如何在 .NET Core 中使用 PROVIDER 读取 connectionString? [英] How to read a connectionString WITH PROVIDER in .NET Core?

问题描述

我加了

.AddJsonFile("Connections.json", optional: true, reloadOnChange: true)

在

 public Startup(IHostingEnvironment env)

Connections.json 包含:

Connections.json contains:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\mssqllocaldb;Database=DATABASE;Trusted_Connection=True;MultipleActiveResultSets=true",
    "COR-W81-101": "Data Source=DATASOURCE;Initial Catalog=P61_CAFM_Basic;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;",
    "COR-W81-100": "Data Source=DATASOURCE;Initial Catalog=Post_PS;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;",
    "MSEDGEWIN10": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"",

    "server": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;User Id=USERID;Password=PASSWORD;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic""
  },


  "conStrings": [
      {
        "name": "COR-W81-101",     
        "connectionString": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"",
        "providerName": "System.Data.SqlClient"
      }

    },

    {
      "name": "server",
      "connectionString": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"",
      "providerName": "System.Data.SqlClient"
    }
  ],



  "conStringDictionary": {
    "COR-W81-101": {
      "connectionString": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"",
      "providerName": "System.Data.SqlClient"
    },

    "server": {
      "connectionString": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"",
      "providerName": "System.Data.SqlClient"
    }

  }
}

现在我想读取 connectionStrings:

Now I wanted to read the connectionStrings:

public class ConnectionString
{
    public string name { get; set; }
    public string connectionString { get; set; }
    public string providerName { get; set; }
}

像这样:

//Microsoft.Extensions.DependencyInjection.OptionsConfigurationServiceCollectionExtensions.Configure<ConnectionString[]>(services, Configuration.GetSection("conStrings"));

// https://stackoverflow.com/questions/31929482/retrieve-sections-from-config-json-in-asp-net-5
//var objectSections = Configuration.GetSection("conStringDictionary").GetChildren();
//foreach (var x in objectSections)
//{
//    System.Console.WriteLine(x.Key);
//    var cs = new ConnectionString();
//    ConfigurationBinder.Bind(x, cs);
//    System.Console.WriteLine(cs);
//}

// http://andrewlock.net/how-to-use-the-ioptions-pattern-for-configuration-in-asp-net-core-rc2/
        Microsoft.Extensions.DependencyInjection.OptionsConfigurationServiceCollectionExtensions.Configure<Dictionary<string, ConnectionString>>(services, Configuration.GetSection("conStrings"));

但我无法让它读取数组或字典.我需要每个 connectionString 的 providerName，并且我希望它与连接字符串位于同一条目中，但不是作为连接字符串.

But I can't get it to read the array or the dictionary. I need the providerName for each connectionString, and I want to have it in the same entry as the connection string, but not as a joined string.

推荐答案

你基本上已经到了，你所要做的就是创建一些强类型类来匹配旧的 ConnectionStringSettings 并利用一些集合序列化逻辑.

You were basically there, all you have to do is make a few strongly typed classes to match the old ConnectionStringSettings and utilize some collection serialization logic.

这是我建议在 json 中格式化它们的方法.与使用旧的 XML app/web.config 方式指定连接字符串的方式非常相似.连接字符串的名称是键.

Here's how I would suggest to format them in json. Rather similar to how you would specify a connection string the old XML app/web.config way. The name of the connection string being the key.

{
  "ConnectionStrings": {
    "Test1": {
      "ConnectionString": "server=localhost;database=db;username=user;password=pass;",
      "ProviderName": "MySql.Data.MySqlClient"
    },
    "Test2": {
      "ConnectionString": "server=localhost;database=db2;username=user2;password=pass2;",
      "ProviderName": "MySql.Data.MySqlClient"
    }
  }
}

现在是要绑定到的类.首先是简单的 ConnectionStringSettings 类本身，它实现了您的基本相等/散列方法(因为我们打算将它放在字典中，所以这将是必要的).

Now for the classes to bind to. First is the simple ConnectionStringSettings class itself, implements your basic equality/hashing methods (will be necessary as we intend to stick this in a Dictionary).

public class ConnectionStringSettings
{
    public String Name { get; set; }
    public String ConnectionString { get; set; }
    public String ProviderName { get; set; }

    public ConnectionStringSettings()
    {
    }

    public ConnectionStringSettings(String name, String connectionString)
        : this(name, connectionString, null)
    {
    }

    public ConnectionStringSettings(String name, String connectionString, String providerName)
    {
        this.Name = name;
        this.ConnectionString = connectionString;
        this.ProviderName = providerName;
    }

    protected bool Equals(ConnectionStringSettings other)
    {
        return String.Equals(Name, other.Name) && String.Equals(ConnectionString, other.ConnectionString) && String.Equals(ProviderName, other.ProviderName);
    }

    public override bool Equals(Object obj)
    {
        if (ReferenceEquals(null, obj)) return false;
        if (ReferenceEquals(this, obj)) return true;
        if (obj.GetType() != this.GetType()) return false;
        return Equals((ConnectionStringSettings) obj);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hashCode = (Name != null ? Name.GetHashCode() : 0);
            hashCode = (hashCode * 397) ^ (ConnectionString != null ? ConnectionString.GetHashCode() : 0);
            hashCode = (hashCode * 397) ^ (ProviderName != null ? ProviderName.GetHashCode() : 0);
            return hashCode;
        }
    }

    public static bool operator ==(ConnectionStringSettings left, ConnectionStringSettings right)
    {
        return Equals(left, right);
    }

    public static bool operator !=(ConnectionStringSettings left, ConnectionStringSettings right)
    {
        return !Equals(left, right);
    }
}

接下来是ConnectionStringSettings的集合.这只是必需的，因为连接字符串的名称是 JSON 表示法中的关键.为了使该名称始终附加，我们需要覆盖 Dictionary 的 Add 方法(但您不能这样做，因为它不是虚拟的).所以我们真正要做的只是在我们自己的 Add 实现中用额外的位在内部包装一个 Dictionary .同样，这看起来像很多代码，但你会发现它是非常单调乏味的东西.

Next is the collection of ConnectionStringSettings. This is only necessary because the Name of the connection string is the key in the JSON notation. In order to keep that name consistently attached we need to override Dictionary's Add method (but you can't do that because its not virtual). So all we are REALLY doing is just wrapping a Dictionary internally with that extra bit in our own Add implementation. Again this looks like a lot of code, but you'll see it's very monotonous boring stuff.

public class ConnectionStringSettingsCollection : IDictionary<String, ConnectionStringSettings>
{
    private readonly Dictionary<String, ConnectionStringSettings> m_ConnectionStrings;

    public ConnectionStringSettingsCollection()
    {
        m_ConnectionStrings = new Dictionary<String, ConnectionStringSettings>();
    }

    public ConnectionStringSettingsCollection(int capacity)
    {
        m_ConnectionStrings = new Dictionary<String, ConnectionStringSettings>(capacity);
    }

    #region IEnumerable methods
    IEnumerator IEnumerable.GetEnumerator()
    {
        return ((IEnumerable)m_ConnectionStrings).GetEnumerator();
    }
    #endregion

    #region IEnumerable<> methods
    IEnumerator<KeyValuePair<String, ConnectionStringSettings>> IEnumerable<KeyValuePair<String, ConnectionStringSettings>>.GetEnumerator()
    {
        return ((IEnumerable<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).GetEnumerator();
    }
    #endregion

    #region ICollection<> methods
    void ICollection<KeyValuePair<String, ConnectionStringSettings>>.Add(KeyValuePair<String, ConnectionStringSettings> item)
    {
        ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).Add(item);
    }

    void ICollection<KeyValuePair<String, ConnectionStringSettings>>.Clear()
    {
        ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).Clear();
    }

    Boolean ICollection<KeyValuePair<String, ConnectionStringSettings>>.Contains(KeyValuePair<String, ConnectionStringSettings> item)
    {
        return ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).Contains(item);
    }

    void ICollection<KeyValuePair<String, ConnectionStringSettings>>.CopyTo(KeyValuePair<String, ConnectionStringSettings>[] array, Int32 arrayIndex)
    {
        ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).CopyTo(array, arrayIndex);
    }

    Boolean ICollection<KeyValuePair<String, ConnectionStringSettings>>.Remove(KeyValuePair<String, ConnectionStringSettings> item)
    {
        return ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).Remove(item);
    }

    public Int32 Count => ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).Count;
    public Boolean IsReadOnly => ((ICollection<KeyValuePair<String, ConnectionStringSettings>>)m_ConnectionStrings).IsReadOnly;
    #endregion

    #region IDictionary<> methods
    public void Add(String key, ConnectionStringSettings value)
    {
        // NOTE only slight modification, we add back in the Name of connectionString here (since it is the key)
        value.Name = key;
        m_ConnectionStrings.Add(key, value);
    }

    public Boolean ContainsKey(String key)
    {
        return m_ConnectionStrings.ContainsKey(key);
    }

    public Boolean Remove(String key)
    {
        return m_ConnectionStrings.Remove(key);
    }

    public Boolean TryGetValue(String key, out ConnectionStringSettings value)
    {
        return m_ConnectionStrings.TryGetValue(key, out value);
    }

    public ConnectionStringSettings this[String key]
    {
        get => m_ConnectionStrings[key];
        set => Add(key, value);
    }

    public ICollection<String> Keys => m_ConnectionStrings.Keys;
    public ICollection<ConnectionStringSettings> Values => m_ConnectionStrings.Values;
    #endregion
}

一些简单的扩展方法，让事情变得更简单.

A few simple extension methods to make things simpler.

public static class ConnectionStringSettingsExtensions
{
    public static ConnectionStringSettingsCollection ConnectionStrings(this IConfigurationRoot configuration, String section = "ConnectionStrings")
    {
        var connectionStringCollection = configuration.GetSection(section).Get<ConnectionStringSettingsCollection>();
        if (connectionStringCollection == null)
        {
            return new ConnectionStringSettingsCollection();
        }

        return connectionStringCollection;
    }

    public static ConnectionStringSettings ConnectionString(this IConfigurationRoot configuration, String name, String section = "ConnectionStrings")
    {
        ConnectionStringSettings connectionStringSettings;

        var connectionStringCollection = configuration.GetSection(section).Get<ConnectionStringSettingsCollection>();
        if (connectionStringCollection == null ||
            !connectionStringCollection.TryGetValue(name, out connectionStringSettings))
        {
            return null;
        }

        return connectionStringSettings;
    }
}

最后是用法.

var configuration = new ConfigurationBuilder()
    .AddJsonFile("config.json")
    .Build();

var connectionStrings = configuration.ConnectionStrings();

foreach (var connectionString in connectionStrings.Values)
{
    Console.WriteLine(connectionString.Name);
    Console.WriteLine(connectionString.ConnectionString);
    Console.WriteLine(connectionString.ProviderName);
}

var specificConnStr1 = connectionStrings["Test1"];
Console.WriteLine(specificConnStr1.Name);
Console.WriteLine(specificConnStr1.ConnectionString);
Console.WriteLine(specificConnStr1.ProviderName);

var specificConnStr2 = configuration.ConnectionString("Test2");
Console.WriteLine(specificConnStr2.Name);
Console.WriteLine(specificConnStr2.ConnectionString);
Console.WriteLine(specificConnStr2.ProviderName);

这篇关于如何在 .NET Core 中使用 PROVIDER 读取 connectionString?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！