From db468cdc28215f3246cc52b2846ae316221d3891 Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Fri, 23 Sep 2022 19:40:46 +0100 Subject: [PATCH 1/7] What's New: Interception --- entity-framework/core/querying/sql-queries.md | 8 +- .../core/what-is-new/ef-core-7.0/whatsnew.md | 557 +++++++++++++++++- .../NewInEFCore7/InjectLoggerSample.cs | 117 ++++ .../LazyConnectionStringSample.cs | 120 ++++ .../NewInEFCore7/NewInEFCore7.csproj | 11 +- ...OptimisticConcurrencyInterceptionSample.cs | 92 +++ .../Miscellaneous/NewInEFCore7/Program.cs | 7 + .../NewInEFCore7/QueryInterceptionSample.cs | 142 +++++ .../QueryStatisticsLoggerSample.cs | 135 +++++ .../SimpleMaterializationSample.cs | 88 +++ .../SqlServer/InMemory/InMemoryContext.cs | 2 +- 11 files changed, 1268 insertions(+), 11 deletions(-) create mode 100644 samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs create mode 100644 samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs create mode 100644 samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs create mode 100644 samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs create mode 100644 samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs create mode 100644 samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs diff --git a/entity-framework/core/querying/sql-queries.md b/entity-framework/core/querying/sql-queries.md index 1e68d96593..f35d5d7ba5 100644 --- a/entity-framework/core/querying/sql-queries.md +++ b/entity-framework/core/querying/sql-queries.md @@ -130,7 +130,7 @@ The following example uses a SQL query that selects from a Table-Valued Function > [!NOTE] > This feature was introduced in EF Core 7.0. -While is useful for querying entities defined in your model, allows you to easily query for scalar, non-entity types via SQL, without needing to drop down to lower-level data access APIs. For example, the following query fetches all the IDs from the `Blogs` table: +While is useful for querying entities defined in your model, [SqlQuery](https://github.com/dotnet/efcore/blob/2cfc7c3b9020daf9d2e28d404a78814e69941421/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs#L380) allows you to easily query for scalar, non-entity types via SQL, without needing to drop down to lower-level data access APIs. For example, the following query fetches all the IDs from the `Blogs` table: [!code-csharp[Main](../../../samples/core/Querying/SqlQueries/Program.cs#SqlQuery)] @@ -140,15 +140,15 @@ You can also compose LINQ operators over your SQL query. However, since your SQL can be used with any scalar type supported by your database provider. If you'd like to use a type not supported by your database provider, you can use [pre-convention configuration](xref:core/modeling/bulk-configuration#pre-convention-configuration) to define a value conversion for it. - allows for dynamic construction of SQL queries, just like does for entity types. +[SqlQueryRaw](https://github.com/dotnet/efcore/blob/2cfc7c3b9020daf9d2e28d404a78814e69941421/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs#L334) allows for dynamic construction of SQL queries, just like does for entity types. ## Executing non-querying SQL -In some scenarios, it may be necessary to execute SQL which does not return any data, typically for modifying data in the database or calling a stored procedure which doesn't return any result sets. This can be done via : +In some scenarios, it may be necessary to execute SQL which does not return any data, typically for modifying data in the database or calling a stored procedure which doesn't return any result sets. This can be done via [ExecuteSql](https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs#L222): [!code-csharp[Main](../../../samples/core/Querying/SqlQueries/Program.cs#ExecuteSql)] -This executes the provided SQL and returns the number of rows modified. protects against SQL injection by using safe parameterization, just like , and allows for dynamic construction of SQL queries, just like does for queries. +This executes the provided SQL and returns the number of rows modified. [ExecuteSql](https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs#L222) protects against SQL injection by using safe parameterization, just like , and allows for dynamic construction of SQL queries, just like does for queries. > [!NOTE] > diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index 1a2bf4371d..9286964afc 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2,7 +2,7 @@ title: What's New in EF Core 7.0 description: Overview of new features in EF Core 7.0 author: ajcvickers -ms.date: 09/19/2022 +ms.date: 09/23/2022 uid: core/what-is-new/ef-core-7 --- @@ -2064,3 +2064,558 @@ Configuration of stored procedures many-to-many join entities can be performed a }); --> [!code-csharp[JoinSprocs](../../../../samples/core/Miscellaneous/NewInEFCore7/DocumentsContext.cs?name=JoinSprocs)] + +## New and improved interceptors and events + +EF Core [interceptors](xref:core/logging-events-diagnostics/interceptors) enable interception, modification, and/or suppression of EF Core operations. EF Core also includes [traditional .NET events](xref:core/logging-events-diagnostics/events) and [logging](xref:core/logging-events-diagnostics/index). + +EF7 includes the following enhancements to interceptors: + +- Interception for [creating and populating new entity instances](https://github.com/dotnet/efcore/issues/15911) (aka "materialization") +- Interception to [modify the LINQ expression tree](https://github.com/dotnet/efcore/issues/28505) before a query is compiled +- Interception for [optimistic concurrency handling](https://github.com/dotnet/efcore/issues/28315) (`DbUpdateConcurrencyException`) +- Interception for [connections _before_ checking if the connection string has been set](https://github.com/dotnet/efcore/issues/23085) +- Interception for when EF Core has [finished consuming a result set](https://github.com/dotnet/efcore/issues/23535), but before that result set is closed +- Interception for [creation of a `DbConnection` by EF Core](https://github.com/dotnet/efcore/issues/23087) +- Interception for [`DbCommand` after it has been initialized](https://github.com/dotnet/efcore/issues/17261) + +In addition, EF7 includes new traditional .NET events for: + +- When an [entity is about to be tracked or change state](https://github.com/dotnet/efcore/issues/27093), but before it is actually tracked or change state +- Before and after EF Core [detects changes to entities and properties](https://github.com/dotnet/efcore/issues/26506) (aka `DetectChanges` interception) + +The following sections show some examples of using these new interception capabilities. + +### Simple actions on entity creation + +> [!TIP] +> The code shown here comes from [SimpleMaterializationSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs). + +The new [`IMaterializationInterceptor`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/IMaterializationInterceptor.cs) supports interception before and after an entity instance is created, and before and after properties of that instance are initialized. The interceptor can change or replace the entity instance at each point. This allows: + +- Setting unmapped properties or calling methods needed for validation, computed values, or flags. +- Using a factory to create instances. +- Creating a different entity instance than EF would normally create, such as an instance from a cache, or of a proxy type. +- Injecting services into an entity instance. + +For example, imagine that we want to keep track of the time that an entity was retrieved from the database, perhaps so it can be displayed to a user editing the data. To accomplish this, we first define an interface: + + +[!code-csharp[IHasRetrieved](../../../../samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs?name=IHasRetrieved)] + +Using an interface is common with interceptors since it allows the same interceptor to work with many different entity types. For example: + + +[!code-csharp[Customer](../../../../samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs?name=Customer)] + +Notice that the `[NotMapped]` attribute is used to indicate that this property is used only while working with the entity, and should not be persisted to the database. + +The interceptor must then implement the appropriate method from `IMaterializationInterceptor` and set the time retrieved: + + +[!code-csharp[SetRetrievedInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs?name=SetRetrievedInterceptor)] + +An instance of this interceptor is registered when configuring the `DbContext`: + + +[!code-csharp[CustomerContext](../../../../samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs?name=CustomerContext)] + +> [!TIP] +> This interceptor is stateless, which is common, so a single instance is created and shared between all `DbContext` instances. + +Now, whenever a `Customer` is queried from the database, the `Retrieved` property will be set automatically. For example: + + +[!code-csharp[QueryCustomer](../../../../samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs?name=QueryCustomer)] + +Produces output: + +```output +Customer 'Alice' was retrieved at '9/22/2022 5:25:54 PM' +``` + +### Injecting services into entities + +> [!TIP] +> The code shown here comes from [InjectLoggerSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs). + +EF Core already has built-in support for injecting some special services into context instances; for example, see [Lazy loading without proxies](xref:core/querying/related-data/lazy#lazy-loading-without-proxies), which works by injecting the `ILazyLoader` service. + +An `IMaterializationInterceptor` can be used to generalize this to any service. The following example shows how to inject an into entities such that they can perform their own logging. + +> [!NOTE] +> Injecting services into entities couples those entity types to the injected services, which some people consider to be an anti-pattern. + +As before, an interface is used to define what can be done. + + +[!code-csharp[IHasLogger](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=IHasLogger)] + +And entity types that will log must implement this interface. For example: + + +[!code-csharp[CustomerIHasLogger](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=CustomerIHasLogger)] + +This time, the interceptor must implement `IMaterializationInterceptor.InitializedInstance`, which is called after every entity instance has been created and its property values have been initialized. The interceptor obtains an `ILogger` from the context and initializes `IHasLogger.Logger` with it: + + +[!code-csharp[LoggerInjectionInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=LoggerInjectionInterceptor)] + +This time a new instance of the interceptor is used for each `DbContext` instance, since the `ILogger` obtained can change per `DbContext` instance, and the `Ilogger` is cached on the interceptor: + + +[!code-csharp[OnConfiguring](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=OnConfiguring)] + +Now, whenever the `Customer.PhoneNumber` is changed, this changed will be logged to the application's log. For example: + +```output +info: CustomersLogger[1] + Updating phone number for 'Alice' from '+1 515 555 0123' to '+1 515 555 0125'. +``` + +### LINQ expression tree interception + +> [!TIP] +> The code shown here comes from [QueryInterceptionSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs). + +EF Core makes use of [.NET LINQ queries](xref:core/querying/how-query-works). This typically involves using the C#, VB, or F# compiler to build an expression tree which is then translated by EF Core into the appropriate SQL. For example, consider a method that returns a page of customers: + + +[!code-csharp[GetPageOfCustomers](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs?name=GetPageOfCustomers)] + +> [!TIP] +> This query uses the method to specify the property to sort by. This allows the application to dynamically pass in the property name, allowing sorting by any property of the entity type. Be aware that sorting by non-indexed columns can be slow. + +This will work fine as long as the property used for sorting always returns a stable ordering. But this may not always be the case. For example, the LINQ query above generates the following on SQLite when ordering by `Customer.City`: + +```sql +SELECT "c"."Id", "c"."City", "c"."Name", "c"."PhoneNumber" +FROM "Customers" AS "c" +ORDER BY "c"."City" +LIMIT @__p_1 OFFSET @__p_0 +``` + +If there are multiple customers with the same `City`, then the ordering of this query is not stable. This could lead to missing or duplicate results as the user pages through the data. + +A common way to fix this problem is to perform a secondary sorting by primary key. However, rather than manually adding this to every query, EF7 allows interception of the query expression tree where the secondary ordering can be added dynamically. To facilitate this, we will again use an interface, this time for any entity that has an integer primary key: + + +[!code-csharp[IHasIntKey](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs?name=IHasIntKey)] + +This interface is implemented by the entity types of interest: + + +[!code-csharp[CustomerIHasIntKey](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs?name=CustomerIHasIntKey)] + +We then need an interceptor that implements [`IQueryExpressionInterceptor`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/IQueryExpressionInterceptor.cs): + + +[!code-csharp[KeyOrderingExpressionInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs?name=KeyOrderingExpressionInterceptor)] + +This probably looks pretty complicated--and it is! Working with expression trees is typically not easy. Let's look at what's happening: + +- Fundamentally, the interceptor encapsulates an . The visitor overrides , which will be called whenever there is a call to a method in the query expression tree. + +- The visitor checks whether or not this is a call to the method we are interested in. +- If it is, then the visitor further checks if the generic method call is for a type that implements our `IHasIntKey` interface. +- At this point we know that the method call is of the form `OrderBy(e => ...)`. We extract the lambda expression from this call and get the parameter used in that expression--that is, the `e`. +- We now build a new using the builder method. In this case, the method being called is `ThenBy(e => e.Id)`. We build this using the parameter extracted above and a property access to the `Id` property of the `IHasIntKey` interface. +- The input into this call is the original `OrderBy(e => ...)`, and so the end result is an expression for `OrderBy(e => ...).ThenBy(e => e.Id)`. +- This modified expression is returned from the visitor, which means the LINQ query has now been appropriately modified to include a `ThenBy` call. +- EF Core continues and compiles this query expression into the appropriate SQL for the database being used. + +This interceptor is registered in the same way as we did for the first example. Executing `GetPageOfCustomers` now generates the following SQL: + +```sql +SELECT "c"."Id", "c"."City", "c"."Name", "c"."PhoneNumber" +FROM "Customers" AS "c" +ORDER BY "c"."City", "c"."Id" +LIMIT @__p_1 OFFSET @__p_0 +``` + +This will now always produce a stable ordering, even if there are multiple customers with the same `City`. + +Phew! That's a lot of code to make a simple change to a query. And even worse, it might not even work for all queries. It is notoriously difficult to write an expression visitor that recognizes all the query shapes it should, and none of the ones it should not. For example, this will likely not work if the ordering is done in a subquery. + +This brings us to a critical point about interceptors--always ask yourself if there is an easier way of doing what you want. Interceptors are powerful, but it's easy to get things wrong. They are, as the saying goes, an easy way to shoot yourself in the foot. + +For example, imagine if we instead changed our `GetPageOfCustomers` method like so: + + +[!code-csharp[GetPageOfCustomers2](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs?name=GetPageOfCustomers2)] + +In this case the `ThenBy` is simply added to the query. Yes, it may need to be done separately to every query, but it's simple, easy to understand, and will always work. + +### Optimistic concurrency interception + +> [!TIP] +> The code shown here comes from [OptimisticConcurrencyInterceptionSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs). + +EF Core supports the [optimistic concurrency pattern](xref:core/saving/concurrency) by checking that the number of rows actually affected by an update or delete is the same as the number of rows expected to be affected. This is often coupled with a concurrency token; that is, a column value that will only match its expected value if the row has not been updated since the expected value was read. + +EF signals a violation of optimistic concurrency by throwing a . In EF7 [`ISaveChangesInterceptor`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ISaveChangesInterceptor.cs) has new methods `ThrowingConcurrencyException` and `ThrowingConcurrencyExceptionAsync` that are called before the `DbUpdateConcurrencyException` is thrown. These interception points allow the exception to be suppressed, possibly coupled with async database changes to resolve the violation. + +For example, if two requests attempt to delete the same entity at almost the same time, then the second delete may fail because the row in the database no longer exists. This may be fine--the end result is that the entity has been deleted anyway. The following interceptor demonstrates how this can be done: + + +[!code-csharp[SuppressDeleteConcurrencyInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs?name=SuppressDeleteConcurrencyInterceptor)] + +There are several things worth noting about this interceptor: + +- Both the synchronous and asynchronous interception methods are implemented. This is important if the application may call either `SaveChanges` or `SaveChangesAsync`. However, if all application code is async, then only `ThrowingConcurrencyExceptionAsync` needs to be implemented. Likewise, if the application never uses synchronous database methods, then only `ThrowingConcurrencyException` needs to be implemented. This is generally true for all interceptors with sync and async methods. (It might be worthwhile implementing the method your application does not use to throw, just in case some sync/async code creeps in.) +- The interceptor has access to objects for the entities being saved. In this case, this is used to check whether or not the concurrency violation is happening for a delete operation. +- If the application is using a relational database provider, then the [`ConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ConcurrencyExceptionEventData.cs) object can be cast to a [`RelationalConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Diagnostics/RelationalConcurrencyExceptionEventData.cs) object. This provides additional, relational-specific information about the database operation being performed. In this case, the relational command text is printed to the console. +- Returning `InterceptionResult.Suppress()` tells EF Core to suppress the action it was about to take--in this case, throwing the `DbUpdateConcurrencyException`. This ability to _change the behavior if EF Core_, rather than just observing what EF Core is doing, is one of the most powerful features of interceptors. + +### Lazy initialization of a connection string + +> [!TIP] +> The code shown here comes from [LazyConnectionStringSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs). + +Connection strings are often static assets read from a configuration file. These can easily be passed to `UseSqlServer` or similar when configuring a `DbContext`. However, sometimes the connection string can change for each context instance. For example, each tenant in a multi-tenant system may have different connection string. + +EF7 makes it easier to handle dynamic connections and connection strings through improvements to the . This starts with the ability to configure the `DbContext` without any connection string. For example: + +```csharp +services.AddDbContext( + b => b.UseSqlServer(); +``` + +One of the `IDbConnectionInterceptor` methods can then be implemented to configure the connection before it is used. `ConnectionOpeningAsync` is a good choice, since it can perform an async operation to obtain the connection string, find an access token, and so on. For example, imagine a service scoped to the current request that understands the current tenant: + +```csharp +services.AddScoped(); +``` + +This can be injected into each `DbContext` instance using constructor injection: + +```csharp +public class CustomerContext : DbContext +{ + private readonly ITenantConnectionStringFactory _connectionStringFactory; + + public CustomerContext( + DbContextOptions options, + ITenantConnectionStringFactory connectionStringFactory) + : base(options) + { + _connectionStringFactory = connectionStringFactory; + } + + // ... +} +``` + +This service is then used when constructing the interceptor implementation for the context: + +```csharp +protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder.AddInterceptors( + new ConnectionStringInitializationInterceptor(_connectionStringFactory)); +``` + +Finally, the interceptor uses this service to obtain the connection string asynchronously and set it the first time that the connection is used: + + +[!code-csharp[ConnectionStringInitializationInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs?name=ConnectionStringInitializationInterceptor)] + +> [!TIP] +> This interceptor overrides the non-async `ConnectionOpening` method to throw since the service to get the connection string must be called from an async code path. + +### Logging SQL Server query statistics + +> [!TIP] +> The code shown here comes from [QueryStatisticsLoggerSample.cs](https://github.com/dotnet/EntityFramework.Docs/tree/main/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs). + +Finally, let's create two interceptors that work together to send SQL Server query statistics to the application log. To generate the statistics, we need an to do two things. + +First, the interceptor will prefix commands with `SET STATISTICS IO ON`, which tells SQL Server to send statistics to the client after a result set has been consumed: + + +[!code-csharp[ReaderExecutingAsync](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs?name=ReaderExecutingAsync)] + +Second, the interceptor will implement the new `DataReaderClosingAsync` method, which is called after the has finished consuming results, but _before_ it has been closed. When SQL Server is sending statistics, it puts them in a second result on the reader, so at this point the interceptor reads that result by calling `NextResultAsync` which populates statistics onto the connection. + + +[!code-csharp[DataReaderClosingAsync](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs?name=DataReaderClosingAsync)] + +The second interceptor is needed to obtain the statistics from the connection and write them out to the application's logger. For this, we'll use an , implementing the new `ConnectionCreated` method. `ConnectionCreated` is called immediately after EF Core has created a connection, and so can be used to perform additional configuration of that connection. In this case, the interceptor obtains an `ILogger` and then hooks into the event to log the messages. + + +[!code-csharp[InfoMessageInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs?name=InfoMessageInterceptor)] + +> [!IMPORTANT] +> The `ConnectionCreating` and `ConnectionCreated` methods are only called when EF Core creates a `DbConnection`. They will not be called if the application creates the `DbConnection` and passes to EF Core. + +Running some code that uses these interceptors show SQL Server query statistics in the log: + +```output +info: Microsoft.EntityFrameworkCore.Database.Command[20101] + Executed DbCommand (26ms) [Parameters=[@p0='?' (Size = 4000), @p1='?' (Size = 4000), @p2='?' (Size = 4000), @p3='?' (Size = 4000)], CommandType='Text', CommandTimeout='30'] + SET STATISTICS IO ON;SET IMPLICIT_TRANSACTIONS OFF; + SET NOCOUNT ON; + MERGE [Customers] USING ( + VALUES (@p0, @p1, 0), + (@p2, @p3, 1)) AS i ([Name], [PhoneNumber], _Position) ON 1=0 + WHEN NOT MATCHED THEN + INSERT ([Name], [PhoneNumber]) + VALUES (i.[Name], i.[PhoneNumber]) + OUTPUT INSERTED.[Id], i._Position; +info: InfoMessageLogger[1] + Table 'Customers'. Scan count 0, logical reads 5, physical reads 0, page server reads 0, read-ahead reads 0, page server read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob page server reads 0, lob read-ahead reads 0, lob page server read-ahead reads 0. +info: Microsoft.EntityFrameworkCore.Database.Command[20101] + Executed DbCommand (3ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] + SET STATISTICS IO ON;SELECT TOP(2) [c].[Id], [c].[Name], [c].[PhoneNumber] + FROM [Customers] AS [c] + WHERE [c].[Name] = N'Alice' +info: InfoMessageLogger[1] + Table 'Customers'. Scan count 1, logical reads 2, physical reads 0, page server reads 0, read-ahead reads 0, page server read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob page server reads 0, lob read-ahead reads 0, lob page server read-ahead reads 0. +``` diff --git a/samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs b/samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs new file mode 100644 index 0000000000..90458f83d2 --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs @@ -0,0 +1,117 @@ +using System.ComponentModel.DataAnnotations.Schema; +using Microsoft.EntityFrameworkCore; +using Microsoft.EntityFrameworkCore.Diagnostics; +using Microsoft.EntityFrameworkCore.Infrastructure; +using Microsoft.Extensions.DependencyInjection; +using Microsoft.Extensions.Logging; + +namespace NewInEfCore7; + +public static class InjectLoggerSample +{ + public static async Task Injecting_services_into_entities() + { + PrintSampleName(); + + var loggerFactory = LoggerFactory.Create(builder => { builder.AddConsole(); }); + + var serviceProvider = new ServiceCollection() + .AddDbContext( + b => b.UseLoggerFactory(loggerFactory) + .UseSqlite("Data Source = customers.db")) + .BuildServiceProvider(); + + using (var scope = serviceProvider.CreateScope()) + { + var context = scope.ServiceProvider.GetRequiredService(); + + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Alice", PhoneNumber = "+1 515 555 0123" }, + new Customer { Name = "Mac", PhoneNumber = "+1 515 555 0124" }); + + await context.SaveChangesAsync(); + } + + using (var scope = serviceProvider.CreateScope()) + { + var context = scope.ServiceProvider.GetRequiredService(); + + var customer = await context.Customers.SingleAsync(e => e.Name == "Alice"); + customer.PhoneNumber = "+1 515 555 0125"; + } + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + public class CustomerContext : DbContext + { + public CustomerContext(DbContextOptions options) + : base(options) + { + } + + public DbSet Customers + => Set(); + + #region OnConfiguring + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder.AddInterceptors(new LoggerInjectionInterceptor()); + #endregion + } + + #region LoggerInjectionInterceptor + public class LoggerInjectionInterceptor : IMaterializationInterceptor + { + private ILogger? _logger; + + public object InitializedInstance(MaterializationInterceptionData materializationData, object instance) + { + if (instance is IHasLogger hasLogger) + { + _logger ??= materializationData.Context.GetService().CreateLogger("CustomersLogger"); + hasLogger.Logger = _logger; + } + + return instance; + } + } + #endregion + + #region IHasLogger + public interface IHasLogger + { + ILogger? Logger { get; set; } + } + #endregion + + #region CustomerIHasLogger + public class Customer : IHasLogger + { + private string? _phoneNumber; + + public int Id { get; set; } + public string Name { get; set; } = null!; + + public string? PhoneNumber + { + get => _phoneNumber; + set + { + Logger?.LogInformation(1, $"Updating phone number for '{Name}' from '{_phoneNumber}' to '{value}'."); + + _phoneNumber = value; + } + } + + [NotMapped] + public ILogger? Logger { get; set; } + } + #endregion +} diff --git a/samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs b/samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs new file mode 100644 index 0000000000..147d212bac --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs @@ -0,0 +1,120 @@ +using Microsoft.EntityFrameworkCore.Diagnostics; +using Microsoft.EntityFrameworkCore.Infrastructure; + +namespace NewInEfCore7; + +public static class LazyConnectionStringSample +{ + public static async Task Lazy_initialization_of_a_connection_string() + { + PrintSampleName(); + + var services = new ServiceCollection(); + + services.AddScoped(); + + services.AddDbContext( + b => b.UseSqlServer() + .LogTo(Console.WriteLine, LogLevel.Information) + .EnableSensitiveDataLogging()); + + var serviceProvider = services.BuildServiceProvider(); + + using (var scope = serviceProvider.CreateScope()) + { + var context = scope.ServiceProvider.GetRequiredService(); + + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Alice" }, + new Customer { Name = "Mac" }); + + await context.SaveChangesAsync(); + + var customer = await context.Customers.SingleAsync(e => e.Name == "Alice"); + Console.WriteLine(); + Console.WriteLine($"Loaded {customer.Name}"); + Console.WriteLine(); + } + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + public class CustomerContext : DbContext + { + private readonly IClientConnectionStringFactory _connectionStringFactory; + + public CustomerContext( + DbContextOptions options, + IClientConnectionStringFactory connectionStringFactory) + : base(options) + { + _connectionStringFactory = connectionStringFactory; + } + + public DbSet Customers + => Set(); + + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder.AddInterceptors( + new ConnectionStringInitializationInterceptor(_connectionStringFactory)); + } + + public interface IClientConnectionStringFactory + { + Task GetConnectionStringAsync(CancellationToken cancellationToken); + } + + public class TestClientConnectionStringFactory : IClientConnectionStringFactory + { + public Task GetConnectionStringAsync(CancellationToken cancellationToken) + { + Console.WriteLine(); + Console.WriteLine(">>> Getting connection string..."); + Console.WriteLine(); + return Task.FromResult(@"Server=(localdb)\mssqllocaldb;Database=LazyConnectionStringSample"); + } + } + + #region ConnectionStringInitializationInterceptor + public class ConnectionStringInitializationInterceptor : DbConnectionInterceptor + { + private readonly IClientConnectionStringFactory _connectionStringFactory; + + public ConnectionStringInitializationInterceptor(IClientConnectionStringFactory connectionStringFactory) + { + _connectionStringFactory = connectionStringFactory; + } + + public override InterceptionResult ConnectionOpening( + DbConnection connection, + ConnectionEventData eventData, + InterceptionResult result) + => throw new NotSupportedException("Synchronous connections not supported."); + + public override async ValueTask ConnectionOpeningAsync( + DbConnection connection, ConnectionEventData eventData, InterceptionResult result, + CancellationToken cancellationToken = new()) + { + if (string.IsNullOrEmpty(connection.ConnectionString)) + { + connection.ConnectionString = (await _connectionStringFactory.GetConnectionStringAsync(cancellationToken)); + } + + return result; + } + } + #endregion + + public class Customer + { + public int Id { get; set; } + public string Name { get; set; } = null!; + } +} diff --git a/samples/core/Miscellaneous/NewInEFCore7/NewInEFCore7.csproj b/samples/core/Miscellaneous/NewInEFCore7/NewInEFCore7.csproj index 9b71960b4e..dcf498f65f 100644 --- a/samples/core/Miscellaneous/NewInEFCore7/NewInEFCore7.csproj +++ b/samples/core/Miscellaneous/NewInEFCore7/NewInEFCore7.csproj @@ -9,11 +9,12 @@ - - - - - + + + + + + diff --git a/samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs b/samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs new file mode 100644 index 0000000000..f15501c5a4 --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/OptimisticConcurrencyInterceptionSample.cs @@ -0,0 +1,92 @@ +using Microsoft.EntityFrameworkCore; +using Microsoft.EntityFrameworkCore.Diagnostics; +using Microsoft.Extensions.Logging; + +namespace NewInEfCore7; + +public static class OptimisticConcurrencyInterceptionSample +{ + public static async Task Optimistic_concurrency_interception() + { + PrintSampleName(); + + await using (var context = new CustomerContext()) + { + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Bill" }, + new Customer { Name = "Bob" }); + + await context.SaveChangesAsync(); + } + + await using (var context1 = new CustomerContext()) + { + var customer1 = await context1.Customers.SingleAsync(e => e.Name == "Bill"); + + await using (var context2 = new CustomerContext()) + { + var customer2 = await context1.Customers.SingleAsync(e => e.Name == "Bill"); + context2.Entry(customer2).State = EntityState.Deleted; + await context2.SaveChangesAsync(); + } + + context1.Entry(customer1).State = EntityState.Deleted; + await context1.SaveChangesAsync(); + } + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + public class CustomerContext : DbContext + { + private static readonly SuppressDeleteConcurrencyInterceptor _concurrencyInterceptor = new(); + + public DbSet Customers + => Set(); + + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder + .AddInterceptors(_concurrencyInterceptor) + .UseSqlite("Data Source = customers.db") + .LogTo(Console.WriteLine, LogLevel.Information); + } + + #region SuppressDeleteConcurrencyInterceptor + public class SuppressDeleteConcurrencyInterceptor : ISaveChangesInterceptor + { + public InterceptionResult ThrowingConcurrencyException( + ConcurrencyExceptionEventData eventData, + InterceptionResult result) + { + if (eventData.Entries.All(e => e.State == EntityState.Deleted)) + { + Console.WriteLine("Suppressing Concurrency violation for command:"); + Console.WriteLine(((RelationalConcurrencyExceptionEventData)eventData).Command.CommandText); + + return InterceptionResult.Suppress(); + } + + return result; + } + + public ValueTask ThrowingConcurrencyExceptionAsync( + ConcurrencyExceptionEventData eventData, + InterceptionResult result, + CancellationToken cancellationToken = default) + => new(ThrowingConcurrencyException(eventData, result)); + } + #endregion + + public class Customer + { + public int Id { get; set; } + public string Name { get; set; } = null!; + } +} diff --git a/samples/core/Miscellaneous/NewInEFCore7/Program.cs b/samples/core/Miscellaneous/NewInEFCore7/Program.cs index a4bfa1ace8..2cb341a278 100644 --- a/samples/core/Miscellaneous/NewInEFCore7/Program.cs +++ b/samples/core/Miscellaneous/NewInEFCore7/Program.cs @@ -35,5 +35,12 @@ public static async Task Main() await StoredProcedureMappingSample.Insert_Update_and_Delete_using_stored_procedures_with_TPH(); await StoredProcedureMappingSample.Insert_Update_and_Delete_using_stored_procedures_with_TPT(); await StoredProcedureMappingSample.Insert_Update_and_Delete_using_stored_procedures_with_TPC(); + + await SimpleMaterializationSample.Simple_actions_on_entity_creation(); + await QueryInterceptionSample.LINQ_expression_tree_interception(); + await OptimisticConcurrencyInterceptionSample.Optimistic_concurrency_interception(); + await InjectLoggerSample.Injecting_services_into_entities(); + await LazyConnectionStringSample.Lazy_initialization_of_a_connection_string(); + await QueryStatisticsLoggerSample.Executing_commands_after_consuming_a_result_set(); } } diff --git a/samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs b/samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs new file mode 100644 index 0000000000..42b5af3d9a --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/QueryInterceptionSample.cs @@ -0,0 +1,142 @@ +using System.Linq.Expressions; +using System.Reflection; +using Microsoft.EntityFrameworkCore; +using Microsoft.EntityFrameworkCore.Diagnostics; +using Microsoft.Extensions.Logging; + +namespace NewInEfCore7; + +public static class QueryInterceptionSample +{ + public static async Task LINQ_expression_tree_interception() + { + PrintSampleName(); + + await using (var context = new CustomerContext()) + { + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Alice", PhoneNumber = "+1 515 555 0123", City = "Ames" }, + new Customer { Name = "Mac", PhoneNumber = "+1 515 555 0124", City = "Ames" }, + new Customer { Name = "Toast" }, + new Customer { Name = "Baxter" }); + + await context.SaveChangesAsync(); + } + + foreach (var customer in await GetPageOfCustomers("City", 0)) + { + Console.WriteLine($"{customer.Name}"); + } + + #region GetPageOfCustomers + Task> GetPageOfCustomers(string sortProperty, int page) + { + using var context = new CustomerContext(); + + return context.Customers + .OrderBy(e => EF.Property(e, sortProperty)) + .Skip(page * 20).Take(20).ToListAsync(); + } + #endregion + + foreach (var customer in await GetPageOfCustomers2("City", 0)) + { + Console.WriteLine($"{customer.Name}"); + } + + #region GetPageOfCustomers2 + Task> GetPageOfCustomers2(string sortProperty, int page) + { + using var context = new CustomerContext(); + + return context.Customers + .OrderBy(e => EF.Property(e, sortProperty)) + .ThenBy(e => e.Id) + .Skip(page * 20).Take(20).ToListAsync(); + } + #endregion + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + public class CustomerContext : DbContext + { + private static readonly KeyOrderingExpressionInterceptor _keyOrderingExpressionInterceptor = new(); + + public DbSet Customers + => Set(); + + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder + .AddInterceptors(_keyOrderingExpressionInterceptor) + .UseSqlite("Data Source = customers.db") + .LogTo(Console.WriteLine, LogLevel.Information); + } + + #region KeyOrderingExpressionInterceptor + public class KeyOrderingExpressionInterceptor : IQueryExpressionInterceptor + { + public Expression QueryCompilationStarting(Expression queryExpression, QueryExpressionEventData eventData) + => new KeyOrderingExpressionVisitor().Visit(queryExpression); + + private class KeyOrderingExpressionVisitor : ExpressionVisitor + { + private static readonly MethodInfo ThenByMethod + = typeof(Queryable).GetMethods() + .Single(m => m.Name == nameof(Queryable.ThenBy) && m.GetParameters().Length == 2); + + protected override Expression VisitMethodCall(MethodCallExpression? methodCallExpression) + { + var methodInfo = methodCallExpression!.Method; + if (methodInfo.DeclaringType == typeof(Queryable) + && methodInfo.Name == nameof(Queryable.OrderBy) + && methodInfo.GetParameters().Length == 2) + { + var sourceType = methodCallExpression.Type.GetGenericArguments()[0]; + if (typeof(IHasIntKey).IsAssignableFrom(sourceType)) + { + var lambdaExpression = (LambdaExpression)((UnaryExpression)methodCallExpression.Arguments[1]).Operand; + var entityParameterExpression = lambdaExpression.Parameters[0]; + + return Expression.Call( + ThenByMethod.MakeGenericMethod( + sourceType, + typeof(int)), + base.VisitMethodCall(methodCallExpression), + Expression.Lambda( + typeof(Func<,>).MakeGenericType(entityParameterExpression.Type, typeof(int)), + Expression.Property(entityParameterExpression, nameof(IHasIntKey.Id)), + entityParameterExpression)); + } + } + + return base.VisitMethodCall(methodCallExpression); + } + } + } + #endregion + + #region IHasIntKey + public interface IHasIntKey + { + int Id { get; } + } + #endregion + + #region CustomerIHasIntKey + public class Customer : IHasIntKey + { + public int Id { get; set; } + public string Name { get; set; } = null!; + public string? City { get; set; } + public string? PhoneNumber { get; set; } + } + #endregion +} diff --git a/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs b/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs new file mode 100644 index 0000000000..789599f323 --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs @@ -0,0 +1,135 @@ +using Microsoft.Data.SqlClient; +using Microsoft.EntityFrameworkCore.Diagnostics; +using Microsoft.EntityFrameworkCore.Infrastructure; + +namespace NewInEfCore7; + +public static class QueryStatisticsLoggerSample +{ + public static async Task Executing_commands_after_consuming_a_result_set() + { + PrintSampleName(); + + var loggerFactory = LoggerFactory.Create(builder => { builder.AddConsole(); }); + + var serviceProvider = new ServiceCollection() + .AddDbContext( + b => b.UseLoggerFactory(loggerFactory) + .UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=ConsumedDataReaderSample")) + .BuildServiceProvider(); + + using (var scope = serviceProvider.CreateScope()) + { + var context = scope.ServiceProvider.GetRequiredService(); + + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Alice", PhoneNumber = "+1 515 555 0123" }, + new Customer { Name = "Mac", PhoneNumber = "+1 515 555 0124" }); + + await context.SaveChangesAsync(); + } + + using (var scope = serviceProvider.CreateScope()) + { + var context = scope.ServiceProvider.GetRequiredService(); + + _ = await context.Customers.SingleAsync(e => e.Name == "Alice"); + } + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + public class CustomerContext : DbContext + { + private static readonly StatisticsCommandInterceptor _statisticsCommandInterceptor = new(); + private static readonly InfoMessageInterceptor _infoMessageInterceptor = new(); + + public CustomerContext(DbContextOptions options) + : base(options) + { + } + + public DbSet Customers + => Set(); + + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder.AddInterceptors(_statisticsCommandInterceptor, _infoMessageInterceptor); + } + + public class InfoMessageInterceptor : DbConnectionInterceptor + { + #region InfoMessageInterceptor + public override DbConnection ConnectionCreated(ConnectionCreatedEventData eventData, DbConnection result) + { + var logger = eventData.Context!.GetService().CreateLogger("InfoMessageLogger"); + ((SqlConnection)eventData.Connection).InfoMessage += (_, args) => + { + logger.LogInformation(1, args.Message); + }; + return result; + } + #endregion + } + + public class StatisticsCommandInterceptor : DbCommandInterceptor + { + public override InterceptionResult ReaderExecuting( + DbCommand command, + CommandEventData eventData, + InterceptionResult result) + { + command.CommandText = "SET STATISTICS IO ON;" + command.CommandText; + + return result; + } + + #region ReaderExecutingAsync + public override ValueTask> ReaderExecutingAsync( + DbCommand command, + CommandEventData eventData, + InterceptionResult result, + CancellationToken cancellationToken = default) + { + command.CommandText = "SET STATISTICS IO ON;" + command.CommandText; + + return new(result); + } + #endregion + + public override InterceptionResult DataReaderClosing( + DbCommand command, + DataReaderClosingEventData eventData, + InterceptionResult result) + { + eventData.DataReader.NextResult(); + + return result; + } + + #region DataReaderClosingAsync + public override async ValueTask DataReaderClosingAsync( + DbCommand command, + DataReaderClosingEventData eventData, + InterceptionResult result) + { + await eventData.DataReader.NextResultAsync(); + + return result; + } + #endregion + } + + public class Customer + { + public int Id { get; set; } + public string Name { get; set; } = null!; + public string? PhoneNumber { get; set; } + } +} diff --git a/samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs b/samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs new file mode 100644 index 0000000000..ab2efba43e --- /dev/null +++ b/samples/core/Miscellaneous/NewInEFCore7/SimpleMaterializationSample.cs @@ -0,0 +1,88 @@ +using System.ComponentModel.DataAnnotations.Schema; +using Microsoft.EntityFrameworkCore; +using Microsoft.EntityFrameworkCore.Diagnostics; + +namespace NewInEfCore7; + +public static class SimpleMaterializationSample +{ + public static async Task Simple_actions_on_entity_creation() + { + PrintSampleName(); + + await using (var context = new CustomerContext()) + { + await context.Database.EnsureDeletedAsync(); + await context.Database.EnsureCreatedAsync(); + + await context.AddRangeAsync( + new Customer { Name = "Alice", PhoneNumber = "+1 515 555 0123" }, + new Customer { Name = "Mac", PhoneNumber = "+1 515 555 0124" }); + + await context.SaveChangesAsync(); + } + + #region QueryCustomer + await using (var context = new CustomerContext()) + { + var customer = await context.Customers.SingleAsync(e => e.Name == "Alice"); + Console.WriteLine($"Customer '{customer.Name}' was retrieved at '{customer.Retrieved.ToLocalTime()}'"); + } + #endregion + } + + private static void PrintSampleName([CallerMemberName] string? methodName = null) + { + Console.WriteLine($">>>> Sample: {methodName}"); + Console.WriteLine(); + } + + #region CustomerContext + public class CustomerContext : DbContext + { + private static readonly SetRetrievedInterceptor _setRetrievedInterceptor = new(); + + public DbSet Customers + => Set(); + + protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) + => optionsBuilder + .AddInterceptors(_setRetrievedInterceptor) + .UseSqlite("Data Source = customers.db"); + } + #endregion + + #region SetRetrievedInterceptor + public class SetRetrievedInterceptor : IMaterializationInterceptor + { + public object InitializedInstance(MaterializationInterceptionData materializationData, object instance) + { + if (instance is IHasRetrieved hasRetrieved) + { + hasRetrieved.Retrieved = DateTime.UtcNow; + } + + return instance; + } + } + #endregion + + #region IHasRetrieved + public interface IHasRetrieved + { + DateTime Retrieved { get; set; } + } + #endregion + + #region Customer + public class Customer : IHasRetrieved + { + public int Id { get; set; } + public string Name { get; set; } = null!; + public string? PhoneNumber { get; set; } + + [NotMapped] + public DateTime Retrieved { get; set; } + } + #endregion +} diff --git a/samples/core/SqlServer/InMemory/InMemoryContext.cs b/samples/core/SqlServer/InMemory/InMemoryContext.cs index ff9d0604a7..6cc670a126 100644 --- a/samples/core/SqlServer/InMemory/InMemoryContext.cs +++ b/samples/core/SqlServer/InMemory/InMemoryContext.cs @@ -9,7 +9,7 @@ public class InMemoryContext : DbContext #region IsMemoryOptimized protected override void OnModelCreating(ModelBuilder modelBuilder) { - modelBuilder.Entity().IsMemoryOptimized(); + modelBuilder.Entity().ToTable(b => b.IsMemoryOptimized()); } #endregion } From 55a7e000329a7b249b3fc8ce8daef0184ff8941f Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Sat, 24 Sep 2022 19:57:40 +0100 Subject: [PATCH 2/7] Update entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md Co-authored-by: Shay Rojansky --- entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index 9286964afc..22bc7cb74d 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2250,7 +2250,7 @@ This time, the interceptor must implement `IMaterializationInterceptor.Initializ --> [!code-csharp[LoggerInjectionInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=LoggerInjectionInterceptor)] -This time a new instance of the interceptor is used for each `DbContext` instance, since the `ILogger` obtained can change per `DbContext` instance, and the `Ilogger` is cached on the interceptor: +This time a new instance of the interceptor is used for each `DbContext` instance, since the `ILogger` obtained can change per `DbContext` instance, and the `ILogger` is cached on the interceptor: [!code-csharp[OnConfiguring](../../../../samples/core/Miscellaneous/NewInEFCore7/InjectLoggerSample.cs?name=OnConfiguring)] -Now, whenever the `Customer.PhoneNumber` is changed, this changed will be logged to the application's log. For example: +Now, whenever the `Customer.PhoneNumber` is changed, this change will be logged to the application's log. For example: ```output info: CustomersLogger[1] From 5d991041fe1bc0cdb2878a29b6ef4b19cc698688 Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Sat, 24 Sep 2022 19:58:19 +0100 Subject: [PATCH 4/7] Update entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md Co-authored-by: Shay Rojansky --- entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index 28a97ede91..3ae932d7b2 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2418,7 +2418,7 @@ In this case the `ThenBy` is simply added to the query. Yes, it may need to be d EF Core supports the [optimistic concurrency pattern](xref:core/saving/concurrency) by checking that the number of rows actually affected by an update or delete is the same as the number of rows expected to be affected. This is often coupled with a concurrency token; that is, a column value that will only match its expected value if the row has not been updated since the expected value was read. -EF signals a violation of optimistic concurrency by throwing a . In EF7 [`ISaveChangesInterceptor`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ISaveChangesInterceptor.cs) has new methods `ThrowingConcurrencyException` and `ThrowingConcurrencyExceptionAsync` that are called before the `DbUpdateConcurrencyException` is thrown. These interception points allow the exception to be suppressed, possibly coupled with async database changes to resolve the violation. +EF signals a violation of optimistic concurrency by throwing a . In EF7, [`ISaveChangesInterceptor`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ISaveChangesInterceptor.cs) has new methods `ThrowingConcurrencyException` and `ThrowingConcurrencyExceptionAsync` that are called before the `DbUpdateConcurrencyException` is thrown. These interception points allow the exception to be suppressed, possibly coupled with async database changes to resolve the violation. For example, if two requests attempt to delete the same entity at almost the same time, then the second delete may fail because the row in the database no longer exists. This may be fine--the end result is that the entity has been deleted anyway. The following interceptor demonstrates how this can be done: From 9dd8e1ac49fde08d744e9020c4e7f22be0b75951 Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Sat, 24 Sep 2022 19:58:42 +0100 Subject: [PATCH 5/7] Update entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md Co-authored-by: Shay Rojansky --- entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index 3ae932d7b2..ab66186728 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2451,7 +2451,7 @@ For example, if two requests attempt to delete the same entity at almost the sam There are several things worth noting about this interceptor: -- Both the synchronous and asynchronous interception methods are implemented. This is important if the application may call either `SaveChanges` or `SaveChangesAsync`. However, if all application code is async, then only `ThrowingConcurrencyExceptionAsync` needs to be implemented. Likewise, if the application never uses synchronous database methods, then only `ThrowingConcurrencyException` needs to be implemented. This is generally true for all interceptors with sync and async methods. (It might be worthwhile implementing the method your application does not use to throw, just in case some sync/async code creeps in.) +- Both the synchronous and asynchronous interception methods are implemented. This is important if the application may call either `SaveChanges` or `SaveChangesAsync`. However, if all application code is async, then only `ThrowingConcurrencyExceptionAsync` needs to be implemented. Likewise, if the application never uses asynchronous database methods, then only `ThrowingConcurrencyException` needs to be implemented. This is generally true for all interceptors with sync and async methods. (It might be worthwhile implementing the method your application does not use to throw, just in case some sync/async code creeps in.) - The interceptor has access to objects for the entities being saved. In this case, this is used to check whether or not the concurrency violation is happening for a delete operation. - If the application is using a relational database provider, then the [`ConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ConcurrencyExceptionEventData.cs) object can be cast to a [`RelationalConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Diagnostics/RelationalConcurrencyExceptionEventData.cs) object. This provides additional, relational-specific information about the database operation being performed. In this case, the relational command text is printed to the console. - Returning `InterceptionResult.Suppress()` tells EF Core to suppress the action it was about to take--in this case, throwing the `DbUpdateConcurrencyException`. This ability to _change the behavior if EF Core_, rather than just observing what EF Core is doing, is one of the most powerful features of interceptors. From 66966f59b9cbdb2ccef26308cfcc3c29e9265476 Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Sat, 24 Sep 2022 19:58:51 +0100 Subject: [PATCH 6/7] Update entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md Co-authored-by: Shay Rojansky --- entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index ab66186728..e944443520 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2454,7 +2454,7 @@ There are several things worth noting about this interceptor: - Both the synchronous and asynchronous interception methods are implemented. This is important if the application may call either `SaveChanges` or `SaveChangesAsync`. However, if all application code is async, then only `ThrowingConcurrencyExceptionAsync` needs to be implemented. Likewise, if the application never uses asynchronous database methods, then only `ThrowingConcurrencyException` needs to be implemented. This is generally true for all interceptors with sync and async methods. (It might be worthwhile implementing the method your application does not use to throw, just in case some sync/async code creeps in.) - The interceptor has access to objects for the entities being saved. In this case, this is used to check whether or not the concurrency violation is happening for a delete operation. - If the application is using a relational database provider, then the [`ConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore/Diagnostics/ConcurrencyExceptionEventData.cs) object can be cast to a [`RelationalConcurrencyExceptionEventData`](https://github.com/dotnet/efcore/blob/main/src/EFCore.Relational/Diagnostics/RelationalConcurrencyExceptionEventData.cs) object. This provides additional, relational-specific information about the database operation being performed. In this case, the relational command text is printed to the console. -- Returning `InterceptionResult.Suppress()` tells EF Core to suppress the action it was about to take--in this case, throwing the `DbUpdateConcurrencyException`. This ability to _change the behavior if EF Core_, rather than just observing what EF Core is doing, is one of the most powerful features of interceptors. +- Returning `InterceptionResult.Suppress()` tells EF Core to suppress the action it was about to take--in this case, throwing the `DbUpdateConcurrencyException`. This ability to _change the behavior of EF Core_, rather than just observing what EF Core is doing, is one of the most powerful features of interceptors. ### Lazy initialization of a connection string From 96dc4f9b39ef622f5049734e0999149ea81e100f Mon Sep 17 00:00:00 2001 From: Arthur Vickers Date: Sat, 24 Sep 2022 20:33:37 +0100 Subject: [PATCH 7/7] Feedback. --- .../core/what-is-new/ef-core-7.0/whatsnew.md | 18 +++++++++++++----- .../QueryStatisticsLoggerSample.cs | 4 ++-- 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md index e944443520..070023e56c 100644 --- a/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md +++ b/entity-framework/core/what-is-new/ef-core-7.0/whatsnew.md @@ -2476,6 +2476,9 @@ One of the `IDbConnectionInterceptor` methods can then be implemented to configu services.AddScoped(); ``` +> [!WARNING] +> Performing a asynchronous lookup for a connection string, access token, or similar every time it is needed can be very slow. Consider caching these things and only refreshing the cached string or token periodically. For example, access tokens can often be used for a significant period of time before needing to be refreshed. + This can be injected into each `DbContext` instance using constructor injection: ```csharp @@ -2536,6 +2539,9 @@ Finally, the interceptor uses this service to obtain the connection string async --> [!code-csharp[ConnectionStringInitializationInterceptor](../../../../samples/core/Miscellaneous/NewInEFCore7/LazyConnectionStringSample.cs?name=ConnectionStringInitializationInterceptor)] +> [!NOTE] +> The connection string is only obtained the first time that a connection is used. After that, the connection string stored on the `DbConnection` will be used without looking up a new connection string. + > [!TIP] > This interceptor overrides the non-async `ConnectionOpening` method to throw since the service to get the connection string must be called from an async code path. @@ -2555,7 +2561,7 @@ First, the interceptor will prefix commands with `SET STATISTICS IO ON`, which t InterceptionResult result, CancellationToken cancellationToken = default) { - command.CommandText = "SET STATISTICS IO ON;" + command.CommandText; + command.CommandText = "SET STATISTICS IO ON;" + Environment.NewLine + command.CommandText; return new(result); } @@ -2599,8 +2605,9 @@ Running some code that uses these interceptors show SQL Server query statistics ```output info: Microsoft.EntityFrameworkCore.Database.Command[20101] - Executed DbCommand (26ms) [Parameters=[@p0='?' (Size = 4000), @p1='?' (Size = 4000), @p2='?' (Size = 4000), @p3='?' (Size = 4000)], CommandType='Text', CommandTimeout='30'] - SET STATISTICS IO ON;SET IMPLICIT_TRANSACTIONS OFF; + Executed DbCommand (4ms) [Parameters=[@p0='?' (Size = 4000), @p1='?' (Size = 4000), @p2='?' (Size = 4000), @p3='?' (Size = 4000)], CommandType='Text', CommandTimeout='30'] + SET STATISTICS IO ON; + SET IMPLICIT_TRANSACTIONS OFF; SET NOCOUNT ON; MERGE [Customers] USING ( VALUES (@p0, @p1, 0), @@ -2612,8 +2619,9 @@ info: Microsoft.EntityFrameworkCore.Database.Command[20101] info: InfoMessageLogger[1] Table 'Customers'. Scan count 0, logical reads 5, physical reads 0, page server reads 0, read-ahead reads 0, page server read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob page server reads 0, lob read-ahead reads 0, lob page server read-ahead reads 0. info: Microsoft.EntityFrameworkCore.Database.Command[20101] - Executed DbCommand (3ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] - SET STATISTICS IO ON;SELECT TOP(2) [c].[Id], [c].[Name], [c].[PhoneNumber] + Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] + SET STATISTICS IO ON; + SELECT TOP(2) [c].[Id], [c].[Name], [c].[PhoneNumber] FROM [Customers] AS [c] WHERE [c].[Name] = N'Alice' info: InfoMessageLogger[1] diff --git a/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs b/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs index 789599f323..0f31bb5839 100644 --- a/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs +++ b/samples/core/Miscellaneous/NewInEFCore7/QueryStatisticsLoggerSample.cs @@ -85,7 +85,7 @@ public override InterceptionResult ReaderExecuting( CommandEventData eventData, InterceptionResult result) { - command.CommandText = "SET STATISTICS IO ON;" + command.CommandText; + command.CommandText = "SET STATISTICS IO ON;" + Environment.NewLine + command.CommandText; return result; } @@ -97,7 +97,7 @@ public override ValueTask> ReaderExecutingAsync InterceptionResult result, CancellationToken cancellationToken = default) { - command.CommandText = "SET STATISTICS IO ON;" + command.CommandText; + command.CommandText = "SET STATISTICS IO ON;" + Environment.NewLine + command.CommandText; return new(result); }