.NET CORE读取自定义配置文件到Configuration中

微软只提供了以下可以读取配置的方式，其中文件配置只能读取INI、JSON和XML文件，如果我想对其他自定义文件进行读取，那么我们可以使用自定义配置提供程序进行配置

比如，我想对以下格式的文件进行读取，而且只想读取上半部分内容

auto eth0
iface eth0 inet static
address 10.50.50.111
netmask 255.255.255.0
gateway 10.50.50.1
dns-nameserver 8.8.8.8
dns-nameserver 114.114.114.114

auto eth1
iface eth1 inet static
address 192.168.3.110
netmask 255.255.255.0
gateway 192.168.3.1
dns-nameserver 8.8.8.8
dns-nameserver 114.114.114.114

1、新建CustomConfigurationProvider文件，继承自ConfigurationProvider

核心：对Data赋值

public class CustomConfigurationProvider : ConfigurationProvider
{
    private readonly string _filePath;
    private readonly int _line;

    public CustomConfigurationProvider(string filePath,int line)
    {
        _filePath = filePath;
        _line = line;
    }

    public override void Load()
    {
        if (!File.Exists(_filePath)) return;
        var line = 0;
        var dic = new Dictionary<string, string>();
        foreach (var str in File.ReadAllLines(_filePath))
        {
            if (line >=_line) break;
            var strArry = str.Split(" ");
            if (strArry.Length > 1)
                dic[strArry[0]] = strArry[1];
            line++;
        }

        Data = dic;
    }
}

2、新建CustomConfigurationSource文件，继承自IConfigurationSource

public class CustomConfigurationSource : IConfigurationSource
{
    private readonly string _filePath;
    private readonly int _line;
    public CustomConfigurationSource(string filePath,int line)
    {
        _filePath = filePath;
        _line = line;
    }

    public IConfigurationProvider Build(IConfigurationBuilder builder) => new CustomConfigurationProvider(_filePath, _line);
}

3、新建扩展文件ConfigurationExtensions

public static class ConfigurationExtensions
{
    /// <summary>
    /// 读取自定义格式配置文件
    /// </summary>
    /// <param name="builder"></param>
    /// <param name="filePath">文件目录</param>
    /// <param name="line">读取到第几行为止</param>
    /// <returns></returns>
    public static IConfigurationBuilder AddCustomConfiguration(
        this IConfigurationBuilder builder,string filePath,int line)
    {
        return builder.Add(new CustomConfigurationSource(filePath,line));
    }
}

4、在程序中读取

var networkConfig = new ConfigurationBuilder()
            .AddCustomConfiguration(Path.Combine("netowrk", "interfaces"),7)
            .Build()

好啦，是不是很简单？想读取其他类型的文件，只需在ConfigurationProvider处进行编写自己的方法即可。

参考文档：

微软官方文档-自定义配置提供程序

杨中科-开发自己的配置提供者