sapl-pymongo

SAPL signal source for PyMongo. Contributes the MONGO_QUERY signal and a mongo:queryRewriting constraint handler provider so a SAPL policy can shape the MongoDB queries an application issues, the same way sapl-sqlalchemy contributes SQL_QUERY for relational queries.

PyMongo's driver-monitoring API is observe-only, so there is no central mutating query hook. The cut point is therefore a thin proxy over the collection's query-issuing methods (find, find_one, aggregate, count_documents, update_*, delete_*). Each wrapped call discharges MONGO_QUERY with the structured query (a filter mapping or an aggregation pipeline) before delegating to the driver. A synchronous proxy backs the blocking enforcement path (Flask, sync Django); an asynchronous proxy backs the async path (FastAPI, Tornado, async Django).

Obligation

MongoDbQueryRewritingProvider handles the mongo:queryRewriting obligation, mirroring the Spring provider so the same obligation narrows identically on every SAPL Mongo PEP. Two shapes, combinable, narrowing-only (criteria and conditions are AND-merged into the user's filter, never widening it):

{
  "type": "mongo:queryRewriting",
  "criteria": [
    {"column": "tenantId", "op": "=", "value": 7},
    {"or": [{"column": "ownerId", "op": "=", "value": "alice"},
            {"column": "public", "op": "=", "value": true}]}
  ],
  "conditions": ["{\"age\": {\"$gte\": 18}}"]
}

criteria ops: =, !=, >, >=, <, <=, in, isNull, isNotNull; and / or group nested criteria. conditions carries raw filter fragments for operators the typed form cannot express ($regex, $exists, $geoWithin); for cross-PEP portability the strings must be double-quoted (extended) JSON. An aggregation pipeline cannot be expressed by this contract, so a pipeline intercept fails closed, as does a malformed condition.

Usage

from sapl_pymongo import MongoDbQueryRewritingProvider, wrap_collection

# At startup: wrap each collection once (this also registers the shim with the planner).
widgets = wrap_collection(database["widgets"])

# Register the provider with the EnforcementPlanner that backs your framework wrapper.
# providers=(MongoDbQueryRewritingProvider(),)

# In a @pre_enforce-protected handler, query the wrapped collection as usual; a
# mongo:queryRewriting obligation on the decision narrows the filter automatically.