I wrote a C# code using NEST, which makes search queries to my ES database. I can see these queries succeed and give a json response body through Postman. I want to use these responses in my code. For example,
ISearchResponse<class> myquery = client.Search<class>(...)
(some successful api call)
The response body is something like:
{
"took": 5,
...
...
"hits": {
"max_score": 1.2,
"hits": [
{
"_index": "sample",
...
"_source": {
"name": "generic name",
"profession": "lawyer",
...
}
}
]
}
"aggs" : {
...
}
}
I can get the "took" value here by doing myquery.Took. Similarly I can see the definition of ISearchResponse<> contains data members for MaxScore, TimedOut etc.
My question is, In the same way if I want to get the value of, say the name field or some bucket in aggr, to use in my code. How can I do this? Please Help.
Note :
The Documentation only explained how to handle error responses and I can see in the debugger that probably .Documents is storing this somehow, but I'm not able to retrieve the data (or probably I can't understand how to). So please also explain how to get it from .Documents if that is the case.
The "_source" JSON object of each hit will be deserialized into the type T specified as the generic type parameter on Search<T>. In your example, "_source" will be deserialized into class, so simply define properties on class for the properties on "_source". For example
public class MyDocument
{
[PropertyName(Name = "name")]
public string Name {get;set;}
[PropertyName(Name = "profession")]
public string Profession {get;set;}
}
var response = client.Search<MyDocument>();
Related
.NET7 Includes a lot of improvements for System.Text.Json serializer, one of which is polymorphic serialization of types using the new [JsonPolymorphic] attribute. I am trying to use it in my Asp.Net web API, however it doesn't seem to serialize the type discriminator despite the fact that the model is properly setup.
It only happens when trying to send the objects over the wire, when using JsonSerializer, everything appears to be working well. For example:
// This is my data model
[JsonPolymorphic]
[JsonDerivedType(typeof(SuccesfulResult), typeDiscriminator: "ok")]
[JsonDerivedType(typeof(ErrorResult), typeDiscriminator: "fail")]
public abstract record Result;
public record SuccesfulResult : Result;
public record ErrorResult(string Error) : Result;
// Some test code that actually works
var testData = new Result[]
{
new SuccesfulResult(),
new ErrorResult("Whoops...")
};
var serialized = JsonSerializer.SerializeToDocument(testData);
// Serialized string looks like this:
// [{ "$type": "ok" }, { "$type": "fail", "error": "Whoops..." }]
// So type discriminators are in place and all is well
var deserialized = serialized.Deserialize<IEnumerable<Result>>()!;
// This assertion passes succesfully!
// We deserialized a collection polymorphically and didn't lose any type information.
testData.ShouldDeepEqual(deserialized);
// However, when sending the object as a response in an API, the AspNet serializer
// seems to be ignoring the attributes:
[HttpGet("ok")]
public Result GetSuccesfulResult() => new SuccesfulResult();
[HttpGet("fail")]
public Result GetFailResult() => new ErrorResult("Whoops...");
Neither of these responses are annotated with a type discriminator
and my strongly-typed clients can't deserialize the results into a proper hierarchy.
GET /api/ok HTTP/1.1
# =>
# ACTUAL: {}
# EXPECTED: { "$type": "ok" }
GET /api/fail HTTP/1.1
# =>
# ACTUAL: { "error": "Whoops..." }
# EXPECTED: { "$type": "fail", "error": "Whoops..." }
Am I missing some sort of API configuration that would make controllers serialize results in a polymorphic manner?
Specifying [JsonDerivedType(...)] on individual subclasses and on the base type seems to resolve an issue but barely seems intentional. This possibly might be fixed in future releases.
[JsonPolymorphic]
[JsonDerivedType(typeof(SuccesfulResult), typeDiscriminator: "ok")]
[JsonDerivedType(typeof(ErrorResult), typeDiscriminator: "fail")]
public abstract record Result;
[JsonDerivedType(typeof(SuccesfulResult), typeDiscriminator: "ok")]
public record SuccesfulResult : Result;
[JsonDerivedType(typeof(ErrorResult), typeDiscriminator: "fail")]
public record ErrorResult(string Error) : Result;
I'm trying to work out how to deserialise a JSON response that can be made up of single or multiple models, so for instance, I have the following URL and Response from that endpoint:
https://api.site.com/products?query=fruit
Which would return something such as this:
{
"fruit": [{ ... },{ ... }]
}
"Fruit" could be anything, but as an alternative, you can also do this:
https://api.site.com/products?query=fruit,pies
{
"fruit": [{ ... }, { ... }],
"pies": [{ ... }, { ... }]
}
So I know how to handle just one of the "selections" provided at a time, however how do I go about deserialising the response when there can be 2 separate models in the same response?
In case you know the json model before hand (also called data contract), then you can create a dedicated class. So, for the above scenario, the class would be
public class AnyClassName
{
public List<Fruit> Fruit { get; set; }
public List<Pie> Pie { get; set; }
}
And then use
Newtonsoft.Json.JsonConvert.DeserializeObject<AnyClassName>(jsonString)
In case you are not aware of the data-contract, then use
Newtonsoft.Json.JsonConvert.DeserializeObject(jsonString)
In this case you have to do a lot of coding to probe for the existence of an element and extract the value.
I couln't find a similar case here, hence my question. I have a json like this:
{
"prop1": "bla",
"propn": "bla",
"Data": {
"42": {
"prop1": "bla",
"prop2": "bla",
"Symbol": "42"
},
"abc": {
"prop1": "bla",
"prop2": "bla",
"Symbol": "abc"
}
},
"Type": 100
}
Now, how do I get all elements from Data, and the most I am interested in the ones that have the symbol property set. I tried Newtonsoft.json.linq and jobject, but got really no clue what to do here. Any guidance anyone? Thanks!
Ronald
What you're looking for is called 'deserialize'. You have a string (the json in you post) and you want to turn it into an object.
The first steps you need to do are:
Create a class that matches your data.
Simply copy your json string in your post and use the option in Visual Studio to 'paste JSON as class'. Perhaps clean it up by changing the name RootObject to something more descriptive.
Install the NuGet package Newtonsoft in Visual Studio.
Now you can use MyClass myObject = JsonConvert.DeserializeObject<MyClass>(myString);
To access Symboljust use myObject.Data.Symbol
I imagine that once you extract partial data from json, if you still need to pass the data through your application, a dedicated model will come handy.
public class Data
{
public Element abc { get; set; }
}
public class Element
{
public string prop1 { get; set; }
public string prop2 { get; set; }
public string Symbol { get; set; }
}
While you certainly can rely on JObject handling the deserialization, i find it more intuitive to work with anonymous templates, especially for partial data retrieval.
var template = new
{
Data = default(Data)
};
var instance = JsonConvert.DeserializeAnonymousType(json, template);
will give you something like
I recomend you to use Jil library, is faster and more simple than Newtonsoft.json
I'm new with Web API 2 / Entity Framework 6 project, I'm making REST services, but for one specific service I'm going to receive (via Post) a JSON before making any CRUD operations over any entity of the model, (have to make some business validations over the data, add or complement some things and decide on wich entity to save), the JSON is:
{
"head": {
"action": "create",
"object": "oneobject",
"user": "theuser"
},
"object": {
"name1": "a name 1",
"name2": "a name 2",
"description": "a description here"
},
"rule": [{
"name": "any name",
"value": "any value"
}, {
"name": "another name",
"value": "another value"
}]
}
So the json not maps directly to an entity, in fact I have no model or object for this. What would be the better way to work with it? I mean how to receive and parse the json. I'm new with web api and rest services, and I would appreciate you can help me and explain me with good details. Thanks guys.
Edit:
Any idea of the POCO or class that match this kind of json. ("rule" list It's variable, can be one or more).
After create this poco or class I would have to make a controller based on this?
As others have said, what you need is a POCO object to represent your request. Based on the information you have provided the following should achieve close enough to what you are after:
public enum CrudAction
{
Create,
Read,
Update,
Delete
}
public sealed class CrudRequestHeader
{
public CrudAction Action { get; set; }
public string Object { get; set; }
public string User { get; set; }
}
public sealed class RuleDefinition
{
public string Name { get; set; }
public string Value { get; set; }
}
public sealed class CrudRequest
{
public CrudRequestHeader Head { get; set;}
public Dictionary<string, string> Object { get; set; }
public List<RuleDefinition> Rule { get; set; }
}
In your Web API controller method you can then take a parameter of type CrudRequest and your JSON will be deserialized to this object, e.g:
public IHttpActionResult Post(CrudRequest crudRequest)
{
// TODO Implementation
}
You may notice I have used Dictionary<string, string> for CrudRequest.Object as it is variable how many key/values we will be supplied with, I have made the assumption that all values are strings, you can use an object value if you prefer but you will then need to handle the type of value. In the same principle I have used List<RuleDefinition> for CrudRequest.Rule to cater for the variable number of rules which may be supplied.
A LINQPad sample containing the above definitions and use with your input can be found here: http://share.linqpad.net/7rvmhh.linq
Although the JSON may not represent a logical entity in your model, you clearly have a mental model of the "shape" of the JSON data - I say this because you define it in your code snippet. You should create a POCO (plain old C# object) to represent this model, and deserialize the incoming JSON request to an object of that type. Once you've deserialized it to your object, it will be trivial to work with this data using object properties and such.
The best thing to do would be to create a class that models the object you expect back.
This way in your Web API method you can use the [FromBody] attribute to automatically parse the body of the request.
Example -
Your data contract would look like this:
public class MyContract
{
public string MyData { get; set;}
}
In your ApiController
[HttpPost]
[Route("api/myobject")]
public async Task ReceiveMyObject([FromBody]MyContract object) {
var data = object.MyData;
// Do whatever you need to do here.
}
This may seem tedious but this will let you keep your code organized.
Edit
So to create a contract out of this:
{
"head": {
"action": "create",
"object": "oneobject",
"user": "theuser"
},
"object": {
"name1": "a name 1",
"name2": "a name 2",
"description": "a description here"
},
"rule": [{
"name": "any name",
"value": "any value"
}, {
"name": "another name",
"value": "another value"
}]
}
You would do something like this:
public class MyContract
{
[JsonProperty("head")]
public MetaObject Head
{
get; set;
}
// Not sure if this will work, but it probably will
[JsonProperty("object")]
public JObject ExtendedInformation
{
get;
set;
}
[JsonProperty("rule")]
public Rule[] Rules
{
get;
set;
}
}
// "MetaObject" definition omitted but you can understand my point with the below
public class Rule
{
[JsonProperty("name")]
public string Name
{
get;
set;
}
[JsonProperty("value")]
public string Value
{
get;
set;
}
}
Usually a REST service issue a contract, which means some kind of metadata to describe the content of its messages, otherwise you cannot call this as a RESTful Web API. Take a look at this post from Roy Fielding, who created the term of REST API, if you want to know better what is REST and what is not.
So if your service is a true REST service you should be able to have a description somewhere that give you the possibility to parse the media.
However, if you still cannot find any way to understand how the JSON should be interpreted you may be able to use it inside a C# class anyway: take a look at the JObject class from Newtonsoft.Json that enables to use a dynamic object at runtime.
Basically, it is used like this:
using Newtonsoft.Json.Linq; // This needs the Newtonsoft.Json package
dynamic entity = JObject.Parse(jsonString);
string value = entity.key1;
string value2 = entity["key2"];
I did this simple demo with your data.
You can also check the full documentation of the class on the Newtonsoft website.
I'm working on a MVC project using C# and have controller method that returns a JsonResult model. The model contains a property called Value.
Based on certain conditions the Value maybe a string value such as "C" or "N". But under other conditions it maybe .5.
When serializing the Model is it possible to check and if the property is a numeric to serialize it as number (no quotes)? If it is not a number then make it a string (quotes)?
For example I have the following class:
public class Answer
{
public int Id{get;set;}
public string Value { get; set; }
}
Let's say I return a list of these back: I'd like to have something like below: (Notice the 1st answer the "value" is not quoted; however, the 2nd and 3rd answer are quoted.
{
"answers": [
{
"id": 1,
"value": .5 <- No quote here.
},
{
"id": 1,
"value": "C" <- Quote here
},
{
"id": 1,
"value": "N" <- Quote here
}
]
}
When it comes back server side (de-serializing), I'd just like the string representation.
I think you will have to implement a custom JSON Converter. See the following link:
http://james.newtonking.com/json/help/index.html?topic=html/CustomJsonConverter.htm