# Signed-request XML fixtures

Canonical `XmlSerializer` output for every `ConnectedRequest` shape that
the .NET reference HMACs in `AsbSystemAuthenticator.Sign`
(`src/MxAsbClient/AsbSystemAuthenticator.cs:79`). The Rust port's
canonical-XML emitter (F28) must produce these exact UTF-8 bytes for
the HMAC to match the server's recomputation.

## Capture procedure

```powershell
dotnet run --project src\MxAsbClient.Probe -c Release -- --dump-signed-xml > capture.txt
```

The probe's `--dump-signed-xml` flag (added 2026-05-05) builds each
shape with deterministic field values and prints the output of
`AsbSerialization.ToXml(...)` (`src/MxAsbClient/AsbSerialization.cs:12`).

## Pinned values

All shapes use the same `ConnectionValidator`:
- `ConnectionId = 8cba964a-74c1-ef74-f6aa-761b3540191b`
- `MessageNumber = 42`
- `MessageAuthenticationCode = AAECAwQFBgcICQoLDA0ODw==` (base64 of bytes 0..15)
- `SignatureInitializationVector = EBESExQVFhcYGRobHB0eHw==` (base64 of bytes 16..31)

`AuthenticateMe` and `Disconnect` use `AuthenticationData` with:
- `Data = "deterministic-ciphertext-bytes"` (base64-encoded)
- `InitializationVector = "0123456789abcdef"` (base64-encoded)

`RegisterItemsRequest` uses one `ItemIdentity` with
`Type = Name (0)`, `ReferenceType = Absolute (1)`,
`Name = "TestChildObject.TestInt"`, `ContextName = ""`.

`UnregisterItemsRequest` uses one `ItemIdentity` with
`Type = Id (1)`, `ReferenceType = Absolute (1)`, `Name = null`,
`ContextName = null`, `Id = 0xCAFEBABEDEADBEEF (14627333968688430831)`,
`IdSpecified = true`.

## Observed serialiser behaviour

These rules were inferred from the captured output and from the .NET
source for `XmlSerializer`:

1. **Element name = class name**, NOT `[MessageContract.WrapperName]`.
   `XmlSerializer` does not honour WCF's MessageContract attributes.

2. **Top-element xmlns ordering** (after `<?xml ... ?>`):
   `xmlns:xsi`, then `xmlns:xsd`, then default `xmlns`.
   The `AsbSerialization.ToXml` post-process (`AsbSerialization.cs:36-47`)
   reparses with `XDocument.Load` and reorders to put `xsi` before
   `xsd` — `XmlSerializer`'s native order is the opposite.

3. **Field order = C# declaration order** (with inherited fields
   first), NOT `[MessageBodyMember.Order]`.

4. **`[XmlType(Namespace = ...)]` on a field's type** triggers an
   `xmlns="..."` redeclaration on EACH child element of that type's
   instance, NOT on the wrapper element itself. e.g. inside
   `<ConnectionValidator>`, every direct child gets
   `xmlns="http://asb.contracts.data/20111111"`.

5. **`byte[]` fields** serialise as base64 text content.
   **`Guid`** as canonical lowercase D-format (`8cba964a-74c1-...`).
   **`ulong`** as decimal.
   **`bool`** as `"true"` / `"false"`.

6. **Null reference-type fields** with `[XmlElement(IsNullable = true)]`
   produce `<Name xsi:nil="true" xmlns="..." />`.
   Empty string fields produce a self-closing `<ContextName xmlns="..." />`.

7. **`*Specified` pattern**: a public bool field named `XxxSpecified` =
   `true` causes XmlSerializer to emit the corresponding `<Xxx>`
   element. `IdSpecified = false` (default) → `<Id>` omitted.
   `IdSpecified = true` → `<Id>` emitted with the int value.
   The `*Specified` field itself is `[XmlIgnore]` and never emitted.

8. **Self-closing elements** use ` />` (space before `/>`).

9. **Indentation**: 2 spaces, `\r\n` line endings, no trailing
   newline after the closing tag.

10. **XML declaration**: `<?xml version="1.0" encoding="utf-16"?>` —
    note `utf-16` even though `AsbSystemAuthenticator.Sign` HMACs
    `Encoding.UTF8.GetBytes(...)` of this string. The declaration is
    a static .NET StringWriter default; the actual byte encoding fed
    to HMAC is UTF-8.

## Files

- `authenticate-me.xml` — `AuthenticateMe`
- `authenticate-me-empty-mac-iv.xml` — `AuthenticateMe` with the
  pre-signing validator (empty MAC + IV) — the actual HMAC input shape.
- `disconnect.xml` — `Disconnect`
- `keep-alive.xml` — `KeepAlive`
- `register-items.xml` — `RegisterItemsRequest`
- `unregister-items.xml` — `UnregisterItemsRequest`

The eight remaining `ConnectedRequest` shapes added 2026-05-06 (F28
step 2) cover the data-plane + subscription ops:

- `read-request.xml` — `ReadRequest`
- `write-basic-request.xml` — `WriteBasicRequest`
- `publish-write-complete-request.xml` — `PublishWriteCompleteRequest`
- `create-subscription-request.xml` — `CreateSubscriptionRequest`
- `delete-subscription-request.xml` — `DeleteSubscriptionRequest`
- `add-monitored-items-request.xml` — `AddMonitoredItemsRequest`
- `delete-monitored-items-request.xml` — `DeleteMonitoredItemsRequest`
- `publish-request.xml` — `PublishRequest`

Pinned values for the new shapes (in addition to the
`ConnectionValidator` above):

- `SubscriptionId = 0x1234_5678_9abc_def0` (decimal `1311768467463790320`)
- `MaxQueueSize = 100`, `SampleInterval = 1000`
- `WriteHandle = 0xDEAD_BEEF` (decimal `3735928559`)
- `WriteBasicRequest` uses one `WriteValue` whose `Value` is
  `Variant.FromInt32(42)` (`Type=4`, `Length=4`, `Payload=[42, 0, 0, 0]`)
- `AddMonitoredItemsRequest` uses one `MonitoredItem` with
  `Item = "TestChildObject.TestInt"` by name + `SampleInterval=1000` +
  `Buffered=false` (other fields default)
- `DeleteMonitoredItemsRequest` uses one `MonitoredItem` with
  `Item.Id = 0xCAFE_BABE_DEAD_BEEF` (the same `IdSpecified` shape as
  `unregister-items.xml`)

Each file is the verbatim UTF-8 representation of `request.ToXml()`,
with literal `\r\n` line endings preserved. Treat as binary (don't
let your editor reformat).