A long time ago, I wrote a blog post about how to translate text in C# using Google Translate. Since then, an official AJAX API has been released, which is a much better solution. Reading the comments of the blog post indicates that the code was broken quite quickly!
Google’s AJAX Language API, also includes functionality to detect language from a given string. All you can do on translate.google.com you can do via the API. Reading the class reference for the Translation API, for Flash and other Non-Javascript environments gives us the information we need to perform translations from C#. Most important is the URL and the parameters required and accepted.
Another very important thing we can read in the documentation is this:
Applications MUST always include a valid and accurate http referer header in their requests
We must remember to add a valid referrer when making the actual call!
The response object
Google’s AJAX Language APIs uses JSON, and returns a JSON object containing 3 properties:
- responseData
- responseDetails
- responseStatus
This means we need to have some C# objects that we can use to deserialize the JSON returned from Google. I’m using a generic class called GoogleAjaxResponse<T>, with T being the specific class I want the JSON to be deserialized to.
using System.Runtime.Serialization;
namespace Milkshake.Integration.Google
{
/// Defines a response from one of Google's AJAX APIs.
/// The type of object, being returned.
[DataContract]
public class GoogleAjaxResponse<T>
{
///
/// Gets or sets the response data.
///
///
/// The responseData from Google AJAX API Call
///
/// The response data.
[DataMember(Name = "responseData", Order = 0)]
public T ResponseData { get; set; }
}
}
To deserialize the Translation specific JSON, I use the TranslationResponse class:
using System.Net;
using System.Runtime.Serialization;
namespace Milkshake.Integration.Google.Translate
{
/// Defines a response from the Google AJAX Translate API.
[DataContract]
public class TranslationResponse
{
/// Initializes a new instance of the class.
public TranslationResponse()
{
this.ResponseStatus = HttpStatusCode.OK;
}
/// Gets or sets the translated text.
/// The translated text.
[DataMember(Name = "translatedText", Order = 0)]
public string TranslatedText { get; set; }
/// Gets or sets the response details.
/// The response details.
[DataMember(Name = "responseDetails", Order = 1)]
public object ResponseDetails { get; set; }
/// Gets or sets the response status.
/// The response status.
[DataMember(Name = "responseStatus", Order = 2)]
public HttpStatusCode ResponseStatus { get; set; }
}
}
Calling the Google AJAX Translate API
To make the actual call, we can use the HttpWebRequest and HttpWebResponse classes.
using System;
using System.Globalization;
using System.IO;
using System.Net;
using System.Web;
using System.Web.Script.Serialization;
namespace Milkshake.Integration.Google.Translate
{
/// An API Client for the Google AJAX Translate API.
public class TranslateApi
{
/// The JavaScript serializer
private JavaScriptSerializer _Serializer = new JavaScriptSerializer();
/// Translates the text.
public string TranslateText(string inputText, string sourceLanguage, string destinationLanguage, string referrer, string apiKey)
{
string requestUrl = string.Format("http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q={0}&langpair={1}|{2}&key={3}", HttpUtility.UrlEncode(inputText), sourceLanguage.ToLowerInvariant(), destinationLanguage.ToLowerInvariant(), apiKey);
try
{
using (HttpClient http = new HttpClient(requestUrl))
{
http.AddReferrer(referrer);
http.ExecuteRequest();
string responseJson = http.GetResponseString();
GoogleAjaxResponse<TranslationResponse> translation = this._Serializer.Deserialize<GoogleAjaxResponse<TranslationResponse>>(responseJson);
if (translation != null && translation.ResponseData != null && translation.ResponseData.ResponseStatus == HttpStatusCode.OK)
{
return translation.ResponseData.TranslatedText;
}
else
{
return String.Empty;
}
}
}
catch
{
return String.Empty;
}
}
}
}
The response JSON and translated text
Doing a simple test, I translate “Hello world” from English to Danish, and I can see that it works like a charm.
Professional translations - even via API!
and learned a lot of useful stuff.
