dotnet-mongodb: A C# repository from .NET School

To create a simple todo app with react and dotnet refer : https://github.com/dotnet-school/dotnet-react

Refer official doc : https://docs.microsoft.com/en-us/aspnet/core/tutorials/first-mongo-app?view=aspnetcore-3.1&tabs=visual-studio

Steps to add mongo

Add mongo driver Nuget package
create mongo configuration in app settings
create model for mongo settings
wire mongo setting with dependency injection in Startup.cs
create a singleton service that uses mongo client
inject settings in service and initialize mongo client
wire controller to use the service
update model for mappign mongo ids

Install mongodb on local machine

install mongodb and make sure it works on local machine
use a gui tool like https://robomongo.org/
We can instead use docker to install mongo db in single step and remove image when we are done :
```
docker run  -i -v $PWD/db:/data/db -p 27017:27017 mongo:3.6.18
```
- this will start a docker container that listens to port 27017
- take a note of the db directory $PWD/db. If you change this, you will not see the data you saved earlier.
- you can run this as a backgroudn task (daemon mode) using flag -d
- connect with db to make sure our db is up and running

Setup project

clone this repo https://github.com/dotnet-school/dotnet-react
Creating a servivce
- Currenlty this has all fake logic in controller, we will move this logic to service
- Then we will make this serice use mongo client to save and fetch data from database

Create a service : TodoApp/Services/TodoService.cs

using System.Collections.Generic;
using System.Linq;
using MongoDB.Driver;
using TodoApp.Models;

namespace TodoApp.Services
{
  public class TodoService
  {
  }
}

Now wire this with the dependency injection in Startup.cs :

public void ConfigureServices(IServiceCollection services)
{
	services.AddControllersWithViews();
+	services.AddSingleton<TodoService>();

Inject the service in controller:

public class TodosController : ControllerBase
{

+		private TodoService _todoService;
+		public TodosController(TodoService service)
+		{
+			_todoService = service;
+		}

[HttpGet]

Now just move all code for fake data items from controller to service:

controller:

using System.Collections.Generic;
using Microsoft.AspNetCore.Mvc;
using TodoApp.Models;
using TodoApp.Services;

namespace TodoApp.Controllers
{
  [ApiController]
  [Route("/api/[controller]")]
  public class TodosController : ControllerBase
  {
    private TodoService _todoService;

    public TodosController(TodoService service)
    {
      _todoService = service;
    }

    [HttpGet]
    public IEnumerable<TodoItem> GetAll()
    {
      return _todoService.GetAll();
    }

    [HttpGet("{id}")]
    public ActionResult<TodoItem> GetById(string id)
    {
      var todoItem = _todoService.GetById(id);
      if (todoItem == null) return NotFound();
      return todoItem;
    }

    [HttpPost]
    public ActionResult CreateItem(TodoItem data)
    {
      TodoItem todoItem = _todoService.CreateItem(data);
      return CreatedAtAction("GetById", new {Id = todoItem.Id}, todoItem);
    }

    [HttpPut("{id}")]
    public ActionResult GetById(string id, TodoItem data)
    {
      if (id != data.Id) return BadRequest("Ids in path and data do not match");

      var item = _todoService.GetById(id);

      if (item == null) return NotFound();

      _todoService.UpdateItem(data);

      return Ok();
    }

    [HttpDelete("{id}")]
    public ActionResult DeleteTas(string id)
    {
      var item = _todoService.GetById(id);
      if (item == null) return NotFound();

      _todoService.Delete(item);
      return Ok();
    }
  }
}

service:

using System.Collections.Generic;
using System.Linq;
using TodoApp.Models;

namespace TodoApp.Services
{
  public class TodoService
  {
    private static IList<TodoItem> fakeItems = new List<TodoItem>()
    {
            new TodoItem() {Id = "one", Description = "task one", IsCompleted = true},
            new TodoItem() {Id = "two", Description = "task two", IsCompleted = false},
            new TodoItem() {Id = "three", Description = "task three", IsCompleted = false}
    };

    public IEnumerable<TodoItem> GetAll()
    {
      return fakeItems;
    }

    public TodoItem GetById(string id)
    {
      return fakeItems.First(item => item.Id == id);
    }

    public TodoItem UpdateItem(TodoItem data)
    {
      var item = fakeItems.First(item => item.Id == data.Id);
      item.Description = data.Description;
      item.IsCompleted = data.IsCompleted;
      return item;
    }

    public TodoItem CreateItem(TodoItem data)
    {
      data.Id = $"task-{fakeItems.Count}";
      fakeItems.Add(data);
      return data;
    }

    public void Delete(TodoItem item)
    {
      fakeItems.Remove(item);
    }
  }
}

Setup Mongo with .NET project

Add mongo driver Nuget package

cd TodoApp
dotnet add package MongoDB.Driver

TodoApp.csproj:

   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.SpaServices.Extensions" Version="3.1.0" />
+    <PackageReference Include="MongoDB.Driver" Version="2.10.4" />
   </ItemGroup>

   <ItemGroup>

Create the mongo db settings in appsettings.Development.json

  "MongoSettings": {
    "ConnectionString": "mongodb://localhost:27017",
    "DbName": "dotnet-mongo-demo",
    "TodoCollection": "Todo"
  }

Create a model class that represents the settings.

dotnet will load settings in object of this model

our service will recive this model to configure the mongo client

namespace TodoApp.Models
{
  public class MongoSettings
  {
    public string ConnectionString { get; set; }
    public string DbName { get; set; }
    public string TodoCollection { get; set; }
  }
}

Wire the settings with DI in TodoApp/Startup.cs

+using Microsoft.Extensions.Options;
+using TodoApp.Models;

public void ConfigureServices(IServiceCollection services)
{

  services.AddControllersWithViews();

+ // This will map the model class to the section in appsettings.json
+ services.Configure<MongoSettings>(Configuration.GetSection(nameof(MongoSettings)));

+ // This will inject the values from appsettings into model instance
+ services.AddSingleton<MongoSettings>(s => s.GetRequiredService<IOptions<MongoSettings>>().Value);

  services.AddSpaStaticFiles(configuration =>

Inject the settings into service:

We wil now inject these settings from appsettings.json into our service

+ using MongoDB.Driver;
using TodoApp.Models;

namespace TodoApp.Services
{
  public class TodoService
  {
+    private IMongoCollection<TodoItem> _todosCollection;
+    public TodoService(MongoSettings settings)
+    {
+      _todosCollection = new MongoClient(settings.ConnectionString)
+              .GetDatabase(settings.DbName)
+              .GetCollection<TodoItem>(settings.TodoCollection);
+    }
  }
}

Update model for mongo

+using MongoDB.Bson;
+using MongoDB.Bson.Serialization.Attributes;
+
 namespace TodoApp.Models
 {
   public class TodoItem
   {
+    // Mongo uses BsonId for keys
+    [BsonId]
+    [BsonRepresentation(BsonType.ObjectId)]
     public string Id {get;set;}

     public string Description {get; set;}
     public bool IsCompleted {get; set;}
   }

Now update service to read/write using mongo collectoins instead of im memory list

using System.Collections.Generic;
using System.Linq;
using MongoDB.Driver;
using TodoApp.Models;

namespace TodoApp.Services
{
  public class TodoService
  {
    private IMongoCollection<TodoItem> _todosCollection;

    public TodoService(MongoSettings settings)
    {
      _todosCollection = new MongoClient(settings.ConnectionString)
              .GetDatabase(settings.DbName)
              .GetCollection<TodoItem>(settings.TodoCollection);
    }

    public IEnumerable<TodoItem> GetAll()
    {
      return _todosCollection.Find(t => true).ToList();
    }

    public TodoItem GetById(string id)
    {
      return _todosCollection.Find(t => t.Id == id).First();
    }

    public TodoItem UpdateItem(TodoItem data)
    {
      _todosCollection.ReplaceOne(t => t.Id == data.Id, data);
      return data;
    }

    public TodoItem CreateItem(TodoItem data)
    {
      _todosCollection.InsertOne(data);
      return data;
    }

    public void Delete(TodoItem item)
    {
      _todosCollection.DeleteOne(t => t.Id == item.Id);
    }
  }
}

dotnet-school/dotnet-mongodb

Steps to add mongo

Install mongodb on local machine

Setup project

Setup Mongo with .NET project