ASP.net mvc API get request and JSON data

Question

Trying to call a weather API using a service for asp.net mvc.

I have a Weather class that looks like this:

public class Weather
{
    public string main { get; set; }
    public string description { get; set; }
}

The method I am using to make the GET request looks like this:

    async public static Task<List<Weather>> GetWeather()
    {
        List<Weather> weatherData = new List<Weather>();

        HttpClient client = new HttpClient();
        HttpResponseMessage response = await client.GetAsync("http://api.openweathermap.org/data/2.5/weather?lat=35&lon=139&APPID=[MYKEY]");

        HttpContent content = response.Content;

        string data = await content.ReadAsStringAsync();
    }

The URI I'm requesting returns JSON objects.

{
  "coord": {
    "lon": 139,
    "lat": 35
  },
  "weather": [
    {
      "id": 804,
      "main": "Clouds",
      "description": "overcast clouds",
      "icon": "04n"
    }
  ],
  "base": "stations",
  "main": {
    "temp": 299.26,
    "pressure": 1007,
    "humidity": 83,
    "temp_min": 296.15,
    "temp_max": 301.15
  },
  "visibility": 16093,
  "wind": {
    "speed": 5.1,
    "deg": 330,
    "gust": 7.2
  },
  "clouds": {
    "all": 90
  },
  "dt": 1533638820,
  "sys": {
    "type": 1,
    "id": 7618,
    "message": 0.0028,
    "country": "JP",
    "sunrise": 1533585473,
    "sunset": 1533634868
  },
  "id": 1851632,
  "name": "Shuzenji",
  "cod": 200
}

I want to access the "weather" object and extract the properties main and description and in my GetWeather return a list where the weather properties from the JSON object match the properties in my class Weather.

I'm lost on what to do with the string data and how to get the JSON data into my List<Weather>.

EDIT

Tried to use JObject.Parse() as mentioned in the answer below but get an error Cannot perform runtime binding on a null reference when trying to print it to the console.

async public static Task<List<Weather>> GetWeather()
        {

            HttpClient client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync("http://api.openweathermap.org/data/2.5/weather?lat=35&lon=139&APPID=[MYKEY]");

            HttpContent content = response.Content;

            string data = await content.ReadAsStringAsync();

            dynamic d = JObject.Parse(data);
            var main = d.main.ToString();
            var description = d.description.ToString();

            var weatherData = new List<Weather>
            {
                new Weather { Main = main,
                              Description = description }
            };

            Console.WriteLine(weatherData);

            return weatherData;
        }

You can use QuickType to map json data into c# classes.

FIL
– FIL

2018-08-07 12:04:55 +00:00
Commented Aug 7, 2018 at 12:04 — FIL
– FIL, Commented Aug 7, 2018 at 12:04

Prasad Telkikar · Accepted Answer · 2018-08-07 12:42:59Z

3

Steps to access value of description from your json

Create model class for given json string, Visual studio provided option for it

Edit -> Paste special -> Paste JSON As class

class look like

public class MyClass
{
    public class Coord {
       public int lon { get; set; }
       public int lat { get; set; } }

    public class Weather {
       public int id { get; set; }
       public string main { get; set; }
       public string description { get; set; }
       public string icon { get; set; } }
 ...

Use NewtonSoft.JSON library to deserialize json

MyClass temp = JsonConvert.DeserializeObject<MyClass >(jsonString);

Now you can access description property of Weather class by

string output = temp.Weather.description

answered Aug 7, 2018 at 12:42

Prasad Telkikar

16.1k7 gold badges26 silver badges49 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Milney · Accepted Answer · 2018-08-07 12:02:51Z

1

You want to look into deserializing the json. The easiest way for an example (although not as maintainable) would be to dump the json into a dynamic and pull the fields you want;

dynamic d = JObject.Parse(data);
var description = d.description.ToString();

If you create classes to match the JSON (it looks like your Weather class doesn't quite match - main is a nested object and not a string) then you can use Json.DeserializeObject< Weather >(data)

answered Aug 7, 2018 at 12:02

Milney

6,4472 gold badges21 silver badges34 bronze badges

8 Comments

anaximander Over a year ago

Edited question

Milney Over a year ago

@anaximander - Assuming the JSON you have posted is correct - you do not have a 'description' property in it? That would explain the null reference...

Milney Over a year ago

@anaximander - Oh sorry i see it now, you will want d.weather.description

Milney Over a year ago

@anaximander - each property with a { ... } is a new object, so will need referenced with a dot

anaximander Over a year ago

Keep running into new errors. Unhandled exception: Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: Newtonsoft.Json.Linq.JArray. Not used to do this with C#, normally do it in expressJS, so kinda clueless on how to handle the data.

|

Collectives™ on Stack Overflow

ASP.net mvc API get request and JSON data

2 Answers 2

Comments

8 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

8 Comments

Your Answer

Sign up or log in

Post as a guest

Related