MongoDB.Extensions provides a set of utility libraries for MongoDB.

MongoDB.Extensions provides several libraries to extend and simplify some MongoDB functionalities like bootstrapping and transactions.

The MongoDB.Extension.Context library provides a bootstrapping context, which is used to initialize the MongoDB connections, databases and collections in a specific and proper way.

Features

• MongoDB Bootstrapping Context
• MongoDB Transactions (InProgress)

Getting Started - MongoDB Bootstrapping

To get started with MongoDB bootstrapping, we have prepared a complete example at SimpleBlog, which is a small REST web-service with the used MongoDB bootstrapping context.

Install

Install the MongoDB.Extensions.Context nuget package for MongoDB bootstrapping:

dotnet add package MongoDB.Extensions.Context

Configure MongoDB Bootstrapping Context

Create a new class and inherit from the MongoDbContext (abstract) class. Add the constructor and override the abstract OnConfiguring method. The MongoOptions only contains the connection string and the database name.

public class SimpleBlogDbContext : MongoDbContext
{
    public SimpleBlogDbContext(MongoOptions mongoOptions)
        : base(mongoOptions)
    {
    }

    protected override void OnConfiguring(IMongoDatabaseBuilder mongoDatabaseBuilder)
    {
        ...
    }
}

In the OnConfiguring method, the MongoDatabaseBuilder is injected. Use this builder to configure your MongoDB connection, database, collections, convention packs, serializer... etc.

protected override void OnConfiguring(IMongoDatabaseBuilder mongoDatabaseBuilder)
{
    mongoDatabaseBuilder
        .RegisterCamelCaseConventionPack()
        .RegisterSerializer(new DateTimeOffsetSerializer())
        .AddAllowedTypes("Namspace.Project")
        .ConfigureConnection(con => con.ReadConcern = ReadConcern.Majority)
        .ConfigureConnection(con => con.WriteConcern = WriteConcern.WMajority)
        .ConfigureConnection(con => con.ReadPreference = ReadPreference.Primary)
        .ConfigureCollection(new TagCollectionConfiguration());
}

To configure a collection of your MongoDB database, create a class with the interface IMongoCollectionConfiguration<TDocument> and register it in the MongoDatabaseBuilder .ConfigureCollection(new TagCollectionConfiguration()) of your MongoDbContext. Configure the collection settings via the injected MongoCollectionBuilder...

public class TagCollectionConfiguration : IMongoCollectionConfiguration<Tag>
{
    public void OnConfiguring(IMongoCollectionBuilder<Tag> mongoCollectionBuilder)
    {
        mongoCollectionBuilder
            .AddBsonClassMap<Tag>(cm => 
            {
                cm.AutoMap();
                cm.SetIgnoreExtraElements(true);
            })
            .WithCollectionSettings(setting =>
            {
                setting.ReadPreference = ReadPreference.Nearest;
                setting.ReadConcern = ReadConcern.Available;
                setting.WriteConcern = WriteConcern.Acknowledged;
            })
            .WithCollectionConfiguration(collection =>
            {
                var timestampIndex = new CreateIndexModel<Tag>(
                    Builders<Tag>.IndexKeys.Ascending(tag => tag.Name),
                    new CreateIndexOptions { Unique = true });

                collection.Indexes.CreateOne(timestampIndex);
            });
    }
}

Register MongoDB Context

To use your MongoDB bootstrapping context, register it in your DI-Container. Example:

public static IServiceCollection AddDatabase(
    this IServiceCollection services, IConfiguration configuration)
{
    MongoOptions blogDbOptions = configuration
        .GetMongoOptions("SimpleBlog:Database");

    services.AddSingleton(blogDbOptions);
    services.AddSingleton<SimpleBlogDbContext>();

    return services;
}

When the MongoDBContext is used the first time, then the connection, database and collections, serializers, classMaps, convention packs etc. will be initialized and configured according your configuration.

Use MongoDB Context

The MongoDbContext contains the configured MongoDB client, database and collections. Therefore we should use always the MongoDbContext to get the client, database or a collection, because they are configured correctly.

public abstract class MongoDbContext : IMongoDbContext
{
    ...
    public IMongoClient Client { get; }
    public IMongoDatabase Database { get; }
    public MongoOptions MongoOptions { get; }

    public IMongoCollection<TDocument> CreateCollection<TDocument>() where TDocument : class;
    ...
}

In the following Repository class example, we use the MongoDbContext to get the configured MongoDB collection.

public class TagRepository : ITagRepository
{
    private IMongoCollection<Tag> _mongoCollection;

    public TagRepository(ISimpleBlogDbContext simpleBlogDbContext)
    {
        if (simpleBlogDbContext == null)
            throw new ArgumentNullException(nameof(simpleBlogDbContext));

        _mongoCollection = simpleBlogDbContext.CreateCollection<Tag>();
    }

    public async Task<IEnumerable<Tag>> GetTagsAsync(
        CancellationToken cancellationToken = default)
    {
        var findOptions = new FindOptions<Tag>();

        IAsyncCursor<Tag> result = await _mongoCollection.FindAsync<Tag>(
            Builders<Tag>.Filter.Empty, findOptions, cancellationToken);

        return await result.ToListAsync();
    }
    ...

A full MongoDB bootstrapping example can be found in our SimpleBlog web-application.

Community

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