CODEWITHSUNDEEP
c#asp.net-core
chemitaxis
chemitaxis

Reputation: 14889

read connectionstring outside startup from appsetting.json in vNext

I have a project class (Nuget Package). I need to read in a static class without constructor my connections string to MongoDB.

Static Class Method:

        /// <summary>
        /// The default key MongoRepository will look for in the appsettings.json 
        /// </summary>
        private const string DefaultConnectionstringName = "Data:MongoDB:MongoServerSettings";

        /// <summary>
        /// Retrieves the default connectionstring from appsettings.json
        /// </summary>
        /// <returns>Returns the default connectionstring from the App.config or Web.config file.</returns>
        public static string GetDefaultConnectionString()
        {
            var config = new Configuration();
            return config.Get<string>(DefaultConnectionstringName);
        }

I have always null... How can I obtain the value outside the Startup.cs without using DI?

It is possible?

In my old code I could do something like that:

/// <summary>
    /// Retrieves the default connectionstring from the App.config or Web.config file.
    /// </summary>
    /// <returns>Returns the default connectionstring from the App.config or Web.config file.</returns>
    public static string GetDefaultConnectionString()
    {
        return ConfigurationManager.ConnectionStrings[DefaultConnectionstringName].ConnectionString;
    }

Thanks!!

Upvotes: 19

Views: 33190

Answers (5)

Leonardo Wildt
Leonardo Wildt

Reputation: 2599

None of the above answers worked for me. I am building a .net core 2.1 api.

I used 

public class Startup 
{
    public static string ConnectionString {get; private set;}


public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
           if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseHsts();
            }
            ConnectionString = Configuration.GetConnectionString("xxxxxx");
            app.UseMvc();
}

Then whenever i need it i call string ConnString = Startup.ConnectionString;

Upvotes: 2

Saineshwar Bageri - MVP
Saineshwar Bageri - MVP

Reputation: 4031

1.ConnectionString in appsetting.json

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  1. Creating Singleton Instance of Configuration in Startup.cs class

enter image description here

  1. Reading Values from Configuration Instance Using Dependency Injection [Constructor injection ]

enter image description here

  1. Finally Output

enter image description here

Upvotes: 48

armen.shimoon
armen.shimoon

Reputation: 6401

Inside your startup, you should save the connection string to a static property on Startup

public class Startup
{
    public static string ConnectionString { get; private set; }

    public Startup(IHostingEnvironment env)
    {
        // Set up configuration sources.
        var builder = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddUserSecrets();

        if (env.IsDevelopment())
        {
            // For more details on using the user secret store see http://go.microsoft.com/fwlink/?LinkID=532709
            builder.AddUserSecrets();
        }

        builder.AddEnvironmentVariables();
        Configuration = builder.Build();
        ConnectionString = Configuration.Get<string>("Data:MongoDB:MongoServerSettings");
    }
    // ...
}

Then you should be able to access it from wherever:

public static string GetDefaultConnectionString()
{
    return Startup.ConnectionString;
}

Upvotes: 24

brettkc
brettkc

Reputation: 250

Something like this should work:

   public Startup(IHostingEnvironment env, IApplicationEnvironment appEnv)
    {
        var builder = new ConfigurationBuilder(appEnv.ApplicationBasePath).AddJsonFile("config.json");
        Configuration = builder.Build();
        var connStr = Configuration.Get("connString");
    }

Docs: http://docs.asp.net/en/latest/fundamentals/configuration.html

Upvotes: 5

Stas Boyarincev
Stas Boyarincev

Reputation: 3990

How can I obtain the value outside the Startup.cs without using DI? It is possible?

Yes, you can using Configuration without DI and throughout your application. But recommended way using Configuration API only in Startup and then Using Options:

create well-factored settings objects that correspond to certain features within your application, thus following the Interface Segregation Principle (ISP) (classes depend only on the configuration settings they use)

Example using Configuration API

appsettings.json:

{
  "Name": "Stas",
  "Surname": "Boyarincev"
}

Using Configuration:

var builder = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddEnvironmentVariables();

var Configuration = builder.Build();

var name = Configuration.GetSection("name");
var surname = Configuration.GetSection("surname");

tutorial on docs.asp.net - but it a bit outdated.

Upvotes: 0

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