Why this google translate code isnt working?

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Text.RegularExpressions;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            TranslateText("hi", "German");
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }


         public static string TranslateText(string input, string languagePair)
        {
            return TranslateText(input, languagePair, System.Text.Encoding.UTF7);
        }

        /// <summary>
        /// Translate Text using Google Translate
        /// </summary>
        /// <param name="input">The string you want translated</param>
        /// <param name="languagePair">2 letter Language Pair, delimited by "|". 
        /// e.g. "en|da" language pair means to translate from English to Danish</param>
        /// <param name="encoding">The encoding.</param>
        /// <returns>Translated to String</returns>
        public static string TranslateText(string input, string languagePair, Encoding encoding)
        {
            string url = String.Format("http://www.google.com/translate_t?hl=en&ie=UTF8&text={0}&langpair={1}", input, languagePair);

            string result = String.Empty;

            using (WebClient webClient = new WebClient())
            {
                webClient.Encoding = encoding;
                result = webClient.DownloadString(url);
            }

            Match m = Regex.Match(result, "(?<=<div id=result_box dir=\"ltr\">)(.*?)(?=</div>)");

            if (m.Success)
                result = m.Value;
            MessageBox.Show(result);

            return result;
        }

    }
}

I added in the constructor the line:

TranslateText("hi", "German");

And in the bottom i added:

MessageBox.Show(result);

I wanted for the test to translate the word "hi" to German But the result im getting and in the messagebox is a very long text wich is containing all the google website.

I tried to go manualy to the web site in the string url address and its working im getting to the google translate website.

I dont understand why it dosent work. I want later to put instead "hi" some text from a text file.

I tried ot use breakpoint and found that this part the Success is all the time return false dont know why:

if (m.Success)
    result = m.Value;

Answer 1

I think you are not getting the translated text or value in your html result from your code and also from Google.

Reason:

If you execute this through the browser, it is not translating to the language you expect, example:

http://www.google.com/translate_t?hl=en&ie=UTF8&text=hi&langpair=de

I used langpair=de or langpair=German and doesn't work, it shows me always "hi" as my initial text and not "hallo" (text in german).

Well, just to answer your question to get the text, do the following:

Add this method to your class:

public static string getBetween(string strSource, string strStart, string strEnd)
{
    int Start, End;
    if (strSource.Contains(strStart) && strSource.Contains(strEnd))
    {
        Start = strSource.IndexOf(strStart, 0) + strStart.Length;
        End = strSource.IndexOf(strEnd, Start);
        return strSource.Substring(Start, End - Start);
    }
    else
    {
        return "";
    }
}

Change the following in your "TranslateText" method:

    //Match m = Regex.Match(result, "(?<=<div id=result_box dir=\"ltr\">)(.*?)(?=</div>)");
    string text = getBetween(result, "<span id=result_box class=\"short_text\">", "</span>");

    //if (m.Success)
    //    result = m.Value;
    return text;

Now execute your code like this:

// this will return empty ("") if no text found.
// or any problem happens (like lose your internet connection)
string translatedText = TranslateText("hi", "German");
Console.Write(translatedText);

At this point, if you get the translated text from google, it will be retrieved in your app.

Recommendations:

• Use a console application and no windows forms, it will be faster.

Warning:

• "Google is not a free translating tool. What you do is terms violation".

Hope this helps :-)

Answer 2

Would be easier, and more robust to parse the html using something other than a regex. You can then search the parsed HTML tree for the result and extract it from there.

See What is the best way to parse html in C#?