由於谷歌翻譯官方API是付費版本，本着免費和開源的精神，分享一下用C#實現谷歌翻譯API的代碼。這個代碼非常簡單，主要分兩塊：通過WebRequest的方式請求內容；獲取Get方式的請求參數（難點在於tk的獲取）。注意該項目需要添加以下幾個引用：
System.Web
Newtonsoft.Json
MSScriptControl(com組件中的Microsoft Script Control 1.0)
一、WebRequest代碼
var webRequest = WebRequest.Create(url) as HttpWebRequest;
webRequest.Method = "GET";
webRequest.CookieContainer = cookie;
webRequest.Referer = referer;
webRequest.Timeout = 20000;
webRequest.Headers.Add("X-Requested-With:XMLHttpRequest");
webRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
webRequest.UserAgent = useragent;
using (var webResponse = (HttpWebResponse)webRequest.GetResponse())
{
using (var reader = new StreamReader(webResponse.GetResponseStream(), Encoding.UTF8))
{
html = reader.ReadToEnd();
reader.Close();
webResponse.Close();
}
}
二、谷歌翻譯接口的實現
1、抓包查看翻譯網絡請求，這里是用谷歌瀏覽器查看的網絡請求，如下圖：
可以看到，請求方式是“Get”方式，后面跟的請求參數很多，如下圖：
其中，最重要的參數有：sl--來源語言，一般設置為auto即自動檢測，tl--目標語言，你想翻譯成的語言，tk--ticket即使發車車票，谷歌就靠這個來防止我們免費調用的，這是本API最難的地方。
2、tk的獲取
在打開https://translate.google.com/頁面是，獲取到的HTML代碼中有如下一個TKK的值：
直接在獲取的源代碼中用正則匹配出這個值：Regex re = new Regex(@"(?<=TKK=')(.*?)(?=')")，可以得到一個字符串：428502.368022592
從監控的網絡中可以發現其中一個JS調用了這個TKK值，這個JS加了密進行混淆的，要破解這個JS需要扎實的基本功，以及足夠的耐心，我也是網上找的別人破解的JS代碼，親測可用，需將此代碼保存在gettk.js文檔中，方便調用：
var b = function (a, b) {
for (var d = 0; d < b.length - 2; d += 3) {
var c = b.charAt(d + 2),
c = "a" <= c ? c.charCodeAt(0) - 87 : Number(c),
c = "+" == b.charAt(d + 1) ? a >>> c : a << c;
a = "+" == b.charAt(d) ? a + c & 4294967295 : a ^ c
}
return a
}
var tk = function (a,TKK) {
for (var e = TKK.split("."), h = Number(e[0]) || 0, g = [], d = 0, f = 0; f < a.length; f++) {
var c = a.charCodeAt(f);
128 > c ? g[d++] = c : (2048 > c ? g[d++] = c >> 6 | 192 : (55296 == (c & 64512) && f + 1 < a.length && 56320 == (a.charCodeAt(f + 1) & 64512) ? (c = 65536 + ((c & 1023) << 10) + (a.charCodeAt(++f) & 1023), g[d++] = c >> 18 | 240, g[d++] = c >> 12 & 63 | 128) : g[d++] = c >> 12 | 224, g[d++] = c >> 6 & 63 | 128), g[d++] = c & 63 | 128)
}
a = h;
for (d = 0; d < g.length; d++) a += g[d], a = b(a, "+-a^+6");
a = b(a, "+-3^+b+-f");
a ^= Number(e[1]) || 0;
0 > a && (a = (a & 2147483647) + 2147483648);
a %= 1E6;
return a.toString() + "." + (a ^ h)
}
要得到tk只需要，運行tk這個函數，它有兩個輸入值：a為翻譯文本內容，TKK是上文正則匹配得到的JS字符串執行的結果值。為方便在C#中執行JS，封裝了一個能執行JS的函數，如下：
/// <summary>
/// 執行JS
/// </summary>
/// <param name="sExpression">參數體</param>
/// <param name="sCode">JavaScript代碼的字符串</param>
/// <returns></returns>
private string ExecuteScript(string sExpression, string sCode)
{
MSScriptControl.ScriptControl scriptControl = new MSScriptControl.ScriptControl();
scriptControl.UseSafeSubset = true;
scriptControl.Language = "JScript";
scriptControl.AddCode(sCode);
try
{
string str = scriptControl.Eval(sExpression).ToString();
return str;
}
catch (Exception ex)
{
string str = ex.Message;
}
return null;
}
3、實現翻譯的完整代碼
using System;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using MSScriptControl;
using System.Web;
namespace GoogleTranslate
{
public class Translate
{
/// <summary>
/// 谷歌翻譯
/// </summary>
/// <param name="text">待翻譯文本</param>
/// <param name="fromLanguage">自動檢測：auto</param>
/// <param name="toLanguage">中文：zh-CN，英文：en</param>
/// <returns>翻譯后文本</returns>
public string GoogleTranslate(string text, string fromLanguage, string toLanguage)
{
CookieContainer cc = new CookieContainer();
string GoogleTransBaseUrl = "https://translate.google.com/";
var BaseResultHtml = GetResultHtml(GoogleTransBaseUrl, cc, "");
Regex re = new Regex(@"(?<=TKK=')(.*?)(?=')");
var TKK = re.Match(BaseResultHtml).ToString();//在返回的HTML中正則匹配TKK的值
var GetTkkJS = File.ReadAllText("./gettk.js");
var tk = ExecuteScript("tk(\"" + text + "\",\"" + TKK + "\")", GetTkkJS);
string googleTransUrl = "https://translate.google.com/translate_a/single?client=t&sl=" + fromLanguage + "&tl=" + toLanguage + "&hl=en&dt=at&dt=bd&dt=ex&dt=ld&dt=md&dt=qca&dt=rw&dt=rm&dt=ss&dt=t&ie=UTF-8&oe=UTF-8&otf=1&ssel=0&tsel=0&kc=1&tk=" + tk + "&q=" + HttpUtility.UrlEncode(text);
var ResultHtml = GetResultHtml(googleTransUrl, cc, "https://translate.google.com/");
dynamic TempResult = Newtonsoft.Json.JsonConvert.DeserializeObject(ResultHtml);
string ResultText = Convert.ToString(TempResult[0][0][0]);
return ResultText;
}
public string GetResultHtml(string url, CookieContainer cookie, string referer)
{
var html = "";
var webRequest = WebRequest.Create(url) as HttpWebRequest;
webRequest.Method = "GET";
webRequest.CookieContainer = cookie;
webRequest.Referer = referer;
webRequest.Timeout = 20000;
webRequest.Headers.Add("X-Requested-With:XMLHttpRequest");
webRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
webRequest.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36";
using (var webResponse = (HttpWebResponse)webRequest.GetResponse())
{
using (var reader = new StreamReader(webResponse.GetResponseStream(), Encoding.UTF8))
{
html = reader.ReadToEnd();
reader.Close();
webResponse.Close();
}
}
return html;
}
/// <summary>
/// 執行JS
/// </summary>
/// <param name="sExpression">參數體</param>
/// <param name="sCode">JavaScript代碼的字符串</param>
/// <returns></returns>
private string ExecuteScript(string sExpression, string sCode)
{
MSScriptControl.ScriptControl scriptControl = new MSScriptControl.ScriptControl();
scriptControl.UseSafeSubset = true;
scriptControl.Language = "JScript";
scriptControl.AddCode(sCode);
try
{
string str = scriptControl.Eval(sExpression).ToString();
return str;
}
catch (Exception ex)
{
string str = ex.Message;
}
return null;
}
}
}