ASP.NET Core WebAPI XML Method argument deserialization - asp.net-core

Question

I'm trying to make a WebAPI controller on .NET Core 3.1 witch supports both JSON and XML as request/response content-type.
Controller works perfectly when it receive JSON with "application/json", but when it receive XML with "application/xml", method argument are created with default values, not values that was posted in request body.
Example project - https://github.com/rincew1nd/ASPNetCore_XMLMethods
Additional XML serializer in startup:
services.AddControllers().AddXmlSerializerFormatters();
Controller with method and test model:
[ApiController]
[Route("[controller]")]
public class TestController : ControllerBase
{
[HttpPost, Route("v1")]
[Consumes("application/json", "application/xml")]
[Produces("application/json", "application/xml")]
public TestRequest Test([FromBody] TestRequest data)
{
return data;
}
}
[DataContract]
public class TestRequest
{
[DataMember]
public Guid TestGuid { get; set; }
[DataMember]
public string TestString { get; set; }
}
P.S. Project contains Swagger for API testing purposes.

Answer 1

Your xml post request body uses camel cases which results in the model binding as null.
Add using Swashbuckle.AspNetCore.SwaggerGen; in starup.cs and try to configure like below code:
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers().AddXmlSerializerFormatters();
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "Neocase <-> 1C Integration", Version = "v1" });
c.SchemaFilter<XmlSchemaFilter>();
});
}
public class XmlSchemaFilter : Swashbuckle.AspNetCore.SwaggerGen.ISchemaFilter
{
public void Apply(OpenApiSchema model, SchemaFilterContext context)
{
if (model.Properties == null) return;
foreach (var entry in model.Properties)
{
var name = entry.Key;
entry.Value.Xml = new OpenApiXml
{
Name = name.Substring(0, 1).ToUpper() + name.Substring(1)
};
}
}
}

Answer 2

Don't use FromBody attribute for application/xml.
When a parameter has [FromBody], Web API uses the Content-Type header to select a formatter. In this example, the content type is "application/json" and the request body is a raw JSON string (not a JSON object).
Using [FromBody]

Answer 3

After some more research i found that swagger generates wrong xml examples without even noticing custom naming of classes or properties.
I wrote custom schema for naming xml attributes as they are named by XML attributes.
Only problem i faced is that SchemaFilterContext doesn't provide description of properties of Enum type. So to name Enums i use custom attribute for swagger name and XMLElementAttribute on property with same names (yeah, it's junky but works).
public class XmlSchemaFilter : ISchemaFilter
{
public void Apply(OpenApiSchema schema, SchemaFilterContext context)
{
//Try to find XmlRootAttribute on class
var xmlroot = context.Type.GetAttributeValue((XmlRootAttribute xra) => xra);
if (xmlroot != null)
{
schema.Xml = new OpenApiXml
{
Name = xmlroot.ElementName
};
}
//Try to find XmlElementAttribute on property
if (context.MemberInfo != null)
{
var xmlelement = context.MemberInfo.GetAttributeValue((XmlElementAttribute xea) => xea);
if (xmlelement != null)
{
schema.Xml = new OpenApiXml
{
Name = xmlelement.ElementName
};
}
}
//Try to find XmlEnumNameAttribute on enums
if (context.Type.IsEnum)
{
var enumname = context.Type.GetAttributeValue((XmlEnumNameAttribute xea) => xea);
if (enumname != null)
{
schema.Xml = new OpenApiXml
{
Name = enumname.ElementName
};
}
}
}
}
public static class AttributeHelper
{
public static TValue GetAttributeValue<TAttribute, TValue>(
this Type type,
Func<TAttribute, TValue> valueSelector)
where TAttribute : Attribute
{
var att = type.GetCustomAttributes(
typeof(TAttribute), true
).FirstOrDefault() as TAttribute;
if (att != null)
{
return valueSelector(att);
}
return default(TValue);
}
public static TValue GetAttributeValue<TAttribute, TValue>(
this MemberInfo mi,
Func<TAttribute, TValue> valueSelector)
where TAttribute : Attribute
{
var att = mi.GetCustomAttributes(
typeof(TAttribute), true
).FirstOrDefault() as TAttribute;
if (att != null)
{
return valueSelector(att);
}
return default(TValue);
}
}