.NET/Web APIからJSONを取得し値を表示する・DataContractJsonSerializer

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Web APIからJSONを取得し値を表示する・DataContractJsonSerializer †

.NET標準のDataContractJsonSerializerを使用して、bitflyer仮想通貨取引所が公開している Ticker Web APIにアクセスし、
取得したJSONをデシリアライズし画面に表示するまでのサンプルコードになります。
本サンプルコードでアクセスするbitflyerのTicker Web API

• https://lightning.bitflyer.com/docs?lang=ja#ticker

サンプルコードは C#, Visual Basic(VB)を公開しています。
尚、HTTPによるアクセスは、以下リンクの記事のサンプルコードを流用しました。

• HttpClientを使って指定したURLのページを取得する
  

関連サイト †

• Microsoft .NET DataContractJsonSerializer クラス

関連記事 †

• HttpClientを使って指定したURLのページを取得する

動作環境 †

• Windows 10 ver.1909
• Visual Studio 2019
• .NET Core 3.1
• コンソールアプリケーション

サンプルコード †

以下にC#,Visual Basic(VB)のサンプルコードを紹介します。
また、実行時のキャプチャもあります。

C# †

using System;
using System.IO;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.Serialization.Json;

class Program
{
    static void Main(string[] args)
    {
        string endpoint = @"https://api.bitflyer.com/v1/";
        string tickerApi = @"ticker?product_code=";
        string product_code = @"BTC_JPY";

        Program app = new Program();

        HttpClient client = new HttpClient();
        string responseJson = (app.HttpContent(endpoint + tickerApi + product_code , client)).Result;

        Console.WriteLine("== TICKER BTC_JPY TICKER ==\n{0}",responseJson);

        DataContractJsonSerializerSettings settings = new DataContractJsonSerializerSettings
        {
            DateTimeFormat = new System.Runtime.Serialization.DateTimeFormat("yyyy-MM-dd'T'HH:mm:ss.FFF")
        };

        Ticker deserialized;
        DataContractJsonSerializer js = new DataContractJsonSerializer(typeof(Ticker), settings);
        using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(responseJson), false))
        {
            deserialized = js.ReadObject(ms) as Ticker;
        }

        Console.WriteLine("== DESERIALIZED TICKER ==");
        app.ShowTicker(deserialized);
    }

    [System.Runtime.Serialization.DataContract]
    public class Ticker
    {
        [System.Runtime.Serialization.DataMember(Name = "product_code")]
        public string product_code { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "timestamp")]
        public DateTime timestamp { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "tick_id")]
        public int tick_id { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "best_bid")]
        public Decimal best_bid { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "best_ask")]
        public Decimal best_ask { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "best_bid_size")]
        public Decimal best_bid_size { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "total_bid_depth")]
        public Decimal total_bid_depth { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "total_ask_depth")]
        public Decimal total_ask_depth { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "ltp")]
        public Decimal ltp { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "volume")]
        public Decimal volume { get; set; }
        [System.Runtime.Serialization.DataMember(Name = "volume_by_product")]
        public Decimal volume_by_product { get; set; }
    }

    private void ShowTicker(Ticker t)
    {
        Console.WriteLine("product_code     :{0}", t.product_code);
        Console.WriteLine("timestamp        :{0}", t.timestamp);
        Console.WriteLine("tick_id          :{0}", t.tick_id);
        Console.WriteLine("best_bid         :{0}", t.best_bid);
        Console.WriteLine("best_ask         :{0}", t.best_ask);
        Console.WriteLine("best_bid_size    :{0}", t.best_bid_size);
        Console.WriteLine("total_bid_depth  :{0}", t.total_bid_depth);
        Console.WriteLine("total_ask_depth  :{0}", t.total_ask_depth);
        Console.WriteLine("ltp              :{0}", t.ltp);
        Console.WriteLine("volume           :{0}", t.volume);
        Console.WriteLine("volume_by_product:{0}", t.volume_by_product);
    }

    private async Task<string> HttpContent(string url, HttpClient clinet)
    {
        HttpResponseMessage response = null;
        try
        {
            response = await clinet.GetAsync(url);
            response.EnsureSuccessStatusCode();
            string responseBody = await response.Content.ReadAsStringAsync();
            return await response.Content.ReadAsStringAsync();
        }
        catch (Exception ex)
        {
            Console.WriteLine("Exception Message :{0} ", ex.Message);
        }
        return null;
    }
}

Visual Basic †

Imports System.IO
Imports System.Text
Imports System.Net.Http
Imports System.Runtime.Serialization.Json

Module Program

    Sub Main(args As String())

        Dim endpoint As String = "https://api.bitflyer.com/v1/"
        Dim tickerApi As String = "ticker?product_code="
        Dim product_code As String = "BTC_JPY"

        Dim client As HttpClient = New HttpClient()
        Dim responseJson As String = (HttpContent(endpoint & tickerApi & product_code, client)).Result
        Console.WriteLine("== TICKER BTC_JPY TICKER ==" & vbCrLf & "{0}", responseJson)

        Dim settings As DataContractJsonSerializerSettings = New DataContractJsonSerializerSettings With {
            .DateTimeFormat = New System.Runtime.Serialization.DateTimeFormat("yyyy-MM-dd'T'HH:mm:ss.FFF")
        }

        Dim deserialized As Ticker
        Dim js As DataContractJsonSerializer = New DataContractJsonSerializer(GetType(Ticker), settings)

        Using ms = New MemoryStream(Encoding.UTF8.GetBytes(responseJson), False)
            deserialized = TryCast(js.ReadObject(ms), Ticker)
        End Using

        Console.WriteLine("== DESERIALIZED TICKER ==")
        ShowTicker(deserialized)

    End Sub

    <System.Runtime.Serialization.DataContract>
    Public Class Ticker
        <System.Runtime.Serialization.DataMember(Name:="product_code")>
        Public Property product_code As String
        <System.Runtime.Serialization.DataMember(Name:="timestamp")>
        Public Property timestamp As DateTime
        <System.Runtime.Serialization.DataMember(Name:="tick_id")>
        Public Property tick_id As Integer
        <System.Runtime.Serialization.DataMember(Name:="best_bid")>
        Public Property best_bid As Decimal
        <System.Runtime.Serialization.DataMember(Name:="best_ask")>
        Public Property best_ask As Decimal
        <System.Runtime.Serialization.DataMember(Name:="best_bid_size")>
        Public Property best_bid_size As Decimal
        <System.Runtime.Serialization.DataMember(Name:="total_bid_depth")>
        Public Property total_bid_depth As Decimal
        <System.Runtime.Serialization.DataMember(Name:="total_ask_depth")>
        Public Property total_ask_depth As Decimal
        <System.Runtime.Serialization.DataMember(Name:="ltp")>
        Public Property ltp As Decimal
        <System.Runtime.Serialization.DataMember(Name:="volume")>
        Public Property volume As Decimal
        <System.Runtime.Serialization.DataMember(Name:="volume_by_product")>
        Public Property volume_by_product As Decimal
    End Class

    Private Sub ShowTicker(ByVal t As Ticker)
        Console.WriteLine("product_code     :{0}", t.product_code)
        Console.WriteLine("timestamp        :{0}", t.timestamp)
        Console.WriteLine("tick_id          :{0}", t.tick_id)
        Console.WriteLine("best_bid         :{0}", t.best_bid)
        Console.WriteLine("best_ask         :{0}", t.best_ask)
        Console.WriteLine("best_bid_size    :{0}", t.best_bid_size)
        Console.WriteLine("total_bid_depth  :{0}", t.total_bid_depth)
        Console.WriteLine("total_ask_depth  :{0}", t.total_ask_depth)
        Console.WriteLine("ltp              :{0}", t.ltp)
        Console.WriteLine("volume           :{0}", t.volume)
        Console.WriteLine("volume_by_product:{0}", t.volume_by_product)
    End Sub

    Private Async Function HttpContent(ByVal url As String, ByVal clinet As HttpClient) As Task(Of String)
        Dim response As HttpResponseMessage = Nothing

        Try
            response = Await clinet.GetAsync(url)
            response.EnsureSuccessStatusCode()
            Dim responseBody As String = Await response.Content.ReadAsStringAsync()
            Return Await response.Content.ReadAsStringAsync()
        Catch ex As Exception
            Console.WriteLine("Exception Message :{0} ", ex.Message)
        End Try

        Return Nothing
    End Function

End Module

実行結果 †

上記サンプルコードの実行結果になります。

以上、.NET標準の DataContractJsonSerializer を使ってJSONをデシリアライズし出力するサンプルコードの紹介でした。