edg3/experiment_software_csharp_12_net_8 · Datasets at Hugging Face

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21:1325	context.Database.Migrate() is useful to quickly set up and update staging and test environments. When deploying in production, if we don’t have the credentials for creating a new database or for modifying its structure, we can also produce an SQL script from the migrations using the migration tools. Then, this script should be examined before being applied by the person in charge of maintaining the database and, finally, applied with their credentials.
21:1326	To create migrations, we must add the aforementioned extension methods to the ASP.NET Core MVC Program.cs file, as shown here:
21:1327	...
21:1328	builder.Services.AddRazorPages();
21:1329	builder.Services.AddDbLayer(
21:1330	builder.Configuration.GetConnectionString(`DefaultConnection`),
21:1331	`PackagesManagementDB`);
21:1332	...
21:1333	app.UseAuthentication();
21:1334	app.UseAuthorization();
21:1335	...
21:1336
21:1337	Please be sure that both the authorization and authentication middleware have been added to the ASP.NET Core pipeline in the right order; otherwise, the authentication/authorization engine will not work.
21:1338	Then, we must add the connection string to the appsettings.json file, as shown here:
21:1339	{
21:1340	`ConnectionStrings`: {
21:1341	`DefaultConnection`: `Server=(localdb)mssqllocaldb;Database=package-management;Trusted_Connection=True;MultipleActiveResultSets=true`
21:1342	},
21:1343	...
21:1344	}
21:1345
21:1346	Finally, let’s add Microsoft.EntityFrameworkCore.Design to the ASP.NET Core project.
21:1347	At this point, let’s open the Visual Studio Package Manager Console, select PackageManagementDB as the default project, and then launch the following command:
21:1348	Add-Migration Initial -Project PackageManagementDB
21:1349
21:1350	The preceding command will scaffold the first migration. We may apply it to the database with the Update-Database command. Please note that if you copy the project from GitHub, you don’t need to scaffold migrations since they have already been created, but you still need to update the database.
21:1351	In the next subsection, we will define the application layer that contains the business logic for manipulating the aggregates.
21:1352	Defining the application layer
21:1353	As a first step, for simplicity, let’s freeze the application culture to en-US by adding the following code to the ASP.NET Core pipeline:
21:1354	app.UseAuthorization();
21:1355	// Code to add: configure the Localization middleware
21:1356	var ci = new CultureInfo(`en-US`);
21:1357	app.UseRequestLocalization(new RequestLocalizationOptions
21:1358	{
21:1359	DefaultRequestCulture = new RequestCulture(ci),
21:1360	SupportedCultures = new List<CultureInfo>
21:1361	{
21:1362	ci,
21:1363	},
21:1364	SupportedUICultures = new List<CultureInfo>
21:1365	{
21:1366	ci,
21:1367	}
21:1368	});
21:1369
21:1370	Then, let’s create a Tools folder and place the ApplicationLayer code there, which you can find in the ch11 code of the GitHub repository associated with this book. With these tools in place, we can add the code that automatically discovers and adds all queries, command handlers, and event handlers to the DI engine, as shown here:
21:1371	...
21:1372	...
21:1373	builder.Services.AddAllQueries(this.GetType().Assembly);
21:1374	builder.Services.AddAllCommandHandlers(this.GetType().Assembly);
21:1375	builder.Services.AddAllEventHandlers(this.GetType().Assembly);
21:1376
21:1377	Then, we must add a Queries folder to place all queries and their associated interfaces. As an example, let’s have a look at the query that lists all packages:
21:1378	public class PackagesListQuery(MainDbContext ctx) :IPackagesListQuery
21:1379	{
21:1380	public async Task<IReadOnlyCollection<PackageInfosViewModel>> GetAllPackages()
21:1381	{
21:1382	return await ctx.Packages.Select(m => new PackageInfosViewModel
21:1383	{
21:1384	StartValidityDate = m.StartValidityDate,
21:1385	EndValidityDate = m.EndValidityDate,
21:1386	Name = m.Name,
21:1387	DurationInDays = m.DurationInDays,
21:1388	Id = m.Id,
21:1389	Price = m.Price,
21:1390	DestinationName = m.MyDestination.Name,
21:1391	DestinationId = m.DestinationId
21:1392	})
21:1393	.OrderByDescending(m=> m.EndValidityDate)
21:1394	.ToListAsync();
21:1395	}
21:1396	}
21:1397
21:1398	The query object is automatically injected into the application DB context. The GetAllPackages method uses LINQ to project all of the required information into PackageInfosViewModel and sorts all results in descending order on the EndValidityDate property.
21:1399	Projections that involve several properties are time-wasting and error-prone; that’s why there are mapping libraries that automatically generate these projections using naming conventions and configuration settings. Mapping libraries helps also in copying data from one object to another, such as, for example, from a ViewModel to a DTO, and vice versa.
21:1400	Among all mapping software, it is worth at least mentioning AutoMapper (https://www.nuget.org/packages/AutoMapper).
21:1401	PackageInfosViewModel is placed in the Models folder together with all other ViewModels. It is common practice to organize ViewModels into folders by defining a different folder for each controller. It is worth analyzing the ViewModel used for editing packages:
21:1402	public class PackageFullEditViewModel: IPackageFullEditDTO
21:1403	{
21:1404	public PackageFullEditViewModel() { }
21:1405	public PackageFullEditViewModel(IPackage o)
21:1406	{
21:1407	Id = o.Id;
21:1408	DestinationId = o.DestinationId;
21:1409	Name = o.Name;
21:1410	Description = o.Description;
21:1411	Price = o.Price;
21:1412	DurationInDays = o.DurationInDays;
21:1413	StartValidityDate = o.StartValidityDate;
21:1414	EndValidityDate = o.EndValidityDate;
21:1415	}
21:1416	...
21:1417	...
21:1418
21:1419	It has a constructor that accepts an IPackage aggregate. This way, package data is copied into the ViewModel that is used to populate the edit view. It implements the IPackageFullEditDTO DTO interface defined in the domain layer. This way, it can be directly used to send IPackage updates to the domain layer.
21:1420	All properties contain validation attributes that are automatically used by client-side and server-side validation engines. Each property contains a Display attribute that defines the label to give to the input field that will be used to edit the property. It is better to place the field labels in the ViewModels than it is to place them directly into the views since, this way, the same names are automatically used in all views that use the same ViewModel. The following code block lists all its properties:
21:1421	public int Id { get; set; }
21:1422	[StringLength(128, MinimumLength = 5), Required]
21:1423	[Display(Name = `name`)]
21:1424	public string Name { get; set; }= null!;

21:1325

context.Database.Migrate() is useful to quickly set up and update staging and test environments. When deploying in production, if we don’t have the credentials for creating a new database or for modifying its structure, we can also produce an SQL script from the migrations using the migration tools. Then, this script should be examined before being applied by the person in charge of maintaining the database and, finally, applied with their credentials.

21:1326

To create migrations, we must add the aforementioned extension methods to the ASP.NET Core MVC Program.cs file, as shown here:

21:1327

...

21:1328

builder.Services.AddRazorPages();

21:1329

builder.Services.AddDbLayer(

21:1330

builder.Configuration.GetConnectionString(`DefaultConnection`),

21:1331

`PackagesManagementDB`);

21:1332

...

21:1333

app.UseAuthentication();

21:1334

app.UseAuthorization();

21:1335

...

21:1336

21:1337

Please be sure that both the authorization and authentication middleware have been added to the ASP.NET Core pipeline in the right order; otherwise, the authentication/authorization engine will not work.

21:1338

Then, we must add the connection string to the appsettings.json file, as shown here:

21:1339

{

21:1340

`ConnectionStrings`: {

21:1341

`DefaultConnection`: `Server=(localdb)mssqllocaldb;Database=package-management;Trusted_Connection=True;MultipleActiveResultSets=true`

21:1342

},

21:1343

...

21:1344

}

21:1345

21:1346

Finally, let’s add Microsoft.EntityFrameworkCore.Design to the ASP.NET Core project.

21:1347

At this point, let’s open the Visual Studio Package Manager Console, select PackageManagementDB as the default project, and then launch the following command:

21:1348

Add-Migration Initial -Project PackageManagementDB

21:1349

21:1350

The preceding command will scaffold the first migration. We may apply it to the database with the Update-Database command. Please note that if you copy the project from GitHub, you don’t need to scaffold migrations since they have already been created, but you still need to update the database.

21:1351

In the next subsection, we will define the application layer that contains the business logic for manipulating the aggregates.

21:1352

Defining the application layer

21:1353

As a first step, for simplicity, let’s freeze the application culture to en-US by adding the following code to the ASP.NET Core pipeline:

21:1354

app.UseAuthorization();

21:1355

// Code to add: configure the Localization middleware

21:1356

var ci = new CultureInfo(`en-US`);

21:1357

app.UseRequestLocalization(new RequestLocalizationOptions

21:1358

{

21:1359

DefaultRequestCulture = new RequestCulture(ci),

21:1360

SupportedCultures = new List<CultureInfo>

21:1361

{

21:1362

ci,

21:1363

},

21:1364

SupportedUICultures = new List<CultureInfo>

21:1365

{

21:1366

ci,

21:1367

}

21:1368

});

21:1369

21:1370

Then, let’s create a Tools folder and place the ApplicationLayer code there, which you can find in the ch11 code of the GitHub repository associated with this book. With these tools in place, we can add the code that automatically discovers and adds all queries, command handlers, and event handlers to the DI engine, as shown here:

21:1371

...

21:1372

...

21:1373

builder.Services.AddAllQueries(this.GetType().Assembly);

21:1374

builder.Services.AddAllCommandHandlers(this.GetType().Assembly);

21:1375

builder.Services.AddAllEventHandlers(this.GetType().Assembly);

21:1376

21:1377

Then, we must add a Queries folder to place all queries and their associated interfaces. As an example, let’s have a look at the query that lists all packages:

21:1378

public class PackagesListQuery(MainDbContext ctx) :IPackagesListQuery

21:1379

{

21:1380

public async Task<IReadOnlyCollection<PackageInfosViewModel>> GetAllPackages()

21:1381

{

21:1382

return await ctx.Packages.Select(m => new PackageInfosViewModel

21:1383

{

21:1384

StartValidityDate = m.StartValidityDate,

21:1385

EndValidityDate = m.EndValidityDate,

21:1386

Name = m.Name,

21:1387

DurationInDays = m.DurationInDays,

21:1388

Id = m.Id,

21:1389

Price = m.Price,

21:1390

DestinationName = m.MyDestination.Name,

21:1391

DestinationId = m.DestinationId

21:1392

})

21:1393

.OrderByDescending(m=> m.EndValidityDate)

21:1394

.ToListAsync();

21:1395

}

21:1396

}

21:1397

21:1398

The query object is automatically injected into the application DB context. The GetAllPackages method uses LINQ to project all of the required information into PackageInfosViewModel and sorts all results in descending order on the EndValidityDate property.

21:1399

Projections that involve several properties are time-wasting and error-prone; that’s why there are mapping libraries that automatically generate these projections using naming conventions and configuration settings. Mapping libraries helps also in copying data from one object to another, such as, for example, from a ViewModel to a DTO, and vice versa.

21:1400

Among all mapping software, it is worth at least mentioning AutoMapper (https://www.nuget.org/packages/AutoMapper).

21:1401

PackageInfosViewModel is placed in the Models folder together with all other ViewModels. It is common practice to organize ViewModels into folders by defining a different folder for each controller. It is worth analyzing the ViewModel used for editing packages:

21:1402

public class PackageFullEditViewModel: IPackageFullEditDTO

21:1403

{

21:1404

public PackageFullEditViewModel() { }

21:1405

public PackageFullEditViewModel(IPackage o)

21:1406

{

21:1407

Id = o.Id;

21:1408

DestinationId = o.DestinationId;

21:1409

Name = o.Name;

21:1410

Description = o.Description;

21:1411

Price = o.Price;

21:1412

DurationInDays = o.DurationInDays;

21:1413

StartValidityDate = o.StartValidityDate;

21:1414

EndValidityDate = o.EndValidityDate;

21:1415

}

21:1416

...

21:1417

...

21:1418

21:1419

It has a constructor that accepts an IPackage aggregate. This way, package data is copied into the ViewModel that is used to populate the edit view. It implements the IPackageFullEditDTO DTO interface defined in the domain layer. This way, it can be directly used to send IPackage updates to the domain layer.

21:1420

All properties contain validation attributes that are automatically used by client-side and server-side validation engines. Each property contains a Display attribute that defines the label to give to the input field that will be used to edit the property. It is better to place the field labels in the ViewModels than it is to place them directly into the views since, this way, the same names are automatically used in all views that use the same ViewModel. The following code block lists all its properties:

21:1421

public int Id { get; set; }

21:1422

[StringLength(128, MinimumLength = 5), Required]

21:1423

[Display(Name = `name`)]

21:1424

public string Name { get; set; }= null!;