I am trying to find the IndexOf in a list using a value as reference. Like lets say Id = 23144, I want the index when entering the Id.
This Object list is made by deserializing a Json retrieved with RestSharp.
{
"not_modified_since":"2018-06-05T22:22:18Z",
"host":[
{
"active":true,
"config_profile_bag_id":0,
"container_id":0,
"db_pickup_tm_utc":"2018-01-11T10:12:55",
"discovery_status":0,
"display_unit_id":0,
"domain_id":103947039,
"geolocation":"(0,0)",
"id":195392183,
"license_end_date":null,
"licensed":true,
"name":"Broadsign Services - Mathias - 16x64",
"nscreens":0,
"primary_mac_address":"00:0c:29:e0:e6:22",
"public_key_fingerprint":"Redacted",
"remote_clear_db_tm_utc":"1970-01-01T00:00:00",
"remote_reboot_tm_utc":"2017-12-12T10:17:23",
"secondary_mac_address":"",
"volume":-1
}
]
}
I have the following code:
private void bRun_Click(object sender, EventArgs e)
{
var client = new RestClient(endPoint);
var request = new RestRequest("/host/v14/by_id", Method.GET);
request.AddHeader("accept", "application/json");
request.AddHeader("Authorization", "Bearer " + key);
request.AddParameter("domain_id", "103947039");
request.AddParameter("ids", "195392183");
request.OnBeforeDeserialization = resp => { resp.ContentType = "application/json"; };
request.RequestFormat = DataFormat.Json;
var response = client.Execute<RootObject>(request);
var rootObject = JsonConvert.DeserializeObject<RootObject>(response.Content);
var hosts = rootObject.Host;
oResponse.Text = hosts.IndexOf();
}
There could be multiple host, so I'd like to be able to find the index of each host so I can then know which one to retrieve the value of following certain conditions, for example those that match the Id. In Sum I'd like to be able to know that id 195392183 is at index 0 so that I can then use that index to retrieve the value for name ( Broadsign Services - Mathias - 16x64 ) for example.
EDIT!
SOLVED! This worked for me:
var index = rootObject.Host.FindIndex(host => host.Id == 195392183);
You can create a dictionary based on the Host
var hostsDict = rootObject.Select(r=> r.Host).ToDictionary<int, Host>(k=> k.Id, v=> v);
return hostDict[195392183];
You could add an index to your deserialized object using a custom coverter.
public class ListWithIndexConverter<T> : JsonConverter where T : IIndexedObject
{
public override bool CanConvert(Type objectType)
{
return (objectType == typeof(List<T>));
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
JToken token = JToken.Load(reader);
if (token.Type != JTokenType.Array)
{
return new List<T>();
}
var returnList = new List<T>();
for(var i=0; i < token.Count(); i++)
{
var returnObject = token[i].ToObject<T>();
returnObject.Index = i;
returnList.Add(returnObject);
}
return returnList;
}
public override bool CanWrite => false;
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
public interface IIndexedObject
{
int Index { get; set; }
}
public class SomeObject
{
[JsonConverter(typeof(ListWithIndexConverter<Host>))]
public List<Host> Hosts { get; set; }
}
public class Host : IIndexedObject
{
//some properties
}
Related
I'm developing a project that will require me to include credentials for things like an SMTP server. I'd like to store this information along with the complete details of the endpoint in an embedded JSON file, but I would like to have that information encrypted and then let my application decrypt it when it needs to establish a connection and log in. The JSON structure looks something like this:
{
"Endpoints" : [
{
"Endpoint" : {
"Host": "smtp.mydomain.tld",
"Port": 587,
"Username": "user#mydomain.tld",
"Password": "mYp#s$w0?d"
}
}
]
}
While what I'd really like to have actually stored in the file would look something like this:
{
"Endpoints" : [
{
"Endpoint" : "<BASE64_ENCODED_STRING>"
}
]
}
Using Newtonsoft's Json.NET, I've built the class object/properties to desriealize this structure:
<JsonProperty("Endpoints")>
Public Property Endpoints As List(Of EndpointContainer) = Nothing
Public Class EndpointContainer
<EditorBrowsable(EditorBrowsableState.Never)> <DebuggerBrowsable(DebuggerBrowsableState.Never)>
Private Const EncryptedPrefix As String = "myappcipher:"
<EditorBrowsable(EditorBrowsableState.Never)> <DebuggerBrowsable(DebuggerBrowsableState.Never)>
<JsonProperty("Endpoint")> <JsonConverter(GetType(EndpointProtector))>
Public Property Endpoint As Endpoint = Nothing
End Class
And I've built the inherited JsonConverter class ("EndpointProtector") like this:
Public Class EndpointProtector
Inherits JsonConverter
Public Sub New()
Using SHAEncryption = New SHA256Managed()
_EncryptionKey = SHAEncryption.ComputeHash(Encoding.UTF8.GetBytes(TestEncryptionKey))
End Using
End Sub
Public Overrides Sub WriteJson(writer As JsonWriter, value As Object, serializer As JsonSerializer)
Dim clearText As String = JsonConvert.SerializeObject(value)
If clearText Is Nothing Then
Throw New ArgumentNullException(NameOf(clearText))
End If
writer.WriteValue(EncryptEndpoint(clearText))
End Sub
Public Overrides Function ReadJson(reader As JsonReader, objectType As Type, existingValue As Object, serializer As JsonSerializer) As Object
Dim DecryptString As String = TryCast(reader.Value, String)
If String.IsNullOrEmpty(DecryptString) Then
Return reader.Value
ElseIf Not DecryptString.StartsWith(EncryptedPrefix, StringComparison.OrdinalIgnoreCase) Then
Return DecryptString
Else
Return DecryptEndpoint(DecryptString)
End If
End Function
Public Overrides Function CanConvert(objectType As Type) As Boolean
Throw New NotImplementedException()
End Function
End Class
Currently I have the JSON file itself with the full object definition (as in the first code block). When my application reads that JSON, it correctly moves to the overridden ReadJson() method I have, but the reader.Value is null (Nothing), so it never actually gets to the DecryptEndpoint() method. Of course, that means there's nothing to encrypt, so the application won't even step into the WriteJson() method.
I've tried a couple of variations, including making the Endpoint property into a private variable with a generic Object type, and then having a separate public property with the <JsonIgnore> decoration to "read" from that, but nothing seems to get me where I need to be. I'm sure I'm overlooking something here, but I can't seem to figure out why it's not getting anything at all.
I looked at a few other SO questions like Encrypt and JSON Serialize an object, but I've still not yet been able to figure out quite where I've gone wrong here.
NOTE: I intentionally didn't include the code for the EncryptEndpoint() or DecryptEndpoint() methods here simply because the code is never making it that far in the process. If you feel it's needed to fully answer the question, please let me know.
this is a linqpad example of working encrypt/decrypt base on JsonAttribute
void Main()
{
string str = "";
var t = new Test() { encName = "some long text some long text some long text", Name = "test" };
JsonSerializerSettings theJsonSerializerSettings = new JsonSerializerSettings();
theJsonSerializerSettings.TypeNameHandling = TypeNameHandling.None;
str = JsonConvert.SerializeObject(t, theJsonSerializerSettings).Dump();
JsonConvert.DeserializeObject<Test>(str, theJsonSerializerSettings).Dump();
}
public class Test
{
[JsonConverter(typeof(EncryptingJsonConverter))]
public string encName { get; set; }
public string Name { get; set; }
}
/// <summary>[JsonConverter(typeof(EncryptingJsonConverter), string 32byte array)]</summary>
public class EncryptingJsonConverter : JsonConverter
{
private readonly byte[] _encryptionKeyBytes;
private readonly string _encryptionKeyString;
///<summary>Key must be 32char length</summary>
public EncryptingJsonConverter()
{
string encryptionKey = "E546C8DF278CD5931069B522E695D4F2"; //get from config
if (string.IsNullOrEmpty(encryptionKey))
throw new ArgumentNullException(nameof(encryptionKey));
_encryptionKeyString = encryptionKey;
_encryptionKeyBytes = Convert.FromBase64String(encryptionKey);
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var stringValue = (string)value;
if (string.IsNullOrEmpty(stringValue))
{
writer.WriteNull();
return;
}
//string enc = stringValue.Encrypt(_encryptionKeyString);
string enc = Crypto.Encrypt(stringValue, _encryptionKeyBytes);
writer.WriteValue(enc);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var value = reader.Value as string;
if (string.IsNullOrEmpty(value))
return reader.Value;
try
{
//return value.Decrypt(_encryptionKeyString);
return Crypto.Decrypt(value, _encryptionKeyBytes);
}
catch
{
return string.Empty;
}
}
/// <inheritdoc />
public override bool CanConvert(Type objectType)
{
return objectType == typeof(string);
}
}
public static class Crypto
{
public static string Encrypt(this string text, string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentException("Key must have valid value.", nameof(key));
if (string.IsNullOrEmpty(text))
throw new ArgumentException("The text must have valid value.", nameof(text));
var buffer = Encoding.UTF8.GetBytes(text);
var hash = SHA512.Create();
var aesKey = new byte[24];
Buffer.BlockCopy(hash.ComputeHash(Encoding.UTF8.GetBytes(key)), 0, aesKey, 0, 24);
using (var aes = Aes.Create())
{
if (aes == null)
throw new ArgumentException("Parameter must not be null.", nameof(aes));
aes.Key = aesKey;
using (var encryptor = aes.CreateEncryptor(aes.Key, aes.IV))
using (var resultStream = new MemoryStream())
{
using (var aesStream = new CryptoStream(resultStream, encryptor, CryptoStreamMode.Write))
using (var plainStream = new MemoryStream(buffer))
{
plainStream.CopyTo(aesStream);
}
var result = resultStream.ToArray();
var combined = new byte[aes.IV.Length + result.Length];
Array.ConstrainedCopy(aes.IV, 0, combined, 0, aes.IV.Length);
Array.ConstrainedCopy(result, 0, combined, aes.IV.Length, result.Length);
return Convert.ToBase64String(combined);
}
}
}
public static string Decrypt(this string encryptedText, string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentException("Key must have valid value.", nameof(key));
if (string.IsNullOrEmpty(encryptedText))
throw new ArgumentException("The encrypted text must have valid value.", nameof(encryptedText));
var combined = Convert.FromBase64String(encryptedText);
var buffer = new byte[combined.Length];
var hash = new SHA512CryptoServiceProvider();
var aesKey = new byte[24];
Buffer.BlockCopy(hash.ComputeHash(Encoding.UTF8.GetBytes(key)), 0, aesKey, 0, 24);
using (var aes = Aes.Create())
{
if (aes == null)
throw new ArgumentException("Parameter must not be null.", nameof(aes));
aes.Key = aesKey;
var iv = new byte[aes.IV.Length];
var ciphertext = new byte[buffer.Length - iv.Length];
Array.ConstrainedCopy(combined, 0, iv, 0, iv.Length);
Array.ConstrainedCopy(combined, iv.Length, ciphertext, 0, ciphertext.Length);
aes.IV = iv;
using (var decryptor = aes.CreateDecryptor(aes.Key, aes.IV))
using (var resultStream = new MemoryStream())
{
using (var aesStream = new CryptoStream(resultStream, decryptor, CryptoStreamMode.Write))
using (var plainStream = new MemoryStream(ciphertext))
{
plainStream.CopyTo(aesStream);
}
return Encoding.UTF8.GetString(resultStream.ToArray());
}
}
}
public static string Encrypt(string text, byte[] key)
{
//string keyString = "encrypt123456789";
//var key = Encoding.UTF8.GetBytes(keyString);//16 bit or 32 bit key string
using (var aesAlg = Aes.Create())
{
using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
{
using (var msEncrypt = new MemoryStream())
{
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
using (var swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(text);
}
var iv = aesAlg.IV;
var decryptedContent = msEncrypt.ToArray();
var result = new byte[iv.Length + decryptedContent.Length];
Buffer.BlockCopy(iv, 0, result, 0, iv.Length);
Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length);
return Convert.ToBase64String(result);
}
}
}
}
public static string Decrypt(string cipherText, byte[] key)
{
var fullCipher = Convert.FromBase64String(cipherText);
var iv = new byte[16];
var cipher = new byte[fullCipher.Length - iv.Length];//new byte[16];
Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);
//var key = Encoding.UTF8.GetBytes(keyString);//same key string
using (var aesAlg = Aes.Create())
{
using (var decryptor = aesAlg.CreateDecryptor(key, iv))
{
string result;
using (var msDecrypt = new MemoryStream(cipher))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
{
result = srDecrypt.ReadToEnd();
}
}
}
return result;
}
}
}
}
to activate encryption just add a tag
[JsonConverter(typeof(EncryptingJsonConverter))]
How can I change the casing of the property names of a json without performing model binding?
JsonElement serialization ignores PropertyNaming JsonSerializer options as is also confirmed here: https://github.com/dotnet/runtime/issues/61843
The suggested use of JsonNode/JsonObject results in the same behavior.
Any hints how I can accomplish this?
As example I want to change this:
{
"MyPoperty" : 5,
"MyComplexProperty" : {
"MyOtherProperty": "value",
"MyThirdProperty": true
}
}
to this:
{
"myPoperty" : 5,
"myComplexProperty" : {
"myOtherProperty": "value",
"myThirdProperty": true
}
}
Cheers.
I think you try to use Newtonsoft json
class Person
{
public string UserName { get; set; }
public int Age { get; set; }
}
coding
static void Main(string[] args)
{
Person person = new Person();
person.UserName = "Bob";
person.Age = 20;
var serializerSettings = new JsonSerializerSettings();
serializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
var json = JsonConvert.SerializeObject(person, serializerSettings);
Console.WriteLine(json);
}
output
{"userName":"Bob","age":20}
not depend on Newtonsoft json but in the case of multi-layer objects
var json = #"{""ShouldWindUpAsCamelCase"":""does it?""}";
var obj = JsonSerializer.Deserialize<Dictionary<string,string>>(json);
var dic = new Dictionary<string, string>();
foreach (var item in obj)
{
dic.Add(item.Key.FirstCharToLower(), item.Value);
}
var serialized = System.Text.Json.JsonSerializer.Serialize(dic);
Console.WriteLine(serialized);
FirstCharToLower() function
public static string FirstCharToLower(this string input)
{
if (String.IsNullOrEmpty(input))
return input;
string str = input.First().ToString().ToLower() + input.Substring(1);
return str;
}
#output
{"shouldWindUpAsCamelCase":"does it?"}
I have a controller action Export which accepts a List of models like below. This is sending back and manipulated dataset back from the view where the user could interact with it. So we have been able to send the data down with much more information.
[HttpPost]
public JsonResult Export(List<MappingExportModel> sources){}
This works fine in all cases but there is one where we have a bigger than normal dataset. This is causing an issue with the export. So far I have tried just passing the values as an object or string but I am unable to convert them into any usable instance after the data is into the controller.
Is it possible to preemptively increase this maxjsonlength value somewhere. The value from the web.config is being ignored from what I have come across so far.
The error I receive is
"Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property"
I need to be able to accept this directly from the ajax request into the controller action. Spinning up a version of JsonResult and then setting the max value will not work because the error is thrown the the data is trying to be deserialized into the object var presented above. We get the value in the original GET request and do set the value before the view is loaded. Now we are taking the data from this view and sending it back plus all the manipulations the users have created.
User posts data to server, the controller action is hit with the data. The error is encountered and spit back out to the browser which handles the error.
You can use custom json length. add the following file in your project and edit your global.asax.cs
Global.asax
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
///// **********
JsonValueProviderFactory jsonValueProviderFactory = null;
foreach (var factory in ValueProviderFactories.Factories)
{
if (factory is JsonValueProviderFactory)
{
jsonValueProviderFactory = factory as JsonValueProviderFactory;
}
}
//remove the default JsonVAlueProviderFactory
if (jsonValueProviderFactory != null) ValueProviderFactories.Factories.Remove(jsonValueProviderFactory);
//add the custom one
ValueProviderFactories.Factories.Add(new CustomJsonValueProviderFactory());
/////*************
}
}
///******** for json length
public sealed class CustomJsonValueProviderFactory : ValueProviderFactory
{
private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, object value)
{
IDictionary<string, object> d = value as IDictionary<string, object>;
if (d != null)
{
foreach (KeyValuePair<string, object> entry in d)
{
AddToBackingStore(backingStore, MakePropertyKey(prefix, entry.Key), entry.Value);
}
return;
}
IList l = value as IList;
if (l != null)
{
for (int i = 0; i < l.Count; i++)
{
AddToBackingStore(backingStore, MakeArrayKey(prefix, i), l[i]);
}
return;
}
// primitive
backingStore[prefix] = value;
}
private static object GetDeserializedObject(ControllerContext controllerContext)
{
if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
{
// not JSON request
return null;
}
StreamReader reader = new StreamReader(controllerContext.HttpContext.Request.InputStream);
string bodyText = reader.ReadToEnd();
if (String.IsNullOrEmpty(bodyText))
{
// no JSON data
return null;
}
JavaScriptSerializer serializer = new JavaScriptSerializer();
serializer.MaxJsonLength = int.MaxValue; //increase MaxJsonLength. This could be read in from the web.config if you prefer
object jsonData = serializer.DeserializeObject(bodyText);
return jsonData;
}
public override IValueProvider GetValueProvider(ControllerContext controllerContext)
{
if (controllerContext == null)
{
throw new ArgumentNullException("controllerContext");
}
object jsonData = GetDeserializedObject(controllerContext);
if (jsonData == null)
{
return null;
}
Dictionary<string, object> backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
AddToBackingStore(backingStore, String.Empty, jsonData);
return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);
}
private static string MakeArrayKey(string prefix, int index)
{
return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
}
private static string MakePropertyKey(string prefix, string propertyName)
{
return (String.IsNullOrEmpty(prefix)) ? propertyName : prefix + "." + propertyName;
}
}
JsonValueProviderFactory.cs
public sealed class JsonValueProviderFactory : ValueProviderFactory
{
private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, object value)
{
IDictionary<string, object> d = value as IDictionary<string, object>;
if (d != null)
{
foreach (KeyValuePair<string, object> entry in d)
{
AddToBackingStore(backingStore, MakePropertyKey(prefix, entry.Key), entry.Value);
}
return;
}
IList l = value as IList;
if (l != null)
{
for (int i = 0; i < l.Count; i++)
{
AddToBackingStore(backingStore, MakeArrayKey(prefix, i), l[i]);
}
return;
}
// primitive
backingStore[prefix] = value;
}
private static object GetDeserializedObject(ControllerContext controllerContext)
{
if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
{
// not JSON request
return null;
}
StreamReader reader = new StreamReader(controllerContext.HttpContext.Request.InputStream);
string bodyText = reader.ReadToEnd();
if (String.IsNullOrEmpty(bodyText))
{
// no JSON data
return null;
}
JavaScriptSerializer serializer = new JavaScriptSerializer();
serializer.MaxJsonLength = int.MaxValue; //increase MaxJsonLength. This could be read in from the web.config if you prefer
object jsonData = serializer.DeserializeObject(bodyText);
return jsonData;
}
public override IValueProvider GetValueProvider(ControllerContext controllerContext)
{
if (controllerContext == null)
{
throw new ArgumentNullException("controllerContext");
}
object jsonData = GetDeserializedObject(controllerContext);
if (jsonData == null)
{
return null;
}
Dictionary<string, object> backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
AddToBackingStore(backingStore, String.Empty, jsonData);
return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);
}
private static string MakeArrayKey(string prefix, int index)
{
return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
}
private static string MakePropertyKey(string prefix, string propertyName)
{
return (String.IsNullOrEmpty(prefix)) ? propertyName : prefix + "." + propertyName;
}
}
by this you can pass lengthy json through ajax to controller and if you want to retrieve a lengthy string back to ajax result from controller then add below code in your controller also
//add this for getting large json string
protected override JsonResult Json(object data, string contentType, System.Text.Encoding contentEncoding, JsonRequestBehavior behavior)
{
return new JsonResult()
{
Data = data,
ContentType = contentType,
ContentEncoding = contentEncoding,
JsonRequestBehavior = behavior,
MaxJsonLength = Int32.MaxValue
};
}
I need to save an object's state into a file and retrieve it later. I found JSON serialization would help and found this method Json.gobject_serialize. Using this method, I can successfully serialize objects containing string properties. But what should I do, if the object A consists of another object (say B) within it and I need to serialize object A.
EDIT
What should I do if the object A consists of array (say B) of objects?
I created a small test program for this purpose and I failed in that try. I cannot find any detailed documentation about JSON Serialization for vala.
public class Foo : Object {
public int iFoo {get; set;}
public string sFoo {get; set;}
Bar[] _bar = {};
public Bar[] bar {get {return _bar;} set{_bar = value;}}
public class Bar : Object {
public int iBar {get; set;}
public string sBar {get; set;}
construct {
iBar = 02;
sBar = "OutOfRange";
}
}
construct {
_bar += new Bar();
iFoo = 74;
sFoo = "GIrafee";
}
public static int main () {
Json.Node root = Json.gobject_serialize (new Foo());
Json.Generator generator = new Json.Generator ();
generator.set_root (root);
stdout.printf(generator.to_data (null) + "\n");
return 0;
}
}
Serialization with JSON-GLib is recursive for properties containing complex types.
If the property of a GObject contains another GObject, json_gobject_serialize() will recursively call json_gobject_serialize() on the instance stored inside the property — or serialize the null if the property is unset.
I've implemented a object to support Json.Serializable interface as follow:
public class DbObject : GLib.Object, Json.Serializable
{
public Json.Object? meta { get; construct set; default = null; }
public VersionSync version { get; set; default = VersionSync.UNKNOWN; }
public virtual Value get_property (ParamSpec pspec)
{
Value prop_value = GLib.Value(pspec.value_type);
(this as GLib.Object).get_property(pspec.name, ref prop_value);
stdout.printf ("%s --> %s\n", prop_value.type_name(), prop_value.strdup_contents());
return prop_value;
}
public virtual void set_property (ParamSpec pspec, Value value)
{
(this as GLib.Object).set_property (pspec.name, value);
}
public unowned ParamSpec? find_property (string name)
{
return ((ObjectClass) get_type ().class_ref ()).find_property (name);
}
public virtual Json.Node serialize_property (string property_name, Value #value, ParamSpec pspec)
{
if (#value.type ().is_a (typeof (Json.Object)))
{
var obj = #value as Json.Object;
if (obj != null)
{
var node = new Json.Node (NodeType.OBJECT);
node.set_object (obj);
return node;
}
}
else if (#value.type ().is_a (typeof (Gee.ArrayList)))
{
unowned Gee.ArrayList<GLib.Object> list_value = #value as Gee.ArrayList<GLib.Object>;
if (list_value != null || property_name == "data")
{
var array = new Json.Array.sized (list_value.size);
foreach (var item in list_value)
{
array.add_element (gobject_serialize (item));
}
var node = new Json.Node (NodeType.ARRAY);
node.set_array (array);
return node;
}
}
else if (#value.type ().is_a (typeof (GLib.Array)))
{
unowned GLib.Array<GLib.Object> array_value = #value as GLib.Array<GLib.Object>;
if (array_value != null || property_name == "data")
{
var array = new Json.Array.sized (array_value.length);
for (int i = 0; i < array_value.length; i++) {
array.add_element (gobject_serialize (array_value.index(i)));
}
var node = new Json.Node (NodeType.ARRAY);
node.set_array (array);
return node;
}
}
else if (#value.type ().is_a (typeof (HashTable)))
{
var obj = new Json.Object ();
var ht_string = #value as HashTable<string, string>;
if (ht_string != null)
{
ht_string.foreach ((k, v) => {
obj.set_string_member (k, v);
});
var node = new Json.Node (NodeType.OBJECT);
node.set_object (obj);
return node;
} else {
var ht_object = #value as HashTable<string, GLib.Object>;
if (ht_object != null)
{
ht_object.foreach ((k, v) => {
obj.set_member (k, gobject_serialize (v));
});
var node = new Json.Node (NodeType.OBJECT);
node.set_object (obj);
return node;
}
}
}
return default_serialize_property (property_name, #value, pspec);
}
public virtual bool deserialize_property (string property_name, out Value #value, ParamSpec pspec, Json.Node property_node)
{
return default_deserialize_property (property_name, out #value, pspec, property_node);
}
}
I have a situation in which I have a very large C# object, however, I only need to return a handful of properties (which can be on nested objects), allow for client-side JavaScript to modify those properties and then send the resulting object back to the server in order to perform in-place partial de-serialization.
The idea is to re-use some very large existing business objects, but be intelligent about only serializing and sending only those properties back to the client application for modification (to keep the amount of data transferred at a minimum).
I basically have an XML file where I pre-define all of the bindings using a "path syntax" which would indicate only those properties I need to serialize. So, I could use something like "WorkOrder.UserField1" or "WorkOrder.Client.Name".
I have tried using a custom contract resolver to determine whether or not a property should be serialized; however, it doesn't seem that I have information as to the "path" (in other words, other properties in the object model up the chain) in order to determine if the property should or should not be serialized.
I have also tried using a custom JsonTextWriter, but it doesn't seem that I can override the methods necessary to keep track of the path, even though there is a Path property available. Is there something perhaps simple that I am overlooking in order to be able to view the path hierarchy of a property being serialized and determine if it should be serialized by looking up the path in a table and making the decision?
The basic difficulty here is that Json.NET is a contract-based serializer which creates a contract for each type to be serialized, then (de)serializes according to the contract. If a type appears in multiple locations in the object hierarchy, the same contract applies. But you want to selectively include properties for a given type depending on its location in the hierarchy, which conflicts with the basic "one type one contract" design.
One quick way to work around this is to serialize to a JObject, then use JToken.SelectTokens() to select only the JSON data you want to return, removing everything else. Since SelectTokens has full support for JSONPath query syntax, you can selectively include using array and property wildcards or other filters, for instance:
"$.FirstLevel[*].Bar"
includes all properties named "Bar" in all array members of a property named "FirstLevel" of the root object.
This should reduce your network usage as desired, but won't save any processing time on the server.
Removal can be accomplished with the following extension methods:
public static partial class JsonExtensions
{
public static TJToken RemoveAllExcept<TJToken>(this TJToken obj, IEnumerable<string> paths) where TJToken : JToken
{
if (obj == null || paths == null)
throw new NullReferenceException();
var keepers = new HashSet<JToken>(paths.SelectMany(path => obj.SelectTokens(path)), ObjectReferenceEqualityComparer<JToken>.Default);
var keepersAndParents = new HashSet<JToken>(keepers.SelectMany(t => t.AncestorsAndSelf()), ObjectReferenceEqualityComparer<JToken>.Default);
// Keep any token that is a keeper, or a child of a keeper, or a parent of a keeper
// I.e. if you have a path ""$.A.B" and it turns out that B is an object, then everything
// under B should be kept.
foreach (var token in obj.DescendantsAndSelfReversed().Where(t => !keepersAndParents.Contains(t) && !t.AncestorsAndSelf().Any(p => keepers.Contains(p))))
token.RemoveFromLowestPossibleParent();
// Return the object itself for fluent style programming.
return obj;
}
public static string SerializeAndSelectTokens<T>(T root, string[] paths, Formatting formatting = Formatting.None, JsonSerializerSettings settings = null)
{
var obj = JObject.FromObject(root, JsonSerializer.CreateDefault(settings));
obj.RemoveAllExcept(paths);
var json = obj.ToString(formatting);
return json;
}
public static TJToken RemoveFromLowestPossibleParent<TJToken>(this TJToken node) where TJToken : JToken
{
if (node == null)
return null;
JToken toRemove;
var property = node.Parent as JProperty;
if (property != null)
{
// Also detach the node from its immediate containing property -- Remove() does not do this even though it seems like it should
toRemove = property;
property.Value = null;
}
else
{
toRemove = node;
}
if (toRemove.Parent != null)
toRemove.Remove();
return node;
}
public static IEnumerable<JToken> DescendantsAndSelfReversed(this JToken node)
{
if (node == null)
throw new ArgumentNullException();
return RecursiveEnumerableExtensions.Traverse(node, t => ListReversed(t as JContainer));
}
// Iterate backwards through a list without throwing an exception if the list is modified.
static IEnumerable<T> ListReversed<T>(this IList<T> list)
{
if (list == null)
yield break;
for (int i = list.Count - 1; i >= 0; i--)
yield return list[i];
}
}
public static partial class RecursiveEnumerableExtensions
{
// Rewritten from the answer by Eric Lippert https://stackoverflow.com/users/88656/eric-lippert
// to "Efficient graph traversal with LINQ - eliminating recursion" http://stackoverflow.com/questions/10253161/efficient-graph-traversal-with-linq-eliminating-recursion
// to ensure items are returned in the order they are encountered.
public static IEnumerable<T> Traverse<T>(
T root,
Func<T, IEnumerable<T>> children)
{
yield return root;
var stack = new Stack<IEnumerator<T>>();
try
{
stack.Push((children(root) ?? Enumerable.Empty<T>()).GetEnumerator());
while (stack.Count != 0)
{
var enumerator = stack.Peek();
if (!enumerator.MoveNext())
{
stack.Pop();
enumerator.Dispose();
}
else
{
yield return enumerator.Current;
stack.Push((children(enumerator.Current) ?? Enumerable.Empty<T>()).GetEnumerator());
}
}
}
finally
{
foreach (var enumerator in stack)
enumerator.Dispose();
}
}
}
/// <summary>
/// A generic object comparerer that would only use object's reference,
/// ignoring any <see cref="IEquatable{T}"/> or <see cref="object.Equals(object)"/> overrides.
/// </summary>
public class ObjectReferenceEqualityComparer<T> : IEqualityComparer<T> where T : class
{
// Adapted from this answer https://stackoverflow.com/a/1890230
// to https://stackoverflow.com/questions/1890058/iequalitycomparert-that-uses-referenceequals
// By https://stackoverflow.com/users/177275/yurik
private static readonly IEqualityComparer<T> _defaultComparer;
static ObjectReferenceEqualityComparer() { _defaultComparer = new ObjectReferenceEqualityComparer<T>(); }
public static IEqualityComparer<T> Default { get { return _defaultComparer; } }
#region IEqualityComparer<T> Members
public bool Equals(T x, T y)
{
return ReferenceEquals(x, y);
}
public int GetHashCode(T obj)
{
return System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(obj);
}
#endregion
}
And then use them like:
public class TestClass
{
public static void Test()
{
var root = new RootObject
{
FirstLevel1 = new FirstLevel
{
SecondLevel1 = new List<SecondLevel> { new SecondLevel { A = "a11", B = "b11", Third1 = new ThirdLevel { Foo = "Foos11", Bar = "Bars11" }, Third2 = new List<ThirdLevel> { new ThirdLevel { Foo = "FooList11", Bar = "BarList11" } } } },
SecondLevel2 = new List<SecondLevel> { new SecondLevel { A = "a12", B = "b12", Third1 = new ThirdLevel { Foo = "Foos12", Bar = "Bars12" }, Third2 = new List<ThirdLevel> { new ThirdLevel { Foo = "FooList12", Bar = "BarList12" } } } },
},
FirstLevel2 = new FirstLevel
{
SecondLevel1 = new List<SecondLevel> { new SecondLevel { A = "a21", B = "b21", Third1 = new ThirdLevel { Foo = "Foos21", Bar = "Bars21" }, Third2 = new List<ThirdLevel> { new ThirdLevel { Foo = "FooList21", Bar = "BarList21" } } } },
SecondLevel2 = new List<SecondLevel> { new SecondLevel { A = "a22", B = "b22", Third1 = new ThirdLevel { Foo = "Foos22", Bar = "Bars22" }, Third2 = new List<ThirdLevel> { new ThirdLevel { Foo = "FooList22", Bar = "BarList22" } } } },
}
};
Assert.IsTrue(JObject.FromObject(root).DescendantsAndSelf().OfType<JValue>().Count() == 24); // No assert
var paths1 = new string[]
{
"$.FirstLevel2.SecondLevel1[*].A",
"$.FirstLevel1.SecondLevel2[*].Third2[*].Bar",
};
Test(root, paths1, 2);
var paths3 = new string[]
{
"$.FirstLevel1.SecondLevel2[*].Third2[*].Bar",
};
Test(root, paths3, 1);
var paths4 = new string[]
{
"$.*.SecondLevel2[*].Third2[*].Bar",
};
Test(root, paths4, 2);
}
static void Test<T>(T root, string [] paths, int expectedCount)
{
var json = JsonExtensions.SerializeAndSelectTokens(root, paths, Formatting.Indented);
Console.WriteLine("Result using paths: {0}", JsonConvert.SerializeObject(paths));
Console.WriteLine(json);
Assert.IsTrue(JObject.Parse(json).DescendantsAndSelf().OfType<JValue>().Count() == expectedCount); // No assert
}
}
public class ThirdLevel
{
public string Foo { get; set; }
public string Bar { get; set; }
}
public class SecondLevel
{
public ThirdLevel Third1 { get; set; }
public List<ThirdLevel> Third2 { get; set; }
public string A { get; set; }
public string B { get; set; }
}
public class FirstLevel
{
public List<SecondLevel> SecondLevel1 { get; set; }
public List<SecondLevel> SecondLevel2 { get; set; }
}
public class RootObject
{
public FirstLevel FirstLevel1 { get; set; }
public FirstLevel FirstLevel2 { get; set; }
}
Note that there is an enhancement request Feature request: ADD JsonProperty.ShouldSerialize(object target, string path) #1857 that would enable this sort of functionality more easily.
Demo fiddles here and here.
The much easier implementation (comparing to the accepted answer) is presented here:
public static class JsonExtensions
{
public static TJToken RemoveAllExcept<TJToken>(this TJToken token, IEnumerable<string> paths) where TJToken : JContainer
{
HashSet<JToken> nodesToRemove = new(ReferenceEqualityComparer.Instance);
HashSet<JToken> nodesToKeep = new(ReferenceEqualityComparer.Instance);
foreach (var whitelistedToken in paths.SelectMany(token.SelectTokens))
TraverseTokenPath(whitelistedToken, nodesToRemove, nodesToKeep);
//In that case neither path from paths has returned any token
if (nodesToKeep.Count == 0)
{
token.RemoveAll();
return token;
}
nodesToRemove.ExceptWith(nodesToKeep);
foreach (var notWhitelistedNode in nodesToRemove)
notWhitelistedNode.Remove();
return token;
}
private static void TraverseTokenPath(JToken value, ISet<JToken> nodesToRemove, ISet<JToken> nodesToKeep)
{
JToken? immediateValue = value;
do
{
nodesToKeep.Add(immediateValue);
if (immediateValue.Parent is JObject or JArray)
{
foreach (var child in immediateValue.Parent.Children())
if (!ReferenceEqualityComparer.Instance.Equals(child, value))
nodesToRemove.Add(child);
}
immediateValue = immediateValue.Parent;
} while (immediateValue != null);
}
}
For most cases this can be achieved by a simple single line extension method
public static string ToJson<T>(this T self, string path) => $#"{{""{path}"":{JObject.FromObject(self)[path]?.ToString(Formatting.None)}}}";
This is only valid for extracting an object nested under the root object but is easily adapted with a separate parameter to specify the output path if needed
Thanks to #dbc answer as a good solution, but like he said, it doesn't affect the performance. Sometimes the data loaded from database has numerous references and only ignoring ReferenceLoopHandling is not enough for serialization; hence the serialized data becomes very large and takes a lot of ram in server, and this is caused by repetition of serializing a single object. In this situation, it's better to make a limited jobject from data straightly, rather than making a jobject and then exclude the unwanted paths from it. This can be done with a little customization of database pure data and a ContractResolver. Let's assume all the database entities inherit from a class or interface like DbModel (this is necessary in this solution). Then by a special ContractResolver, serialization of objects can be limited. A sample is like below:
class TypeName
{
public Type Type { get; set; }
public string Name { get; set; }
}
class MyContractResolver : DefaultContractResolver
{
private List<List<TypeName>> allTypeNames = new List<List<TypeName>>();
public MyContractResolver(Type parentType, string[] includePaths)
{
foreach (var includePath in includePaths)
{
List<TypeName> typeNames = new List<TypeName>() { new TypeName() { Type = parentType } };
var pathChilderen = includePath.Split('.');
for(int i = 0; i < pathChilderen.Length; i++)
{
var propType = typeNames[i].Type.GetProperties().FirstOrDefault(c => c.Name == pathChilderen[i]).PropertyType;
if (propType.GetInterface(nameof(IEnumerable)) != null && propType != typeof(String))
{
propType = propType.GetGenericArguments().Single();
}
typeNames.Add(new TypeName() { Name = pathChilderen[i], Type = propType });
}
allTypeNames.Add(typeNames);
}
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
IList<JsonProperty> properties = base.CreateProperties(type, memberSerialization);
// only serializer properties that are in include paths
List<JsonProperty> excludeProperties = new List<JsonProperty>();
foreach (var property in properties)
{
if (typeof(DbModel).IsAssignableFrom(property.PropertyType) || (property.PropertyType.GetInterface(nameof(IEnumerable)) != null && property.PropertyType != typeof(String)))
{
Console.WriteLine(property.PropertyType.ToString());
var exclude = true;
foreach (var typeNames in allTypeNames)
{
var index = typeNames.FindIndex(c => c.Name == property.PropertyName && c.Type == property.PropertyType);
if (index > 0)
{
if (typeNames[index - 1].Type == type)
{
exclude = false;
goto EndSearch;
}
}
}
EndSearch:
if (exclude)
excludeProperties.Add(property);
}
}
properties = properties.Where(c => excludeProperties.All(d => d.PropertyName != c.PropertyName)).ToList();
return properties;
}
}
This class can be used like this:
// return Ok(data);
var jObject = JObject.FromObject(data,
JsonSerializer.CreateDefault(new JsonSerializerSettings()
{
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
Converters = new List<JsonConverter>()
{
new ValidationProblemDetailsConverter(),
new ProblemDetailsConverter(),
new StringEnumConverter()
},
ContractResolver = new MyContractResolver(typeof(Foo), new[] { "bar", "baz.qux" })
}));
return Ok(jObject);
In this example Foo is the class of main object to return, and bar and baz are properties that are going to be serialized (they are loaded from database too). In addition qux is one of the baz properties that is loaded from database and has to be serialized. In this example all the other properties of each model that are not entities of database (so are not inherited from DbModel) are serialized and all the entities of database that exist in original data but not in the including paths, are ignored to be serialized.