C#实现谷歌翻译API
2017-06-07 15:45 marso 阅读(12545) 评论(34) 编辑 收藏 举报由于谷歌翻译官方API是付费版本，本着免费和开源的精神，分享一下用C#实现谷歌翻译API的代码。这个代码非常简单，主要分两块：通过WebRequest的方式请求内容；获取Get方式的请求参数（难点在于tk的获取）。注意该项目需要添加以下几个引用：
System.Web
Newtonsoft.Json
MSScriptControl(com组件中的Microsoft Script Control 1.0)
一、WebRequest代码
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、谷歌翻译接口的实现
1、抓包查看翻译网络请求，这里是用谷歌浏览器查看的网络请求，如下图：
可以看到，请求方式是“Get”方式，后面跟的请求参数很多，如下图：
其中，最重要的参数有：sl--来源语言，一般设置为auto即自动检测，tl--目标语言，你想翻译成的语言，tk--ticket即使发车车票，谷歌就靠这个来防止我们免费调用的，这是本API最难的地方。
2、tk的获取
在打开https://translate.google.com/页面是，获取到的HTML代码中有如下一个TKK的值：
直接在获取的源代码中用正则匹配出这个值：Regex re = new Regex(@"(?<=TKK=')(.*?)(?=')")，可以得到一个字符串：428502.368022592
从监控的网络中可以发现其中一个JS调用了这个TKK值，这个JS加了密进行混淆的，要破解这个JS需要扎实的基本功，以及足够的耐心，我也是网上找的别人破解的JS代码，亲测可用，需将此代码保存在gettk.js文档中，方便调用：
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，运行tk这个函数，它有两个输入值：a为翻译文本内容，TKK是上文正则匹配得到的JS字符串执行的结果值。为方便在C#中执行JS，封装了一个能执行JS的函数，如下：
/// <summary>
/// 执行JS
/// </summary>
/// <param name="sExpression">参数体</param>
/// <param name="sCode">JavaScript代码的字符串</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、实现翻译的完整代码
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>
/// 谷歌翻译
/// </summary>
/// <param name="text">待翻译文本</param>
/// <param name="fromLanguage">自动检测：auto</param>
/// <param name="toLanguage">中文：zh-CN，英文：en</param>
/// <returns>翻译后文本</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中正则匹配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>
/// 执行JS
/// </summary>
/// <param name="sExpression">参数体</param>
/// <param name="sCode">JavaScript代码的字符串</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;
}
}
}
