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.NET Core

[ASP.Net Core] 如何讓 Godaddy 跑 .NET Core 3.1 ?

作者lex.xu
/
9 月 08, 2020
/
心得筆記

最近心血來潮逛看看最近有哪些 web hosting 的時候發現 Godaddy 竟然支援 .Net Core 了 !!
於是乎抱著滿心期待的拿了魔法小卡刷了一個月來試玩看看，刷完才發現竟然只支援 .Net Core 2.0 …

[C#][.NET Core] Encoding.GetEncoding(950) 取得繁體中文失效 !?

作者lex.xu
/
12 月 02, 2018
/
心得筆記

今天測試開啟文字檔案時發生亂碼，用 Notepad++ 開啟後發現該檔案編碼是 big5 ，心想著簡單那就用 Encoding.GetEncoding(950) 來開起就好了，誰知道撞璧了…

[C#][DI] 相互依賴造成循環注入死結

作者lex.xu
/
8 月 29, 2018
/
心得筆記

問題緣由

最近在寫 .NET Core 的時候遇到了一個問題

A circular dependency was detected for the service of type 'WebApplication1.Service.A1Service'

A1Service

public class A1Service
{
    private readonly string guid = null;
    private readonly A2Service _a2Service = null;

    public A1Service(A2Service a2Service)
    {
        _a2Service = a2Service;

        if (guid == null)
        {
            guid = Guid.NewGuid().ToString();
        }
    }

    public void Run()
    {
        Console.WriteLine("A1Service: " + guid);
    }

    public void RunOther()
    {
        _a2Service.Run();
    }
}

這是網路教學文章上常見的從建構子中依賴注入 A2Service 的程式
接著我們再來看看另外一支程式

A2Service

public class A2Service
{
    private readonly string guid = null;
    private readonly A1Service _a1Service = null;

    public A2Service(A1Service a1Service)
    {
        _a1Service = a1Service;

        if (guid == null)
        {
            guid = Guid.NewGuid().ToString();
        }
    }

    public void Run()
    {
        Console.WriteLine("A2Service: " + guid);
    }

    public void RunOther()
    {
        _a1Service.Run();
    }
}

這裡就發生了一個循環依賴的問題 A1Service 在建構子中注入了 A2Service，而 A2Service 也在建構子中注入了 A1Service，造成兩個物件互相依賴造成 Exception

解決方法

改成不直接在建構子中注入 Service ，改注入 IServiceProvider，再利用 GetService 這個方法來取得物件，這樣就可以順利解決這個問題囉。

A3Service

public class A3Service
{
    private readonly string guid = null;
    private readonly IServiceProvider _serviceProvider = null;

    public A3Service(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;

        if (guid == null)
        {
            guid = Guid.NewGuid().ToString();
        }
    }

    public void Run()
    {
        Console.WriteLine("A3Service: " + guid);
    }

    public void RunOther()
    {
        _serviceProvider.GetService<A4Service>().Run();
    }
}

A4Service

public class A4Service
{
    private readonly string guid = null;
    private readonly IServiceProvider _serviceProvider = null;

    public A4Service(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;

        if (guid == null)
        {
            guid = Guid.NewGuid().ToString();
        }
    }

    public void Run()
    {
        Console.WriteLine("A4Service: " + guid);
    }

    public void RunOther()
    {
        _serviceProvider.GetService<A3Service>().Run();
    }
}

[.NET Core] 將 NET Core 部署至 Ubuntu Server 16.04

作者lex.xu
/
3 月 14, 2017
/
心得筆記

最近裝了個Linux Server想來玩玩看NET Core並佈署到上面，結果發現好多眉眉角角，網路上的文件似乎有點舊讓我一直撞牆撞不停，經過了幾個小時的煎熬最後終於成功了，這裡筆記一下方便下次使用…

首先按照官網提供的步驟進行安裝如下：

加入apt-get來源

sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ xenial main" > /etc/apt/sources.list.d/dotnetdev.list'
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 417A0893
sudo apt-get update

開始安裝
```
sudo apt-get install dotnet-dev-1.0.4
```
建立一個空資料夾
```
mkdir HelloWebApp
cd HelloWebApp
```

初始化MVC專案

dotnet new mvc

Templates清單：

Templates                 Short Name      Language      Tags
----------------------------------------------------------------------
Console Application       console         [C#], F#      Common/Console
Class library             classlib        [C#], F#      Common/Library
Unit Test Project         mstest          [C#], F#      Test/MSTest
xUnit Test Project        xunit           [C#], F#      Test/xUnit
ASP.NET Core Empty        web             [C#]          Web/Empty
ASP.NET Core Web App      mvc             [C#], F#      Web/MVC
ASP.NET Core Web API      webapi          [C#]          Web/WebAPI
Solution File             sln                           Solution

檢查套件是否遺失並安裝
```
dotnet restore
```

安裝Apache反向代理(Reverse-Proxy)

sudo a2enmod proxy
sudo a2enmod proxy_http
sudo a2enmod proxy_ajp
sudo a2enmod rewrite
sudo a2enmod deflate
sudo a2enmod headers
sudo a2enmod proxy_balancer
sudo a2enmod proxy_connect
sudo a2enmod proxy_html

設定000-default.conf

<VirtualHost *:80>
	ProxyPreserveHost On
	ProxyPass / http://127.0.0.1:5000/
	ProxyPassReverse / http://127.0.0.1:5000/
</VirtualHost>

重新啟動Apach並啟動.NET Core專案
```
sudo service apache2 restart
dotnet run
```
完成 !!

2017/05/24 開啟啟動&背景執行
新增：/etc/systemd/system/kestrel-hellomvc.service

[Unit]
Description = https://blog.exfast.me/

[Service]
WorkingDirectory = /home/user/HelloWebApp/
ExecStart = /usr/bin/dotnet run /home/user/HelloWebApp/HelloWebApp.dll
Restart = always
# Restart service after 10 seconds if dotnet service crashes
RestartSec = 10
SyslogIdentifier = dotnet-example
User = user
Environment = ASPNETCORE_ENVIRONMENT = Production 

[Install]
WantedBy = multi-user.target

指令：

sudo systemctl stop kestrel-hellomvc
sudo systemctl disable kestrel-hellomvc
sudo systemctl enable kestrel-hellomvc
sudo systemctl start kestrel-hellomvc
sudo systemctl status kestrel-hellomvc

來源：