using System;

using System.Threading.Tasks;

using System.Net.Http;

​

var requests = new QuoteRequest[]

{

    new QuoteRequest(

        "GOOG",

        new DateTime(2004, 1, 1),

        new DateTime(2019, 12, 31),

        "1d"),

    new QuoteRequest(

        "MSFT",

        new DateTime(2004, 1, 1),

        new DateTime(2019, 12, 31),

        "1d"),

    new QuoteRequest(

        "INTC",

        new DateTime(2004, 1, 1),

        new DateTime(2019, 12, 31),

        "1d"),

    new QuoteRequest(

        "AMZN",

        new DateTime(2004, 12, 1),

        new DateTime(2019, 12, 31),

        "1d"),

    new QuoteRequest(

        "IBM",

        new DateTime(2004, 12, 1),

        new DateTime(2019, 12, 31),

        "1d")

};

​

var cookie = "";

var crumb = await RevalidateCrumbAsync();

cookie = await RevalidateCookiesAsync();

//Console.WriteLine($"crumb = '{crumb}'");

//Console.WriteLine($"cookie = '{cookie}'");

​

foreach(var req in requests)

{

    Console.WriteLine(req);

    var csv = await DownloadQuoteFromYahooAsync(req.symbol, req.from, req.to, req.interval, crumb);

    Console.WriteLine($"{csv.Length} bytes");

    Console.WriteLine();

}

​

return;

​

HttpClient newConfiguredHttpClient(bool useCookie = false)

{

    var httpClient = new HttpClient();

    httpClient.DefaultRequestHeaders.Add("User-Agent",

        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0");

    if (useCookie && cookie.Length > 0)

    {

        httpClient.DefaultRequestHeaders.Add("Cookie", cookie);

    }

    httpClient.Timeout = TimeSpan.FromSeconds(15);

​

    return httpClient;

}

​

async Task<string> RevalidateCrumbAsync(string symbol = "GOOG")

{

    var url = $"https://finance.yahoo.com/quote/{symbol}";

    HttpClient httpClient = newConfiguredHttpClient();

    var response = await httpClient.GetAsync(url);

​

    var html = await response.Content.ReadAsStringAsync();

​

    var pos = html.IndexOf("\"crumb\":\"");

    if (pos <= 0) return "";

    var pos1 = html.IndexOf(":\"", pos) + 2;

    var pos2 = html.IndexOf('"', pos1);

    if (pos2 <= 0) return "";

​

    return html.Substring(pos1, pos2 - pos1);

}

​

async Task<string> RevalidateCookiesAsync()

{

    var url = "https://login.yahoo.com/";

    HttpClient httpClient = newConfiguredHttpClient();

    var response = await httpClient.GetAsync(url);

    foreach (var header in response.Headers)

    {

        if (header.Key != "Set-Cookie") continue;

        var cookies = "";

        foreach (var cookie in header.Value)

        {

            if(cookies.Length > 0)

            {

                cookies += "; ";

            }

            var pos = cookie.IndexOf(";");

            if(pos > 0)

            {

                cookies += cookie.Substring(0, pos);

            }

            else

            {

                cookies += cookie;

            }

        }

        return cookies;

    }

    return "";

}

​

​

async Task<string> DownloadQuoteFromYahooAsync(string symbol, DateTime startDate, DateTime endDate, string interval, string crumb = "")

{

    // Set URL for API request

    var period1 = (int)(startDate.Subtract(new DateTime(1970, 1, 1)).TotalSeconds);

    var period2 = (int)(endDate.Subtract(new DateTime(1970, 1, 1)).TotalSeconds);

    var url = $"https://query1.finance.yahoo.com/v7/finance/download/{symbol}?period1={period1}&period2={period2}&interval={interval}&events=history";

    if (crumb.Length > 0)

    {

        url += "&crumb=" + crumb;

    }

    Console.WriteLine(url);

​

    HttpClient httpClient = newConfiguredHttpClient(true);

    var response = await httpClient.GetAsync(url).ConfigureAwait(false);

​

    Console.WriteLine($"status = {response.StatusCode}");

    //Console.WriteLine($"headers = {response.Headers}");

    return await response.Content.ReadAsStringAsync().ConfigureAwait(false);

}

​

internal record QuoteRequest(string symbol, DateTime from, DateTime to, string interval);

​