package database import ( "context" "fmt" "reflect" "strconv" "strings" "go.mongodb.org/mongo-driver/bson/primitive" "go.mongodb.org/mongo-driver/mongo/options" "github.com/mainnika/mongox-go-driver/v2/mongox" "github.com/mainnika/mongox-go-driver/v2/mongox/query" ) // Database handler type Database struct { client *mongox.Client dbname string ctx context.Context } // NewDatabase function creates new database instance with mongo client and empty context func NewDatabase(client *mongox.Client, dbname string) mongox.Database { db := &Database{} db.client = client db.dbname = dbname return db } // Client function returns a mongo client func (d *Database) Client() *mongox.Client { return d.client } // Context function returns a context func (d *Database) Context() (ctx context.Context) { ctx = d.ctx if ctx == nil { ctx = context.Background() } return } // Name function returns a database name func (d *Database) Name() string { return d.dbname } // New function creates new database context with same client func (d *Database) New(ctx context.Context) mongox.Database { if ctx == nil { ctx = context.Background() } return &Database{ client: d.client, dbname: d.dbname, ctx: ctx, } } // GetCollectionOf returns the collection object by the «collection» tag of the given document; // the «collection» tag should exists, e.g.: // type Foobar struct { // base.ObjectID `bson:",inline" json:",inline" collection:"foobars"` // ... // Will panic if there is no «collection» tag func (d *Database) GetCollectionOf(document interface{}) *mongox.Collection { el := reflect.TypeOf(document).Elem() numField := el.NumField() for i := 0; i < numField; i++ { field := el.Field(i) tag := field.Tag found, ok := tag.Lookup("collection") if !ok { continue } return d.client.Database(d.dbname).Collection(found) } panic(fmt.Errorf("document %v does not have a collection tag", document)) } func (d *Database) createSimpleLoad(target interface{}, composed *query.Query) (cursor *mongox.Cursor, err error) { collection := d.GetCollectionOf(target) opts := options.Find() opts.Sort = composed.Sorter() opts.Limit = composed.Limiter() opts.Skip = composed.Skipper() return collection.Find(d.Context(), composed.M(), opts) } func (d *Database) createAggregateLoad(target interface{}, composed *query.Query) (cursor *mongox.Cursor, err error) { collection := d.GetCollectionOf(target) opts := options.Aggregate() pipeline := primitive.A{} if !composed.Empty() { pipeline = append(pipeline, primitive.M{"$match": composed.M()}) } if composed.Sorter() != nil { pipeline = append(pipeline, primitive.M{"$sort": composed.Sorter()}) } if composed.Skipper() != nil { pipeline = append(pipeline, primitive.M{"$skip": *composed.Skipper()}) } if composed.Limiter() != nil { pipeline = append(pipeline, primitive.M{"$limit": *composed.Limiter()}) } el := reflect.ValueOf(target).Elem() elType := el.Type() numField := elType.NumField() _, preloads := composed.Preloader() for i := 0; i < numField; i++ { field := elType.Field(i) tag := field.Tag preloadTag, ok := tag.Lookup("preload") if !ok { continue } jsonTag, ok := tag.Lookup("json") if jsonTag == "-" { return nil, fmt.Errorf("preload private field is impossible") } jsonData := strings.SplitN(jsonTag, ",", 2) jsonName := field.Name if len(jsonData) > 0 { jsonName = strings.TrimSpace(jsonData[0]) } preloadData := strings.Split(preloadTag, ",") if len(preloadData) == 0 { continue } if len(preloadData) == 1 { panic("there is no foreign field") } localField := strings.TrimSpace(preloadData[0]) if len(localField) == 0 { localField = "_id" } foreignField := strings.TrimSpace(preloadData[1]) if len(foreignField) == 0 { panic("there is no foreign field") } preloadLimiter := 100 preloadReversed := false if len(preloadData) > 2 { stringLimit := strings.TrimSpace(preloadData[2]) intLimit := preloadLimiter preloadReversed = strings.HasPrefix(stringLimit, "-") if preloadReversed { stringLimit = stringLimit[1:] } intLimit, err = strconv.Atoi(stringLimit) if err == nil { preloadLimiter = intLimit } } for _, preload := range preloads { if preload != jsonName { continue } isSlice := el.Field(i).Kind() == reflect.Slice typ := el.Field(i).Type() if typ.Kind() == reflect.Slice { typ = typ.Elem() } if typ.Kind() != reflect.Ptr { panic("preload field should have ptr type") } lookupCollection := d.GetCollectionOf(reflect.Zero(typ).Interface()) lookupVars := primitive.M{"selector": "$" + localField} lookupPipeline := primitive.A{ primitive.M{"$match": primitive.M{"$expr": primitive.M{"$eq": primitive.A{"$" + foreignField, "$$selector"}}}}, } if preloadReversed { lookupPipeline = append(lookupPipeline, primitive.M{"$sort": primitive.M{"_id": -1}}) } if isSlice && preloadLimiter > 0 { lookupPipeline = append(lookupPipeline, primitive.M{"$limit": preloadLimiter}) } else if !isSlice { lookupPipeline = append(lookupPipeline, primitive.M{"$limit": 1}) } pipeline = append(pipeline, primitive.M{ "$lookup": primitive.M{ "from": lookupCollection.Name(), "let": lookupVars, "pipeline": lookupPipeline, "as": jsonName, }, }) if isSlice { continue } pipeline = append(pipeline, primitive.M{ "$unwind": primitive.M{ "preserveNullAndEmptyArrays": true, "path": "$" + jsonName, }, }) } } return collection.Aggregate(d.Context(), pipeline, opts) }