mongodb

data-mongo

MongoDB adapter for the "data" interface

data-mongo implements the benpate/data interfaces (Server, Session, Collection, Iterator) on top of the official MongoDB Go driver. It lets application code perform CRUD operations against MongoDB through the generic data abstraction, without importing the driver directly. Queries are written as benpate/exp expressions, which this package translates into native BSON.

server, err := mongodb.New("mongodb://localhost:27017", "mydatabase", nil)
session, err := server.Session(ctx)
collection := session.Collection("users")

err = collection.Load(exp.Equal("username", "sarah"), &user)

What matters here

• String-match operators are escaped against regex injection. BeginsWith / Contains / EndsWith compile to MongoDB $regex, so the user value is run through regexp.QuoteMeta before embedding. Removing that escaping would let input inject metacharacters (a . matching anything) or a pathological pattern (ReDoS). See operatorBSON in expression.go.

• Delete is a virtual delete; HardDelete is physical. Delete marks the object deleted and re-saves it (the row stays in the database); only HardDelete issues a real DeleteMany. Don't assume Delete removes data.

• Session.Close is intentionally a no-op. Connections are owned by the long-lived *mongo.Client pool, not the session. Per-request cleanup happens by cancelling the context.Context passed to Server.Session, not by calling Close. The method exists only to satisfy the interface.

• The query context is carried on the Collection/Session structs, set when the session is opened. This is a deliberate deviation from "don't store a context in a struct," dictated by the data interface shape — methods like Load/Save take no ctx argument.

• Slow-query logging is off by default and global. Call SetLogTimeout(ms) to enable it. The threshold is read atomically, so it is safe to change while queries are in flight. When disabled, the per-query timer is skipped entirely (no time.Now() cost).

• Transactions require a replica set or mongos. Server.WithTransaction uses majority read/write concern and causal consistency; it will fail against a standalone mongod.

• Geometry values are passed through as-is. The GeoWithin / GeoIntersects operators expect the value to already be a GeoJSON map[string]any — produced upstream by exp.GeoWithin / exp.GeoIntersects calling GeoJSON() on a geo shape. This package does no GeoJSON conversion of its own.