Collector Common RestClient

Configuration through config section

startup.cs:

var section = new ConfigurationBuilder()
				.AddJsonFile("appsettings.json")
				.Build()
				.GetSection("RestClient");

var restApiClient = new ApiClientBuilder()
				.ConfigureFromConfigSection(section)
				.Build(); // The client returned here should be used/registered as a singleton.

appsettings.json:

{
  "RestClient": {
    "ClientId": "my_client_id",
    "ClientSecret": "my_client_secret",
    "Authentication": "oauth2",
    "Issuer": "my_issuer.com",

    "Apis": {
      "MyApi": {
        "Audience": "https://my-api.com",
        "BaseUrl": "https://my-api.com",
        "Timeout": "00:00:30"
      }
    }
  }
}

Note that it is valid to configure anything on the api level, so if you add a property "ClientId" to the "MyApi" object then that client id will be used for MyApi, but for all other apis the global one will be used.

Configuration through app/web.config

startup.cs:

var restApiClient = new ApiClientBuilder()
                .ConfigureFromAppSettings()
                .Build(); // The client returned here should be used/registered as a singleton.

app.config:

<configuration>
  <appSettings>
    <add key="RestClient:ClientId" value="my_client_id"/>
    <add key="RestClient:ClientSecret" value="my_client_secret"/>
    <add key="RestClient:Authentication" value="oauth2"/>
    <add key="RestClient:Issuer" value="my_issuer.com"/>
    
    <add key="RestClient:MyApi.Audience" value="https://my-api.com"/>
    <add key="RestClient:MyApi.BaseUrl" value="https://my-api.com"/>
    <add key="RestClient:MyApi.Timeout" value="00:00:30"/>
  </appSettings>
</configuration>

Note that it is valid to configure anything on the api level, so if you add a property "RestClient:MyApi.ClientId" then that client id will be used for MyApi, but for all other apis the global one will be used.

Other configuration options

It is also highly recommended to configure a serilog logger and context management:

var provider = new ApiClientBuilder()
                .WithLogger(Log.Logger) //Serilog
                .WithContextFunction(() => CorrelationState.GetCurrentCorrelationId()?.ToString()) // Collector.Common.Correlation
                .Build();

Overriding default response parsers

Implement ISuccessfulResponseParser and IErrorResponseParser in a base class, and let all request contracts inherit from this class.

public abstract class MyApiBaseRequest<TResourceIdentifier, TResponse>
    : RequestBase<TResourceIdentifier, TResponse>,
        ISuccessfulResponseParser<TResponse>,
        IErrorResponseParser
    where TResourceIdentifier : class, IResourceIdentifier
    where TResponse : class
{
    protected MyApiBaseRequest(TResourceIdentifier resourceIdentifier)
        : base(resourceIdentifier)
    {
    }

    public TResponse ParseResponse(string content)
    {
        // Plain JSON parser
        return JsonConvert.DeserializeObject<TResponse>(content);
    }

    public Error ParseError(string content)
    {
        // Plain JSON parser
        var myError = JsonConvert.DeserializeObject<MyApiErrorResponse>(content);

        return new Error(
            code: myError.ErrorCode.ToString(),
            message: myError.ErrorMessage
        );
    }
}

public class MyApiExampleRequest
    : MyApiBaseRequest<MyApiExampleResourceIdentifier, MyApiExampleResponse>
{
    public MyApiExampleRequest()
        : base(new MyApiExampleResourceIdentifier())
    {
    }

    public override HttpMethod GetHttpMethod()
    {
        return HttpMethod.GET;
    }

    public override string GetConfigurationKey()
    {
        return "MyApi";
    }
}

public class MyApiExampleResourceIdentifier : ResourceIdentifier
{
    public override string Uri => "myapi/example";
}

public class MyApiExampleResponse
{
    public MyApiExampleResponse(string message)
    {
        Message = message;
    }

    public string Message { get; }
}

public class MyApiErrorResponse
{
    public MyApiErrorResponse(string errorMessage, int errorCode)
    {
        ErrorMessage = errorMessage;
        ErrorCode = errorCode;
    }

    [JsonRequired]
    public string ErrorMessage { get; }

    [JsonRequired]
    public int ErrorCode { get; }
}