.NET 6 MVC read config from Model

Question

Hello.

I'm trying to find the right way to read config in appsettings.json from Model.

I have a BaseModel with a common method for making GET request to an Api. All models inherit from BaseModel, so, on a specific Model, I can execute the base method for GET.
In appstettings.json I have an entry "ApiURL". I want from BaseModel to read that config key.

I have tried to add a constructor parameter "IConfiguration configuration" in the base class, but the problem is that I get an error saying that you need an empty constructor. But if I create an empty constructor, configuration is never initialized.

¿How do you read appsettings.json from a model?

Thanks

Answer 1

Hi @Eligio Morgado ,

In the BaseModel constructor method, you can refer the following code to create a configuration instance:

public class BaseModel  
{  
    private readonly IConfiguration _config;  
    public BaseModel()  
    {  
        _config = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();   
    }  
    public string Name { get; set; }  

    public string GetConnection()  
    {  
        return _config.GetConnectionString("DefaultConnection");  
    }  
}  

Then, the result is like this:

---

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Best regards,
Dillion

Answer 2

This is a poor design. You should not have models (or actions) read a configuration file. Your model really should only have methods that access model data. An api call should be done outside the model with an adapter.

The adapter should be created at startup and injected.

Please study standard design patterns

Answer 3

See if this will work for you. C:\OED needs to be replaced with were the file you want to read resides. And as mentioned, placing this in the model is not a good idea.

Class

public class Example
{
    public string SomeProperty { get; set; }
}

Read json

public class Helper
{

    public static string ConfigurationFileName { get; set; } = "appsettings.json";
    public static Example Example()
    {
        var config = InitMainConfiguration();
        return config.GetSection("Section1").Get<Example>();
    }
    private static IConfigurationRoot InitMainConfiguration()
    {

        var builder = new ConfigurationBuilder()
            // change the path to where ever the json file resides
            .SetBasePath("C:\\OED")
            .AddJsonFile(ConfigurationFileName);
        return builder.Build();
    }
}

Model

public class SomeModel
{
    public int  Id { get; set; }
    public void DoSomething()
    {
        Example result = Helper.Example();
        Debug.WriteLine(result.SomeProperty);
    }
}

Execution

SomeModel someModel = new SomeModel();
someModel.DoSomething();