今天坐高鐵時嘗試了一種學習ASP.NET 5的笨方法,從空檔案夾開始,根據運作dnx . kestrel指令的錯誤資訊,一步一步寫代碼,直至将一個最簡單的ASP.NET程式運作起來。雖然是用最笨的方法寫了一個最簡單的程式,但是這麼動手操作一次,感覺就是不一樣。
今天坐高鐵時嘗試了一種學習ASP.NET 5的笨方法,從空檔案夾開始,根據運作dnx . kestrel指令的錯誤資訊,一步一步寫代碼,直至将一個最簡單的ASP.NET程式運作起來。
嘗試的具體步驟如下。
建立一個空檔案夾HelloCnblogs:
mkdir HelloCnblogs && cd $_
在這個空HelloCnblogs檔案夾中運作 dnx . kestrel 指令(基于CoreCLR的dnx),運作結果是如下的出錯資訊:
System.InvalidOperationException: Unable to resolve project 'HelloCnblogs' from /Git/HelloCnblogs
at Microsoft.Framework.Runtime.ApplicationHostContext..ctor
...
添加一個空project.json檔案(指令為touch project.json),運作dnx . kestrel指令,錯誤資訊如下:
Error: Microsoft.Framework.Runtime.FileFormatException:
The JSON file can't be deserialized to a JSON object.
at Microsoft.Framework.Runtime.Project.GetProjectFromStream(
Stream stream, String projectName, String projectPath, ICollection`1 diagnostics)
在project.json檔案中添加 {} ,運作dnx . kestrel指令,錯誤資訊如下:
System.InvalidOperationException: Unable to load application or execute command 'kestrel'.
at Microsoft.Framework.ApplicationHost.Program.ThrowEntryPointNotfoundException(
DefaultHost host, String applicationName, Exception innerException)
在project.json中添加kestrel command:
"commands": {
"kestrel": "Microsoft.AspNet.Hosting --server Kestrel --server.urls http://localhost:8080"
}
運作dnx . kestrel,出錯資訊如下:
System.InvalidOperationException: Unable to load application or execute command 'Microsoft.AspNet.Hosting'.
Available commands: kestrel.
at Microsoft.Framework.ApplicationHost.Program.ThrowEntryPointNotfoundException(
DefaultHost host, String applicationName, Exception innerException)
在project.json中添加對Kestrel的引用
"dependencies": {
"Kestrel": "1.0.0-*"
}
運作dnu restore之後(基于mono的dnu),再運作dnx . kestrel,出錯資訊變為:
System.InvalidOperationException:
Failed to resolve the following dependencies for target framework 'DNXCore,Version=v5.0':
Kestrel 1.0.0-beta6-11871
在project.json中添加frameworks:
"frameworks": {
"dnxcore50": { }
}
運作dnu restore && dnx . kestrel,出現錯誤:
System.InvalidOperationException: A type named 'StartupProduction' or 'Startup' could not be found in assembly 'HelloCnblogs'.
at Microsoft.AspNet.Hosting.Startup.StartupLoader.FindStartupType(String startupAssemblyName, IList`1 diagnosticMessages)
建立Startup.cs檔案,并添加一個Startup類:
namespace HelloCnblogs
{
public class Startup
{
}
}
繼續dnx . kestrel,出現錯誤:
System.InvalidOperationException:
A method named 'ConfigureProduction' or 'Configure' in the type 'HelloCnblogs.Startup' could not be found.
at Microsoft.AspNet.Hosting.Startup.StartupLoader.FindMethod(
Type startupType, String methodName, String environmentName, Type returnType, Boolean required)
給Startup類添加Configure方法:
public class Startup
{
public void Configure(IApplicationBuilder app)
{
}
}
error CS0246: The type or namespace name 'IApplicationBuilder' could not be found (are you missing a using directive or an assembly reference?)
在Startup.cs中添加命名空間:
using Microsoft.AspNet.Builder;
繼續dnx . kestrel,這次成功運作!
Started
這裡用浏覽器通路 http://localhost:8080/ ,能成功通路,但頁面一片空白,因為我們在程式中沒進行任何内容輸出操作。
于是,在Startup.cs中添加輸入内容的代碼:
public class Startup
{
public void Configure(IApplicationBuilder app)
{
app.Run(async context => await context.Response.WriteAsync("Hello, cnblogs!"));
}
}
繼續用dnx . kestrel指令運作,出現錯誤:
error CS1061: 'HttpResponse' does not contain a definition for 'WriteAsync' and no extension method 'WriteAsync' accepting a first argument of type 'HttpResponse' could be found (are you missing a using directive or an assembly reference?)
using Microsoft.AspNet.Http;
再次運作,成功!
$ dnx . kestrel
Started
浏覽器通路 http://localhost:8080/ ,得到正常的響應内容:
Hello, cnblogs!
通過這樣的試錯法,得到了運作一個最簡單的ASP.NET 5程式的最小配置:
一個檔案夾,2個檔案(project.json與Startup.cs)。
project.json檔案中的内容:
{
"commands": {
"kestrel": "Microsoft.AspNet.Hosting --server Kestrel --server.urls http://localhost:8080"
},
"dependencies": {
"Kestrel": "1.0.0-*"
},
"frameworks": {
"dnxcore50": { }
}
}
Startup.cs中的内容:
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Http;
namespace HelloCnblogs
{
public class Startup
{
public void Configure(IApplicationBuilder app)
{
app.Run(async context => await context.Response.WriteAsync("Hello, cnblogs!"));
}
}
}
雖然是用最笨的方法寫了一個最簡單的程式,但是這麼動手操作一次,感覺就是不一樣。