Working With MongoDB Transactions With C# and the .NET Framework

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using MongoDB.Bson;
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using MongoDB.Bson.Serialization.Attributes;
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using MongoDB.Driver;
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using System;
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using System.Threading.Tasks;
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namespace MongoDBTransaction
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{
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    public static class Program
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    {
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        public class Product
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        {
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            [BsonId]
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            public ObjectId Id { get; set; }
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            [BsonElement("SKU")]
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            public int SKU { get; set; }
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            [BsonElement("Description")]
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            public string Description { get; set; }
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            [BsonElement("Price")]
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            public Double Price { get; set; }
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        }
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        // replace with your connection string if it is different
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        const string MongoDBConnectionString = "mongodb://localhost"; 
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        public static async Task Main(string[] args)
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        {
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            if (!await UpdateProductsAsync()) { Environment.Exit(1); }
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            Console.WriteLine("Finished updating the product collection");
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            Console.ReadKey();
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        }
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        private static async Task<bool> UpdateProductsAsync()
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        {
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            // Create client connection to our MongoDB database
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            var client = new MongoClient(MongoDBConnectionString);
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            // Create the collection object that represents the "products" collection
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            var database = client.GetDatabase("MongoDBStore");
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            var products = database.GetCollection<Product>("products");
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            // Clean up the collection if there is data in there
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            await database.DropCollectionAsync("products");
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            // collections can't be created inside a transaction so create it first
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            await database.CreateCollectionAsync("products"); 
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            // Create a session object that is used when leveraging transactions
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            using (var session = await client.StartSessionAsync())
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            {
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                // Begin transaction
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                session.StartTransaction();
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                try
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                {
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                    // Create some sample data
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                    var tv = new Product { Description = "Television", 
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                                    SKU = 4001, 
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                                    Price = 2000 };
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                    var book = new Product { Description = "A funny book", 
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                                    SKU = 43221, 
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                                    Price = 19.99 };
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                    var dogBowl = new Product { Description = "Bowl for Fido", 
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                                    SKU = 123, 
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                                    Price = 40.00 };
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                    // Insert the sample data 
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                    await products.InsertOneAsync(session, tv);
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                    await products.InsertOneAsync(session, book);
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                    await products.InsertOneAsync(session, dogBowl);
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                    var resultsBeforeUpdates = await products
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                                    .Find<Product>(session, Builders<Product>.Filter.Empty)
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                                    .ToListAsync();
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                    Console.WriteLine("Original Prices:\n");
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                    foreach (Product d in resultsBeforeUpdates)
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                    {
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                        Console.WriteLine(
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                                    String.Format("Product Name: {0}\tPrice: {1:0.00}", 
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                                        d.Description, d.Price)
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                        );
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                    }
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                    // Increase all the prices by 10% for all products
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                    var update = new UpdateDefinitionBuilder<Product>()
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                            .Mul<Double>(r => r.Price, 1.1);
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                    await products.UpdateManyAsync(session, 
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                            Builders<Product>.Filter.Empty, 
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                            update); //,options);
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                    // Made it here without error? Let's commit the transaction
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                    await session.CommitTransactionAsync();
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                }
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                catch (Exception e)
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                {
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                    Console.WriteLine("Error writing to MongoDB: " + e.Message);
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                    await session.AbortTransactionAsync();
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                    return false;
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                }
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                // Let's print the new results to the console
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                Console.WriteLine("\n\nNew Prices (10% increase):\n");
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                var resultsAfterCommit = await products
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                        .Find<Product>(session, Builders<Product>.Filter.Empty)
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                        .ToListAsync();
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                foreach (Product d in resultsAfterCommit)
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                {
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                    Console.WriteLine(
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                        String.Format("Product Name: {0}\tPrice: {1:0.00}", 
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                                                    d.Description, d.Price)
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                    );
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                }
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                return true;
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            }
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        }
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    }
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}