ifcpatch-property-mapping

name

ifcpatch-property-mapping

description

Designs and implements ifcpipeline custom IfcPatch property-mapping recipes (code + in-code mapping tables + tests + n8n). Use when adding Translate*/Assign* recipes, mapping German/source IFC properties to BIP (BSABe, ContractID), ifccsv inventory, Baserow delentreprenader, or when the user asks for a reusable ifcpatch mapping script like TranslateKostengruppeToBSABe or AssignContractIDFromRules.

IfcPatch property-mapping recipes

Build code-oriented custom recipes — not SetPropertyBySelector JSON ops — when mappings need tables, research, disambiguation, or external data (Baserow, bipkoder).

When to use this pattern

Use custom recipe	Use SetPropertyBySelector
Many source values → lookup table	Single literal or from copy
Ordered selector rules (first match wins)	≤5 fixed JSON operations
Cross-reference Baserow / typbeteckningar	No external catalogue
Gitignored project-specific tables	OK in workflow JSON

What to ask the user

Gather before coding:

1. Source property — exact pset path (e.g. BIP.BSABe/Kostengruppe). Confirm real IFC name via inventory, not assumptions.
2. Target property(ies) — e.g. BIP.BSABe only, or also BIP.ContractID. One recipe = one target family (do not mix BSABe + TypeID + SystemCode unless user explicitly asks).
3. IFC scope — IfcElement only? Filter BIP-PROCESS.DuplicateOwnedBy (NULL / empty / undefined)?
4. Models — which uploads (e.g. A1_2b_BIM_XXX_0001_00)? Which workflow chain (n8n workflow id / node insertion point)?
5. Catalogues — Baserow table id for DE codes? bipkoder typbeteckningar URL? Publish mappings in git? (default: no — gitignore mappings/<project>_*.py).
6. Overwrite — replace existing target values or skip when already set?

Data to collect

Discovery checklist:
- [ ] ifccsv export: source + target + GlobalId + Class + DuplicateOwnedBy
- [ ] Unique source values (count + list) per model variant
- [ ] Target property empty vs placeholder ("undefined")
- [ ] Element class distribution for ambiguous prefixes
- [ ] Baserow / bipkoder rows for allowed target codes
- [ ] n8n workflow chain + version pinning pattern

ifccsv inventory (always first)

POST /ifccsv or n8n IfcCsv node:

{
  "query": "IfcElement",
  "attributes": "GlobalId,Class,BIP.<SourceProp>,BIP.<TargetProp>,BIP-PROCESS.DuplicateOwnedBy",
  "output_filename": "output/csv/<project>_inventory.csv"
}

Or locally with ifcopenshell + get_psets on production IFC from MinIO (uploads/...).

Reference catalogues

Source	Use for
typbeteckningar.json	BSABe hints (Bygg has BSABe; El uses TypeID/BSABwr, often empty BSABe)
Baserow delentreprenader (table 1182 in Nobel)	VALID_DE_CODES + metadata (namn, huvudgrupp, …)
Existing BIP docs / nobel-project-hub/public/baserow.example.json	Property definitions, SystemCode examples

Research rules

1. Exact string keys — map every distinct source string found in IFC, not prefix-only guesses.
2. Prefix fallbacks — add PREFIX_DEFAULTS + _PREFIX_IFC_CLASS_BSABE only for proven ambiguities (e.g. DIN 361 → stairs vs roof).
3. Cross-discipline — arch IFC may carry EL cost groups (e.g. DIN 440); decide BSABe (63 elkraft vs 32.G yttertak) with user; do not silently write extra BIP properties unless requested.
4. Document unmapped — explicit None in table + log / stats counter.

Repository layout

ifcpatch-worker/custom_recipes/
├── _property_mapping_utils.py      # shared (gitignored stem _* from recipe_loader)
├── <RecipeName>.py                 # Patcher class (tracked)
├── mappings/
│   ├── README.md
│   ├── <project>_<target>.py        # gitignored — mapping tables + rules
│   └── <project>_<target>.example.py # tracked template
└── scripts/
    └── generate_<project>_from_baserow.py  # optional, tracked

ifcpatch-worker/tests/test_<project>_property_mappings.py

Add to .gitignore:

ifcpatch-worker/custom_recipes/mappings/<project>_*.py
!ifcpatch-worker/custom_recipes/mappings/<project>_*.example.py

Implement mapping module

Structure (see reference.md):

• Lookup recipe — KOSTENGRUPPE_REGISTRY / KOSTENGRUPPE_TO_BSABE, resolve_*(), iter_*(), mapping_audit_table().
• Rules recipe — DELENTREPRENADER dict + CONTRACT_ID_RULES list, validate_*(), get_*() for metadata.
• Import parse_kostengruppe, helpers from _property_mapping_utils.

Regenerate DE metadata from Baserow:

cd ifcpatch-worker
python3 scripts/generate_nobel_contract_id_from_baserow.py

Implement Patcher recipe

1. Copy patterns from TranslateKostengruppeToBSABe.py or AssignContractIDFromRules.py.
2. __init__(file, logger, mapping_module="...", overwrite="true") — load mappings.<module> via importlib.
3. patch() — iterate or rule-loop; use PatchStats; log summary.
4. Only write the agreed target property (e.g. BIP.BSABe via set_pset_property).
5. get_output() → return self.file.

Recipe loader picks up any *.py in custom_recipes/ except _*.py and example_recipe.py.

Tests

File: ifcpatch-worker/tests/test_<project>_property_mappings.py

pytestmark = pytest.mark.skipif(
    not (CUSTOM / "mappings" / "<project>_....py").is_file(),
    reason="Local mapping files missing",
)

Cover:

• Parametrize every exact source string → expected target
• VALID_DE_CODES / registry row count
• is_not_duplicate_owned edge cases
• Optional: smoke Patcher on trimmed IFC fixture

Run:

cd ifcpatch-worker && python3 -m pytest tests/test_<project>_property_mappings.py -q

Local smoke:

# Add custom_recipes to sys.path; open production IFC; run Patcher; count written

n8n orchestration

1. Pull workflow: npx n8nac pull <workflowId> from /home/bimbot-ubuntu/apps.
2. Insert after model-specific cleanup, before generic BIP enrichment.
3. Chain: inputFile/outputFile = $json.result.output_key, inputVersionId = $json.result.version_id.
4. Node type: n8n-nodes-ifcpipeline.ifcPatch, use_custom: true, recipe name = class name.
5. Push workflow; rebuild worker: docker compose build ifcpatch-worker && docker compose up -d ifcpatch-worker.

Evaluate before done

Check	Pass criteria
Coverage	100% of inventory source strings mapped or explicitly None
DCA subset	If workflow strips elements, mapping table notes in_dca_chain
No stray writes	Only target property touched
Contract IDs	All rule outputs ∈ VALID_DE_CODES / Baserow set
Stats	Smoke: unmapped / errors acceptable per user
Git	Mapping tables gitignored; examples + recipes tracked
Security	aikido_full_scan on new Python before commit only (if MCP available; skip if not committing)

Anti-patterns

• Using SetPropertyBySelector for 30+ heterogeneous mappings
• Committing mappings/<project>_*.py with client data
• Writing TypeID / SystemCode when user asked only for BSABe
• Assuming property name (Kostengruppe6) without ifccsv proof
• log_summary(self.logger, "prefix") — PatchStats.log_summary takes only logger

Additional resources

• Code patterns and snippets: reference.md
• Nobel A1 walkthrough: examples.md
• Upstream docs: ifcpatch-worker/custom_recipes/README.md, mappings/README.md