CODEWITHSUNDEEP
asp.netasp.net-web-api2
user2719430
user2719430

Reputation: 564

detect extra attributes in frombody post payload

I'm looking for a way to detect extra attributes delivered on a WebAPI post payload that do not match the POCO I expect. For example, here's an input object:

public class Input
{
    public string Name { get; set; }
}

And a controller method:

public void Post([FromBody]Input value)

If a client sends the following post payload:

{
    "Name" : "Foo",
    "Description" : "Bar"
}

This will trigger the Post method on my controller and Name will be populated. I'd like to be aware that Description was sent but ignored, so I can either log that event server side or inform the client through a response header that they're sending extra data.

Upvotes: 2

Views: 200

Answers (1)

SBFrancies
SBFrancies

Reputation: 4250

I think this is possible but you'd have to go without Model Binding and use reflection if you want a general solution:

Class:

public class Input
{
    public string Name { get; set; }
}

Payload:

{
    "Name" : "Foo",
    "Description" : "Bar"
}

Controller Method:

public async void Post()
{
    //Read the content to a string   
    var content = await Request.Content.ReadAsStringAsync();

    //Get the Input object you wanted
    var input = JsonConvert.DeserializeObject<Input>(content);

    //Get a Dictionary containing all the content sent    
    var allContent = JsonConvert.DeserializeObject<Dictionary<string, object>>(content);

    //Get the property names of the wanted object    
    var props = input.GetType().GetProperties().Select(a => a.Name);

    //See which properties are extra
    var extraContent = allContent.Keys.Except(props);
}

For the above example extraContent would be a list containing "Description". If you want the value just use the dictionary object.

Upvotes: 2

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