Basically I'm trying to create a method in my webapi controller:
The method looks like this(the method body is relevant):
[HttpPost]
public HttpResponseMessage CpaLead([FromBody]CpaLeadVM model)
{
Here's the class declaration of the object being passed:
public class CpaLeadVM
{
public string UserIp = "";
public string UserCountry = "";
public double Earn = 0.0;
public string SurveyType = "";
}
The thing is; when I send a post request to the method, the model is always null.
The post request has the following data:
UserIp=hello
Earn=44.4
UserCountry=denmark
SurveyType=free
Shouldn't it be able to bind to the model or am I missing something here?
The problem is the "properties" you are trying to bind to are fields and not actual properties. The model binders and formatters in Web Api doesn't look at fields. If you change your model to:
public class CpaLeadVM
{
public CpaLeadVm()
{
UserIp = "";
UserCountry = "";
Earn = 0.0;
SurveyType = "";
}
public string UserIp {get;set;}
public string UserCountry {get;set;}
public double Earn {get;set;}
public string SurveyType {get;set;}
}
Your binding will work. As a side note, the [FromBody] attribute on your action is redundant since non-primitive values are bound from the request body by default.
As you may know, you can only get a single value from the body, which must be sent as "=value". See this article for more info
http://encosia.com/using-jquery-to-post-frombody-parameters-to-web-api/
I'm not sure, but I think you could create your own model binder, which parses the body into your class. Another approach is to use JSON. Read more about that here
ASP.NET MVC 4 Post FromBody Not Binding From JSON
Related
I would like to bind an object in a controller through the body of a HTTP Post.
It works like this
public class MyModelBinder : IModelBinder
{
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
throw new ArgumentNullException("No context found");
string modelName = bindingContext.ModelName;
if (String.IsNullOrEmpty(modelName)) {
bindingContext.Result = ModelBindingResult.Failed();
return Task.CompletedTask;
}
string value = bindingContext.ValueProvider.GetValue(modelName).FirstValue;
...
The modelName is viewModel (honestly, I don't know why, but it works...)
My controller looks like this
[HttpPost]
[Route("my/route")]
public IActionResult CalcAc([ModelBinder(BinderType = typeof(MyModelBinder))]IViewModel viewModel)
{
....
i.e. it works, when I make this HTTP-Post request
url/my/route?viewModel=URLparsedJSON
I would like however to pass it through the body of the request, i.e.
public IActionResult Calc([FromBody][ModelBinder(BinderType = typeof(MyModelBinder))]IViewModel viewModel)
In my Modelbinder then, the modelName is "" and the ValueProvider yields null... What am I doing wrong?
UPDATE
Example; Assume you have an interface IGeometry and many implementations of different 2D shapes, like Circle: IGeometry or Rectangle: IGeometry or Polygon: IGeometry. IGeometry itself has the method decimal getArea(). Now, my URL shall calculate the area for any shape that implements IGeometry, that would look like this
[HttpPost]
[Route("geometry/calcArea")]
public IActionResult CalcArea([FromBody]IGeometry geometricObject)
{
return Ok(geometricObject.getArea());
// or for sake of completness
// return Ok(service.getArea(geometricObject));
}
the problem is, you cannot bind to an interface, that yields an error, you need a class! That's where the custom model binder is used. Assume your IGeometryalso has the following property string Type {get; set;}
the in the custom model binding you would simply search for that Type in the passed json and bind it to the correct implementation. Something like
if (bodyContent is Rectangle) // that doesn't work ofc, but you get the point
var boundObject = Newtonsoft.Json.JsonConvert.DeserializeObject<Rectangle>(jsonString);
ASP.Net EF
In ASP.Net EF the custom model binding looks like this
public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
here you get the body of the HTTPPost request like this
string json = actionContext.Request.Content.ReadAsStringAsync().Result;
in ASP.Net Core you don't have the actionContext, only the bindingContext where I can't find the body of the HTTP Post.
UPDATE 2
Ok, I found the body, see accepted answer. Now inside the controller method I really have an object from type IGeometry (an interface) that is instantiated inside the custom model binder! My controller method looks like this:
[HttpPost]
[Route("geometry/calcArea")]
public IActionResult CalcArea([FromBody]IGeometry geometricObject)
{
return Ok(service.getArea(geometricObject));
}
And my injected service like this
public decimal getArea(IGeometry viewModel)
{
return viewModel.calcArea();
}
IGeometry on the other hand looks like this
public interface IGeometry
{
string Type { get; set; } // I use this to correctly bind to each implementation
decimal calcArea();
...
Each class then simply calculates the area accordingly, so
public class Rectangle : IGeometry
{
public string Type {get; set; }
public decimal b0 { get; set; }
public decimal h0 { get; set; }
public decimal calcArea()
{
return b0 * h0;
}
or
public class Circle : IGeometry
{
public string Type {get; set; }
public decimal radius { get; set; }
public decimal calcArea()
{
return radius*radius*Math.Pi;
}
I found a solution. The body of a HTTP Post request using ASP.NET Core can be obtained in a custom model binder using this lines of code
string json;
using (var reader = new StreamReader(bindingContext.ActionContext.HttpContext.Request.Body, Encoding.UTF8))
json = reader.ReadToEnd();
I found the solution after looking at older EF projects. There the body is inside the ActionContext which is passed separately as an argument in the BindModel method. I found that the same ActionContext is part of the ModelBindingContext in ASP.Net Core, where you get an IO.Stream instead of a string (easy to convert :-))
I want to assign my url parameters to Model properties, passed as a parameter to the associated Action. For example;
Say, my url is http://www.example.com/Item/Index?color=red&size=50
My action inside the controller is like below:
public class ItemController : Controller
{
public ActionResult Index(MyModel myModel)
{
//
return View(myModel);
}
}
I want to configure the model or whatever necessary so that my model takes the color and size as field values. The following didn't work:
public class MyModel
{
[Display(Name = "color")]
public string Color{ get; set; }
[Display(Name = "size")]
public string Size{ get; set; }
}
What would be the correct way to solve the problem?
Thanks for any suggestion.
Update
Well, yes! The code above would work correctly, because Url parameter names are the same as model property names. I should explain my problem exactly as I encounter for the next time, sorry.
I must correct a part of my question to make it clear. The url should have been: http://www.example.com/Item/Index?c=red&s=50 to detect the problem.
If the url is like that, the code would not work. Because Url parameters don't have the same name as Model properties.
Updated model is below:
public class MyModel
{
[Display(Name = "c")]
public string Color{ get; set; }
[Display(Name = "s")]
public string Size{ get; set; }
}
Try adding [FromUri] in front of the parameter.
public class ItemController : Controller
{
public ActionResult Index([FromUri] MyModel myModel)
{
// do something
return View();
}
}
debugging the issue
Here are some suggestions in debugging the issue, as it should work out of the box.
try binding to primitive types
public class ItemController : Controller
{
public ActionResult Index(string color, string size)
{
// do something
return View();
}
}
Try reading out of the request object directly
var size = this.Request["size"];
If either of those work there is an issue with your model binding.
Update
If you want to have the query string parameters different to the model in MVC you'll need to have a custom model binder. Take a look at Asp.Net MVC 2 - Bind a model's property to a different named value and http://ole.michelsen.dk/blog/bind-a-model-property-to-a-different-named-query-string-field.html which extends the answer a little.
https://github.com/yusufuzun/so-view-model-bind-20869735 has an example with some html helpers that could be useful.
I want to log the each action method parameter name and its
corresponding values in the database as key value pair. As part of
this, I am using OnActionExecuting ActionFilterAttribute, since it
will be the right place (OnActionExecuting method will get invoke for
all controller action methods call) to get Action Executing context.
I am getting the value for .Net types (string, int, bool). But I am
unable to get the value of the User defined types (custom types).
(ex: Login model). My model might have some other nested user
defined types as well.
I was trying to get the values of the user defined types but I am
getting the only class name as string. I hope we can do in
reflection.
Could you please anyone assist to resolve the issue. since I am new
to reflection. It will helpful to me. Thanks in Advance.
I need to get the name and value of these types in OnActionExecuting.
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
ActionParameter = new SerializableDictionary<string,string>();
if(filterContext.ActionParameter != null)
{
foreach(var paramter in filterContext.ActionParameter)
{
//able to get returnUrl value
//unable to get model values
ActionParameter.Add(paramter.Key, paramter.Value);
}
}
}
public ActionResult Login(LoginModel model, string returnUrl)
{
return View(model);
}
User defined type
public class LoginModel
{
public string UserName {get;set;}
public string Password {get;set;}
//User defined type
public UserRequestBase Request {get;set;}
}
//User defined type
public class UserRequestBase
{
public string ApplicationName {get;set;}
}
I am able to get the value of the returnUrl (login method param) in OnActionExecuting but not for model (login method param). I am able to see the values, but don't know how to access it, I used typeof even though I am unable to get it, but I need generic because i have 20 methods in controller so I could not only for LoginModel.
This answer isn't exactly what you want - based on your question - but I think it will work better for what want to accomplish. Quick aside...
Playing around with reflection and nested classes in this instance, lead to some SO (a propos?) errors for me...
So, a better path, maybe? Rather than trying to get/cast the property names, values (types?) from 'context.ActionParameters,` I found it was much easier to let a Json serialization do the work for me. You can then persist the Json object, then deserialize... pretty easy.
Anyway, here's the code:
using Newtonsoft.Json; // <-- or some other serialization entity
//...
public class LogActions : ActionFilterAttribute, IActionFilter
{
// Using the example -- LoginModel, UserRequestBase objects and Login controller...
void IActionFilter.OnActionExecuting(ActionExecutingContext context)
{
var param = (Dictionary<String, Object>)context.ActionParameters;
foreach (var item in param.Values)
{
string itemName = item.GetType().Name.ToString();
string itemToJson = JsonConvert.SerializeObject(item);
// Save JsonObject along with whatever other values you need (route, etc)
}
}
}
Then when you retrieve the Json object from the database you just have to deserialize / cast it.
LoginModel model = (LoginModel)JsonConvert.DeserializeObject(itemToJson, typeof(LoginModel));
From example:
public class LoginModel
{
public string UserName {get;set;}
public string Password {get;set;}
//User defined type
public UserRequestBase Request {get;set;}
}
//User defined type
public class UserRequestBase
{
public string ApplicationName {get;set;}
}
Controller used in example:
public ActionResult Login(LoginModel model, string returnUrl)
{
return View(model);
}
Hope this helps. If there are further issues with this please let me know and I will try to help.
I have stumbled up on some thing today. The below are my sample classes.
public class Employee
{
public string Name{get;set;}
Public Department Dept {get;set;}
public IList<Roles> Roles;
}
public Department{
public string Name{get;set;}
}
public Role {
public string Name{get;set;}
}
sampleApiController : ApiContrller{
public IEnumerable<string> Get(){
return new List<string>{"Pavan", "Josyula"};
}
public Employee GetEmp(int id){
Employee e = new Employee();
e.Dept = "IT";
e.Name="Pav";
IList<Roles> r = new IListRoles();
r.Add(new Role{Name="Integrator"});
e.Roles = r;
return e;
}
}
Now when I call this GetEmp Method from my broswer it is always giving me response in JSON format no matter what my content type in AcceptHeaders. But when I call my Get method, it returns collection of strings in XML format also it acts based on accept verb in request header. Can some body tell me the reason for this default JSON behaviour for custom types.
This is because XmlSerializer can't serialize IList<T>. Please read below answer for more details:
Differences in content negotiation between collections and single values in MVC 4
I m trying to rest-ify our existing WCF service and one of the hurdle is mapping complex type using Uritemplate. For example take a look at the below code
[DataContract]
public class Stock
{
[DataMember]
public string Symbol { get;set; }
[DataMember]
public double FaceValue { get; set; }
}
[ServiceContract]
public interface IRestService
{
[OperationContract]
[WebGet(UriTemplate = "?Symbol={stk.Symbol}")]
void Test1(Stock stk);
}
The above Uritemplate declaration will definitely not work, but this is what is my intention of mapping the input query variable to one of the property of that object.. Is this possible ?
Tks in advance for your help.
The example you give doesn't illustrate the problem. In that case, all that's needed is to pass a stock symbol, a simple string, and there's no need for a complex type.
In cases where you want to pass a more complex set of data, a JSON-encoded object, use WebInvoke with PUT or POST, a non-parameterized UriTemplate, and pass form data. See this answer for details.
In cases where you want GET, and can pass a small set of discrete parameters, you can use WebGet, an appropriate UriTemplate, and do the manual mapping. like so:
public enum OptionFlavor { Put, Call }
public class OptionInqury { public String Symbol; public String Month; public OptionFlavor Flavor;}
[OperationContract]
[WebGet(UriTemplate = "/optionquote/{stockSymbol}/{month}/{flavor}")]
void GetOptionPrice(string stockSymbol, string month, string flavor)
{
var x = new OptionInquiry {
Symbol = stockSymbol,
Month = month,
Flavor = (flavor.Equals("put")) ? OptionFlavor.Put : OptionFlavor.Call
};
// off you go...
}
If you want to map your query string parameters to the properties in your object, you need to go with WebInvoke. Unfortunately with GET, you will have to do this manually.