c# - 如何使用 'POST'方法使用c#获取JSON数据？

Question

我正在尝试从 BLS 网站请求一组特定数据:

http://www.bls.gov/developers/api_signature_v2.htm#parameters

在该链接上，我专门尝试获取一个带有可选参数的系列。我非常接近，但好像我的 JSON 发布请求没有被处理。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Net;
using System.Data.SqlClient;
using System.Web;
using System.Configuration;
using System.Data;
using System.Globalization;
using System.ComponentModel;
using Newtonsoft.Json;
using System.Web.Script.Serialization;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;



namespace ConsoleApplication5
{


//Classes needed to deserialze JSON data (JSON to C# website)
public class DataObject
{
    public string Name { get; set; }
}

public class Footnote
{
}

public class Datum
{
    public string year { get; set; }
    public string period { get; set; }
    public string periodName { get; set; }
    public string value { get; set; }
    public List<Footnote> footnotes { get; set; }

}

public class Series
{
    public string seriesID { get; set; }
    public List<Datum> data { get; set; }


}

public class Results
{
    public List<Series> series { get; set; }
}

public class RootObject
{
    public string status { get; set; }
    public int responseTime { get; set; }
    public List<object> message { get; set; }
    public Results Results { get; set; }

    public override string ToString()
    {
        return string.Format("Status: {0}", status);
    }

}

class Program
{

    static double octLY;
    static double oct2y;

    static void Main(string[] args)
    {
        TryParsing();

    }


    static void TryParsing()
    {
        var httpWebRequest = (HttpWebRequest)WebRequest.Create("http://api.bls.gov/publicAPI/v2/timeseries/data/CUUR0000SA0");
        httpWebRequest.ContentType = "application/json";
        httpWebRequest.Method = "POST";

        using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
        {
            //string json = new JavaScriptSerializer().Serialize(new
            //{
            //    seriesid = "CUUR0000SA0",
            //    startYear = "2010",
            //    endYear = "2015",
            //    catalog = "true",
            //    calculations = "true",
            //    annualAverage = "true",
            //    registrationKey = "f3171173a8ce4b969b5085ba9a83202f"


            //});

            string json = "{\"seriesid\":[\"CUUR0000SA0\"],\"startyear\":\"2010\",\"endyear\":\"2015\",\"catalog\":true,\"calculations\":true,\"annualAverage\":true,\"registrationKey\":\"f3171173a8ce4b969b5085ba9a83202f\"}";

            //Console.WriteLine(json.ToString());
            //Console.ReadLine();

            streamWriter.Write(json);
            streamWriter.Flush();
            streamWriter.Close();
        }

        var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
            {
            var result = streamReader.ReadToEnd();
            Console.WriteLine(result.ToString());
            Console.ReadLine();
            }
        }

    }
}

我在 JSON 发布数据中进行了硬编码，以完全符合 BLS 链接上示例的显示方式。问题是它忽略了我所有的参数。尽管要求 5 年等，但我只得到 3 年的数据......

可以使用我的授权码，因为这是通用的，稍后会更改。

有人可以告诉我如何使用 POST 方法请求此数据吗？我觉得我只是在这里缺少一些基本的东西，但无法理解。

仅供引用，如果您要重新创建此问题，这将很容易，因为它都是开源数据等...但是由于它没有在请求中看到我的授权，它限制用户每天只能请求 25 个请求。 . 所以如果你按原样运行 26 次......你会收到一条请求超出的消息。如果这开始工作，则从 25 次增加到 500 次。

这是我尝试的另一种方法:

static void TryParse()
    {
        //Get JSON data
        using (WebClient wc = new WebClient())
        {
            var json = wc.DownloadString("http://api.bls.gov/publicAPI/v2/timeseries/data/CUUR0000SA0");

            //Deserialize JSON data
            var p1 = new JavaScriptSerializer();
            RootObject j = p1.Deserialize<RootObject>(json);

            RootObject r1 = JsonConvert.DeserializeObject<RootObject>(json);


            //check to see if JSON data was successfully downloaded
            if (r1.ToString() == "Status: REQUEST_SUCCEEDED")
            {

                //Loop through the JSON to find values
                foreach (Datum d in j.Results.series[0].data)
                {
                    //Filters data based on year value
                    if ((Int16.Parse(d.year) == DateTime.Now.Year - 1 && d.period == "M10" )) //|| (Int16.Parse(d.year) == DateTime.Now.Year - 1 && d.period == "M10" )))
                    {
                        octLY = (double.Parse(d.value));
                        Console.WriteLine("OCT14: {0}", octLY);

                        //Console.WriteLine(d.year + " : " + d.period + " : " + d.periodName + " : " + d.value);
                    }

                    if (Int16.Parse(d.year) == DateTime.Now.Year - 2 && d.period == "M10")
                    {
                        oct2y = (double.Parse(d.value));
                        Console.WriteLine("OCT13: {0}", oct2y);

                    }
                    else { }
                }

                Console.WriteLine("CPI: {0}", (octLY - oct2y) / oct2y + 1);
            }

            else
            {
                Console.WriteLine(r1.ToString());
                Console.ReadLine();
            }


            Console.ReadLine();
        }

    }

Answer 1

使用您的代码重新创建我能够在我的 RootObject 类 Results.Series 集合中取回有效数据。首先，我创建了一个名为 Series Post 的新类。

public class SeriesPost 
{
    public string[] seriesid { get; set; }
    public string startyear { get; set; }
    public string endyear { get; set; }
    public bool catalog { get; set; }
    public bool calculations { get; set; }
    public bool annualaverage { get; set; }
    public string registrationKey { get; set; }
}

从那里我稍微修改了你的 JSON 序列化

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
        string newJson = Newtonsoft.Json.JsonConvert.SerializeObject(new SeriesPost()
        {
            seriesid = (new List<string>() { "CUUR0000SA0" }).ToArray(),
            startyear = "2010",
            endyear = "2015",
            catalog = false,
            calculations = true,
            annualaverage = true,
            registrationKey = "f3171173a8ce4b969b5085ba9a83202f"

        });
        //So you can see the JSON thats output
        System.Diagnostics.Debug.WriteLine(newJson);
        streamWriter.Write(newJson);
        streamWriter.Flush();
        streamWriter.Close();
   }
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            var result = streamReader.ReadToEnd();
            //Here your RootObject is the Type thats returned with your results
            RootObject obj = Newtonsoft.Json.JsonConvert.DeserializeObject<RootObject>(result);
            // Loop over the series in the results
            foreach(Series ser in obj.Results.series)
            {
                // Loop over the Data in each of the series.
                foreach(var data in ser.data)
                {
                    //Output the year, in my test I got multiple entries for each year between 2010 to 2015
                    Console.WriteLine(data.year);
                } 
            }
            Console.ReadLine();
        }