Web应用程序开发教程 - 第十章: 图书到作者的关系

关于本教程

在本系列教程中, 你将构建一个名为 Acme.BookStore 的用于管理书籍及其作者列表的基于ABP的应用程序. 它是使用以下技术开发的:

• **** 做为ORM提供程序.
• Angular 做为UI框架.

本教程分为以下部分:

• Part 1: 创建服务端
• Part 2: 图书列表页面
• Part 3: 创建,更新和删除图书
• Part 4: 集成测试
• Part 5: 授权
• Part 6: 作者: 领域层
• Part 7: 作者: 数据库集成
• Part 8: 作者: 应用服务层
• Part 9: 作者: 用户页面
• Part 10: 图书到作者的关系 (本章)

下载源码

本教程根据你的UI 和 数据库偏好有多个版本,我们准备了几种可供下载的源码组合:

• MVC (Razor Pages) UI 与 EF Core
• Blazor UI 与 EF Core
• Angular UI 与 MongoDB

如果你在Windows中遇到 "文件名太长" or "解压错误", 很可能与Windows最大文件路径限制有关. Windows文件路径的最大长度为250字符. 为了解决这个问题,参阅 在Windows 10中启用长路径.

如果你遇到与Git相关的长路径错误, 尝试使用下面的命令在Windows中启用长路径. 参阅 https://github.com/msysgit/msysgit/wiki/Git-cannot-create-a-file-or-directory-with-a-long-path git config --system core.longpaths true

简介

我们已经为图书管理应用程序创建了 图书 和 作者 功能. 然而, 这些实体间还没有关联.

在本章, 我们会在 作者 和 图书 实体间建立 1 对 N 的关系.

在图书实体中加入关系

打开 Acme.BookStore.Domain 项目中的 Books/Book.cs, 在 Book 实体中加入下列属性:

public Guid AuthorId { get; set; }

数据库 & 数据迁移

为 Book 实体新增一个不为空的 AuthorId 属性. 但是, 数据库中已存在的图书怎么办? 它们没有 AuthorIds, 当我们尝试运行应用程序时会出问题.

这是一个 典型的迁移问题, 解决方案依赖于你的具体情况;

• 如果你还没有发布应用程序到生产环境, 你可以直接删除数据库中的图书数据, 甚至你可以删除开发环境中的整个数据库.
• 你可以在数据迁移或生成种子阶段使用代码更新已有数据.
• 你可以手工处理这些数据.

我们倾向于 删除数据库 , 因为这只是个示例项目, 数据丢失并不要紧. 因为这个主题不是关于ABP框架的, 我们不会深入所有的场景.

修改数据种子

因为 AuthorId 是 Book 实体的不可为空属性, 当前的数据种子代码不能工作. 打开 Acme.BookStore.Domain 项目中的 BookStoreDataSeederContributor, 修改成以下代码:

using System;
using System.Threading.Tasks;
using Acme.BookStore.Authors;
using Acme.BookStore.Books;
using Volo.Abp.Data;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Domain.Repositories;

namespace Acme.BookStore
{
    public class BookStoreDataSeederContributor
        : IDataSeedContributor, ITransientDependency
    {
        private readonly IRepository<Book, Guid> _bookRepository;
        private readonly IAuthorRepository _authorRepository;
        private readonly AuthorManager _authorManager;

        public BookStoreDataSeederContributor(
            IRepository<Book, Guid> bookRepository,
            IAuthorRepository authorRepository,
            AuthorManager authorManager)
        {
            _bookRepository = bookRepository;
            _authorRepository = authorRepository;
            _authorManager = authorManager;
        }

        public async Task SeedAsync(DataSeedContext context)
        {
            if (await _bookRepository.GetCountAsync() > 0)
            {
                return;
            }

            var orwell = await _authorRepository.InsertAsync(
                await _authorManager.CreateAsync(
                    "George Orwell",
                    new DateTime(1903, 06, 25),
                    "Orwell produced literary criticism and poetry, fiction and polemical journalism; and is best known for the allegorical novella Animal Farm (1945) and the dystopian novel Nineteen Eighty-Four (1949)."
                )
            );

            var douglas = await _authorRepository.InsertAsync(
                await _authorManager.CreateAsync(
                    "Douglas Adams",
                    new DateTime(1952, 03, 11),
                    "Douglas Adams was an English author, screenwriter, essayist, humorist, satirist and dramatist. Adams was an advocate for environmentalism and conservation, a lover of fast cars, technological innovation and the Apple Macintosh, and a self-proclaimed 'radical atheist'."
                )
            );

            await _bookRepository.InsertAsync(
                new Book
                {
                    AuthorId = orwell.Id, // SET THE AUTHOR
                    Name = "1984",
                    Type = BookType.Dystopia,
                    PublishDate = new DateTime(1949, 6, 8),
                    Price = 19.84f
                },
                autoSave: true
            );

            await _bookRepository.InsertAsync(
                new Book
                {
                    AuthorId = douglas.Id, // SET THE AUTHOR
                    Name = "The Hitchhiker's Guide to the Galaxy",
                    Type = BookType.ScienceFiction,
                    PublishDate = new DateTime(1995, 9, 27),
                    Price = 42.0f
                },
                autoSave: true
            );
        }
    }
}

唯一的区别是设置 Book 实体的 AuthorId 属性.

执行 DbMigrator 前删除已有图书或数据库. 参阅上面的 数据库 & 数据迁移 小节获取详细信息.

你现在可以运行 .DbMigrator 控制台应用程序, 迁移 数据库 schema 并生成 种子 初始数据.

应用层

我们将修改 BookAppService, 支持作者关系.

数据传输对象

让我们从DTOs开始.

BookDto

打开 Acme.BookStore.Application.Contracts 项目的 Books 文件夹下的 BookDto 类, 添加如下属性:

public Guid AuthorId { get; set; }
public string AuthorName { get; set; }

最终的 BookDto 类应该如下:

using System;
using Volo.Abp.Application.Dtos;

namespace Acme.BookStore.Books
{
    public class BookDto : AuditedEntityDto<Guid>
    {
        public Guid AuthorId { get; set; }

        public string AuthorName { get; set; }

        public string Name { get; set; }

        public BookType Type { get; set; }

        public DateTime PublishDate { get; set; }

        public float Price { get; set; }
    }
}

CreateUpdateBookDto

打开 Acme.BookStore.Application.Contracts 项目的 Books 文件夹下的 CreateUpdateBookDto 类, 添加 AuthorId 属性:

public Guid AuthorId { get; set; }

AuthorLookupDto

在 Acme.BookStore.Application.Contracts 项目的 Books 文件夹下新建一个类 AuthorLookupDto:

using System;
using Volo.Abp.Application.Dtos;

namespace Acme.BookStore.Books
{
    public class AuthorLookupDto : EntityDto<Guid>
    {
        public string Name { get; set; }
    }
}

它会被一个将要添加到 IBookAppService 的新方法使用.

IBookAppService

打开 Acme.BookStore.Application.Contracts 项目的 Books 文件夹下的 IBookAppService 接口, 添加一个名为 GetAuthorLookupAsync 的新方法:

using System;
using System.Threading.Tasks;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;

namespace Acme.BookStore.Books
{
    public interface IBookAppService :
        ICrudAppService< //Defines CRUD methods
            BookDto, //Used to show books
            Guid, //Primary key of the book entity
            PagedAndSortedResultRequestDto, //Used for paging/sorting
            CreateUpdateBookDto> //Used to create/update a book
    {
        // ADD the NEW METHOD
        Task<ListResultDto<AuthorLookupDto>> GetAuthorLookupAsync();
    }
}

这个新方法将被UI用来获取作者列表, 填充一个下拉框. 使用这个下拉框选择图书作者.

BookAppService

打开 Acme.BookStore.Application 项目的 Books 文件夹下的 BookAppService 类, 更新为以下代码:

using System;
using System.Collections.Generic;
using System.Linq.Dynamic.Core;
using System.Linq;
using System.Threading.Tasks;
using Acme.BookStore.Authors;
using Acme.BookStore.Permissions;
using Microsoft.AspNetCore.Authorization;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;
using Volo.Abp.Domain.Repositories;

namespace Acme.BookStore.Books
{
    [Authorize(BookStorePermissions.Books.Default)]
    public class BookAppService :
        CrudAppService<
            Book, //The Book entity
            BookDto, //Used to show books
            Guid, //Primary key of the book entity
            PagedAndSortedResultRequestDto, //Used for paging/sorting
            CreateUpdateBookDto>, //Used to create/update a book
        IBookAppService //implement the IBookAppService
    {
        private readonly IAuthorRepository _authorRepository;

        public BookAppService(
            IRepository<Book, Guid> repository,
            IAuthorRepository authorRepository)
            : base(repository)
        {
            _authorRepository = authorRepository;
            GetPolicyName = BookStorePermissions.Books.Default;
            GetListPolicyName = BookStorePermissions.Books.Default;
            CreatePolicyName = BookStorePermissions.Books.Create;
            UpdatePolicyName = BookStorePermissions.Books.Edit;
            DeletePolicyName = BookStorePermissions.Books.Create;
        }

        public async override Task<BookDto> GetAsync(Guid id)
        {
            var book = await Repository.GetAsync(id);
            var bookDto = ObjectMapper.Map<Book, BookDto>(book);

            var author = await _authorRepository.GetAsync(book.AuthorId);
            bookDto.AuthorName = author.Name;

            return bookDto;
        }

        public async override Task<PagedResultDto<BookDto>>
            GetListAsync(PagedAndSortedResultRequestDto input)
        {
            //Set a default sorting, if not provided
            if (input.Sorting.IsNullOrWhiteSpace())
            {
                input.Sorting = nameof(Book.Name);
            }

            //Get the IQueryable<Book> from the repository
            var queryable = await Repository.GetQueryableAsync();

            //Get the books
            var books = await AsyncExecuter.ToListAsync(
                queryable
                    .OrderBy(input.Sorting)
                    .Skip(input.SkipCount)
                    .Take(input.MaxResultCount)
            );

            //Convert to DTOs
            var bookDtos = ObjectMapper.Map<List<Book>, List<BookDto>>(books);

            //Get a lookup dictionary for the related authors
            var authorDictionary = await GetAuthorDictionaryAsync(books);

            //Set AuthorName for the DTOs
            bookDtos.ForEach(bookDto => bookDto.AuthorName =
                             authorDictionary[bookDto.AuthorId].Name);

            //Get the total count with another query (required for the paging)
            var totalCount = await Repository.GetCountAsync();

            return new PagedResultDto<BookDto>(
                totalCount,
                bookDtos
            );
        }

        public async Task<ListResultDto<AuthorLookupDto>> GetAuthorLookupAsync()
        {
            var authors = await _authorRepository.GetListAsync();

            return new ListResultDto<AuthorLookupDto>(
                ObjectMapper.Map<List<Author>, List<AuthorLookupDto>>(authors)
            );
        }

        private async Task<Dictionary<Guid, Author>>
            GetAuthorDictionaryAsync(List<Book> books)
        {
            var authorIds = books
                .Select(b => b.AuthorId)
                .Distinct()
                .ToArray();

            var queryable = await _authorRepository.GetQueryableAsync();

            var authors = await AsyncExecuter.ToListAsync(
                queryable.Where(a => authorIds.Contains(a.Id))
            );

            return authors.ToDictionary(x => x.Id, x => x);
        }
    }
}

我们做了以下修改:

• 给所有新建/覆写的方法增加 [Authorize(BookStorePermissions.Books.Default)] 进行授权(当授权特性应用于类时, 它对这个类的所有方法有效).
• 注入 IAuthorRepository, 从作者中查询.
• 覆写基类 CrudAppService 的 GetAsync 方法. 这个方法根据给定的 id 返回单一 BookDto 对象.
• 覆写 CrudAppService 基类的 GetListAsync 方法, 返回图书列表. 这里将从数据库中查询作者和在应用层设置作者名进行了分离. 你也可以创建一个自定义repository方法, 执行一个join查询, 或者利用MongoDB AP在一个查询中获取图书的作者, 这种做法性能会更好.
• 新建一个方法: GetAuthorLookupAsync. 这个方法只是简单地获取所有作者. UI使用这个方法填充一个下拉框, 当编辑图书时用来选择作者.

对象到对象映射映射

引入 AuthorLookupDto 类, 在 GetAuthorLookupAsync 方法中使用对象映射. 所以, 我们需要在 Acme.BookStore.Application 项目的 BookStoreApplicationAutoMapperProfile.cs 文件中加入一个新的映射定义.

CreateMap<Author, AuthorLookupDto>();

单元测试

因为修改了 AuthorAppService, 一些单元测试失败了. 打开 Acme.BookStore.Application.Tests 项目的 Books 目录中的 BookAppService_Tests, 修改成以下代码:

using System;
using System.Linq;
using System.Threading.Tasks;
using Acme.BookStore.Authors;
using Shouldly;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Modularity;
using Volo.Abp.Validation;
using Xunit;

namespace Acme.BookStore.Books;

public abstract class BookAppService_Tests<TStartupModule> : BookStoreApplicationTestBase<TStartupModule>
    where TStartupModule : IAbpModule
{
    private readonly IBookAppService _bookAppService;
    private readonly IAuthorAppService _authorAppService;

    protected BookAppService_Tests()
    {
        _bookAppService = GetRequiredService<IBookAppService>();
        _authorAppService = GetRequiredService<IAuthorAppService>();
    }

    [Fact]
    public async Task Should_Get_List_Of_Books()
    {
        //Act
        var result = await _bookAppService.GetListAsync(
            new PagedAndSortedResultRequestDto()
        );

        //Assert
        result.TotalCount.ShouldBeGreaterThan(0);
        result.Items.ShouldContain(b => b.Name == "1984" &&
                                        b.AuthorName == "George Orwell");
    }

    [Fact]
    public async Task Should_Create_A_Valid_Book()
    {
        var authors = await _authorAppService.GetListAsync(new GetAuthorListDto());
        var firstAuthor = authors.Items.First();

        //Act
        var result = await _bookAppService.CreateAsync(
            new CreateUpdateBookDto
            {
                AuthorId = firstAuthor.Id,
                Name = "New test book 42",
                Price = 10,
                PublishDate = System.DateTime.Now,
                Type = BookType.ScienceFiction
            }
        );

        //Assert
        result.Id.ShouldNotBe(Guid.Empty);
        result.Name.ShouldBe("New test book 42");
    }

    [Fact]
    public async Task Should_Not_Create_A_Book_Without_Name()
    {
        var exception = await Assert.ThrowsAsync<AbpValidationException>(async () =>
        {
            await _bookAppService.CreateAsync(
                new CreateUpdateBookDto
                {
                    Name = "",
                    Price = 10,
                    PublishDate = DateTime.Now,
                    Type = BookType.ScienceFiction
                }
            );
        });

        exception.ValidationErrors
            .ShouldContain(err => err.MemberNames.Any(m => m == "Name"));
    }
}

• 修改 Should_Get_List_Of_Books 中的断言条件, 从 b => b.Name == "1984" 修改为 b => b.Name == "1984" && b.AuthorName == "George Orwell", 检查用户名是否被填充.
• 修改 Should_Create_A_Valid_Book 方法, 当新建图书时, 设置 AuthorId, 因为它现在是不可为空的了.

用户页面

生成服务代理

因为修改了 HTTP APIs, 你需要更新 Angular 客户端 服务代理. 运行 generate-proxy 命令前, 应用程序必须启动运行.

在 angular 文件夹中运行下面的命令 (你可能需要停止angular应用程序):

abp generate-proxy -t ng

这个命令将会更新 /src/app/proxy/ 文件夹中的服务代理文件.

图书列表

图书列表页面的修改很小. 打开 /src/app/book/book.component.html, 在 Name 和 Type 列之间加入以下列定义:

<ngx-datatable-column
  [name]="'::Author' | abpLocalization"
  prop="authorName"
  [sortable]="false"
></ngx-datatable-column>

运行应用程序, 你会在表格中看到 作者 列:

新建/编辑 表单

下一步是添加作者选择下拉框到新建/编辑表单. 最终的页面如下图:

添加作者下拉框, 作为表单中的第一个元素.

打开 /src/app/book/book.component.ts, 修改文件内容为:

import { ListService, PagedResultDto } from '@abp/ng.core';
import { Component, OnInit } from '@angular/core';
import { BookService, BookDto, bookTypeOptions, AuthorLookupDto } from '@proxy/books';
import { FormGroup, FormBuilder, Validators } from '@angular/forms';
import { NgbDateNativeAdapter, NgbDateAdapter } from '@ng-bootstrap/ng-bootstrap';
import { ConfirmationService, Confirmation } from '@abp/ng.theme.shared';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

@Component({
  selector: 'app-book',
  templateUrl: './book.component.html',
  styleUrls: ['./book.component.scss'],
  providers: [ListService, { provide: NgbDateAdapter, useClass: NgbDateNativeAdapter }],
})
export class BookComponent implements OnInit {
  book = { items: [], totalCount: 0 } as PagedResultDto<BookDto>;

  form: FormGroup;

  selectedBook = {} as BookDto;

  authors$: Observable<AuthorLookupDto[]>;

  bookTypes = bookTypeOptions;

  isModalOpen = false;

  constructor(
    public readonly list: ListService,
    private bookService: BookService,
    private fb: FormBuilder,
    private confirmation: ConfirmationService
  ) {
    this.authors$ = bookService.getAuthorLookup().pipe(map((r) => r.items));
  }

  ngOnInit() {
    const bookStreamCreator = (query) => this.bookService.getList(query);

    this.list.hookToQuery(bookStreamCreator).subscribe((response) => {
      this.book = response;
    });
  }

  createBook() {
    this.selectedBook = {} as BookDto;
    this.buildForm();
    this.isModalOpen = true;
  }

  editBook(id: string) {
    this.bookService.get(id).subscribe((book) => {
      this.selectedBook = book;
      this.buildForm();
      this.isModalOpen = true;
    });
  }

  buildForm() {
    this.form = this.fb.group({
      authorId: [this.selectedBook.authorId || null, Validators.required],
      name: [this.selectedBook.name || null, Validators.required],
      type: [this.selectedBook.type || null, Validators.required],
      publishDate: [
        this.selectedBook.publishDate ? new Date(this.selectedBook.publishDate) : null,
        Validators.required,
      ],
      price: [this.selectedBook.price || null, Validators.required],
    });
  }

  save() {
    if (this.form.invalid) {
      return;
    }

    const request = this.selectedBook.id
      ? this.bookService.update(this.selectedBook.id, this.form.value)
      : this.bookService.create(this.form.value);

    request.subscribe(() => {
      this.isModalOpen = false;
      this.form.reset();
      this.list.get();
    });
  }

  delete(id: string) {
    this.confirmation.warn('::AreYouSureToDelete', 'AbpAccount::AreYouSure').subscribe((status) => {
      if (status === Confirmation.Status.confirm) {
        this.bookService.delete(id).subscribe(() => this.list.get());
      }
    });
  }
}

• 为 AuthorLookupDto, Observable 和 map 添加引用.
• 在 selectedBook 后添加 authors$: Observable<AuthorLookupDto[]>; 成员.
• 在构造函数中添加 this.authors$ = bookService.getAuthorLookup().pipe(map((r) => r.items));.
• 在 buildForm() 函数中添加 authorId: [this.selectedBook.authorId || null, Validators.required].

打开 /src/app/book/book.component.html, 在图书名称表单组前加入下列表单组:

<div class="form-group">
  <label for="author-id">Author</label><span> * </span>
  <select class="form-control" id="author-id" formControlName="authorId">
    <option [ngValue]="null">Select author</option>
    <option [ngValue]="author.id" *ngFor="let author of authors$ | async">
      {{ author.name }}
    </option>
  </select>
</div>

这就是全部了. 运行应用程序, 尝试新建或编辑一个作者.