Files
mxaccess/design
Joseph Doherty b543eb1f84 [M5] mxaccess-asb: F25 step 8 — subscription operations
CreateSubscription / AddMonitoredItems / Publish / DeleteSubscription.
Completes the IASBIDataV2 read-and-subscribe path; remaining ops
(Write/PublishWriteComplete/DeleteMonitoredItems) are mechanical
extensions of the same pattern.

Contracts:
* `MonitoredItemValue` codec (IAsbCustomSerializableType binary
  fast-path: ItemIdentity + RuntimeValue + AsbVariant per
  `AsbContracts.cs:1064-1068`) with array codec (4-byte int32
  count + per-element body, mirrors `WriteArrayToStream` at
  `cs:1095-1103`).

Request builders:
* `build_create_subscription_request_body(max_queue_size,
  sample_interval)` — primitive fields per `cs:215-223`.
* `build_delete_subscription_request_body(subscription_id)` —
  primitive field per `cs:232-237`.
* `build_publish_request_body(subscription_id)` — primitive field
  per `cs:287-292`.
* `build_add_monitored_items_request_body(subscription_id, items,
  require_id)` — minimal MonitoredItem shape (Item +
  SampleInterval + Buffered). Full optional-field set
  (Active/TimeDeadband/ValueDeadband/UserData) deferred to a later
  iteration once a live capture confirms the WCF DataContract
  XML wire form.

Response decoders:
* `decode_create_subscription_response` — single int64
  SubscriptionId field. Decoder accepts Int64Text, Int32Text,
  Zero/One, or numeric-string Chars (covers all WCF binary
  numeric encodings).
* `decode_add_monitored_items_response` — Status array +
  ItemCapabilities-presence flag (mirrors RegisterItemsResponse).
* `decode_publish_response` — Status array + Values
  (MonitoredItemValue) array.

`BodyField::Int64Element` variant added for the primitive
SubscriptionId / MaxQueueSize / SampleInterval fields. `uint64`
helper casts to i64 (covers proven value range; if ulong > i64::MAX
ever appears we'll add UInt64Text to F21's NbfxText enum).

Client wrappers (4 new methods on AsbClient):
* `create_subscription(max_queue_size, sample_interval)`
* `add_monitored_items(subscription_id, items, require_id)`
* `publish(subscription_id)`
* `delete_subscription(subscription_id)`

11 new tests cover:
* MonitoredItemValue round-trip + array round-trip.
* CreateSubscription request body shape (Int64 payloads).
* CreateSubscription response decoder via Int64Text.
* CreateSubscription response decoder via Chars text fallback.
* CreateSubscription response missing-field error.
* AddMonitoredItems body carries SubscriptionId + MonitoredItem
  elements.
* AddMonitoredItems response Status round-trip.
* DeleteSubscription body carries SubscriptionId.
* Publish request body shape.
* Publish response Status + Values round-trip.

Workspace: 691 tests pass (was 680, +11). The asb-subscribe example
can now do create_subscription → add_monitored_items → publish-loop
→ delete_subscription once wire-byte reconciliation against a live
capture confirms the MonitoredItem XML shape.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-05 12:57:59 -04:00
..

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 M2M6 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 .cs file path in src/MxNativeCodec/, src/MxNativeClient/, or src/MxAsbClient/, or
  • a docs/*.md spec file, or
  • a captures/0NN-frida-* directory or analysis/frida/*.tsv row.

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.md for the per-phase parallelism map.
  • Driving M2M6 autonomously via /loop: prompt.md (and the followups.md triage log it maintains).