v0.0.131

mongoext/aggregation.go

@@ -0,0 +1,57 @@
+package mongoext
+
+import (
+	"context"
+	"go.mongodb.org/mongo-driver/mongo"
+	"gogs.mikescher.com/BlackForestBytes/goext/rfctime"
+	"inopart/backend/common/cursortoken"
+	"inopart/backend/models"
+)
+
+func HandleMongoCursorWithToken[T models.Entity](ctx context.Context, cursor *mongo.Cursor, pageSize *int) ([]T, string, error) {
+	var tokenStr string
+	var docs []T
+	numDocs := cursor.RemainingBatchLength()
+
+	if pageSize == nil || (numDocs <= *pageSize) && numDocs > 0 {
+		docs = make([]T, numDocs)
+
+		err := cursor.All(ctx, &docs)
+		if err != nil {
+			return []T{}, "", err
+		}
+
+	} else if numDocs == *pageSize+1 {
+
+		docs = make([]T, numDocs-1)
+
+		for i := 0; i < numDocs-1; i++ {
+			cursor.Next(ctx)
+			err := cursor.Decode(&docs[i])
+			if err != nil {
+				return []T{}, "", err
+			}
+		}
+
+		var nextPageDoc T
+		cursor.Next(ctx)
+		err := cursor.Decode(&nextPageDoc)
+		if err != nil {
+			return []T{}, "", err
+		}
+
+		nextPageToken := cursortoken.CursorToken{
+			Timestamp: rfctime.RFC3339NanoTime{},
+			Id:        nextPageDoc.GetId(),
+			Offset:    0,
+			PageSize:  *pageSize,
+		}
+
+		tokenStr, err = nextPageToken.Token()
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
+	return docs, tokenStr, nil
+}