Circular references errror messaget in Azure OpenAPI function

Question

Hi I am using C# Azure OpenAPI function with return typeOf (customer), On Swagger.json validation online I am getting the below error message

Azure function::

   [FunctionName("Function1")]

    [OpenApiOperation(operationId: "Run", tags: new[] { "name" })]

    [OpenApiParameter(name: "name", In = ParameterLocation.Query, Required = true, Type = typeof(string), Description = "The **Name** parameter")]

    [OpenApiResponseWithBody(statusCode: HttpStatusCode.OK, contentType: "application/json", bodyType: typeof(Customer), Description = "The OK response")]

    public async Task<IActionResult> Run(

        [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req)

    {

        _logger.LogInformation("C# HTTP trigger function processed a request.");


        string name = req.Query["name"];


        string requestBody = await new StreamReader(req.Body).ReadToEndAsync();

        dynamic data = JsonConvert.DeserializeObject(requestBody);

        name = name ?? data?.name;


        string responseMessage = string.IsNullOrEmpty(name)

            ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."

            : $"Hello, {name}. This HTTP triggered function executed successfully.";


        return new OkObjectResult(responseMessage);

    }

}


public class Customer

{

    [OpenApiProperty]

    string code { set; get; }


    [OpenApiProperty]

    public Customer c { set; get; }

}

Error Message::

This API is valid, but it cannot be shown because it contains circular references

TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    |     property 'properties' -> object with constructor 'Object'
    --- property 'c' closes the circle

Answer 1

@Anonymous

The Customer class has a public property "c" which seems to be a recursive reference to the same class. This may cause an infinite loop when serializing/deserializing JSON.
To avoid an infinite loop scenario in the Customer class, you can remove the property "c" or change it to reference a different class that doesn't have a reference back to Customer.

For example:

public class Customer
{
    [OpenApiProperty]
    public string code { set; get; }

    [OpenApiProperty]
    public AnotherClass anotherClass { set; get; }
}

public class AnotherClass
{
    // Properties and methods here
}