在WEB API 2中使用属性路由创建REST API 之书籍管理系统

WEB API2支持新的属性路由，本章会使用到一些实际项目中，此API会支持以下的一些Action

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所有方法都是只读的HTTP请求
我们会使用Entity Framework，图书记录会包含以下字段
ID
Title
Genre
Publication date
Price
Description
AuthorID (foreign key to an Authors table)
首先创建一个WEB API空项目，此过程不做详细说明。

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然后右键项目文件夹 Models添加类名称Author

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添加另外一个类，名称Book

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添加控制器右键Controllers 文件夹，添加控制器

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在添加窗口中名称是Books 模型类为Book,勾选使用异步控制器操作

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新建上下文添加确定

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会添加成功2个文件

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创建数据库选择工具栏 NuGet包管理器程序包管理控制台
输入 enable-migrations

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生成了新的文件

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打开此文件，替换以下代码。

protected override void Seed(BooksAPI.Models.BooksAPIContext context)
{
    context.Authors.AddOrUpdate(new Author[] {
        new Author() { AuthorId = 1, Name = "Ralls, Kim" },
        new Author() { AuthorId = 2, Name = "Corets, Eva" },
        new Author() { AuthorId = 3, Name = "Randall, Cynthia" },
        new Author() { AuthorId = 4, Name = "Thurman, Paula" }
        });

    context.Books.AddOrUpdate(new Book[] {
        new Book() { BookId = 1,  Title= "Midnight Rain", Genre = "Fantasy", 
        PublishDate = new DateTime(2000, 12, 16), AuthorId = 1, Description =
        "A former architect battles an evil sorceress.", Price = 14.95M }, 

        new Book() { BookId = 2, Title = "Maeve Ascendant", Genre = "Fantasy", 
            PublishDate = new DateTime(2000, 11, 17), AuthorId = 2, Description =
            "After the collapse of a nanotechnology society, the young" +
            "survivors lay the foundation for a new society.", Price = 12.95M },

        new Book() { BookId = 3, Title = "The Sundered Grail", Genre = "Fantasy", 
            PublishDate = new DateTime(2001, 09, 10), AuthorId = 2, Description =
            "The two daughters of Maeve battle for control of England.", Price = 12.95M },

        new Book() { BookId = 4, Title = "Lover Birds", Genre = "Romance", 
            PublishDate = new DateTime(2000, 09, 02), AuthorId = 3, Description =
            "When Carla meets Paul at an ornithology conference, tempers fly.", Price = 7.99M },

        new Book() { BookId = 5, Title = "Splish Splash", Genre = "Romance", 
            PublishDate = new DateTime(2000, 11, 02), AuthorId = 4, Description =
            "A deep sea diver finds true love 20,000 leagues beneath the sea.", Price = 6.99M},
    });
}

在程序包管理器控制台窗口中，键入以下命令

add-migration Initial

update-database

PM> add-migration Initial
Scaffolding migration 'Initial'.
The Designer Code for this migration file includes a snapshot of your current Code First model. This snapshot is used to calculate the changes to your model when you scaffold the next migration. If you make additional changes to your model that you want to include in this migration, then you can re-scaffold it by running 'Add-Migration Initial' again.
PM> Add-Migration Initial
Re-scaffolding migration 'Initial'.
PM> update-database
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
Applying explicit migrations: [201701170713346_Initial].
Applying explicit migration: 201701170713346_Initial.
Running Seed method.

这些命令可以创建一个本地数据库，并且运行Seed方法填充数据。

添加DTO类解决方案中添加新文件夹，命名为Dto,然后添加BookDto到该文件夹下

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace BooksAPI.Dto
{
    public class BookDto
    {
        public string Title { get; set; }
        public string Author { get; set; }
        public string Genre { get; set; }
    }
}

添加另一个名为BookDetailDto的类.

using System;

namespace BooksAPI.DTOs
{
    public class BookDetailDto
    {
        public string Title { get; set; }
        public string Genre { get; set; }
        public DateTime PublishDate { get; set; }
        public string Description { get; set; }
        public decimal Price { get; set; }         
        public string Author { get; set; }
    }
}

以下是BookCtrl中的代码

using BooksAPI.Dto;
using BooksAPI.DTOs;
using BooksAPI.Models;
using System;
using System.Data.Entity;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.Description;

namespace BooksAPI.Controllers
{
    public class BooksController : ApiController
    {
        private BooksAPIContext db = new BooksAPIContext();

        // Typed lambda expression for Select() method. 
        private static readonly Expression<Func<Book, BookDto>> AsBookDto =
            x => new BookDto
            {
                Title = x.Title,
                Author = x.Author.Name,
                Genre = x.Genre
            };

        // GET api/Books
        public IQueryable<BookDto> GetBooks()
        {
            return db.Books.Include(b => b.Author).Select(AsBookDto);
        }

        // GET api/Books/5
        [ResponseType(typeof(BookDto))]
        public async Task<IHttpActionResult> GetBook(int id)
        {
            BookDto book = await db.Books.Include(b => b.Author)
                .Where(b => b.BookId == id)
                .Select(AsBookDto)
                .FirstOrDefaultAsync();
            if (book == null)
            {
                return NotFound();
            }

            return Ok(book);
        }

        protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }
    }
}

下来添加属性路由
首先给控制器添加RoutePrefix属性

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添加属性路由

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获取书籍详细信息

        [Route("{id:int}/Details")]
        [ResponseType(typeof(BookDetailDto))]
        public async Task<IHttpActionResult> GetBookDetail(int id)
        {
            var book = await (from b in db.Books.Include(b => b.Author)
                              where b.AuthorId == id
                              select new BookDetailDto
                              {
                                  Title = b.Title,
                                  Genre = b.Genre,
                                  PublishDate = b.PublishDate,
                                  Price = b.Price,
                                  Description = b.Description,
                                  Author = b.Author.Name
                              }).FirstOrDefaultAsync();
            if (book == null)
            {
                return NotFound();
            } else
            {
                return Ok(book);
            }
        }

获取指定分类的书籍

        [Route("{genre}")]
        public IQueryable<BookDto> GetBookByGenre(string genre)
        {
            return db.Books.Include(b => b.Author)
               .Where(b => b.Genre.Equals(genre, StringComparison.OrdinalIgnoreCase))
               .Select(AsBookDto);
        }

获取指定作者的书籍列表

        [Route("~/api/authors/{authorId}/books")]
        public IQueryable<BookDto> GetBooksByAuthor(int authorId)
        {
            return db.Books.Include(b => b.Author)
                .Where(b => b.AuthorId == authorId)
                .Select(AsBookDto);
        }

按出版日期获取书籍

        //此处使用正则表达式来匹配日期格式,并且匹配多个格式的时间
        [Route("date/{pubdate:datetime:regex(\\d{4}-\\d{2}-\\d{2})}")]
        [Route("date/{*pubdate:datetime:regex(\\d{4}/\\d{2}/\\d{2})}")] 
        public IQueryable<BookDto> GetBooks(DateTime pubdate)
        {
            return db.Books.Include(b => b.Author)
                .Where(b => DbFunctions.TruncateTime(b.PublishDate)
                == DbFunctions.TruncateTime(pubdate))
                .Select(AsBookDto);
            
        }

分别请求测试

获取所有书籍