如何针对POST的无效数据类型发送用户友好的错误消息？

Question

The data is being validated correctly in the below code, but I would like to send back a more user-friendly error message than just returning a 500 if the data formatting is bad.

public class PostData
{
    public DateTime DateOfBirth {get; set;}
}

[HttpPost]
public string MakeAWish([FromBody] PostData data)
{
    return "Happy BirthDay!";
}

The following value works fine. { "dateOfBirth" : "1980-01-01" }

The value below obviously does not. { "dateOfBirth" : "1980" }

How can I send back a user friendly message when the dateOfBirth is formatted incorrectly?

Answer 1

Set DateOfBirth to be a string. Then have another property that is the DateTime, ie DateOfBirthDT.

When the user submits the string DateOfBirth you can use DateTime.TryParse() to test if the string value can parse to a valid DateTime value, if not you can return a friendly error.

For example:

public class PostData
{
    public string DateOfBirth {get; set;}
    public DateTime DateOfBirthDT {get; set;}
}

[HttpPost]
public string MakeAWish([FromBody] PostData data)
{
    if(DateTime.TryParse(data.DateOfBirth, out DateTime dob)) {
        data.DateOfBirthDT = dob;
        return "success";
    }else {
        return "Please post a valid date";
    }
}