Investigation via examples/asb-relay.rs middleman captured the full
S→C bytes of a working PublishResponse from the .NET probe against
MxDataProvider. Decoder fix verified by regression test against the
captured fixture; one further wire-format gap surfaced and is filed.
Closed in this commit:
1. collect_asbidata_payloads filtered out empty <ASBIData/> elements
so positional payload[N] indexing collapsed when Status was
empty-but-present. The wire form for PublishResponse is:
<Status><ASBIData/></Status> ← empty placeholder
<Values><ASBIData>{bytes}</ASBIData></Values>
Our decoder lost the positional info and read Values as Status,
then panicked on the malformed parse. Fix: always push every
<ASBIData> element (empty or not) so payloads[0]=Status and
payloads[1]=Values stay aligned. New regression test
tests/publish_capture.rs runs the full decode chain over the
captured wire bytes (305-byte frame at
tests/fixtures/publish-response-with-value.bin) and asserts
values.len() == 1.
2. MinimalMonitoredItem.active: Option<bool> + new with_active()
constructor. The .NET reference's MxAsbDataClient.AddMonitoredItems
defaults to active: true (cs:441). Without <Active>true</Active>
on the wire, MxDataProvider treats the subscription as inactive
and Publish polls return empty Values. Both binary build and
canonical XML emitters now conditionally emit <Active> when
active.is_some(). Shared push_monitored_item_body helper
eliminates the duplicate MonitoredItem encoder between
AddMonitoredItems and DeleteMonitoredItems builders.
3. SampleInterval unit: clarified as **milliseconds** in
MinimalMonitoredItem.sample_interval doc + the example
(sample_interval_ticks → sample_interval_ms = 1000). Matches the
.NET reference's `ulong sampleInterval = 1000` default.
Open: F34's deeper finding — `MonitoredItem`'s wire schema is
DataContract field-suffix names (`activeField`, `bufferedField`,
`itemField`, `sampleIntervalField`, etc., per the per-session NBFX
dictionary the .NET probe declares), NOT XmlSerializer property
names (`Active`, `Buffered`, `Item`, `SampleInterval`). Our binary
NBFX builder still uses the property names, so MxDataProvider
silently fails to register monitored items — successField=true with
a 0-length Status array. The fix needs a complete rebuild of
build_add_monitored_items_request_body and
build_delete_monitored_items_request_body to use the field-suffix
names plus emit the *Specified siblings (activeFieldSpecified,
idFieldSpecified, etc.) as their own elements. The HMAC canonical
XML side is unaffected (XmlSerializer naming is correct there;
verified byte-equal to .NET via the F28 fixtures). Detailed in
design/followups.md F34's "Open" section.
Live verification of the F34-partial bonus context:
- Read still returns 99 end-to-end via canonical XML signing.
- AddMonitoredItems still returns Status[0] = 0 items
(server doesn't recognize our DataContract-misnamed payload).
- Publish still returns 0 values (the F34-open consequence).
- All other 13 canonical-XML signed ops succeed at the request
level (no SOAP faults, no HMAC rejections).
Workspace: mxaccess-asb 95 → 96 (+1 capture-driven decoder test);
default-feature clippy clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
design/ — Rust port architectural plan
This folder is the design contract for the Rust replacement of AVEVA/Wonderware MXAccess. It is the gap between the .NET reference in src/ and the Rust crates that will be written under a sibling rust/ workspace (per CLAUDE.md).
The folder is structured as a small set of focused documents. Read in order; each builds on the previous.
| File | Purpose |
|---|---|
00-overview.md |
Mission, two-layer goal, architectural principles, non-goals |
10-raw-layer.md |
Byte-accurate raw MXAccess layer (codec + transport + session) |
20-async-layer.md |
Idiomatic Tokio async layer on top of the raw layer |
30-crate-topology.md |
Cargo workspace, crates, dependencies, build/test commands |
40-protocol-invariants.md |
Bill of materials: IIDs, opnums, envelope/handle bytes |
50-error-model.md |
MxStatus, error types, panic/cancellation policy |
60-roadmap.md |
Milestones M0..M6, validation strategy |
70-risks-and-open-questions.md |
Parity gaps, unproven flows, cross-platform constraints |
dependencies.md |
Cross- and within-milestone parallelism map; agent budget per phase |
review.md |
Adversarial review log (BLOCKER/MAJOR/MINOR/NIT findings, all resolved) |
prompt.md |
/loop driver prompt for autonomous M2–M6 execution |
followups.md |
Open / resolved deferred work items; auto-triaged by prompt.md Step 0 (created on first /loop run if missing) |
The design is grounded in the .NET reference at src/ and the protocol artifacts in docs/, analysis/, and captures/. Do not introduce protocol behavior in these documents that is not already proven in the reference. When adding a new claim about wire format, cite either:
- a
.csfile path insrc/MxNativeCodec/,src/MxNativeClient/, orsrc/MxAsbClient/, or - a
docs/*.mdspec file, or - a
captures/0NN-frida-*directory oranalysis/frida/*.tsvrow.
This folder is documentation, not code. When the Rust workspace is created, the design here is the contract it must satisfy. When evidence in captures/ invalidates a design decision here, update the design first, then the code.
Reading order
- New contributor: 00 → 30 → 10 → 40 → 20 → 50 → 60 → 70.
- Protocol question: 40 first, then the relevant section of 10.
- API question: 20 first, then 50.
- Planning a milestone: 60 first, cross-reference 70 for blockers.
- Scheduling concurrent work:
dependencies.mdfor the per-phase parallelism map. - Driving M2–M6 autonomously via
/loop:prompt.md(and thefollowups.mdtriage log it maintains).