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【ASP.NET Core学习】Web API

WilsonPan 人气:0

 这里介绍在ASP.NET Core中使用Web API创建 RESTful 服务,本文使用VSCode + NET Core3.0

  1. 创建简单Rest API
  2. 格式化输出
  3. JSON Patch请求
  4. Open API(Swagger)集成

创建简单Rest API

在终端输入

dotnet new webapi -n WebAPI

1. 创建Order模型,然后初始化数据

public class OrderStore
{
    public List<Order> Orders { get; } = new List<Order>();

    public OrderStore()
    {
        var random = new Random();
        foreach (var item in Enumerable.Range(1, 10))
        {
            Orders.Add(new Order
            {
                Id = item,
                OrderNo = DateTime.Now.AddSeconds(random.Next(100, 200)).AddMilliseconds(random.Next(20, 50)).Ticks.ToString(),
                Quantity = random.Next(1, 10),
                Amount = Math.Round(((decimal)random.Next(100, 500) / random.Next(2, 6)), 2)
            });
        }
    }
}
View Code

2. 简单REST API接口

/// <summary>
/// 订单模块
/// </summary>
[ApiController]
[Route("[controller]")]
[FormatFilter]
public class OrderController : ControllerBase
{

    readonly Models.OrderStore _orderStore = null;
    public OrderController(Models.OrderStore orderStore)
    {
        _orderStore = orderStore;
    }

    /// <summary>
    /// 查询所有订单
    /// </summary>
    [HttpGet]
    public ActionResult<List<Models.Order>> GetAll() => _orderStore.Orders;

    /// <summary>
    /// 获取订单    
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    [HttpGet("{id:int}.{format?}")]
    public ActionResult<Models.Order> GetById(int id)
    {
        var order = _orderStore.Orders.FirstOrDefault(m => m.Id == id);

        if (order == null)
        {
            return NotFound();
        }

        return order;
    }

    /// <summary>
    /// 创建订单
    /// </summary>
    /// <param name="order"></param>
    /// <returns>成功返回订单Id,失败返回-1</returns>
    [HttpPost]
    public ActionResult<int> Create(Models.Order order)
    {
        if (_orderStore.Orders.Any(m => m.OrderNo == order.OrderNo))
        {
            return -1;
        }

        order.Id = _orderStore.Orders.Max(m => m.Id) + 1;
        _orderStore.Orders.Add(order);

        return order.Id;
    }

    /// <summary>
    /// 更新订单
    /// </summary>
    /// <returns></returns>
    [HttpPut]
    public ActionResult<bool> Update(Models.Order model)
    {
        Console.WriteLine($"OrderNo:{model.OrderNo}");
        var order = _orderStore.Orders.FirstOrDefault(m => m.OrderNo == model.OrderNo);

        if (order == null)
        {
            return NotFound();
        }

        order.Amount = model.Amount;
        order.Quantity = model.Quantity;

        return true;
    }

    /// <summary>
    /// 更新订单指定信息
    /// </summary>
    /// <remarks>
    /// Sample request:
    /// 
    ///     PATCH  /Order/{orderNo} 
    ///     [
    ///         {
    ///             "op": "test",
    ///             "path": "/quantity",
    ///             "value": "2"
    ///         },
    ///         {
    ///             "op": "test",
    ///             "path": "/amount",
    ///             "value": "38.28"
    ///         },
    ///         {
    ///             "op": "add",
    ///             "path": "/isComplete",
    ///             "value": "true"
    ///         },
    ///     ]
    /// </remarks>
    /// <returns>返回是否成功</returns>
    /// <response code="200">提交成功</response>
    /// <response code="400">提交参数异常</response>    
    /// <response code="404">订单号不存在</response>
    [HttpPatch("{orderNo:length(18)}")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    [ProducesResponseType(StatusCodes.Status404NotFound)]
    [ProducesResponseType(StatusCodes.Status400BadRequest)]
    public ActionResult<bool> Update([FromBody] JsonPatchDocument<Models.Order> patchDoc, [FromRoute] string orderNo)
    {
        var order = _orderStore.Orders.FirstOrDefault(m => m.OrderNo == orderNo);

        if (order == null)
        {
            return NotFound();
        }

        patchDoc.ApplyTo(order, ModelState);

        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        return Ok(true);
    }
}
View Code

3. 推荐一个VS Code插件(REST Client)测试接口,官方介绍

@baseUrl = https://localhost:5001

###
GET {{baseUrl}}/Order HTTP/1.1

### 
# @name order
POST {{baseUrl}}/Order HTTP/1.1
Accept: application/json
Content-Type: application/json

{
    "OrderNo": "637109312996909246",
    "Quantity": 2,
    "Amount": 38.28
}

### 

@orderId = {{order.response.body.*}}
GET {{baseUrl}}/Order/{{orderId}}.json HTTP/1.1

### 
GET {{baseUrl}}/Order/{{orderId}}.xml HTTP/1.1
###
GET {{baseUrl}}/Order/{{orderId}} HTTP/1.1
###

PUT {{baseUrl}}/Order HTTP/1.1
Content-Type: application/json
Accept: application/json

{
    "Id": 12,
    "OrderNo": "2019112235759329",
    "Quantity": 2,
    "Amount": 38.28
}

###

GET {{baseUrl}}/Order/11

###

PATCH  {{baseUrl}}/Order/637109312996909246 HTTP/1.1
Accept: application/json
Content-Type: application/json

[
  {
    "op": "test",
    "path": "/quantity",
    "value": "2"
  },
  {
    "op": "test",
    "path": "/amount",
    "value": "38.28"
  },
  {
    "op": "add",
    "path": "/isComplete",
    "value": "true"
  },
]




Sample request:

PATCH  /Order/{orderNo} 

[
  {
    "op": "test",
    "path": "/quantity",
    "value": "2"
  },
  {
    "op": "test",
    "path": "/amount",
    "value": "38.28"
  },
  {
    "op": "add",
    "path": "/isComplete",
    "value": "true"
  },
]
View Code

简单介绍一下,

文件后缀是http 或 rest

定义全局变量:@baseUrl = https://localhost:5001   ,注意链接不加引号

### 分割多个请求

POST/PUT 请求紧跟Head请求信息,换行加上请求内容

Ctrl + Alt + R 快捷键 / 点Send Request发起请求
 

格式化输出

Api接口通常会是不同客户端调用,这样会有可能出现需要不同响应格式,例如常用的Json,XML。
ASPNET Core 默认情况下是忽略 Accept 标头,JSON格式返回
一、支持XML格式
1. 添加xml格式化
services.AddControllers(options =>
    {
        options.RespectBrowserAcceptHeader = true;  //接受浏览器标头
    })
    .AddXmlSerializerFormatters();                   //添加XMl格式化
}

 2. 请求是添加标头

@orderId = {{order.response.body.*}}
GET {{baseUrl}}/Order/{{orderId}} HTTP/1.1
Accept: text/xml

 若不添加标头,默认使用JSON格式输出

 

二、URL格式映射

1. 添加[FormatFilter]过滤器,它会检查路由中格式是否存在,并且使用相应的格式化程序输出

2. 路由规则添加{format?}

[HttpGet("{id:int}.{format?}")]
public ActionResult<Models.Order> GetById(int id)
{
    var order = _orderStore.Orders.FirstOrDefault(m => m.Id == id);

    if (order == null)
    {
        return NotFound();
    }

    return order;
}
View Code

 

Url响应
GET {{baseUrl}}/Order/{{orderId}} HTTP/1.1
JSON(若配置格式化输出)
GET {{baseUrl}}/Order/{{orderId}}.xml
XML(若配置格式化输出)
GET {{baseUrl}}/Order/{{orderId}}.json
JSON(若配置格式化输出)
 
三、添加基于 Newtonsoft.Json 的 JSON 格式支持
 
在ASPNET Core 3.0开始,不再使用Newtonsoft.Json格式化JSON,而是使用System.Text.Json格式化,我们可以替换成Newtonsoft.Json
 
1. 添加包
dotnet add package Microsoft.AspNetCore.Mvc.NewtonsoftJson

 2. 配置Newtonsoft.Json

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers()
        .AddNewtonsoftJson(options =>                   //添加基于NewtonsoftJson格式化
        {
            options.SerializerSettings.DateFormatHandling = Newtonsoft.Json.DateFormatHandling.MicrosoftDateFormat;
            options.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";
            options.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
        });
}
 
JSON Patch请求

PUT 和 PATCH 方法用于更新现有资源。 它们之间的区别是,PUT 会替换整个资源,而PATCH 仅指定更改。

什么是JSON Patch?

JSON Patch官网 里面有一句介绍的很清楚:JSON Patch is a format for describing changes to a JSON document. (一种描述Json的变化的格式)

什么时候需要用到JSON Patch

  1. 我们返回的JSON很大,修改可能只是某些字段
  2. 对性能要求比较大的地方
  3. 一个大的对象,好几个地方修改,然后统一接口修改

ASPNET Core如何处理JSON Patch 请求

1. 添加包支持

dotnet add package Microsoft.AspNetCore.JsonPatch

2. 使用 HttpPatch 属性进行批注

3. 接受 JsonPatchDocument<T>,通常带有 [FromBody]

4. 调用 ApplyTo 以应用更改

假设我们现在有一个完成订单的需求

  1. 检查金额,数量是否有变更
  2. 更新IsComplete = true

下面附上代码和提交的JSON

控制器代码

[HttpPatch("{orderNo:length(18)}")]
[ProducesResponseType(StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
[ProducesResponseType(StatusCodes.Status400BadRequest)]
public ActionResult<bool> Update([FromBody] JsonPatchDocument<Models.Order> patchDoc, [FromRoute] string orderNo)
{
    var order = _orderStore.Orders.FirstOrDefault(m => m.OrderNo == orderNo);

    if (order == null)
    {
        return NotFound();
    }

    patchDoc.ApplyTo(order, ModelState);

    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    return Ok(true);
}
View Code

失败的JSON(金额校验不过)

PATCH  {{baseUrl}}/Order/637109312996909246 HTTP/1.1
Accept: application/json
Content-Type: application/json

[
  {
    "op": "test",
    "path": "/quantity",
    "value": "2"
  },
  {
    "op": "test",
    "path": "/amount",
    "value": "38.28"
  },
  {
    "op": "add",
    "path": "/isComplete",
    "value": "true"
  },
]
View Code

 

会在ModelState里面列出校验不过的信息

 成功的JSON

PATCH  {{baseUrl}}/Order/637109312996909246 HTTP/1.1
Accept: application/json
Content-Type: application/json

[
  {
    "op": "test",
    "path": "/quantity",
    "value": "2"
  },
  {
    "op": "test",
    "path": "/amount",
    "value": "36.8"
  },
  {
    "op": "add",
    "path": "/isComplete",
    "value": "true"
  },
]
View Code

 

我们用Get请求重新查一下,可以看到IsComplete成功被修改了

这里只是简单介绍JSON Patch使用,更多使用方法参考JSON Pan官网 和 微软文档

 

Open API(Swagger)集成

Api 通常需要跟客户端,前端进行沟通,需要编写文档,这需要花费大量时间。

Open Api是专门解决这种问题,它为RESTful api定义了一个标准的、与语言无关的接口,利用工具生成文档,可以做到代码即文档(逼着开发者完善注释)

ASPNET Core 可以使用Swashbuckle.AspNetCore或NSwag 生成Swagger 文档

下面介绍如何使用Swashbuckle.AspNetCore

一、使用Swashbuckle.AspNetCore

  1. 安装Swashbuckle.AspNetCore包

    dotnet add package Swashbuckle.AspNetCore
  2. 添加并配置 Swagger 中间件

    引用命名空间:using Microsoft.OpenApi.Models;
    services.AddSingleton<Models.OrderStore>();
                            
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "Web Api Doc", Version = "v1" });
    });
    app.UseSwagger();
                                    
    app.UseSwaggerUI(c =>
    {
      c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    });

     经过上面两步就可以使用SwaggerUI来查看文档和测试,浏览器打开(http://{url}/swagger)

二、添加XML注释

上面生成的Swagger文档是不包含XML注释,下面介绍如何添加XML注释

  1. 项目文件(*.csproj)添加以下

    <PropertyGroup>
        <GenerateDocumentationFile>true</GenerateDocumentationFile>
        <NoWarn>$(NoWarn);1591</NoWarn>
    </PropertyGroup>

     加上上面生成文档后,未注释的函数,属性会发出警告,警告代码1591,忽略警告可以添加多个,分号分割

  2. AddSwaggerGen添加下面XML支持

    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "Web Api Doc", Version = "v1" });
    
        var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
        var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);
        c.IncludeXmlComments(xmlPath);
    });
  3. 方法添加注释

    /// <summary>
    /// 更新订单指定信息
    /// </summary>
    /// <remarks>
    /// Sample request:
    /// 
    ///     PATCH  /Order/{orderNo} 
    ///     [
    ///         {
    ///             "op": "test",
    ///             "path": "/quantity",
    ///             "value": "2"
    ///         },
    ///         {
    ///             "op": "test",
    ///             "path": "/amount",
    ///             "value": "38.28"
    ///         },
    ///         {
    ///             "op": "add",
    ///             "path": "/isComplete",
    ///             "value": "true"
    ///         },
    ///     ]
    /// </remarks>
    /// <returns>返回是否成功</returns>
    /// <response code="200">提交成功</response>
    /// <response code="400">提交参数异常</response>    
    /// <response code="404">订单号不存在</response>
    View Code

    ProducesResponseType 描述返回类型

    remarks 会生成请求说明

  4. 效果

Web Api 使用就介绍这些,如有错漏,希望指出。

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