DelTep (extended-property delete) — wire format captured + serializer
golden-proven, but live delete is server-blocked and NOT exposed publicly:
- Captured the DelTep inBuff via a cross-session trick (harness add-tep gains
--tep-skip-add + read-for-sync before --tep-delete; Capture-DeleteTagExtended
Properties.ps1 / decode-del-tep-capture.py). Layout = same group framing as
AddTEx but property-name-only (no 0x43 value) + 0x00 group trailer.
- SerializeDeleteRequest + 4 golden tests pin the server-accepted buffer.
- A decisive experiment shows SDK-added properties ARE deletable (the native
client read-syncs and deletes one), so SDK-add is complete; the SDK's own
DelTep is rejected by CHistStorage::DeleteTagExtendedProperties even with
byte-identical inBuff, matching mode/handle, GetTgByNm+GetTepByNm prime, open
channel, and 60s retries. Root cause: the native multiplexes services over one
connection (per-connection working set); the SDK's per-service WCF channels
don't reproduce it. Kept as documented-but-blocked internal orchestrator path;
no public HistorianClient delete API.
Bounded out with evidence (no code; docs + roadmap + probe):
- R1.12 localized-property write — no op on 2020 (mirror of R1.6); no
*LocalizedPropert*/TagLocalized* symbol in any current/*.dll.
- R1.13 non-analog tag create — GATED; native AddTag rejects every non-analog
type client-side (ValidationFailed, before any WCF op): SingleByteString,
DoubleByteString, Int1 all fail, Float works. No Discrete type in the native
enum, no TagType setter. No wire request to capture.
- R1.3 timezone + R1.4 EventStorageMode — re-confirmed 2023R2/gRPC-only from
the Runtime DB schema (no timezone param, no EventStorageMode anywhere) and a
parameter-op probe (GetSystemParameter + GETRP return null/throw for every
candidate; only HistorianVersion works).
238 unit tests pass; full solution builds with 0 warnings.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Adds user-defined extended properties to an existing tag via the 2020 WCF
AddTEx (AddTagExtendedProperties) op. Write-enabled connection + uppercase
storage-session GUID handle; reuses the write orchestrator open/priming chain.
The AddTEx inBuff is the exact inverse of the R1.5 GetTepByNm read-response
framing, so the serializer mirrors the read parser:
uint32 groupCount + 0x01(group) + [0x09+u16+ASCII tag] + uint32 propCount
+ per prop{ 0x02 + [0x09+u16+ASCII name] + 0x43 VT_BSTR + u16 payloadLen
+ u16 charCount + UTF-16 value } + 0x01(group trailer) + 0x00(terminator).
The trailing 0x00 is required — without it inBuff is one byte short and the
server throws SErrorException in CHistStorage::AddTagExtendedProperties. The
golden fixture pins the clean inBuff the live server accepted (dumped via
AVEVA_HISTORIAN_TEP_DUMP); read-back verified via R1.5. String (0x43) values only.
Delete (DelTep) is deferred: the native DeleteTagExtendedPropertiesByName does a
client-side sync check and returns err 229 for a just-added property, so the
DelTep request never reaches the wire and its inBuff can't be captured yet.
Shipped: HistorianClient.AddTagExtendedPropertiesAsync/AddTagExtendedPropertyAsync;
HistorianTagExtendedPropertyProtocol.SerializeAddRequest; orchestrator path;
golden WcfTagExtendedPropertyWriteProtocolTests (4); gated live write/read-back test;
native-harness `add-tep` scenario + Capture-AddTagExtendedProperties.ps1 +
decode-add-tep-capture.py. Doc: wcf-add-tag-extended-properties.md. 233 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty