[hma] Storing and fetching metadata from banked content is unimplemented

[Pezmc]

POST /bank/<bank_name>/content accepts and stores metadata, but GET /bank/<bank_name>/content/<id> does not return it. The response includes original_media_uri and collab_metadata, but not the user-supplied metadata.

Repro

1. POST /bank/MYBANK/content with metadata (content_id, content_uri, json).
2. GET /bank/MYBANK/content/<id>.
3. See that metadata is missing in the response.

Current code (abridged)

response: BankContentResponse = {
    "id": content_config.id,
    "disable_until_ts": content_config.disable_until_ts,
    "collab_metadata": content_config.collab_metadata,
    "original_media_uri": content_config.original_media_uri,
    "bank": content_config.bank,
}

Full `bank_get_content` method

ThreatExchange/hasher-matcher-actioner/src/OpenMediaMatch/blueprints/curation.py

Lines 147 to 173 in 2e5f23f

	def bank_get_content(bank_name: str, content_id: int):
	storage = persistence.get_storage()
	bank = storage.get_bank(bank_name)
	if not bank:
	abort(404, f"bank '{bank_name}' not found")
	include_signals = request.args.get("include_signals", "false").lower() == "true"
	content = storage.bank_content_get([content_id])
	if not content:
	abort(404, f"content '{content_id}' not found")
	content_config = content[0]
	# Create base response
	response: BankContentResponse = {
	"id": content_config.id,
	"disable_until_ts": content_config.disable_until_ts,
	"collab_metadata": content_config.collab_metadata,
	"original_media_uri": content_config.original_media_uri,
	"bank": content_config.bank,
	}
	# If signals were requested, fetch them separately and include in response
	if include_signals:
	signals = storage.bank_content_get_signals([content_id])
	if content_id in signals:
	response["signals"] = signals[content_id]
	return jsonify(response)

Expected

Return the stored user metadata:

"metadata": {
  "content_id": "...",
  "content_uri": "...",
  "json": { "..." : "..." }
}

Proposal

Include metadata in the response:

response["metadata"] = content_config.metadata

Optionally support ?include_metadata=true|false, similar to include_signals.

Why

We're been banking descriptive metadata for curation and audit, and need it on read.

Related

#1681

[Pezmc]

Digging a bit keeper, it looks like metadata isn't actually wired up at all: #1593

[Dcallies]

Looks like an oversight on following up implementing the rest of the feature. Metadata is important for a lot of the experimentation paths, so let's implement the rest of it.