You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
abp/docs/en/Blog-Posts/2021-01-14 v4_2_Preview/POST.md

154 lines
6.8 KiB

# ABP Framework 4.2 RC Has Been Published
Today, we have released the [ABP Framework](https://abp.io/) and the [ABP Commercial](https://commercial.abp.io/) 4.2.0 RC (Release Candidate). This blog post introduces the new features and important changes in this new version.
> **The planned release date for the [4.2.0 final](https://github.com/abpframework/abp/milestone/48) version is January 28, 2021**.
## Get Started with the 4.2 RC
If you want to try the version `4.2.0` today, follow the steps below;
1) **Upgrade** the ABP CLI to the version `4.2.0-rc.1` using a command line terminal:
````bash
dotnet tool update Volo.Abp.Cli -g --version 4.2.0-rc.1
````
**or install** if you haven't installed before:
````bash
dotnet tool install Volo.Abp.Cli -g --version 4.2.0-rc.1
````
2) Create a **new application** with the `--preview` option:
````bash
abp new BookStore --preview
````
See the [ABP CLI documentation](https://docs.abp.io/en/abp/latest/CLI) for all the available options.
> You can also use the *Direct Download* tab on the [Get Started](https://abp.io/get-started) page by selecting the **Preview checkbox**.
## What's new with the ABP Framework 4.2
## IRepository.GetQueryableAsync()
> **This version comes with an important change about using `IQueryable` features over the [repositories](https://docs.abp.io/en/abp/4.2/Repositories). It is suggested to read this section carefully and apply in your applications.**
`IRepository` interface inherits `IQueryable`, so you can directly use the standard LINQ extension methods, like `Where`, `OrderBy`, `First`, `Sum`... etc.
**Example: Using LINQ directly over the repository object**
````csharp
public class BookAppService : ApplicationService, IBookAppService
{
private readonly IRepository<Book, Guid> _bookRepository;
public BookAppService(IRepository<Book, Guid> bookRepository)
{
_bookRepository = bookRepository;
}
public async Task DoItInOldWayAsync()
{
//Apply any standard LINQ extension method
var query = _bookRepository
.Where(x => x.Price > 10)
.OrderBy(x => x.Name);
//Execute the query asynchronously
var books = await AsyncExecuter.ToListAsync(query);
}
}
````
*See [the documentation](https://docs.abp.io/en/abp/4.2/Repositories#iqueryable-async-operations) if you wonder what is the `AsyncExecuter`.*
Beginning from the version 4.2, the recommended way is using `IRepository.GetQueryableAsync()` to obtain an `IQueryable`, then use the LINQ extension methods over it.
**Example: Using the new GetQueryableAsync method**
````csharp
public async Task DoItInNewWayAsync()
{
//Use GetQueryableAsync to obtain the IQueryable<Book> first
var queryable = await _bookRepository.GetQueryableAsync();
//Then apply any standard LINQ extension method
var query = queryable
.Where(x => x.Price > 10)
.OrderBy(x => x.Name);
//Finally, execute the query asynchronously
var books = await AsyncExecuter.ToListAsync(query);
}
````
ABP may start a database transaction when you get an `IQueryable` (If current [Unit Of Work](https://docs.abp.io/en/abp/latest/Unit-Of-Work) is transactional). In this new way, it is possible to **start the database transaction in an asynchronous way**. Previously, we could not get the advantage of asynchronous while starting the transactions.
> **The new way has a significant performance and scalability gain. The old usage (directly using LINQ over the repositories) will be removed in the next major version.** You have a lot of time for the change, but we recommend to immediately take the action since the old usage has a big scalability problem.
#### About IRepository Async Extension Methods
Using IRepository Async Extension Methods has no such a problem. The examples below are pretty fine:
````csharp
var countAll = await _personRepository
.CountAsync();
var count = await _personRepository
.CountAsync(x => x.Name.StartsWith("A"));
var book1984 = await _bookRepository
.FirstOrDefaultAsync(x => x.Name == "John");
````
See the [repository documentation](https://docs.abp.io/en/abp/4.2/Repositories#iqueryable-async-operations) to understand the relation between `IQueryable` and asynchronous operations.
### Repository Bulk Operations
This version adds the following methods to the repositories:
* `InsertManyAsync`
* `UpdateManyAsync`
* `DeleteManyAsync`
The purpose of these methods to insert, update or delete many entities in one call with a better performance.
Currently, **MongoDB** provider implements these methods as a single bulk operation since MongoDB API natively supports. But current **Entity Framework Core** implementation is not a real bulk operation. Instead, it does its best with the native API of the EF Core. If you want to implement in a more performant way, you can [customize the bulk operations](https://docs.abp.io/en/abp/4.2/Entity-Framework-Core#customize-bulk-operations) with your own implementation or by using a library. We could find a good open source library for EF Core 5.0 to implement it.
### Selecting DBMS on Template Creation
And DbMigrator creates the initial migration if no migration exists.
**TODO**
### Angular Unit Testing
We've improved the modules and the startup template to setup and write unit tests easier with the Angular UI. See the [Angular Unit Testing document](https://docs.abp.io/en/abp/4.2/UI/Angular/Testing) for details.
### Other News
* Improved HTTP **request-response performance** by resolving dependencies in a deferred way in the action/page filters, interceptors and some other services.
* Removed `MultipleActiveResultSets` from connection strings for new templates for SQL Server, since the new EF Core gives a warning when using it. If you want to use it, you need to change the connection string yourself.
* Added `HardDeleteAsync` extension method that takes a predicate to delete multiple entities. This extension method is available if the entity [Soft Delete](https://docs.abp.io/en/abp/latest/Data-Filtering).
* Implemented the [Page Alerts](https://docs.abp.io/en/abp/4.2/UI/Angular/Page-Alerts) for Angular UI.
* Implemented [Page Progressbar](https://github.com/abpframework/abp/blob/dev/docs/en/UI/Blazor/Page-Progress.md). It automatically shows an undetermined progress bar on top of the page while performing an AJAX request. It also proves an API to you if you need to show/hide the progress bar in your code.
## What's new with the ABP Commercial 4.2
TODO
## ABP Commercial
TODO
## About the Next Release(s)
TODO
## Feedback
Please check out the ABP Framework 4.2.0 RC and [provide feedback](https://github.com/abpframework/abp/issues/new) to help us to release a more stable version. **The planned release date for the [4.2.0 final](https://github.com/abpframework/abp/milestone/48) version is January 28, 2021**.