How to read/parse Content from OkNegotiatedContentResult? - c#

In one of my API actions (PostOrder) I may be consuming another action in the API (CancelOrder). Both return a JSON formatted ResultOrderDTO type, set as a ResponseTypeAttribute for both actions, which looks like this:
public class ResultOrderDTO
{
public int Id { get; set; }
public OrderStatus StatusCode { get; set; }
public string Status { get; set; }
public string Description { get; set; }
public string PaymentCode { get; set; }
public List<string> Issues { get; set; }
}
What I need is reading/parsing the ResultOrderDTO response from CancelOrder, so that I can use it as response for PostOrder. This is what my PostOrder code looks like:
// Here I call CancelOrder, another action in the same controller
var cancelResponse = CancelOrder(id, new CancelOrderDTO { Reason = CancelReason.Unpaid });
if (cancelResponse is OkNegotiatedContentResult<ResultOrderDTO>)
{
// Here I need to read the contents of the ResultOrderDTO
}
else if (cancelResponse is InternalServerErrorResult)
{
return ResponseMessage(Request.CreateResponse(HttpStatusCode.InternalServerError, new ResultError(ErrorCode.InternalServer)));
}
When I use the debugger, I can see that the ResultOrderDTO it is there somewhere in the response (looks like the Content) as shown in the pic below:
but cancelResponse.Content does not exist (or at least I don't have access to it before I cast my response to something else) and I have no idea about how to read/parse this Content. Any idea?

Simply cast the response object to OkNegotiatedContentResult<T>. The Content property is object of type T. which in your case is object of ResultOrderDTO.
if (cancelResponse is OkNegotiatedContentResult<ResultOrderDTO>)
{
// Here's how you can do it.
var result = cancelResponse as OkNegotiatedContentResult<ResultOrderDTO>;
var content = result.Content;
}

Related

Custom error objects for .Net Core 3 web api

I am currently developing a web api in .NET Core 3. I currently have the following model for my error response object:
public class ErrorRo
{
public string Message { get; set; }
public int StatusCode { get; set; }
public string Endpoint { get; set; }
public string Parameters { get; set; }
public string IpAddress { get; set; }
}
This is a mandated response I need to implement, management has pushed this. It allows more verbose error messages for people hitting our API so that they know what went wrong.
At the moment I am currently populating this object manually in the methods themselves. Is there a way where I can overwrite the response methods. I.e. can I override the BadRequest of IActionResult to automatically populate these fields?
Thanks!
You can use result filters for this purpose. Add a filter which repalces result before sending it back
Model
public class CustomErroModel
{
public string Message { get; set; }
public int StatusCode { get; set; }
public string Endpoint { get; set; }
public string Parameters { get; set; }
public string IpAddress { get; set; }
}
Filter
public class BadRequestCustomErrorFilterAttribute : ResultFilterAttribute
{
public override void OnResultExecuting(ResultExecutingContext context)
{
//todo: check for BadRequestObjectResult if anything is returned for bad request
if (context.Result is BadRequestResult)
{
var result = new CustomErroModel
{
StatusCode = 200, //you status code
Endpoint = context.HttpContext.Request.GetDisplayUrl(),
Message = "some message",
IpAddress = context.HttpContext.Connection.RemoteIpAddress.ToString(), //find better implementation in case of proxy
//this returns only parameters that controller expects but not those are not defined in model
Parameters = string.Join(", ", context.ModelState.Select(v => $"{v.Key}={v.Value.AttemptedValue}"))
};
context.Result = new OkObjectResult(result); // or any other ObjectResult
}
}
}
Then apply filter per action or globally
[BadRequestCustomErrorFilter]
public IActionResult SomeAction(SomeModel model)
or
services
.AddMvc(options =>
{
options.Filters.Add<BadRequestCustomErrorFilterAttribute>();
//...
}
Well it depends on the scenario, but one possible approach could be to use a middleware using a similar strategy like the one described in this question, so that you complete the response with extra information.

Deserialize json into c# classes

I am trying to make a UWP app using the RIOT API for League of Legends.
When I go to their website to generate the JSON I get something like this:
{"gigaxel": {
"id": 36588106,
"name": "Gigaxel",
"profileIconId": 713,
"revisionDate": 1451577643000,
"summonerLevel": 30
}}
When I select this JSON and copy it into a new class using the special paste method in Visual Studio 2015 I get these classes with these properties:
public class Rootobject
{
public Gigaxel gigaxel { get; set; }
}
public class Gigaxel
{
public int id { get; set; }
public string name { get; set; }
public int profileIconId { get; set; }
public long revisionDate { get; set; }
public int summonerLevel { get; set; }
}
I created a new class called LOLFacade for connecting to the RiotAPI:
public class LOLFacade
{
private const string APIKey = "secret :D";
public async static Task<Rootobject> ConnectToRiot(string user,string regionName)
{
var http = new HttpClient();
string riotURL = String.Format("https://{0}.api.pvp.net/api/lol/{0}/v1.4/summoner/by-name/{1}?api_key={2}",regionName, user, APIKey);
var response = await http.GetAsync(riotURL);
var result = await response.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<Rootobject>(result);
}
}
This is the button event handler method:
Rootobject root = new Rootobject { gigaxel = new Gigaxel() };
root = await LOLFacade.ConnectToRiot("gigaxel","EUNE");
string name = root.gigaxel.name;
int level = root.gigaxel.summonerLevel;
InfoTextBlock.Text = name + " is level " + level;
I hard coded the regionName and the user for testing purposes. This works with my username: "gigaxel".
When I try another username for example like "xenon94" I get an exception:
Object reference not set to an instance of an object.
When I change the property name in Rootobject from gigaxel to xenon94 like this:
public class Rootobject
{
public Gigaxel xenon94 { get; set; }
}
When I recompile my code it works for the username xenon94 but it doesn't work for my username "gigaxel".
I want it to work for any given username.
The problem is that the json object has a property that is named gigaxel. You will have to retrieve the inside object, like so:
var json = JsonConvert.DeserializeObject<JObject>(x).First.First;
From there, you can get the name and other things by the indexer:
string name = (string)json["name"];
int summonerlevel = (int)json["summonerLevel"]
To elaborate, the JsonConvert.DeserializeObject(x) will return a new JObject which has only one object. Hence the First call. Moreover, this object has only one property, named "gigaxel". The value of this property is the information we require, e.g. name. We want to retrieve this information regardless of what the property is named. Therefore we call First again to retrieve the value of this property.

WebApi Newtonsoft.Json.JsonConvert.DeserializeObject <Class> Error

I am doing a WebApi Method in Visual Studio 2013 and I want to Deserialize a Class Type. My Class is like this
[JsonObject]
class JOTA
{
[JsonProperty("ProductId")]
public int ProductId { get; set; }
[JsonProperty("Name")]
public string Name { get; set; }
}
My call is like this.
public void ReturnListProd(JOTA PP)
{
JOTA product = Newtonsoft.Json.JsonConvert.DeserializeObject<JOTA>(PP);
}
I have a compile error
'Network.Json.Json.Converter[] has some invalid argument'
But, if a define an ArrayList
public void ReturnListProd(ArrayList PP)
{
JOTA product = Newtonsoft.Json.JsonConvert.DeserializeObject<JOTA>(PP[0].ToString());
}
I have no error. But in this case, it does not help on what I need.
What I am missing?
Thanks
If you want a JOTA object to become a string representation of itself (serialize it) then you should be using
string serialized = Newtonsoft.Json.JsonConvert.SerializeObject(PP);
If you want the string to become a JOTA object then you are using
JOTA product = Newtonsoft.Json.JsonConvert.DeserializeObject<JOTA>(serialized);
the problem is that you are trying to deserialize an object that is not serialized (already deserialized).
You don't need the attributes if the property names are not different.
public class JOTA
{
public int ProductId { get; set; }
public string Name { get; set; }
}
public void ReturnListProd(JOTA PP)
{
var product = PP; //not really needed you can just use PP directly
}
You only need to deserialize if you are receiving a json string. Because you are using WebAPI I would suggest changing your API endpoint to a proper REST endpoint. Example:
[HttpPost, Route("api/products/add")]
public IHttpActionResult ReturnListProd([FromBody]JOTA PP)
{
try
{
//do something with passed in data
var name = PP.Name;
//always at minimum return a status code
return Ok();
}
catch
{
//returns 500
return InternalServerError();
}
}
Then change your ajax url from:
url: "yourController/ReturnListProd"
to:
url: "/api/products/add"

Parse a Json String to create a new custom object c#

I am returning a json string to a WebMethod in WebForms and I want to take the json string and parse it into custom Order objects.
I have a class:
public class Order
{
public string Item { get; set; }
public string Color { get; set; }
public string Qty { get; set; }
public string Size { get; set; }
}
And a WebMethod:
[WebMethod]
public static string SendOrder(string json)
{
List<Order> orders = new List<Order>();
return json;
}
I am passing this string:
{
json: [
{
"Item":"Nike Polo #286772 - Women's Dri-FIT Micro Pique Short Sleeved Polo",
"Size":"XL",
"Color":"Light Blue",
"Quantity":"3"
},
{
"Item":"Port Authority Women's Jacket #L790 - Black",
"Size":"Medium",
"Color":"Black",
"Quantity":"3"
}
]
}
I want to loop through this string and creating new Orders.
What is the best way to do this?
That JSON is a little oddly formatted as it maps to the following classes (using http://json2csharp.com):
public class Json
{
public string Item { get; set; }
public string Size { get; set; }
public string Color { get; set; }
public string Quantity { get; set; }
}
public class RootObject
{
public List<Json> json { get; set; }
}
I'm not sure why you have a top-level variable named json, but whatever.
At this point just use JSON.NET to deserialize into the structure.
JsonConvert.DeserializeObject<RootObject>(yourJsonString);
If you want to rename the object from Json to Order you'll need to use an attribute for that. I don't recall the name off the top of my head but it should be easy to find in the JSON.NET documentation.
I recently completed a Windows Phone app that retrieved info from a Web API-based server as Json strings. I ended up using the JsonConvert class to convert my lists of objects from Json strings to my custom objects. Here's an example of one of my client-side methods that receives and converts the Json strings:
public async void GetGames()
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("base url");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.GetAsync("specific url extention (like api/Order)");
if (response.IsSuccessStatusCode)
{
string s = await response.Content.ReadAsStringAsync();
var deserializedResponse = JsonConvert.DeserializeObject<List<Order>>(s);
//rest of code
}
}
}
Also, make sure that your web method is actually doing something. The example web method you posted creates creates a new list then just returns the parameter you passed in. Using Web API, you could return a list of all Order objects in your database via a method similar to the following:
public IQueryable<Order> GetOrders()
{
return db.Orders; //db is an instance of your DbContext class
}
I hope this is helpful. Let me know if you have any questions.

Metro App - deserialize JSON String

I'd like to deserialize a JSON string which I get from a webservice. My problem is, that the deserialized object class array (of type Result) has always 0 items in it....
But the webservice returns the correct string.
So I think the failure occurs in the way how I deserialize the string/stream.
Any ideas what's my fault?
//JSON result string:
{"Results":
[{"Result":{
"Name":"Rechnung2",
"Date1":"2012-10-05",
"Item1":"50",
"Item2":"10",
"CompanyName":"Contoso",
"Description":"My description"}}]
}
[DataContract]
public class Result
{
[DataMember]
public string Name { get; set; }
[DataMember]
public string Date1 { get; set; }
[DataMember]
public string Item1 { get; set; }
[DataMember]
public string Item2 { get; set; }
[DataMember]
public string CompanyName { get; set; }
[DataMember]
public string Description { get; set; }
}
public async void GetjsonStream()
{
HttpClient client = new HttpClient();
string url = "http://localhost/test/api.php?format=json&key=12345";
HttpResponseMessage response = await client.GetAsync(url);
//ReadAsStringAsync() works fine, so I think ReadAsStreamAsync() works also fine
var str = await response.Content.ReadAsStreamAsync();
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(Result[]));
//Result has always 0 items
Result[] res = (Result[])ser.ReadObject(str);
}
I haven't used DataContractJsonSerializer myself, so this may not be the best approach - but I suspect that the problem is that the JSON represents "an object containing a collection of results" - not "a collection of results".
Try this, in addition to your existing code:
[DataContract]
public class ResultCollection
{
[DataMember]
public Result[] Results { get; set; }
}
...
var ser = new DataContractJsonSerializer(typeof(ResultCollection));
var collection = (ResultCollection)ser.ReadObject(str);
var results = collection.Results;
You may be able to change the type of Results to List<Result> too, if that's helpful.
(I've just tried the code above, and it gave me the right result, so it looks like this is at least along the right lines...)

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