ASP.NET Core [FromBody] vs MVC 5 binding - asp.net-mvc

Question

I got an MVC 5 application that i'm porting to asp.net Core.
In the MVC application call to controller we're made using AngularJS $resource (sending JSON) and we we're POSTing data doing :
ressource.save({ entries: vm.entries, projectId: vm.project.id }).$promise...
that will send a JSON body like:
{
entries:
[
{
// lots of fields
}
],
projectId:12
}
the MVC controller looked like this :
[HttpPost]
public JsonResult Save(List<EntryViewModel> entries, int projectId) {
// code here
}
How can I replicate the same behaviour with .NET Core since we can't have multiple [FromBody]

Answer 1

you cannot have multiple parameter with the FromBody attibute in an action method. If that is need, use a complex type such as a class with properties equivalent to the parameter or dynamic type like that
[HttpPost("save/{projectId}")]
public JsonResult Save(int projectId, [FromBody] dynamic entries) {
// code here
}

Answer 2

As pointed out in the comment, one possible solution is to unify the properties you're posting onto a single model class.
Something like the following should do the trick:
public class SaveModel
{
public List<EntryViewModel> Entries{get;set;}
public int ProjectId {get;set;}
}
Don't forget to decorate the model with the [FromBody] attribute:
[HttpPost]
public JsonResult Save([FromBody]SaveViewModel model)
{
// code here
}
Hope this helps!

Answer 3

It's still rough but I made a Filter to mimic the feature.
public class OldMVCFilter : IActionFilter
{
public void OnActionExecuted(ActionExecutedContext context)
{
}
public void OnActionExecuting(ActionExecutingContext context)
{
if (context.HttpContext.Request.Method != "GET")
{
var body = context.HttpContext.Request.Body;
JToken token = null;
var param = context.ActionDescriptor.Parameters;
using (var reader = new StreamReader(body))
using (var jsonReader = new JsonTextReader(reader))
{
jsonReader.CloseInput = false;
token = JToken.Load(jsonReader);
}
if (token != null)
{
var serializer = new JsonSerializer();
serializer.DefaultValueHandling = DefaultValueHandling.Populate;
serializer.FloatFormatHandling = FloatFormatHandling.DefaultValue;
foreach (var item in param)
{
JToken model = token[item.Name];
if (model == null)
{
// try to cast the full body as the current object
model = token.Root;
}
if (model != null)
{
model = this.RemoveEmptyChildren(model, item.ParameterType);
var res = model.ToObject(item.ParameterType, serializer);
context.ActionArguments[item.Name] = res;
}
}
}
}
}
private JToken RemoveEmptyChildren(JToken token, Type type)
{
var HasBaseType = type.GenericTypeArguments.Count() > 0;
List<PropertyInfo> PIList = new List<PropertyInfo>();
if (HasBaseType)
{
PIList.AddRange(type.GenericTypeArguments.FirstOrDefault().GetProperties().ToList());
}
else
{
PIList.AddRange(type.GetTypeInfo().GetProperties().ToList());
}
if (token != null)
{
if (token.Type == JTokenType.Object)
{
JObject copy = new JObject();
foreach (JProperty jProp in token.Children<JProperty>())
{
var pi = PIList.FirstOrDefault(p => p.Name == jProp.Name);
if (pi != null) // If destination type dont have this property we ignore it
{
JToken child = jProp.Value;
if (child.HasValues)
{
child = RemoveEmptyChildren(child, pi.PropertyType);
}
if (!IsEmpty(child))
{
if (child.Type == JTokenType.Object || child.Type == JTokenType.Array)
{
// nested value has been checked, we add the object
copy.Add(jProp.Name, child);
}
else
{
if (!pi.Name.ToLowerInvariant().Contains("string"))
{
// ignore empty value when type is not string
var Val = (string)child;
if (!string.IsNullOrWhiteSpace(Val))
{
// we add the property only if it contain meningfull data
copy.Add(jProp.Name, child);
}
}
}
}
}
}
return copy;
}
else if (token.Type == JTokenType.Array)
{
JArray copy = new JArray();
foreach (JToken item in token.Children())
{
JToken child = item;
if (child.HasValues)
{
child = RemoveEmptyChildren(child, type);
}
if (!IsEmpty(child))
{
copy.Add(child);
}
}
return copy;
}
return token;
}
return null;
}
private bool IsEmpty(JToken token)
{
return (token.Type == JTokenType.Null || token.Type == JTokenType.Undefined);
}
}