OpenApi convert to snackcase

[codewithmecoder]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

Microsoft.AspNetCore.OpenApi 9.0.2

builder.Services.AddOpenApi(options =>
{
    
    options.AddHeader("os", "ios");
    options.AddHeader("lang", "en");
    options.AddHeader("appearance", "1");
    options.AddDocumentTransformer((doc, _, _) =>
    {
        doc.Info = new OpenApiInfo
        {
            Title = "Mobile User Setting API",
            Version = "v1",
            Description = "API for get user general settings."
        };
        return Task.CompletedTask;
    });
});

Describe the solution you'd like

I want request and response in snackcase.

Additional context

No response

[martincostello]

Use ConfigureHttpJsonOptions() to enable snake case naming for your endpoints' JSON serialization.

[codewithmecoder]

Hi @martincostello, thank you for your response.
I am working on a project with .NET9 and use Scalar for documentation UI Microsoft OpenApi. I applied Newtonsoft for json Serialize and Deserialize. For response I got snackcase but for request I got camelcase in Scalar UI. How can I configure it to snackcase in request?

Thanks

[martincostello]

You would configure the OpenAPI document to use snake case in the way I already described.

builder.Services.ConfigureHttpJsonOptions(options =>
{
    options.SerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
});

However, note that Microsoft.AspNetCore.OpenApi does not support Newtonsoft.Json. See #60458 for more details.

[codewithmecoder]

You would configure the OpenAPI document to use snake case in the way I already described.

builder.Services.ConfigureHttpJsonOptions(options =>
{
options.SerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
});
However, note that Microsoft.AspNetCore.OpenApi does not support Newtonsoft.Json. See #60458 for more details.

Thank you 🙏 and noted

[codewithmecoder]

builder.Services.AddControllers(options =>
{
    options.ValueProviderFactories.Add(new SnakeCaseQueryValueProviderFactory());
}).AddJsonOptions(options =>
{
    options.JsonSerializerOptions.PropertyNamingPolicy = new JsonSerializerSnakeCaseNamingPolicy();
    options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
    options.JsonSerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
    options.JsonSerializerOptions.WriteIndented = false;
    options.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
});

builder.Services.ConfigureHttpJsonOptions(options =>
{
    options.SerializerOptions.PropertyNamingPolicy = new JsonSerializerSnakeCaseNamingPolicy();
    options.SerializerOptions.Converters.Add(new JsonStringEnumConverter());
    options.SerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
    options.SerializerOptions.WriteIndented = false;
    options.SerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
});

public class JsonSerializerSnakeCaseNamingPolicy : JsonNamingPolicy
{
    public override string ConvertName(string name)
    {
        return name.ToSnakeCase();
    }
}

public static string ToSnakeCase(this string o) =>
    SnakeCase().Replace(o, "$1_$2").ToLower();

[GeneratedRegex(@"(\w)([A-Z])")]
private static partial Regex SnakeCase();

This get to work, but this could be improve?

[martincostello]

Add a method to configure the options so you don't repeat it:

builder.Services.AddControllers(options =>
{
    options.ValueProviderFactories.Add(new SnakeCaseQueryValueProviderFactory());
}).AddJsonOptions(options => ConfigureJsonSerializer(options.JsonSerializerOptions));

builder.Services.ConfigureHttpJsonOptions(options => ConfigureJsonSerializer(options.SerializerOptions));

static void ConfigureJsonSerializer(JsonSerializerOptions options)
{
    options.PropertyNamingPolicy = new JsonSerializerSnakeCaseNamingPolicy();
    options.Converters.Add(new JsonStringEnumConverter());
    options.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
    options.WriteIndented = false;
    options.ReferenceHandler = ReferenceHandler.IgnoreCycles;
}

For the second snippet, use the built-in snake case options I already linked you to (JsonNamingPolicy.SnakeCaseLower).

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