ASP.NET Core快速入门(第2章:配置管理)–学习笔记
课程链接:http://video.jessetalk.cn/course/explore
良心课程,大家一起来学习哈!
任务9:配置介绍
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命令行配置
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Json文件配置
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从配置文件文本到c#对象实例的映射 – Options 与 Bind
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配置文件热更新
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框架设计:Configuration
任务10:命令行配置
新建项目CommandLineSample–控制台应用(.NET Core)
管理NuGet程序包–下载microsoft.aspnetcore.all
传入参数
using System; using Microsoft.Extensions.Configuration; namespace CommandLineSample { class Program { static void Main(string[] args) { var builder = new ConfigurationBuilder() .AddCommandLine(args); var configuration = builder.Build(); Console.WriteLine($"name: {configuration ["name"]}"); Console.WriteLine($"age: {configuration["age"]}"); Console.ReadLine(); } } }
项目右键–调试–输入参数:name=mingsonzheng age=18
启动项目
默认参数
using System; using System.Collections.Generic; using Microsoft.Extensions.Configuration; namespace CommandLineSample { class Program { static void Main(string[] args) { var settings = new Dictionary { {"name", "mingsonzheng" }, {"age", "18" } }; var builder = new ConfigurationBuilder() .AddInMemoryCollection(settings) .AddCommandLine(args); var configuration = builder.Build(); Console.WriteLine($"name: {configuration ["name"]}"); Console.WriteLine($"age: {configuration["age"]}"); Console.ReadLine(); } } }
清空应用程序参数
启动项目
通过PowerShell运行程序,默认参数与传入参数对比
PS D:\jessetalk\CommandLineSample\CommandLineSample\bin\Debug\netcoreapp2.1> dotnet CommandLineSample.dll name: mingsonzheng age: 18 PS D:\jessetalk\CommandLineSample\CommandLineSample\bin\Debug\netcoreapp2.1> dotnet CommandLineSample.dll name=jim age=22 name: jim age: 22
任务11:Json文件配置
新建项目JsonComfigSample–控制台应用(.NET Core)
管理NuGet程序包–下载microsoft.aspnetcore.all
添加Json文件:项目右键–添加新建项class.json
{ "ClassNo": "1", "ClassDesc": "ASP.NET Core 101", "Students": [ { "name": "mingsonzheng", "age": "18" }, { "name": "jim", "age": "28" }, { "name": "tom", "age": "38" } ] }
由于class.json不在bin\Debug目录下,所以默认不会被编译,文件右键属性,修改为始终复制
using System; using Microsoft.Extensions.Configuration; namespace JsonComfigSample { class Program { static void Main(string[] args) { var builder = new ConfigurationBuilder() .AddJsonFile("class.json"); Console.ReadLine(); } } }
启动项目,可以看到class.json被复制到bin\Debug目录,这样dll就可以读取到class.json文件
读取json文件
using System; using Microsoft.Extensions.Configuration; namespace JsonComfigSample { class Program { static void Main(string[] args) { var builder = new ConfigurationBuilder() .AddJsonFile("class.json"); // 调用Build之前请确保拷贝的class.json文件没有格式错误 var configuration = builder.Build(); Console.WriteLine($"ClassNo: { configuration["ClassNo"]}"); Console.WriteLine($"ClassDesc: { configuration["ClassDesc"]}"); Console.WriteLine("Students"); Console.Write(configuration["Students:0:name"]); Console.WriteLine(configuration["Students:0:age"]); Console.Write(configuration["Students:1:name"]); Console.WriteLine(configuration["Students:1:age"]); Console.Write(configuration["Students:2:name"]); Console.WriteLine(configuration["Students:2:age"]); Console.ReadLine(); } } }
启动项目
任务12:Bind读取配置到C#实例
新建ASP.NET Core Web 应用程序OptionsBindSample,直接选择 空,确定
在Startup.cs中通过依赖注入添加configuration
public IConfiguration Configuration { get; set; } public Startup(IConfiguration configuration) { Configuration = configuration; }
项目右键,新建项,添加一个类Class.cs
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; namespace OptionsBindSample { public class Class { public int ClassNo { get; set; } public string ClassDesc { get; set; } public List Students { get; set; } } public class Student { public string Name { get; set; } public string Age { get; set; } } }
项目右键,新建项,添加一个Json文件appsettings.json
为什么取名appsettings.json呢?
因为Program.cs中的CreateDefaultBuilder默认读取一个名为appsettings.json的Json文件并把它的内容添加到配置文件
拷贝前面的内容到appsettings.json
{ "ClassNo": "1", "ClassDesc": "ASP.NET Core 101", "Students": [ { "name": "mingsonzheng", "age": "18" }, { "name": "jim", "age": "28" }, { "name": "tom", "age": "38" } ] }
在Startup.cs中通过Bind读取配置
app.Run(async (context) => { var myClass = new Class(); Configuration.Bind(myClass);// 实现配置文件信息与对象的映射 await context.Response.WriteAsync($"ClassNo: { myClass.ClassNo}"); await context.Response.WriteAsync($"ClassDesc: { myClass.ClassDesc}"); await context.Response.WriteAsync($" {myClass.Students.Count } Students"); });
完整Startup.cs
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.AspNetCore.Http; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; namespace OptionsBindSample { public class Startup { public IConfiguration Configuration { get; set; } // 通过依赖注入添加configuration public Startup(IConfiguration configuration) { Configuration = configuration; } // This method gets called by the runtime. Use this method to add services to the container. // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940 public void ConfigureServices(IServiceCollection services) { } // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IHostingEnvironment env) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app.Run(async (context) => { var myClass = new Class(); Configuration.Bind(myClass);// Bind读取配置 await context.Response.WriteAsync($"ClassNo: { myClass.ClassNo}"); await context.Response.WriteAsync($"ClassDesc: { myClass.ClassDesc}"); await context.Response.WriteAsync($" {myClass.Students.Count } Students"); }); } } }
启动项目
任务13:在Core Mvc中使用Options
在项目OptionsBindSample新建三个文件夹目录如下
在Controllers文件夹右键,添加一个控制器,默认,HomeController
在Home文件夹右键,添加一个视图,默认,Index
在Startup.cs中注释掉这一段代码,不然会把整个管道提交,只输出这一段
//app.Run(async (context) => //{ // var myClass = new Class(); // Configuration.Bind(myClass);// Bind读取配置 // await context.Response.WriteAsync($"ClassNo: { myClass.ClassNo}"); // await context.Response.WriteAsync($"ClassDesc: { myClass.ClassDesc}"); // await context.Response.WriteAsync($" {myClass.Students.Count } Students"); //});
依赖注入配置添加MVC
services.AddMvc();
使用默认路由
app.UseMvcWithDefaultRoute();
HomeController中通过IOptions方式依赖注入
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using Microsoft.Extensions.Options; namespace OptionsBindSample.Controllers { public class HomeController : Controller { private readonly Class _myClass; // 通过IOptions方式依赖注入 public HomeController(IOptions classAccesser) { _myClass = classAccesser.Value; } public IActionResult Index() { return View(_myClass); } } }
在Index中定义模型,输出
@model OptionsBindSample.Class @{ ViewData["Title"] = "Index"; }Index
Class No: @Model.ClassNo
Class Desc: @Model.ClassDesc
Students:
@foreach (var student in Model.Students) { Name: @student.Name Age: @student.Age }
注册Class,可以通过Configuration读取到option
services.Configure(Configuration);
Startup.cs完整代码
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.AspNetCore.Http; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; namespace OptionsBindSample { public class Startup { public IConfiguration Configuration { get; set; } // 通过依赖注入添加configuration public Startup(IConfiguration configuration) { Configuration = configuration; } // This method gets called by the runtime. Use this method to add services to the container. // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940 public void ConfigureServices(IServiceCollection services) { // 注册Class,可以通过Configuration读取到option services.Configure(Configuration); // 依赖注入配置添加MVC services.AddMvc(); } // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IHostingEnvironment env) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } // 使用默认路由 app.UseMvcWithDefaultRoute(); //app.Run(async (context) => //{ // var myClass = new Class(); // Configuration.Bind(myClass);// Bind读取配置 // await context.Response.WriteAsync($"ClassNo: { myClass.ClassNo}"); // await context.Response.WriteAsync($"ClassDesc: { myClass.ClassDesc}"); // await context.Response.WriteAsync($" {myClass.Students.Count } Students"); //}); } } }
启动项目
如果仅仅在视图中使用options的话,HomeController的代码有点多余,可以直接在视图中注入
Index
@using Microsoft.Extensions.Options; @inject IOptions ClassAccesser @{ ViewData["Title"] = "Index"; }Index
Class No: @ClassAccesser.Value.ClassNo
Class Desc: @ClassAccesser.Value.ClassDesc
Students:
@foreach (var student in ClassAccesser.Value.Students) { Name: @student.Name Age: @student.Age }
HomeController
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using Microsoft.Extensions.Options; namespace OptionsBindSample.Controllers { public class HomeController : Controller { public IActionResult Index() { return View(); } } }
启动项目得到同样结果
任务14:配置的热更新
ASP.NET修改web.config后站点会自动重启实现热更新
ASP.NET Core不同,实现如下:
将Index的这一行
@inject IOptions ClassAccesser
修改为
@inject IOptionsSnapshot ClassAccesser
启动项目
修改appsettings的ClassNo为222,保存
"ClassNo": "222",
刷新网页
实现原理
对比控制台程序JsonComfigSample的Program读取配置文件
// 第二个参数表示文件不存在时是否抛异常 // 第三个参数表示配置文件更新的时候是否重新加载 var builder = new ConfigurationBuilder() .AddJsonFile("class.json",false,true);
而在ASP.NET Core程序OptionsBindSample在Program中的CreateDefaultBuilder的源码实现了
public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup();
WebHost源码:
https://github.com/aspnet/MetaPackages/blob/master/src/Microsoft.AspNetCore/WebHost.cs
源码里面实现热更新(165行)
config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true) .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true);
由于它是WebHostBuilder的一个扩展函数,所以可以覆盖该方法
public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) // 如果业务场景不需要一个线程一直关注配置文件变更,可以关闭热更新 .ConfigureAppConfiguration(config => { config.AddJsonFile("appsettings.json", false, false); }) .UseStartup();
启动项目,修改配置文件,保存,刷新网页,内容不会热更新
任务15:配置框架设计浅析
var builder = new ConfigurationBuilder();// 初始化Builder builder.Add(source);// 将source添加到Builder => JsonConfigurationSource source = new JsonConfigurationSource() { Path = "settings.json"; }; var configurationRoot = builder.Build();// Build => foreach(var source in sources) { var provider = source.Build(); providers.add(provider); } return new ConfigurationRoot(providers); configurationRoot["Key"]// Use => foreach(var provider in providers.Reverse()) { string value; provider.TryGet(Key, out Value) return value; }