Property naming policy for headers

[juchom]

I need to send data to an api who accepts JSON and CSV.

I'm asked that CSV headers must match JSON property naming policy

var JsonSerializerOptions = new JsonSerializerOptions 
 { 
     PropertyNamingPolicy = JsonNamingPolicy.CamelCase, 
 }; 

I have created this small linqpad program

void Main()
{
	var jsonSerializerOptions = new JsonSerializerOptions
	{
		PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
	};

	
	var p = new Person { Id = 1, FirstName = "John", LastName = "Doe" };
	var json = JsonSerializer.Serialize(p, jsonSerializerOptions);
	json.Dump();

	using (var writer = new StringWriter())
	using (var csv = new CsvWriter(writer,
                         new CsvConfiguration(CultureInfo.InvariantCulture) { LeaveOpen = true, HasHeaderRecord = true }))
	{
		csv.WriteHeader<Person>();
		csv.NextRecord();
		csv.WriteRecord(p);
		csv.Flush();
		var newRecord = writer.ToString();
		newRecord.Dump();
	}
}

public class Person
{
	public int Id { get; set; }
	public string FirstName { get; set; }
	public string LastName { get; set; }
}

Which output this :

{"id":1,"firstName":"John","lastName":"Doe"}

Id,FirstName,LastName
1,John,Doe

I tried creating an extension method on CsvWriter

public static class CsvWriterExtensions
{
	public static void WriteHeaderCamelCase<T>(this CsvWriter csv, CultureInfo cultureInfo = null)
	{
		cultureInfo = cultureInfo ?? CultureInfo.InvariantCulture;
		foreach (var prop in typeof(T).GetProperties())
		{
			var pName = prop.Name;
			csv.WriteField(Char.ToLower(pName[0], cultureInfo) + pName.Substring(1));
		}
	}
}

The problem is that it doesn't work with anonymous types and does not support the CsvConfiguration class.

I also tried to inherit from CsvWriter and override the WriteHeader methods, but there is no easy way to just add this behavior.

Last thing, I cannot use ClassMap or Attributes because I don't know the object I will receive.

Any idea on how to solve this issue ?

Thanks

[juchom]

This piece of code made the job

var mapType = typeof(DefaultClassMap<>).MakeGenericType(p.GetType());
var map = (ClassMap)ObjectResolver.Current.Resolve(mapType);
map.AutoMap(csv.Context);
foreach (var memberMap in map.MemberMaps)
{
	memberMap.Data.Names.Add(System.Text.Json.JsonNamingPolicy.CamelCase.ConvertName(memberMap.Data.Member.Name));
}
csv.Context.RegisterClassMap(map);

Are there any edge case am I missing with this ?