CODEWITHSUNDEEP
azureasp.net-web-api
Rikalous
Rikalous

Reputation: 4564

Confusion between .config files and Azure settings on ASP.Net core web app

I have built a project (to provide an API to a SPA web app) as a Asp.Net Core Web Application (.net framework) with the WebApi option (VS 2017 Community). This created a project with an app.config file and no web.config file. I have a section in app.config that I read using System.Configuration.ConnectionManager.ConnectionStrings['MainDb'] in my Startup.cs class which works fine locally.

When I deploy the app to Azure and set a 'MainDb' connection string in the portal, it does not get read by the web app. I have set these via the portal directly and via the settings pane available via the Azure server explorer in VS2017. In the server explorer I can see a web.config file but no app.config file, the web.config file has no connectionstring node but the web app seems to be seeing the connection string that was in app.config when I deployed.

I am somewhat confused as to the interaction between the app.config and the web.config here - where do I need to declare my connection string so that it can be overridden by the Azure portal setting?

Upvotes: 1

Views: 266

Answers (1)

juunas
juunas

Reputation: 58733

Typically in ASP.NET Core we use an appsettings.json file for configuration. Though there are many other options too (XML, user secrets etc.): https://joonasw.net/view/asp-net-core-1-configuration-deep-dive.

So you would have an appsettings.json file like this:

{
  "ConnectionStrings": {
    "MainDb": "Data Source=.;Initial Catalog=MainDb;Integrated Security=True"
  }
}

You can then read it by accessing the IConfiguration object in Startup:

public class Startup
{
    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
        Configuration = builder.Build();
    }

    public IConfiguration Configuration { get; set; }

    public void ConfigureServices(IServiceCollection services)
    {
        string connStr = Configuration.GetConnectionString("MainDb);
    }
}

GetConnectionString("name") is actually a shorthand for Configuration.GetSection("ConnectionStrings")["name"].

Upvotes: 1

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