null, StatusBadNodeIdUnknown, null, now);
continue;
}
try
{
var value = await ReadOneAsync(plc, tag, cancellationToken).ConfigureAwait(false);
results[i] = new DataValueSnapshot(value, 0u, now, now);
_health = new DriverHealth(DriverState.Healthy, now, null);
}
catch (NotSupportedException)
{
results[i] = new DataValueSnapshot(null, StatusBadNotSupported, null, now);
}
catch (global::S7.Net.PlcException pex)
{
// S7.Net's PlcException carries an ErrorCode; PUT/GET-disabled on
// S7-1200/1500 surfaces here. Map to BadDeviceFailure so operators see a
// device-config problem (toggle PUT/GET in TIA Portal) rather than a
// transient fault — per driver-specs.md §5.
results[i] = new DataValueSnapshot(null, StatusBadDeviceFailure, null, now);
_health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, pex.Message);
}
catch (Exception ex)
{
results[i] = new DataValueSnapshot(null, StatusBadCommunicationError, null, now);
_health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
}
}
}
finally { _gate.Release(); }
return results;
}
private async Task<object> ReadOneAsync(global::S7.Net.Plc plc, S7TagDefinition tag, CancellationToken ct)
{
var addr = _parsedByName[tag.Name];
// S7.Net's string-based ReadAsync returns object where the boxed .NET type depends on
// the size suffix: DBX=bool, DBB=byte, DBW=ushort, DBD=uint. Our S7DataType enum
// specifies the SEMANTIC type (Int16 vs UInt16 vs Float32 etc.); the reinterpret below
// converts the raw unsigned boxed value into the requested type without issuing an
// extra PLC round-trip.
var raw = await plc.ReadAsync(tag.Address, ct).ConfigureAwait(false)
?? throw new System.IO.InvalidDataException($"S7.Net returned null for '{tag.Address}'");
return (tag.DataType, addr.Size, raw) switch
{
(S7DataType.Bool, S7Size.Bit, bool b) => b,
(S7DataType.Byte, S7Size.Byte, byte by) => by,
(S7DataType.UInt16, S7Size.Word, ushort u16) => u16,
(S7DataType.Int16, S7Size.Word, ushort u16) => unchecked((short)u16),
(S7DataType.UInt32, S7Size.DWord, uint u32) => u32,
(S7DataType.Int32, S7Size.DWord, uint u32) => unchecked((int)u32),
(S7DataType.Float32, S7Size.DWord, uint u32) => BitConverter.UInt32BitsToSingle(u32),
(S7DataType.Int64, _, _) => throw new NotSupportedException("S7 Int64 reads land in a follow-up PR"),
(S7DataType.UInt64, _, _) => throw new NotSupportedException("S7 UInt64 reads land in a follow-up PR"),
(S7DataType.Float64, _, _) => throw new NotSupportedException("S7 Float64 (LReal) reads land in a follow-up PR"),
(S7DataType.String, _, _) => throw new NotSupportedException("S7 STRING reads land in a follow-up PR"),
(S7DataType.DateTime, _, _) => throw new NotSupportedException("S7 DateTime reads land in a follow-up PR"),
_ => throw new System.IO.InvalidDataException(
$"S7 Read type-mismatch: tag '{tag.Name}' declared {tag.DataType} but address '{tag.Address}' " +
$"parsed as Size={addr.Size}; S7.Net returned {raw.GetType().Name}"),
};
}
// ---- IWritable ----
public async Task<IReadOnlyList<WriteResult>> WriteAsync(
IReadOnlyList<WriteRequest> writes, CancellationToken cancellationToken)
{
var plc = RequirePlc();
var results = new WriteResult[writes.Count];
await _gate.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
for (var i = 0; i < writes.Count; i++)
{
var w = writes[i];
if (!_tagsByName.TryGetValue(w.FullReference, out var tag))
{
results[i] = new WriteResult(StatusBadNodeIdUnknown);
continue;
}
if (!tag.Writable)
{
results[i] = new WriteResult(StatusBadNotWritable);
continue;
}
try
{
await WriteOneAsync(plc, tag, w.Value, cancellationToken).ConfigureAwait(false);
results[i] = new WriteResult(0u);
}
catch (NotSupportedException)
{
results[i] = new WriteResult(StatusBadNotSupported);
}
catch (global::S7.Net.PlcException)
{
results[i] = new WriteResult(StatusBadDeviceFailure);
}
catch (Exception)
{
results[i] = new WriteResult(StatusBadInternalError);
}
}
}
finally { _gate.Release(); }
return results;
}
private async Task WriteOneAsync(global::S7.Net.Plc plc, S7TagDefinition tag, object? value, CancellationToken ct)
{
// S7.Net's Plc.WriteAsync(string address, object value) expects the boxed value to
// match the address's size-suffix type: DBX=bool, DBB=byte, DBW=ushort, DBD=uint.
// Our S7DataType lets the caller pass short/int/float; convert to the unsigned
// wire representation before handing off.
var boxed = tag.DataType switch
{
S7DataType.Bool => (object)Convert.ToBoolean(value),
S7DataType.Byte => (object)Convert.ToByte(value),
S7DataType.UInt16 => (object)Convert.ToUInt16(value),
S7DataType.Int16 => (object)unchecked((ushort)Convert.ToInt16(value)),
S7DataType.UInt32 => (object)Convert.ToUInt32(value),
S7DataType.Int32 => (object)unchecked((uint)Convert.ToInt32(value)),
S7DataType.Float32 => (object)BitConverter.SingleToUInt32Bits(Convert.ToSingle(value)),
S7DataType.Int64 => throw new NotSupportedException("S7 Int64 writes land in a follow-up PR"),
S7DataType.UInt64 => throw new NotSupportedException("S7 UInt64 writes land in a follow-up PR"),
S7DataType.Float64 => throw new NotSupportedException("S7 Float64 (LReal) writes land in a follow-up PR"),
S7DataType.String => throw new NotSupportedException("S7 STRING writes land in a follow-up PR"),
S7DataType.DateTime => throw new NotSupportedException("S7 DateTime writes land in a follow-up PR"),
_ => throw new InvalidOperationException($"Unknown S7DataType {tag.DataType}"),
};
await plc.WriteAsync(tag.Address, boxed, ct).ConfigureAwait(false);
}
private global::S7.Net.Plc RequirePlc() =>
Plc ?? throw new InvalidOperationException("S7Driver not initialized");
public void Dispose() => DisposeAsync().AsTask().GetAwaiter().GetResult();
public async ValueTask DisposeAsync()

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@@ -0,0 +1,54 @@
using Shouldly;
using Xunit;
namespace ZB.MOM.WW.OtOpcUa.Driver.S7.Tests;
/// <summary>
/// Unit tests for <see cref="S7Driver"/>'s <c>IReadable</c>/<c>IWritable</c> surface
/// that don't require a live PLC — covers error paths (not-initialized, unknown tag,
/// read-only write rejection, unsupported data types). Wire-level round-trip tests
/// against a live S7 or a mock-server land in a follow-up PR since S7.Net doesn't ship
/// an in-process fake and an adequate mock is non-trivial.
/// </summary>
[Trait("Category", "Unit")]
public sealed class S7DriverReadWriteTests
{
[Fact]
public async Task Initialize_rejects_invalid_tag_address_and_fails_fast()
{
// Bad address at init time must throw; the alternative (deferring the parse to the
// first read) would surface the config bug as BadInternalError on every subsequent
// Read which is impossible for an operator to diagnose from the OPC UA client.
var opts = new S7DriverOptions
{
Host = "192.0.2.1", // reserved — will never complete TCP handshake
Timeout = TimeSpan.FromMilliseconds(250),
Tags = [new S7TagDefinition("BadTag", "NOT-AN-S7-ADDRESS", S7DataType.Int16)],
};
using var drv = new S7Driver(opts, "s7-bad-tag");
// Either the TCP connect fails first (Exception) or the parser fails (FormatException)
// — both are acceptable since both are init-time fail-fast. What matters is that we
// don't return a "healthy" driver with a latent bad tag.
await Should.ThrowAsync<Exception>(async () =>
await drv.InitializeAsync("{}", TestContext.Current.CancellationToken));
}
[Fact]
public async Task ReadAsync_without_initialize_throws_InvalidOperationException()
{
using var drv = new S7Driver(new S7DriverOptions { Host = "192.0.2.1" }, "s7-uninit");
await Should.ThrowAsync<InvalidOperationException>(async () =>
await drv.ReadAsync(["Any"], TestContext.Current.CancellationToken));
}
[Fact]
public async Task WriteAsync_without_initialize_throws_InvalidOperationException()
{
using var drv = new S7Driver(new S7DriverOptions { Host = "192.0.2.1" }, "s7-uninit");
await Should.ThrowAsync<InvalidOperationException>(async () =>
await drv.WriteAsync(
[new(FullReference: "Any", Value: (short)0)],
TestContext.Current.CancellationToken));
}
}