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Package an experience into a content-addressable artifact.
A ``PackagedExperience`` pairs the manifest dict with a stable
SHA-256 digest of its canonical JSON form, so:
- The publish flow can detect "manifest unchanged since last
publish" and skip emitting a duplicate channel record.
- A future signed-distribution channel can hash + sign the same
bytes the consumer would verify.
Determinism: ``json.dumps(..., sort_keys=True, separators=(",", ":"))``
is the canonical form. Pydantic's model_dump produces dict-of-
primitives so this round-trips cleanly.
"""
from __future__ import annotations
import hashlib
import json
from dataclasses import dataclass
from typing import Any, Dict
from ..models import Experience
from .manifest import build_manifest
@dataclass(frozen=True)
class PackagedExperience:
"""Manifest + canonical digest."""
experience_id: str
manifest: Dict[str, Any]
digest: str # hex SHA-256 of canonical JSON
canonical_bytes: bytes
def _canonical_json(payload: Dict[str, Any]) -> bytes:
return json.dumps(payload, sort_keys=True, separators=(",", ":")).encode("utf-8")
def package_experience(experience: Experience) -> PackagedExperience:
"""Build the manifest + digest for an experience.
Pure read — no DB writes. Safe to call repeatedly; same input
rows produce the same digest.
"""
manifest = build_manifest(experience)
blob = _canonical_json(manifest)
digest = hashlib.sha256(blob).hexdigest()
return PackagedExperience(
experience_id=experience.id,
manifest=manifest,
digest=digest,
canonical_bytes=blob,
)
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