I am developing a Web API using Core 6.0 with localization. Localization should be supported for both static (e.g., basic strings like greeting) and dynamic content (e.g., Values of the Product Instance).
I have implemented the localization for static content using JsonStringLocalizerFactory as discussed in this article - https://christian-schou.dk/how-to-add-localization-in-asp-net-core-web-api/.
public class LocalizerController : ControllerBase
{
private readonly IStringLocalizer<LocalizerController> _stringLocalizer;
public LocalizerController(IStringLocalizer<LocalizerController> stringLocalizer)
{
_stringLocalizer = stringLocalizer;
}
[HttpGet]
public IActionResult Get()
{
var message = _stringLocalizer["hi"].ToString();
return Ok(message);
}
[HttpGet("{name}")]
public IActionResult Get(string name)
{
var message = string.Format(_stringLocalizer["welcome"], name);
return Ok(message);
}
[HttpGet("all")]
public IActionResult GetAll()
{
var message = _stringLocalizer.GetAllStrings();
return Ok(message);
}
}
Next, I would like to implement localization for dynamic content (e.g., Details of the Product which will be sent to the WEB API and stored in the postgresql database table).
A possible approach is to duplicate the postgresql database table for each language (English and French). Could there be a better approach to avoid duplicate data and additional manual work?
You can create language table for each multi-language entity.
Langugage model;
public class Language
{
public int Id { get; set; }
public string Name { get; set; }
public string IsoCode { get; set; }
}
Static language list;
public class Constant
{
public static List<Language> Languages { get; set; } = new()
{
new Language
{
Id = 1,
Name = "English(United States)",
IsoCode = "en-US"
},
new Language
{
Id = 2,
Name = "Turkish",
IsoCode = "tr-TR"
}
};
}
Entities;
public class Product
{
public int Id { get; set; }
public decimal Price { get; set; }
public virtual ICollection<ProductLang> ProductLangs { get; set; }
}
public class ProductLang
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
[ForeignKey("Products")]
public Guid ProductId { get; set; }
public virtual Product Product { get; set; }
public int LanguageId { get; set; }
}
You can change the LanguageId property name. If you want to store languages in database, you can create a Languages table and create a relationship with that table from entity language tables. This can reduce duplication.
After include the language table to the entity, you can write an extension method to easily get the requested language data.
public static string GetLang<TEntity>(this IEnumerable<TEntity> langs, Expression<Func<TEntity, string>> propertyExpression, int defaultLangId)
{
var languageIdPropName = nameof(ProductLang.LanguageId);
var requestedLangId = GetCurrentOrDefaultLanguageId(defaultLangId);
if (langs.IsNullOrEmpty())
return string.Empty;
var propName = GetPropertyName(propertyExpression);
TEntity requestedLang;
if (requestedLangId != defaultLangId)
requestedLang = langs.FirstOrDefault(lang => (int)lang.GetType()
.GetProperty(languageIdPropName)
.GetValue(lang) == requestedLangId)
?? langs.FirstOrDefault(lang => (int)lang.GetType()
.GetProperty(languageIdPropName)
.GetValue(lang) == defaultLangId);
else requestedLang = langs.FirstOrDefault(lang => (int)lang.GetType().GetProperty(languageIdPropName).GetValue(lang) == defaultLangId);
requestedLang ??= langs.FirstOrDefault();
return requestedLang.GetType().GetProperty(propName).GetValue(requestedLang, null)?.ToString();
static int GetCurrentOrDefaultLanguageId(int defaultLanguageId)
{
var culture = CultureInfo.CurrentCulture;
var currentLanguage = Constant.Languages.FirstOrDefault(i => i.IsoCode == culture.Name);
if (currentLanguage != null)
return currentLanguage.Id;
else
return defaultLanguageId;
}
static string GetPropertyName<T, TPropertyType>(Expression<Func<T, TPropertyType>> expression)
{
if (expression.Body is MemberExpression tempExpression)
{
return tempExpression.Member.Name;
}
else
{
var op = ((UnaryExpression)expression.Body).Operand;
return ((MemberExpression)op).Member.Name;
}
}
}
This extension method checks for 3 conditions;
If there is data in the requsted language, it returns this data,
If there is no data in the requsted language, it checks if there is data in the default language. If the data is available in the default language, it will return the data,
Returns the first available language data if there is no data in the default language
Usage;
var defaultLangId = 1;
Product someProduct = await _dbContext.Set<Product>().Include(i => i.ProductLangs).FirstOrDefaultAsync();
var productName = someProduct.ProductLangs.GetLang(i => i.Name, defaultLangId);
It is up to you to modify this extension method according to your own situation. I gave you an example scenario where languages are kept in a static list.
We have some configuration files which were generated by serializing C# objects with Json.net.
We'd like to migrate one property of the serialised class away from being a simple enum property into a class property.
One easy way to do this, would be to leave the old enum property on the class, and arrange for Json.net to read this property when we load the config, but not to save it again when we next serialize the object. We'll deal with generating the new class from the old enum separately.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
There are actually several fairly simple approaches you can use to achieve the result you want.
Let's assume, for example, that you have your classes currently defined like this:
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
}
enum Fizz { Alpha, Beta, Gamma }
class Bang
{
public string Value { get; set; }
}
And you want to do this:
string json = #"{ ""ObsoleteSetting"" : ""Gamma"" }";
// deserialize
Config config = JsonConvert.DeserializeObject<Config>(json);
// migrate
config.ReplacementSetting =
new Bang { Value = config.ObsoleteSetting.ToString() };
// serialize
json = JsonConvert.SerializeObject(config);
Console.WriteLine(json);
To get this:
{"ReplacementSetting":{"Value":"Gamma"}}
Approach 1: Add a ShouldSerialize method
Json.NET has the ability to conditionally serialize properties by looking for corresponding ShouldSerialize methods in the class.
To use this feature, add a boolean ShouldSerializeBlah() method to your class where Blah is replaced with the name of the property that you do not want to serialize. Make the implementation of this method always return false.
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
public bool ShouldSerializeObsoleteSetting()
{
return false;
}
}
Note: if you like this approach but you don't want to muddy up the public interface of your class by introducing a ShouldSerialize method, you can use an IContractResolver to do the same thing programmatically. See Conditional Property Serialization in the documentation.
Approach 2: Manipulate the JSON with JObjects
Instead of using JsonConvert.SerializeObject to do the serialization, load the config object into a JObject, then simply remove the unwanted property from the JSON before writing it out. It's just a couple of extra lines of code.
JObject jo = JObject.FromObject(config);
// remove the "ObsoleteSetting" JProperty from its parent
jo["ObsoleteSetting"].Parent.Remove();
json = jo.ToString();
Approach 3: Clever (ab)use of attributes
Apply a [JsonIgnore] attribute to the property that you do not want to be serialized.
Add an alternate, private property setter to the class with the same type as the original property. Make the implementation of that property set the original property.
Apply a [JsonProperty] attribute to the alternate setter, giving it the same JSON name as the original property.
Here is the revised Config class:
class Config
{
[JsonIgnore]
public Fizz ObsoleteSetting { get; set; }
[JsonProperty("ObsoleteSetting")]
private Fizz ObsoleteSettingAlternateSetter
{
// get is intentionally omitted here
set { ObsoleteSetting = value; }
}
public Bang ReplacementSetting { get; set; }
}
For any situation where it's acceptable to have your deserialization-only property be marked internal, there's a remarkably simple solution that doesn't depend on attributes at all. Simply mark the property as internal get, but public set:
public class JsonTest {
public string SomeProperty { internal get; set; }
}
This results in correct deserialization using default settings/resolvers/etc., but the property is stripped from serialized output.
I like sticking with attributes on this one, here is the method I use when needing to deserialize a property but not serialize it or vice versa.
STEP 1 - Create the custom attribute
public class JsonIgnoreSerializationAttribute : Attribute { }
STEP 2 - Create a custom Contract Reslover
class JsonPropertiesResolver : DefaultContractResolver
{
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
//Return properties that do NOT have the JsonIgnoreSerializationAttribute
return objectType.GetProperties()
.Where(pi => !Attribute.IsDefined(pi, typeof(JsonIgnoreSerializationAttribute)))
.ToList<MemberInfo>();
}
}
STEP 3 - Add attribute where serialization is not needed but deserialization is
[JsonIgnoreSerialization]
public string Prop1 { get; set; } //Will be skipped when serialized
[JsonIgnoreSerialization]
public string Prop2 { get; set; } //Also will be skipped when serialized
public string Prop3 { get; set; } //Will not be skipped when serialized
STEP 4 - Use it
var sweet = JsonConvert.SerializeObject(myObj, new JsonSerializerSettings { ContractResolver = new JsonPropertiesResolver() });
Hope this helps! Also it's worth noting that this will also ignore the properties when Deserialization happens, when I am derserializing I just use the converter in the conventional way.
JsonConvert.DeserializeObject<MyType>(myString);
Use setter property:
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { _ignoreOnSerializing = value; } }
[JsonIgnore]
private string _ignoreOnSerializing;
[JsonIgnore]
public string IgnoreOnSerializing
{
get { return this._ignoreOnSerializing; }
set { this._ignoreOnSerializing = value; }
}
Hope this help.
After i spent a quite long time searching how to flag a class property to be De-Serializable and NOT Serializable i found that there's no such thing to do that at all; so i came up with a solution that combines two different libraries or serialization techniques (System.Runtime.Serialization.Json & Newtonsoft.Json) and it worked for me like the following:
flag all your class and sub-classes as "DataContract".
flag all the properties of your class and sub-classes as "DataMember".
flag all the properties of your class and sub-classes as "JsonProperty" except those you want them not to be serialized.
now flag the properties the you do NOT want it to be serialized as "JsonIgnore".
then Serialize using "Newtonsoft.Json.JsonConvert.SerializeObject" and De-Serialize using "System.Runtime.Serialization.Json.DataContractJsonSerializer".
using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using System.Runtime.Serialization;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
namespace LUM_Win.model
{
[DataContract]
public class User
{
public User() { }
public User(String JSONObject)
{
MemoryStream stream = new MemoryStream(Encoding.Unicode.GetBytes(JSONObject));
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(User));
User user = (User)dataContractJsonSerializer.ReadObject(stream);
this.ID = user.ID;
this.Country = user.Country;
this.FirstName = user.FirstName;
this.LastName = user.LastName;
this.Nickname = user.Nickname;
this.PhoneNumber = user.PhoneNumber;
this.DisplayPicture = user.DisplayPicture;
this.IsRegistred = user.IsRegistred;
this.IsConfirmed = user.IsConfirmed;
this.VerificationCode = user.VerificationCode;
this.Meetings = user.Meetings;
}
[DataMember(Name = "_id")]
[JsonProperty(PropertyName = "_id")]
public String ID { get; set; }
[DataMember(Name = "country")]
[JsonProperty(PropertyName = "country")]
public String Country { get; set; }
[DataMember(Name = "firstname")]
[JsonProperty(PropertyName = "firstname")]
public String FirstName { get; set; }
[DataMember(Name = "lastname")]
[JsonProperty(PropertyName = "lastname")]
public String LastName { get; set; }
[DataMember(Name = "nickname")]
[JsonProperty(PropertyName = "nickname")]
public String Nickname { get; set; }
[DataMember(Name = "number")]
[JsonProperty(PropertyName = "number")]
public String PhoneNumber { get; set; }
[DataMember(Name = "thumbnail")]
[JsonProperty(PropertyName = "thumbnail")]
public String DisplayPicture { get; set; }
[DataMember(Name = "registered")]
[JsonProperty(PropertyName = "registered")]
public bool IsRegistred { get; set; }
[DataMember(Name = "confirmed")]
[JsonProperty(PropertyName = "confirmed")]
public bool IsConfirmed { get; set; }
[JsonIgnore]
[DataMember(Name = "verification_code")]
public String VerificationCode { get; set; }
[JsonIgnore]
[DataMember(Name = "meeting_ids")]
public List<Meeting> Meetings { get; set; }
public String toJSONString()
{
return JsonConvert.SerializeObject(this, new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore });
}
}
}
Hope that helps ...
Depending on where in the application this takes place and if it's just one property, one manual way you can do this is by setting the property value to null and then on the model you can specify that the property be ignored if the value is null:
[JsonProperty(NullValueHandling = NullValue.Ignore)]
public string MyProperty { get; set; }
If you are working on an ASP.NET Core web app, you can globally set this for all properties in all models by setting this in your Startup.cs file:
public void ConfigureServices(IServiceCollection services) {
// other configuration here
services.AddMvc()
.AddJsonOptions(options => options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore);
}
with reference to #ThoHo's solution, using the setter is actually all that is needed, with no additional tags.
For me I previously had a single reference Id, that I wanted to load and add to the new collection of reference Ids. By changing the definition of the reference Id to only contain a setter method, which added the value to the new collection. Json can't write the value back if the Property doesn't have a get; method.
// Old property that I want to read from Json, but never write again. No getter.
public Guid RefId { set { RefIds.Add(value); } }
// New property that will be in use from now on. Both setter and getter.
public ICollection<Guid> RefIds { get; set; }
This class is now backwards compatible with the previous version and only saves the RefIds for the new versions.
To build upon Tho Ho's answer, this can also be used for fields.
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { IgnoreOnSerializing = value; } }
[JsonIgnore]
public string IgnoreOnSerializing;
If you use JsonConvert,IgnoreDataMemberAttribute is ok.My standard library not refrence Newton.Json,and I use [IgnoreDataMember] to control object serialize.
From Newton.net help document.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
The easiest way I've found as of this writing is to include this logic in your IContractResolver.
Sample code from above link copied here for posterity:
public class Employee
{
public string Name { get; set; }
public Employee Manager { get; set; }
public bool ShouldSerializeManager()
{
// don't serialize the Manager property if an employee is their own manager
return (Manager != this);
}
}
public class ShouldSerializeContractResolver : DefaultContractResolver
{
public new static readonly ShouldSerializeContractResolver Instance = new ShouldSerializeContractResolver();
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (property.DeclaringType == typeof(Employee) && property.PropertyName == "Manager")
{
property.ShouldSerialize =
instance =>
{
Employee e = (Employee)instance;
return e.Manager != e;
};
}
return property;
}
}
All of the answers are good but this approach seemed like the cleanest way. I actually implemented this by looking for an attribute on the property for SkipSerialize and SkipDeserialize so you can just mark up any class you control. Great question!
Jraco11's answer is very neat. In case, if you want to use the same IContractResolver both for serialization and deserialization, then you can use the following:
public class JsonPropertiesResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (member.IsDefined(typeof(JsonIgnoreSerializationAttribute)))
{
property.ShouldSerialize = instance => false;
}
return property;
}
}
thats will do the trick, create a property with set only
example 1:
https://dotnetfiddle.net/IxMXcG
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => IsPartialResult = (value != null && value.HasValues); }
public bool IsPartialResult { get; private set; }
example 2:
private JArray _disabledProtections;
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => _disabledProtections = value; }
public bool IsPartialResult => _disabledProtections != null && _disabledProtections.HasValues;
Use [JsonIgnore] attribute in the public property of the model class.
I have code like this
public class Person<T>
{
public Person()
{
Result = default(T);
}
public bool IsValid { get; set; }
public T Result { get; set; }
public int StatusCode { get; set; }
}
public class PersonValidator<T> : AbstractValidator<Person<T>>
{
public PersonValidator()
{
RuleFor(r => r.StatusCode).GreaterThan(0);
}
}
in Startup.cs
mvcBuilder.AddFluentValidation(fv => fv.RegisterValidatorsFromAssemblyContaining(typeof(PersonValidator<>)));
There is no error and error count is coming zero even though rule is not satisfied.
When I remove this T from PersonValidator and update AbstractValidator<Person<T>> to AbstractValidator<Person<long>> then it works fine.
I have added validators as PersonValidator. Also registered validator as above. I have to validate generic class, please help understand what is going wrong here, and how I can fix it.
public class ListKeywords
{
public int ID { set; get; }
public string Keyword { set; get; } //关键词
public string Language { set; get; } //语种
public int WordCount { set; get; } //单词数
public int WordLength { set; get; } // 字符数
public int Status { set; get; } //采集状态 0-未采集 1-采集成功 2-保存失败 3-保存成功 4-发布失败 5-发布成功
public bool Taken { set; get; }
public bool FTPStatus { set; get; }
public bool DBStatus { set; get; }
public string UrlName { set; get; }
public ListKeywords()
{
}
public ListKeywords(string keyword)
{
this.Keyword = keyword;
}
}
List<string> lines = new List<string>();
List<ListKeywords> keywordsList = new List<ListKeywords>();
using (StreamReader sr = File.OpenText(filePath))
{
string s = String.Empty;
while ((s = sr.ReadLine()) != null)
{
//lines.Add(s); //Operating normally
eywordsList.Add(new ListKeywords("some keywords")); // Operating normally
keywordsList.Add(new ListKeywords(s)); // it will be out of memeory
}
}
In text file, have 1,000,000 line data, if i use above code to load the large data to list< keywordsList >, it will raises an OutOfMemoryException, but if i load it to list< string >, it run normally. How to solved it ?
Instead of using a List maybe try using an IEnumerable w/ yield?
static IEnumerable<ListKeywords> Keywords()
{
using (StreamReader sr = File.OpenText(path))
{
string s = String.Empty;
while ((s = sr.ReadLine()) != null)
{
yield return new ListKeywords(s);
}
}
}
Note that Jon Skeet's C# in Depth offers a great explanation about this in Chapter 6. I imagine he also has some articles or posts on StackOverflow about this topic. As he points out, you want to be careful about modifying this method to pass in a StreamReader (or TextReader as is used in his example) as you would want to take ownership of the reader so it will be properly disposed of. Rather, you would want to pass in a Func<StreamReader> if you have such a need. Another interesting note he adds here - which I will point out because there are some edge cases where the reader will not actually be properly disposed of even if you don't allow the reader to be provided by the caller - it's possible for the caller to abuse the IEnumerable<ListKeywords> by doing something like Keywords().GetEnumerator() - this could result in a memory leak and could even potentially cause security issues if you have security-related code which relies on the using statement to clean up the resource.
Im fairly new to ASP.NET MCV 4 as well as Mongo DB and trying to build web API.
I thought I had finally got it right but when I start the app and enter: http://localhost:50491/api/document into my browser I get this error message
The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.
Here is my code
This is the Document Class
public class Document
{
[BsonId]
public ObjectId DocumentID { get; set; }
public IList<string> allDocs { get; set; }
}
This is where the Connection to the DB is made:
public class MongoConnectionHelper
{
public MongoCollection<BsonDocument> collection { get; private set; }
public MongoConnectionHelper()
{
string connectionString = "mongodb://127.0.0.1";
var server = MongoServer.Create(connectionString);
if (server.State == MongoServerState.Disconnected)
{
server.Connect();
}
var conn = server.GetDatabase("cord");
collection = conn.GetCollection("Mappings");
}
Here is the ApiController Class:
public class DocumentController : ApiController
{
public readonly MongoConnectionHelper docs;
public DocumentController()
{
docs = new MongoConnectionHelper();
}
public IList<BsonDocument> getAllDocs()
{
var alldocs = (docs.collection.FindAll().ToList());
return alldocs;
}
}
I read futher on and the error message suggested:
Type 'MongoDB.Bson.BsonObjectId' with data contract name 'BsonObjectId:http://schemas.datacontract.org/2004/07/MongoDB.Bson' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.
That is all good and well but how do I do that?
Either a) don't serialize your document classes over Web API, and create some DTOs meant to be serialized, or b) use something else as ID.
If you want an easy auto-generated ID, and you're OK with the fact that it will consume slightly more space, you can resort to the following "hack":
public class Document
{
public Document()
{
Id = ObjectId.GenerateNewId().ToString();
}
public string Id { get; set; }
}
This way, you'll get MongoIDs, but they'll be stored as a string.
If you need Web API2 responce in XML format , you need to handle the default Id like below
eg: ObjectId("507f191e810c19729de860ea")
Either you need to remove the Id from serialization.
[DataContract]
public class Document
{
[BsonId]
public string Id { get; set; }
[DataMember]
public string Title { get; set; } //other properties you use
}
Or You can change the Type of ID with custom logic
public class GuidIdGenerator : IIdGenerator
{
public object GenerateId(object container, object document)
{
return Guid.NewGuid();
}
public bool IsEmpty(object id)
{
return string.IsNullOrEmpty(id.ToString());
}
}
public class Document
{
[BsonId(IdGenerator = typeof(GuidIdGenerator))]
public string Id { get; set; }
public string Title { get; set; } //other properties you use
}