Develop Reference

How to mask sensetive data for particular requests (NLog)

Some of my actions accept models like:
public class PaymentRequest
{
public decimal Amount { get; set; }
public bool? SaveCard { get; set; }
public int? SmsCode { get; set; }
public BankCardDetails Card { get; set; }
}
public class BankCardDetails
{
public string Number { get; set; }
public string HolderName { get; set; }
public string ExpiryDate { get; set; }
public string ValidationCode { get; set; }
}
And the action method looks like:
[HttpPost]
[Route("api/v1/payment/pay")]
public Task<BankCardActionResponse> Pay([FromBody] PaymentRequest request)
{
if (request == null)
throw new HttpResponseException(HttpStatusCode.BadRequest);
return _paymentService.PayAsync(DataUserHelper.PhoneNumber, request);
}
I use Nlog. I think it's clear this is a bad idea to log all this bank data. My log config file contained the following line:
<attribute name="user-requestBody" layout="${aspnet-request-posted-body}"/>
I logged the request. I decided to refactor that and planned the following strategy. Actions that contain sensitive data into their requests I will mark with an attribute like
[RequestMethodFormatter(typeof(PaymentRequest))]
then take a look at my custom renderer:
[LayoutRenderer("http-request")]
public class NLogHttpRequestLayoutRenderer : AspNetRequestPostedBody
{
protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
{
base.DoAppend(builder, logEvent);
var body = builder.ToString();
// Get attribute of the called action.
var type = ... // How can I get "PaymentRequest" from the [RequestMethodFormatter(typeof(PaymentRequest))]
var res = MaskHelper.GetMaskedJsonString(body, type);
// ... and so on
}
}
I think you understand the idea. I need the type from the method's RequestMethodFormatter attribute. Is it even possible to get it into the renderer? I need it because I'm going to deserialize request JSON into particular models (it's gonna be into the MaskHelper.GetMaskedJsonString), work with the models masking the data, serialize it back into JSON.
So, did I choose a wrong approach? Or it's possible to get the type from the attribute into the renderer?

After some research, I ended up with the following solution:
namespace ConsoleApp7
{
internal class Program
{
private static void Main()
{
var sourceJson = GetSourceJson();
var userInfo = JsonConvert.DeserializeObject(sourceJson, typeof(User));
Console.WriteLine("----- Serialize without Resolver-----");
Console.WriteLine(JsonConvert.SerializeObject(userInfo));
Console.WriteLine("----- Serialize with Resolver-----");
Console.WriteLine(JsonConvert.SerializeObject(userInfo, new JsonSerializerSettings
{
ContractResolver = new MaskPropertyResolver()
}));
}
private static string GetSourceJson()
{
var guid = Guid.Parse("3e92f0c4-55dc-474b-ae21-8b3dac1a0942");
return JsonConvert.SerializeObject(new User
{
UserId = guid,
Age = 19,
Name = "John",
BirthDate = new DateTime(1990, 5, 12),
Hobbies = new[]
{
new Hobby
{
Name = "Football",
Rating = 5,
DurationYears = 3,
},
new Hobby
{
Name = "Basketball",
Rating = 7,
DurationYears = 4,
}
}
});
}
}
public class User
{
[MaskGuidValue]
public Guid UserId { get; set; }
[MaskStringValue("***")] public string Name { get; set; }
public int Age { get; set; }
[MaskDateTimeValue]
public DateTime BirthDate { get; set; }
public Hobby[] Hobbies { get; set; }
}
public class Hobby
{
[MaskStringValue("----")]
public string Name { get; set; }
[MaskIntValue(replacement: 11111)]
public int Rating { get; set; }
public int DurationYears { get; set; }
}
public class MaskPropertyResolver : DefaultContractResolver
{
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
var props = base.CreateProperties(type, memberSerialization);
var allowedPropertyTypes = new Type[]
{
typeof(Guid),
typeof(DateTime),
typeof(string),
typeof(int),
};
foreach (var prop in props.Where(p => allowedPropertyTypes.Contains(p.PropertyType)))
{
if (prop.UnderlyingName == null)
continue;
var propertyInfo = type.GetProperty(prop.UnderlyingName);
var attribute =
propertyInfo?.GetCustomAttributes().FirstOrDefault(x => x is IMaskAttribute) as IMaskAttribute;
if (attribute == null)
{
continue;
}
if (attribute.Type != propertyInfo.PropertyType)
{
// Log this case, cause somebody used wrong attribute
continue;
}
prop.ValueProvider = new MaskValueProvider(propertyInfo, attribute.Replacement, attribute.Type);
}
return props;
}
private class MaskValueProvider : IValueProvider
{
private readonly PropertyInfo _targetProperty;
private readonly object _replacement;
private readonly Type _type;
public MaskValueProvider(PropertyInfo targetProperty, object replacement, Type type)
{
_targetProperty = targetProperty;
_replacement = replacement;
_type = type;
}
public object GetValue(object target)
{
return _replacement;
}
public void SetValue(object target, object value)
{
_targetProperty.SetValue(target, value);
}
}
}
[AttributeUsage(AttributeTargets.Property)]
public class MaskStringValueAttribute : Attribute, IMaskAttribute
{
public Type Type => typeof(string);
public object Replacement { get; }
public MaskStringValueAttribute(string replacement)
{
Replacement = replacement;
}
}
[AttributeUsage(AttributeTargets.Property)]
public class MaskIntValueAttribute : Attribute, IMaskAttribute
{
public object Replacement { get; }
public Type Type => typeof(int);
public MaskIntValueAttribute(int replacement)
{
Replacement = replacement;
}
}
[AttributeUsage(AttributeTargets.Property)]
public class MaskGuidValueAttribute : Attribute, IMaskAttribute
{
public Type Type => typeof(Guid);
public object Replacement => Guid.Empty;
}
[AttributeUsage(AttributeTargets.Property)]
public class MaskDateTimeValueAttribute : Attribute, IMaskAttribute
{
public Type Type => typeof(DateTime);
public object Replacement => new DateTime(1970, 1, 1);
}
public interface IMaskAttribute
{
Type Type { get; }
object Replacement { get; }
}
}
I hope somebody will find it helpful.

You can try nuget package https://www.nuget.org/packages/Slin.Masking and https://www.nuget.org/packages/Slin.Masking.NLog.
It can easily be integrated with DotNet projects with slight changes, and you can define your rules for it. But the document needs some improvement.
As a suggestion, you can use two files:
masking.json (can be a generic one, that shared across all projects)
masking.custom.json (can be used with particular rules for specific projects)

make a snapshoot object of the current status of a static class

I have a static class in my system keeping track of the frequency of measurements, the number of samples currently read, what sensors are on an which are off and all those nice details.
Now I make a measurement and want to create a report in the report I want to save all the information stored in the static class. something like this :
public static class Details{
public static int samplesRead { get; set;}
public static int frequency { get; set;}
public static List<devices> devices { get; set;}
}
public class Patient{...} // name, surname , blabla
public class ResultsSet {
public DateTime date;
public Patient patient;
public *DetailsObject* details;
}
public void main {
patient p = new patient(...);
... make the measurements ...
var results = new ResultSet();
results.patient = p;
results.DateTime = DateTime.Now();
results.details = **here the magic ** Details.ToObject();
results.Serialize(myFilePath);
}
How can one acomplish that conversion to a single defined object?

it is the capability of making an snapshot of the static class in an object. [...] Just make an object.
So what you could do is to create a DTO that has the same properties as your static class:
public class DetailsSnapshot
{
public int samplesRead { get; set; }
public int frequency { get; set; }
public List<device> devices { get; set; }
}
Not you can map and return such an object at any given time:
public static class Details{
public static int samplesRead { get; set;}
public static int frequency { get; set; }
public static List<device> devices { get; set; }
public static DetailsSnapshot MakeSnapShot()
{
return new DetailsSnapshot
{
samplesRead = samplesRead,
frequency = frequency,
devices = devices.ToList()
};
}
}
You can have then such an snap-shot-object in your results:
public class ResultsSet
{
public DateTime date;
public Patient patient;
public DetailsSnapshot detailsSnapShot;
}
and make the snap shot (here the magic) the following way:
results.detailsSnapShot = Details.MakeSnapShot();
EDIT:
There is also a way using reflection. With this approach you would scan your Details class for the properties and extract the values. You could return a Dictionary which basically maps the names of the properties to the values:
public static Dictionary<string, object> MakeSnapShotReflection()
{
PropertyInfo [] allPorperties = typeof(Details).GetProperties(BindingFlags.Public | BindingFlags.Static);
Dictionary<string, object> valuemapping = new Dictionary<string, object>();
for (int i = 0; i < allPorperties.Length; i++)
{
valuemapping.Add(allPorperties[i].Name, allPorperties[i].GetValue(null));
}
return valuemapping;
}
This way would allow you to extend the Details class with further properties without worrying about extending anything else.
Or the short version:
public static Dictionary<string, object> MakeSnapShotReflection()
{
PropertyInfo[] allPorperties = typeof(Details).GetProperties(BindingFlags.Public | BindingFlags.Static);
return allPorperties.ToDictionary(key => key.Name, value => value.GetValue(null));
}
With this approach you could still use intellisens to access the correct values:
Test Data:
public static class Details
{
public static int samplesRead { get; set;} = 100;
public static int frequency { get; set; } = 2700;
public static List<device> devices { get; set; } = new List<device>()
{
new device { Name = "sensor1" },
new device { Name = "sensor 2" }
};
}
public class device
{
public string Name { get; set; }
}
Test Code to access values:
void Main()
{
Dictionary<string, object> details = Details.MakeSnapShotReflection();
Console.WriteLine(details[nameof(Details.frequency)]);
Console.WriteLine(details[nameof(Details.samplesRead)]);
foreach (var element in details[nameof(Details.devices)] as IEnumerable<device>)
{
Console.WriteLine(element.Name);
}
}
OUTPUT:
2700
100
sensor1
sensor 2

If you want to save and restore it, make it a non-static class and serialise/deserialise it using JSON or XML. You can then go JsonConvert.SerialiseObject and JsonConvert.Deserialise object. Nice and simple.
If you want to ensure only one instance, make the class a singleton.
public class Details
{
private static readonly Details _instance = new Details();
static Details()
{
}
private Details()
{
}
public Details Intance
{
get
{
return _instance;
}
}
public int samplesRead { get; set;}
public int frequency { get; set;}
public List<devices> devices { get; set; }
}
Then you can access it's properties this way:
Details.Instance.samplesRead
If the class has to be static, you can use reflection to serialise it:
public static string SerializeStaticProperties(Type type)
{
var properties = type.GetProperties(BindingFlags.Static | BindingFlags.Public);
var data = new List<Property>();
foreach (var property in properties)
{
data.Add(new Property
{
Name = property.Name,
Type = property.PropertyType,
Value = JsonConvert.SerializeObject(property.GetValue(null))
});
}
return JsonConvert.SerializeObject(data);
}
public static void DeserializeStaticProperties(Type type, string json)
{
var data = JsonConvert.DeserializeObject<List<Property>>(json);
foreach (var item in data)
{
var property = type.GetProperty(item.Name, BindingFlags.Static | BindingFlags.Public);
if (property != null)
{
property.SetValue(null, JsonConvert.DeserializeObject(item.Value, item.Type));
}
}
}
public class Property
{
public string Name { get; set; }
public Type Type { get; set; }
public string Value { get; set; }
}

moving property to anther property in class throws exception "System.InvalidCastException: 'Object must implement IConvertible.'"?

what I am trying to find away to move DynamicProperties property to JSONdata property because of that I have this reflection function to do the job when it came to DynamicProperties it throws exception "System.InvalidCastException: 'Object must implement IConvertible.'" can someone help me?
public IHttpActionResult Get(ODataQueryOptions<Client> options)
{
if(queryNew.ElementType == typeof(Client)){}
else //if (queryNew.ElementType.Name == "SelectSome`1")
{
var results = new List<Client>();
try
{
foreach (var item in queryNew)
{
var dict = ((ISelectExpandWrapper)item).ToDictionary();
var model = DictionaryToObject<Client>(dict);
results.Add(model);
}
return Ok(results);
}
catch (Exception)
{
throw;
}
}
private static T DictionaryToObject<T>(IDictionary<string, object> dict) where T : new()
{
T t = new T();
PropertyInfo[] properties = t.GetType().GetProperties();
foreach (PropertyInfo property in properties)
{
if (!dict.Any(x => x.Key.Equals(property.Name, StringComparison.InvariantCultureIgnoreCase)))
continue;
KeyValuePair<string, object> item = dict.First(x => x.Key.Equals(property.Name, StringComparison.InvariantCultureIgnoreCase));
Type tPropertyType = t.GetType().GetProperty(property.Name).PropertyType;
Type newT = Nullable.GetUnderlyingType(tPropertyType) ?? tPropertyType;
if(dict.Any(x => x.Key.Equals("DynamicProperties", StringComparison.InvariantCultureIgnoreCase)))
{
object temp = JsonConvert.SerializeObject(item.Value, Formatting.Indented); //Convert.ChangeType(item.Value.ToString(), newT);
t.GetType().GetProperty("JsonData").SetValue(t, temp, null);
}
object newA = Convert.ChangeType(item.Value, newT);
t.GetType().GetProperty(property.Name).SetValue(t, newA, null);
}
return t;
}
client class
public class Client
{
public Guid Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string ParticipantId { get; set; }
public DateTime? BirthDate { get; set; }
public int Gender { get; set; }
public byte? Age { get; set; }
public int Status { get; set; }
public string Notes { get; set; }
public DateTime CreatedDate { get; set; }
public DateTime? UpdatedDate { get; set; }
public DateTime? DeletedDate { get; set; }
public bool IsDeleted { get; set; }
public int? DefaultLanguageId { get; set; }
public Guid UserId { get; set; }
public string JsonData { get; set; }
public virtual ICollection<ClientTag> ClientTags { get; private set; }
protected IDictionary<string, object> _dynamicProperties;
public IDictionary<string, object> DynamicProperties
{
get
{
if (_dynamicProperties == null)
{
if (this.JsonData == null)
{
_dynamicProperties = new Dictionary<string, object>();
}
else
{
_dynamicProperties = Mapper.Map<IDictionary<string, object>>(JObject.Parse(this.JsonData));
}
//_dynamicProperties.Source.ListChanged += (sender, e) => { this.AssessmentData = _dynamicProperties.Source.ToString(); };
}
return _dynamicProperties;
}
}
public void UpdateJsonDataFromDynamicProperties()
{
this.JsonData = Mapper.Map<JObject>(_dynamicProperties).ToString();
}
}

When you get an IConvertable error, that means that you have tried to assign one type to another.
for example, if you try to assign textbox to string, you will get an error because you cannot assign object to string, you will have to use Iconvertible.
e.g.:
String.ToString();
Which implicitly implements Iconvertible.
I cannot tell exactly where your code fails, you didn't mention it either, I can just tell you that somewhere in the client methods, you are trying to assign two different types and you just cannot do that.
Use debug on both the server and client class and check where you are trying to assign two different types, then implement the desired Iconvertible, meaning make the needed conversion.
The only problem in your code here, is that you are trying to assign to different types.
My guess, is that this line caused trouble:
if (this.JsonData == null)
{
_dynamicProperties = new Dictionary<string, object>();
}
else
{
_dynamicProperties = Mapper.Map<IDictionary<string, object>>(JObject.Parse(this.JsonData));
}
When you are trying to assign _dynamicProperties into a dictionary object when in fact you declared _dynamicProperties as IDictionary object.
There is a subtle different between Idictionary and dictionary object, they are not of the same type. this is the change need to be done:
if (this.JsonData == null)
{
_dynamicProperties = new IDictionary<string, object>();
}
else
{
_dynamicProperties = Mapper.Map<IDictionary<string, object>>(JObject.Parse(this.JsonData));
}

How to configure JSON.net deserializer to track missing properties?

Sample class:
public class ClassA
{
public int Id { get; set; }
public string SomeString { get; set; }
public int? SomeInt { get; set; }
}
Default deserializer:
var myObject = JsonConvert.DeserializeObject<ClassA>(str);
Create the same object for two different inputs
{"Id":5}
or
{"Id":5,"SomeString":null,"SomeInt":null}
How can I track properties that were missing during deserialization process and preserve the same behavior? Is there a way to override some of JSON.net serializer methods (e.g. DefaultContractResolver class methods) to achive this. For example:
List<string> missingProps;
var myObject = JsonConvert.DeserializeObject<ClassA>(str, settings, missingProps);
For the first input list should contains the names of the missing properties ("SomeString", "SomeInt") and for second input it should be empty. Deserialized object remains the same.

1. JSON has a property which is missing in your class
Using property JsonSerializerSettings.MissingMemberHandling you can say whether missing properties are handled as errors.
Than you can install the Error delegate which will register errors.
This will detect if there is some "garbage" property in JSON string.
public class ClassA
{
public int Id { get; set; }
public string SomeString { get; set; }
}
internal class Program
{
private static void Main(string[] args)
{
const string str = "{'Id':5, 'FooBar': 42 }";
var myObject = JsonConvert.DeserializeObject<ClassA>(str
, new JsonSerializerSettings
{
Error = OnError,
MissingMemberHandling = MissingMemberHandling.Error
});
Console.ReadKey();
}
private static void OnError(object sender, ErrorEventArgs args)
{
Console.WriteLine(args.ErrorContext.Error.Message);
args.ErrorContext.Handled = true;
}
}
2. Your class has a property which is missing in JSON
Option 1:
Make it a required property:
public class ClassB
{
public int Id { get; set; }
[JsonProperty(Required = Required.Always)]
public string SomeString { get; set; }
}
Option 2:
Use some "special" value as a default value and check afterwards.
public class ClassB
{
public int Id { get; set; }
[DefaultValue("NOTSET")]
public string SomeString { get; set; }
public int? SomeInt { get; set; }
}
internal class Program
{
private static void Main(string[] args)
{
const string str = "{ 'Id':5 }";
var myObject = JsonConvert.DeserializeObject<ClassB>(str
, new JsonSerializerSettings
{
DefaultValueHandling = DefaultValueHandling.Populate
});
if (myObject.SomeString == "NOTSET")
{
Console.WriteLine("no value provided for property SomeString");
}
Console.ReadKey();
}
}
Option 3:
Another good idea would be to encapsulate this check iside the class istself. Create a Verify() method as shown below and call it after deserialization.
public class ClassC
{
public int Id { get; set; }
[DefaultValue("NOTSET")]
public string SomeString { get; set; }
public int? SomeInt { get; set; }
public void Verify()
{
if (SomeInt == null ) throw new JsonSerializationException("SomeInt not set!");
if (SomeString == "NOTSET") throw new JsonSerializationException("SomeString not set!");
}
}

Another way to find null/undefined tokens during De-serialization is to write a custom JsonConverter , Here is an example of custom converter which can report both omitted tokens (e.g. "{ 'Id':5 }") and null tokens (e.g {"Id":5,"SomeString":null,"SomeInt":null})
public class NullReportConverter : JsonConverter
{
private readonly List<PropertyInfo> _nullproperties=new List<PropertyInfo>();
public bool ReportDefinedNullTokens { get; set; }
public IEnumerable<PropertyInfo> NullProperties
{
get { return _nullproperties; }
}
public void Clear()
{
_nullproperties.Clear();
}
public override bool CanConvert(Type objectType)
{
return true;
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
existingValue = existingValue ?? Activator.CreateInstance(objectType, true);
var jObject = JObject.Load(reader);
var properties =
objectType.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
foreach (var property in properties)
{
var jToken = jObject[property.Name];
if (jToken == null)
{
_nullproperties.Add(property);
continue;
}
var value = jToken.ToObject(property.PropertyType);
if(ReportDefinedNullTokens && value ==null)
_nullproperties.Add(property);
property.SetValue(existingValue, value, null);
}
return existingValue;
}
//NOTE: we can omit writer part if we only want to use the converter for deserializing
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var objectType = value.GetType();
var properties =
objectType.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
writer.WriteStartObject();
foreach (var property in properties)
{
var propertyValue = property.GetValue(value, null);
writer.WritePropertyName(property.Name);
serializer.Serialize(writer, propertyValue);
}
writer.WriteEndObject();
}
}
Note: we can omit the Writer part if we don't need to use it for serializing objects.
Usage Example:
class Foo
{
public int Id { get; set; }
public string SomeString { get; set; }
public int? SomeInt { get; set; }
}
class Program
{
static void Main(string[] args)
{
var nullConverter=new NullReportConverter();
Console.WriteLine("Pass 1");
var obj0 = JsonConvert.DeserializeObject<Foo>("{\"Id\":5, \"Id\":5}", nullConverter);
foreach(var p in nullConverter.NullProperties)
Console.WriteLine(p);
nullConverter.Clear();
Console.WriteLine("Pass2");
var obj1 = JsonConvert.DeserializeObject<Foo>("{\"Id\":5,\"SomeString\":null,\"SomeInt\":null}" , nullConverter);
foreach (var p in nullConverter.NullProperties)
Console.WriteLine(p);
nullConverter.Clear();
nullConverter.ReportDefinedNullTokens = true;
Console.WriteLine("Pass3");
var obj2 = JsonConvert.DeserializeObject<Foo>("{\"Id\":5,\"SomeString\":null,\"SomeInt\":null}", nullConverter);
foreach (var p in nullConverter.NullProperties)
Console.WriteLine(p);
}
}

I got this problem, but defaultValue was not solution due to POCO object. I think this is simpler approach than NullReportConverter.
There are three unit tests. Root is class that encapsulate whole json. Key is type of the Property. Hope this helps someone.
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Newtonsoft.Json;
namespace SomeNamespace {
[TestClass]
public class NullParseJsonTest {
[TestMethod]
public void TestMethod1()
{
string slice = "{Key:{guid:\"asdf\"}}";
var result = JsonConvert.DeserializeObject<Root>(slice);
Assert.IsTrue(result.OptionalKey.IsSet);
Assert.IsNotNull(result.OptionalKey.Value);
Assert.AreEqual("asdf", result.OptionalKey.Value.Guid);
}
[TestMethod]
public void TestMethod2()
{
string slice = "{Key:null}";
var result = JsonConvert.DeserializeObject<Root>(slice);
Assert.IsTrue(result.OptionalKey.IsSet);
Assert.IsNull(result.OptionalKey.Value);
}
[TestMethod]
public void TestMethod3()
{
string slice = "{}";
var result = JsonConvert.DeserializeObject<Root>(slice);
Assert.IsFalse(result.OptionalKey.IsSet);
Assert.IsNull(result.OptionalKey.Value);
}
}
class Root {
public Key Key {
get {
return OptionalKey.Value;
}
set {
OptionalKey.Value = value;
OptionalKey.IsSet = true; // This does the trick, it is never called by JSON.NET if attribute missing
}
}
[JsonIgnore]
public Optional<Key> OptionalKey = new Optional<Key> { IsSet = false };
};
class Key {
public string Guid { get; set; }
}
class Optional<T> {
public T Value { get; set; }
public bool IsSet { get; set; }
}
}

XML Deserialization Rules

I need to deserialize xml file and its structured this way:
<NPCs>
<LabAssistant1>
<Questions>
<Question>
<Type>CheckBox</Type>
<Points>10</Points>
<Text>Q1</Text>
<Answers>
<Answer>
<Correct>False</Correct>
<Text>A1</Text>
</Answer>
<Answer>
<Correct>True</Correct>
<Text>A2</Text>
</Answer>
<Answer>
<Correct>False</Correct>
<Text>A3</Text>
</Answer>
</Answers>
</Question>
</Questions>
</LabAssistant1>
<LabAssistant2>
<Questions>
...
</Questions>
</LabAssistant2>
</NPCs>
So as you can see am having root node NPCs and my goal is to read questions separately by LabAssistant1 name or any tag name in NPCs.
String questionsPath = path+"/questions.xml";
XmlReader reader=XmlReader.Create(new StreamReader(questionsPath));
XmlRootAttribute xmlRoot = new XmlRootAttribute();
xmlRoot.ElementName = npc;
reader.ReadToDescendant(npc);
XmlSerializer se = new XmlSerializer(typeof(Question[]),xmlRoot);
Question[] qs=se.Deserialize(reader) as Question[];
Console.WriteLine(qs.Length.ToString()); // Always 0
Above code should output 2 objects of Question as array, but it doesn't
Here are the classes Question and Answer, anything is wrong with my attached attributes?
public class Question
{
[XmlElement(ElementName="Text")]
public String Text { get; set; }
[XmlArray(ElementName = "Answers")]
public Answer[] Answers { get; set; }
[XmlElement(ElementName = "Type")]
public QuestionType Type { get; set; }
[XmlElement(ElementName = "Points")]
public int Points { get; set; }
public Question()
{
}
public Question(String text, Answer[] answers, QuestionType type,int points)
{
this.Text = text;
this.Answers = answers;
this.Type = type;
this.Points = points;
}
}
public class Answer
{
[XmlElement(ElementName="Text")]
public String Text { get; set; }
[XmlElement(ElementName = "Correct")]
public bool Correct { get; set; }
public Answer()
{
}
public Answer(String text, bool correct)
{
this.Text = text;
this.Correct = correct;
}
}

You could use the UnknownElement event of XmlSerializer to load all the lab assistants into memory, like so:
public class LabAssistant
{
static XmlSerializer listSerializer;
static LabAssistant()
{
// This must be cached to prevent memory & resource leaks.
// See http://msdn.microsoft.com/en-us/library/System.Xml.Serialization.XmlSerializer%28v=vs.110%29.aspx
listSerializer = new XmlSerializer(typeof(List<Question>), new XmlRootAttribute("Questions"));
}
public List<Question> Questions { get; set; }
public static bool TryDeserializeFromXml(XmlElement element, out string name, out LabAssistant assistant)
{
name = element.Name;
var child = element.ChildNodes.OfType<XmlElement>().Where(el => el.Name == "Questions").FirstOrDefault();
if (child != null)
{
var list = child.OuterXml.LoadFromXML<List<Question>>(listSerializer);
if (list != null)
{
assistant = new LabAssistant() { Questions = list };
return true;
}
}
assistant = null;
return false;
}
}
public class NPCs
{
public NPCs()
{
this.LabAssistants = new Dictionary<string, LabAssistant>();
}
public static XmlSerializer CreateXmlSerializer()
{
// No need to cache this.
var serializer = new XmlSerializer(typeof(NPCs));
serializer.UnknownElement += new XmlElementEventHandler(NPCs.XmlSerializer_LoadLabAssistants);
return serializer;
}
[XmlIgnore]
public Dictionary<string, LabAssistant> LabAssistants { get; set; }
public static void XmlSerializer_LoadLabAssistants(object sender, XmlElementEventArgs e)
{
var obj = e.ObjectBeingDeserialized;
var element = e.Element;
if (obj is NPCs)
{
var npcs = (NPCs)obj;
string name;
LabAssistant assistant;
if (LabAssistant.TryDeserializeFromXml(element, out name, out assistant))
npcs.LabAssistants[name] = assistant;
}
}
}
Using the following helper methods:
public static class XmlSerializationHelper
{
public static T LoadFromXML<T>(this string xmlString)
{
return xmlString.LoadFromXML<T>(new XmlSerializer(typeof(T)));
}
public static T LoadFromXML<T>(this string xmlString, XmlSerializer serial)
{
T returnValue = default(T);
using (StringReader reader = new StringReader(xmlString))
{
object result = serial.Deserialize(reader);
if (result is T)
{
returnValue = (T)result;
}
}
return returnValue;
}
}
Having done this, you now have a dictionary of lab assistants by name.
While this code will deserialize your data correctly, it won't reserialize it. Custom code to serialize the dictionary would be required.
One final note - XmlSerializer will choke on the XML you provided because it requires that Boolean values be in lowercase. Thus the following will throw an exception:
<Correct>False</Correct>
If you did not mistype the XML and it really contains Booleans in this format, you will need to manually handle these fields.

I needed to create QuestionCollection class to hold the array of questions (having typeof(Question[]) throws <TagName xmlns="> was not expected, probably because the deserializer is not smart enough).
What i do next is first reading to tag LabAssistant or any tag name, next reading to its child Questions tag and after that i deserialize the questions into QuestionCollection, so with ReadToDescendant I can access any child elements of the NPCs
String questionsPath = Application.dataPath + "/Resources/questions.xml";
XmlReader reader=XmlReader.Create(new StreamReader(questionsPath));
reader.ReadToDescendant("LabAssistant");
reader.ReadToDescendant("Questions");
XmlSerializer se = new XmlSerializer(typeof(QuestionCollection));
QuestionCollection qc=(QuestionCollection)se.Deserialize(reader);
QuestionCollection class:
[XmlType("Questions")]
public class QuestionCollection
{
[XmlElement("Question")]
public Question[] Questions { get; set; }
public QuestionCollection() { }
}
Question class
[XmlType("Question")]
public class Question
{
[XmlElement("Text")]
public String Text { get; set; }
[XmlArray("Answers")]
public Answer[] Answers { get; set; }
[XmlElement("Type")]
public QuestionType Type { get; set; }
[XmlElement("Points")]
public int Points { get; set; }
public Question() { }
}
Answer class:
[XmlType("Answer")]
public class Answer
{
[XmlElement("Text")]
public String Text { get; set; }
[XmlElement("Correct")]
public bool Correct { get; set; }
public Answer() { }
}