自從筆者開始研究量化交易之後,就聽說股價跟籌碼面脫不了關係,其中的重點就是要分析分點交易狀況。台灣證券交易所與證券櫃檯買賣中心都有提供買賣日報表查詢,但是為了避免太多機器人爬蟲造成主機負擔,一個需要輸入圖形驗證碼,一個需要勾選reCaptcha我不是機器人的欄位。
這一篇就先以程式自動輸入圖形驗證碼,並取得證券交易所每一檔股票的買賣日報表當作範例。
這邊要注意的是OCR套件不一定每次都可以辨識出正確的數字,因為台灣證券交易所的數字長度永遠都是5,所以我們可以在辨識的結尾判斷長度,如果不正確,就重新判斷一次。
另外就是台灣證券交易所如果偵測到大量的索取要求,將會直接把IP鎖住一陣子,所以在每次索取要求之間,我們都先暫停一段時間,這邊我們是設定一分鐘。主要程式碼就如下所示:
private async Task<bool> GetTWSEBroker(string code, string path)
{
// https://bsr.twse.com.tw/bshtm/bsMenu.aspx
// https://bsr.twse.com.tw/bshtm/bsContent.aspx
int dlretry = 0;
int ocrretry = 0;
begin:
string reqtwse = "https://bsr.twse.com.tw/bshtm/bsMenu.aspx";
CookieContainer _cookies = new CookieContainer();
string csvtwse = await GetAsync(reqtwse, _cookies, 65001);
again:
string Captcha = FindImg(csvtwse);
//Debug.WriteLine(code + " 辨識驗證碼 " + Captcha);
if (Captcha.Length != 5)
{
if (ocrretry++ < 5)
{
goto again;
}
else
{
Debug.WriteLine(code + " 辨識驗證碼錯誤 " + Captcha);
}
}
NameValueCollection postParams = System.Web.HttpUtility.ParseQueryString(string.Empty);
postParams.Add("__EVENTTARGET", "");
postParams.Add("__EVENTARGUMNET", "");
postParams.Add("__LASTFOCUS", "");
postParams.Add("__VIEWSTATE", FindToken(csvtwse, "__VIEWSTATE"));
postParams.Add("__VIEWSTATEGENERATOR", FindToken(csvtwse, "__VIEWSTATEGENERATOR"));
postParams.Add("__EVENTVALIDATION", FindToken(csvtwse, "__EVENTVALIDATION"));
postParams.Add("RadioButton_Normal", "RadioButton_Normal");
postParams.Add("TextBox_Stkno", code);
postParams.Add("CaptchaControl1", Captcha);
postParams.Add("btnOK", "%E6%9F%A5%E8%A9%A2");
string responseInString = SetAsync(reqtwse, _cookies, postParams);
//Debug.WriteLine(responseInString);
if (FindContent(responseInString))
{
string csvurl = "https://bsr.twse.com.tw/bshtm/bsContent.aspx";
string csvline = await GetAsync(csvurl, _cookies, 950);
if (csvline.Count() > 0)
{
File.WriteAllText(path, "證券代碼 " + code + " 序號,券商,價格,買進股數,賣出股數\r\n");
int skipline = 0;
foreach (var line in csvline.Split(new string[] { "\n" }, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Replace(" ", "")).Select(s => s.Replace(" ", "")))
{
if (skipline++ < 3) continue;
try
{
string[] csv = line.Split(",");
string strData = string.Empty;
if (csv.Count() == 11)
{
if (csv[6] != "")
{
strData = string.Format("{0},{1},{2},{3},{4}\r\n{5},{6},{7},{8},{9}\r\n",
csv[0], csv[1], csv[2], csv[3], csv[4], csv[6], csv[7], csv[8], csv[9], csv[10]
);
}
else
{
strData = string.Format("{0},{1},{2},{3},{4}\r\n",
csv[0], csv[1], csv[2], csv[3], csv[4]
);
}
File.AppendAllText(path, strData);
}
else
{
File.Delete(path);
Debug.WriteLine("TWSE Err inline " + code);
}
}
catch
{
File.Delete(path);
Debug.WriteLine("TWSE Err File " + code);
}
}
}
return true;
}
else if (dlretry++ < 5)
{
//Debug.WriteLine("驗證碼錯誤");
Thread.Sleep(60000);
goto begin;
}
Debug.WriteLine("TWSE Err download " + code);
return false;
}
為了可以取得網頁上面的資料,在這邊我們採用HtmlAgilityPack的HtmlDocument套件,幫助我們把網頁內容抓下來,並提取指定的欄位,其中辦識圖片中的數字,可以透過OpenCV先做圖片的切割,再透過Tesseract OCR的幫助,把每個圖片數字轉成實際數值,所以使用上要在C#先安裝HtmlAgilityPack、OpenCvSharp4以及Tesseract的套件。
我把相關的程式碼都放在下方,提供大家做參考。
private string FindImg(string webdata)
{
try
{
if (webdata.Length == 0)
{
Debug.WriteLine("CaptchaImage has no challenge. Sleeping for a while now.");
Thread.Sleep(1800000);
return string.Empty;
}
string imgname = string.Empty;
HtmlDocument document = new HtmlDocument();
document.LoadHtml(webdata);
foreach (HtmlNode tag in document.DocumentNode.SelectNodes("//img"))
{
if (tag.Attributes["src"].Value.Contains("CaptchaImage"))
{
imgname = tag.Attributes["src"].Value;
}
}
string fname = @s_temppath + "CaptchaImage.JFIF";
if (File.Exists(fname))
{
File.Delete(fname);
}
using (WebClient webClient = new WebClient())
{
webClient.DownloadFile(new Uri("https://bsr.twse.com.tw/bshtm/" + imgname), fname);
//webClient.DownloadData
}
return DecodeCaptcha(@s_temppath + "CaptchaImage.JFIF");
}
catch (NullReferenceException)
{
// web return no page
Debug.WriteLine("CaptchaImage has no challenge. Sleeping for a while now.");
Thread.Sleep(1800000);
}
catch
{
//Debug.WriteLine("Exception in CaptchaImage");
Thread.Sleep(5000);
}
return string.Empty;
}
private string FindToken(string webdata, string item)
{
try
{
HtmlDocument document = new HtmlDocument();
document.LoadHtml(webdata);
string description = string.Empty;
foreach (HtmlNode tag in document.DocumentNode.SelectNodes("//input"))
{
if (tag.Attributes["name"] != null && tag.Attributes["id"] != null && tag.Attributes["name"].Value == item)
{
description = tag.Attributes["value"].Value;
}
}
return description;
//return System.Web.HttpUtility.UrlEncode(description);
}
catch (NullReferenceException)
{
// web return no page
Debug.WriteLine("CaptchaImage has no challenge. Sleeping for a while now.");
Thread.Sleep(1800000);
}
catch
{
;
}
return string.Empty;
}
private string DecodeCaptcha(string img)
{
var ocrtext = string.Empty;
// OpenCV#
using Mat captcha = new Mat(img, ImreadModes.Grayscale);
if (captcha.Empty())
{
return ocrtext;
}
// Convert the captcha to black and white.
using Mat captcha_bw = new Mat();
Cv2.Threshold(captcha, captcha_bw, 128, 255, ThresholdTypes.Binary | ThresholdTypes.Otsu);
// Erode the image to remove dot noise and that wierd line. I use a 3x3 rectengal as the kernal.
using Mat captcha_erode = new Mat();
using Mat element = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(3, 3));
Cv2.Erode(captcha_bw, captcha_erode, element);
// Some cosmetic
using Mat captcha_denoise = new Mat();
Cv2.FastNlMeansDenoising(captcha_erode, captcha_denoise, 50);
byte[] buffer = captcha_denoise.ToMemoryStream().ToArray();
// OCR
var path = Path.GetDirectoryName(Assembly.GetExecutingAssembly().CodeBase);
path = Path.Combine(path, "tessdata");
path = path.Replace("file:\\", "");
using (var engine = new TesseractEngine(path, "eng", EngineMode.Default))
{
engine.SetVariable("tessedit_char_whitelist", "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ");
engine.SetVariable("tessedit_unrej_any_wd", true);
using (var ocr = Pix.LoadFromMemory(buffer))
{
using (var page = engine.Process(ocr))
{
ocrtext = page.GetText();
}
}
}
return ocrtext.Trim('\n');
}
一開始,我對於網頁互動爬取資料也不是很熟悉,所以土炮煉製了這一大段的程式去抓資料,中間走過不少冤枉路,雖然我實在找不到籌碼面怎麼樣可以幫助程式交易,但是還是把這些結果記錄下來,留個紀念。