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

我添加了

.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"
    }

  }
}

现在我想阅读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"));

但是我无法读取数组或字典。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，而不是与连接字符串相同。

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

基本上，您要做的就是创建一些强类型的类以匹配旧的ConnectionStringSettings并利用一些收集序列化逻辑。

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.

以下是我建议在json中格式化它们的方式。类似于以旧的XML app / web.config方式指定连接字符串的方式。连接字符串的名称是密钥。

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"
    }
  }
}

现在可以绑定类了。首先是简单的ConnectionStringSettings类本身，实现您的基本相等/哈希方法（因为我们打算将其粘贴在Dictionary中，所以这是必需的）。

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。这仅是必需的，因为连接字符串的名称是JSON表示法中的键。为了使名称始终如一，我们需要重写Dictionary的Add方法（但是您不能这样做，因为它不是虚拟的）。因此，我们真正要做的只是将内部的Dictionary封装在自己的Add实现中。再次，这看起来像很多代码，但是您会看到它们是非常单调的无聊内容。

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可以使事情变得更简单。

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。

Finally the usage.

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！