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5. Data access - entityframework integration

2022-07-07 05:33:00 【MASA team】

Preface

Masa Provides the basis for EntityFramework Data integration for , It also provides the functions of data filtering and soft deletion , Now we will introduce how to use it ？

MasaDbContext introduction

install .Net 6.0

newly build ASP.NET Core Empty item Assignment.MasaEntityFramework, And install Masa.Contrib.Data.EntityFrameworkCore、Swashbuckle.AspNetCore、Microsoft.EntityFrameworkCore.InMemory、Microsoft.EntityFrameworkCore.Tools
```
dotnet add package Masa.Contrib.Data.EntityFrameworkCore --version 0.4.0-rc.4
dotnet add package Swashbuckle.AspNetCore --version 6.2.3
dotnet add package Microsoft.EntityFrameworkCore.InMemory --version 6.0.5
dotnet add package Microsoft.EntityFrameworkCore.Tools --version 6.0.5
```
install Swashbuckle.AspNetCore For the convenience of passing Swagger To operate the service
install Microsoft.EntityFrameworkCore.InMemory It's for convenience , So use an in memory database , If you need to use other databases , Please install the corresponding package by yourself
install Microsoft.EntityFrameworkCore.Tools To use CodeFirst Create database

The new class User

public class User
{
    public int Id { get; set; }

    public string Name { get; set; }

    public uint Gender { get; set; }

    public DateTime BirthDay { get; set; }

    public DateTime CreationTime { get; set; }

    public User()
    {
        this.CreationTime = DateTime.Now;
    }
}

New user context UserDbContext.cs
```
public class UserDbContext : MasaDbContext
{
    public DbSet<User> User { get; set; }

    public UserDbContext(MasaDbContextOptions options) : base(options)
    {
    }
}
```
UserDbContext Instead of inheritance MasaDbContext, And add a parameter constructor , Parameter type is MasaDbContextOptions
When there are multiple DbContext when , It needs to be inherited MasaDbContext<TDbContext>, The constructor parameter type is changed to MasaDbContext<TDbContext>

The new class AddUserRequest As a parameter for adding users

public class AddUserRequest
{
    public string Name { get; set; }

    public uint Gender { get; set; }

    public DateTime BirthDay { get; set; }
}

The new class HostExtensions For migrating databases （ Use CodeFirst）

public static class HostExtensions
{
    public static void MigrateDbContext<TContext>(
        this IHost host, Action<TContext, IServiceProvider> seeder) where TContext : DbContext
    {
        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            var context = services.GetRequiredService<TContext>();
            context.Database.EnsureCreated();
            seeder(context, services);
        }
    }
}

modify Program.cs, newly added Swagger Support

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

app.UseSwagger();
app.UseSwaggerUI();

Unwanted Swagger Don't add , Use Swagger Just to test and invoke the service , Use Postman Or something else Http Tools can also

modify Program.cs, Add user context （ a key ）

builder.Services.AddMasaDbContext<UserDbContext>(options => 
{
  options.Builder = (_, dbContextOptionsBuilder) => dbContextOptionsBuilder.UseInMemoryDatabase("test")
});

modify Program.cs, Make the project support CodeFirst
```
app.MigrateDbContext<UserDbContext>((context, services) =>
{
});
```
Unwanted CodeFirst, Code generation is not supported, and the database cannot be added

test MasaDbContext, modify Program.cs

app.MapPost("/add", (UserDbContext dbContext, [FromBody] AddUserRequest request) =>
{
    dbContext.Set<User>().Add(new User()
    {
        Name = request.Name,
        Gender = request.Gender,
        BirthDay = request.BirthDay
    });
    dbContext.SaveChanges();
});

app.MapGet("/list", (UserDbContext dbContext) =>
{
    return dbContext.Set<User>().ToList();
});

Run the project by yourself , perform add Then create a new user , After performing list Get more than one user data , Then prove MasaDbContext Correct use

How to use soft delete

Choose Assignment.MasaEntityFramework And install Masa.Contrib.Data.Contracts.EF
```
dotnet add package Masa.Contrib.Data.Contracts.EF --version 0.4.0-rc.4
```

Modify the class User, And implement ISoftDelete, Change the code to ：

public class User : ISoftDelete// a key ： Change to implementation ISoftDelete
{
    public int Id { get; set; }

    public string Name { get; set; }

    public uint Gender { get; set; }

    public DateTime BirthDay { get; set; }

    public DateTime CreationTime { get; set; }

    public bool IsDeleted { get; private set; }

    public User()
    {
        this.CreationTime = DateTime.Now;
    }
}

Increase implementation ISoftDelete, And for IsDeleted Attribute addition set Support （ It can be private set;）

modify Program.cs, And enable data filtering

builder.Services.AddMasaDbContext<UserDbContext>(options =>
{
    options.Builder = (_, dbContextOptionsBuilder) => dbContextOptionsBuilder.UseInMemoryDatabase("test");
    options.UseFilter();// Enable data filtering , Complete writing ：options.UseFilter(filterOptions => filterOptions.EnableSoftDelete = true);
});

Test whether the soft deletion is successful

modify Program.cs, Add delete method

app.MapDelete("/delete", (UserDbContext dbContext, int id) =>
{
    var user = dbContext.Set<User>().First(u => u.Id == id);
    dbContext.Set<User>().Remove(user);
    dbContext.SaveChanges();
});

Last , First call add Method after creating the user , Call later list Method to get the list of all users , And take out any one id Information , Then call delete Method to delete the user , Last call list Method , View removed id Whether there is , To verify whether the soft deletion is effective .

How to temporarily disable soft deletion filtering

In the default query, the data marked with deleted tags will be filtered and no longer be queried , But there are also some scenarios that need to query all the data , At this point, you need to use data filtering IDataFilter

newly added All Method is used to query all data （ Contains data marked as deleted ）

app.MapGet("/all", (UserDbContext dbContext, [FromServices] IDataFilter dataFilter) =>
{
    // adopt DI Get IDataFilter, And call it Disable Method can be temporarily disabled ISoftDelete filter 
    using (dataFilter.Disable<ISoftDelete>())
    {
        return dbContext.Set<User>().ToList();
    }
});

Rerun the project , Repeat the steps of verifying soft deletion , Make sure to pass list Method cannot access data
The reason for repeating the verify soft delete step is that this example uses an in memory database , After the project stops , All data will be cleared , Re execution is to ensure that the data exists , Only marked for deletion
perform all Method , Get all the data , see id Whether the corresponding user data exists

Get the database connection string from the configuration file

Selected items Assignment.MasaEntityFramework, And install Masa.Contrib.Data.EntityFrameworkCore.InMemory
```
dotnet add package Masa.Contrib.Data.EntityFrameworkCore.InMemory --version 0.4.0-rc.4
```
Install the corresponding database package as needed , Such as ：Masa.Contrib.Data.EntityFrameworkCore.SqlServer (SqlServer)、Masa.Contrib.Data.EntityFrameworkCore.Pomelo.MySql (Pomelo Provided MySql)、Masa.Contrib.Data.EntityFrameworkCore.Oracle (Oracle) etc.

modify Program.cs, Adjust the configuration of adding user context to :

builder.Services.AddMasaDbContext<UserDbContext>(options => options.UseInMemoryDatabase().UseFilter());

modify appsettings.json, Add user database connection string :

{
      
  "ConnectionStrings": {
      
    "DefaultConnection": "test"// Replace with the specified database connection string 
  }
}

modify Program.cs, newly added database Method , Verify that the current database is test

app.MapGet("/database", (UserDbContext dbContext) =>
{
    var field = typeof(MasaDbContext).GetField("Options", BindingFlags.Public | BindingFlags.Instance | BindingFlags.NonPublic)!;
    var masaDbContextOptions = field.GetValue(dbContext) as MasaDbContextOptions;
    foreach (var dbContextOptionsExtension in masaDbContextOptions!.Extensions)
    {
        if (dbContextOptionsExtension is InMemoryOptionsExtension memoryOptionsExtension)
        {
            return memoryOptionsExtension.StoreName;
        }
    }

    return "";
});

Last visit http://localhost:5002/database, Verify whether the current database name is consistent with the modified database name
Verify that the database is test

common problem

How to change the default read configuration node ?

Modify user context UserDbContext And increase ConnectionStringName characteristic :

[ConnectionStringName("User")]// Custom node name 
public class UserDbContext : MasaDbContext
{
    public DbSet<User> User { get; set; }

    public UserDbContext(MasaDbContextOptions options) : base(options)
    {
    }
}

Modify the configuration appsettings.json

{
  "ConnectionStrings": {
    "User": "test"// Instead of from User The node reads the database connection string 
  }
}

In addition to getting from the configuration file , Does it also support getting database connection strings from other places ？

There are currently two ways to change the database connection string .

Method 1: modify Program.cs, And delete appsettings.json Configuration of database connection string

modify Program.cs

builder.Services.Configure<MasaDbConnectionOptions>(option =>
{
    option.ConnectionStrings = new ConnectionStrings(new List<KeyValuePair<string, string>>()
    {
        new("User", "test2")// Where the key is the node name , And ConnectionStringName Characteristic Name Keep the values consistent , If not specified ConnectionStringName, It should be DefaultConnection, The value is the database connection string 
    });
});

modify appsettings.json To configure

//  "ConnectionStrings": {
//    "User": "test"
//  },

call database Method , Verify whether the current database is test2

Verify that the database is test2

Method 2: rewrite IConnectionStringProvider and IDbConnectionStringProvider And add to DI in

The new class CustomizeConnectionStringProvider

public class CustomizeConnectionStringProvider : IConnectionStringProvider
{
    public Task<string> GetConnectionStringAsync(string name = "DefaultConnection") => Task.FromResult    (GetConnectionString(name));

    public string GetConnectionString(string name = "DefaultConnection") => "test3";
}

The new class CustomizeDbConnectionStringProvider

public class CustomizeDbConnectionStringProvider : IDbConnectionStringProvider
{
    public List<MasaDbContextConfigurationOptions> DbContextOptionsList { get; } = new()
    {
        new MasaDbContextConfigurationOptions("test3")
    };
}

modify Program.cs

builder.Services.AddSingleton<IConnectionStringProvider,CustomizeConnectionStringProvider>();
builder.Services.AddSingleton<IDbConnectionStringProvider,CustomizeDbConnectionStringProvider>();

call database Method , Verify whether the current database is test3

summary

This article mainly explains MasaDbContext Basic usage and soft deletion 、 How to use data filtering , In the next article, we will explain MasaDbContext How to realize soft deletion 、 Data filtered , And how to realize it when using the database without specifying the database link string mentioned in this article