MongoDB Context

This package fills a gap in the MongoDB driver by providing a convenient way to create a unified context for database access. It allows you to register a single object within your application, making it easier to interact with the database without worrying about table names, schema configurations, connection strings, and other low-level details.

⚠️ This project is currently used in production across several internal applications without issues. However, please use it with caution — we are planning a refactor to enhance its resilience and expand its functionality.

Compatibilities and driver version

Version	.NET SDK	MongoDB*	MongoDB Driver
>= 1.9	netstandard2.0	7, 8	3

*this version is included in our integration tests. You may try connecting to other compatible driver versions, but stability and compatibility are not guaranteed.

Examples

A running example of the usage is this test project inside the test folder.

Installation

You need to reference two projects:

dotnet add package FmiSrl.MongoDbContext.Abstractions
dotnet add package FmiSrl.MongoDbContext.SourceGenerator

The FmiSrl.MongoDbContext.Abstractions project contains all the abstraction layer and base functionalities for the db context. The FmiSrl.MongoDbContext.SourceGenerator project contains the source generator for generating the specialized code for your db context.

Usage

As usual, create your database layer models, keep in mind, that if the model is a root class with an id and not a nested object you should inherit from IAggregateRoot (in the next versions this requirement will be removed).

public class TestObject : IAggregateRoot
{
    [BsonId(IdGenerator = typeof(StringObjectIdGenerator))]
    public string? Id { get; set; } = null!;
    
    public string Name { get; set; } = null!;
}

---

Create an interface that inherits from IDbContext with all your collections like that.

public interface ITestDbContext : IDbContext
{
    [Collection("Test_Objects")]
    IMongoCollection<TestObject> TestObjects { get; }
    
    IMongoCollection<TestGenericObject<string>> TestGenericObjects { get; }
    
    string GetEmptyString { get; }

    string GetHelloString();
}

As you can see, every collection is registered with type IMongoCollection<T> where T is the type of your object. If you do not provide collection's name with the [Collection("<name>")] attribute, the name of the property was used.

You can place your own methods and properties in the interface to implement it later, they are ignored by the generator.

---

Create a partial class that implements the interface.

public partial class TestDbContext : ITestDbContext
{
    public string GetEmptyString => string.Empty;

    public string GetHelloString()
    {
        return "Say Hello!";
    }
}

You must implement yourself all the methods and properties that are not generated by the generator. The code behind the collection properties will be generated by the source generator.

---

Now you can create a connection to your database and use it directly in your application.

const string connectionString = "mongodb://mongoadmin:mysupersecretpassword@localhost:27017";
const string databaseName = "test";

var dbContext = new TestDbContext(); 
dbContext.OpenConnection(connectionString, databaseName);

or share it using the dependency injection.

builder.Services.AddSingleton<ITestDbContext, TestDbContext>(dbContext);