This will be the first post of a series about creating a class library for Microsoft Bing APIs in C#. I had ignore Microsoft offering in the past because Google APIs have always done the work for me; however, I recently worked in my first WP7 application and found Bing services to be really mature and capable of delivering results just as good as Google’s.
Let’s Begin
NOTE: You need to register and create an AppID at http://www.bing.com/developers.
Create a new project called .NET 4.0 Class Library called DeveloperCaster.Bing; we will wrap all API calls within this class library.
I want to be able to expand this library beyond the translation API so I will leave room to extend it in future posts.
We will begin by adding the following objects:
The Bing Parameter Class - It is a simple value pair class that will be used to represent request parameters to the API.
Source code:
public class BingParameter
{
public string Name
{
set;
get;
}
public string Value
{
set;
get;
}
}
The IBingRequest Interface – Will be our datatype for request to the Bing service (see BingService class).
Source code:
public interface IBingRequest
{
List<BingParameter> List { get; }
}
The BingService class – We are going to use this class to execute all our requests to the Bing API. BingService provide one method to perform a request and I also added an extra method that will take a IBingRequest plus an anonymous method to process a request using the Request(IBingRequest) method to send its return value to the ResponseHandler parameter (not really needed for core functionality). Our class will embed the Bing API URL (“http://api.bing.net/xml.aspx”); however, you may choose not to do so and pass it as a parameter.
Source Code:
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
namespace DeveloperCaster.Bing
{
public delegate void ResponseHandler(HttpWebResponse response);
public class BingService
{
private string _api = "http://api.bing.net/xml.aspx";
private string _appId = "";
/// <summary>
/// Default constructor
/// </summary>
public BingService()
: this("")
{ }
/// <summary>
/// Contructor with ApiId
/// </summary>
/// <param name="appId">AppId</param>
public BingService(string appId)
{
_appId = appId;
}
/// <summary>
/// Request with response handler
/// </summary>
/// <param name="r"></param>
/// <param name="response"></param>
public void ProcessRequest(IBingRequest r, ResponseHandler response)
{
response(Request(r));
}
/// <summary>
/// Request from Api
/// </summary>
/// <param name="list"></param>
/// <returns></returns>
public HttpWebResponse Request(IBingRequest r)
{
StringBuilder req = new StringBuilder();
req.Append(this.Api);
foreach (BingParameter field in r.List)
{
req.Append("&" + field.Name + "=" + field.Value);
}
HttpWebRequest webRq = (HttpWebRequest)HttpWebRequest.Create(req.ToString());
HttpWebResponse result = (HttpWebResponse)webRq.GetResponse();
return result;
}
/// <summary>
/// Get Api
/// </summary>
public string Api
{
get { return _api + "?AppId=" + _appId; }
}
/// <summary>
/// Set/Get Api
/// </summary>
public string AppId
{
set { _appId = value; }
get { return _appId; }
}
}
}
Translation Request Object
The translation request will be the first Bing request of our series so let’s being. The Bing API allows us to request services based on SourceTypes. A SourceType is a source of information available by the API (see full documentation).
To work with the Bing Translation SourceType we will need the following two classes for our object:
The TranslationResponse Class – We will use this object to store our translation API results.
Source Code
using System;
namespace DeveloperCaster.Bing
{
public class TranslationResponse
{
public string SearchedTerms
{
set;
get;
}
public string TranslatedTerm
{
set;
get;
}
}
}
The TranslationRequest Class – This is or main request object
Note: Our request object must inherit from the IBingRequest Interface.
Source Code:
using System;
using System.Collections.Generic;
using System.Net;
using System.Xml;
namespace DeveloperCaster.Bing
{
public class TranslationRequest : IBingRequest
{
private List<BingParameter> _items;
private string _query;
private string _sourceLanguage;
private string _targetLanguage;
private string _version;
public static TranslationResponse ParseResponse(HttpWebResponse response)
{
TranslationResponse result = new TranslationResponse();
XmlDocument doc = new XmlDocument();
doc.Load(response.GetResponseStream());
if (doc.HasChildNodes)
{
try
{
if (doc.HasChildNodes)
{
if (doc["SearchResponse"] != null)
{
if (doc["SearchResponse"]["Query"]["SearchTerms"] != null)
{
result.SearchedTerms = doc["SearchResponse"]["Query"]["SearchTerms"].InnerText;
}
if (doc["SearchResponse"]["tra:Translation"] != null)
{
result.TranslatedTerm = doc["SearchResponse"]
["tra:Translation"]
["tra:Results"]
["tra:TranslationResult"]["tra:TranslatedTerm"].InnerText;
}
}
}
}
catch (NullReferenceException ex)
{
}
catch (XmlException ex)
{
}
}
return result;
}
/// <summary>
/// Default constructor
/// </summary>
public TranslationRequest()
: this("", "", "", "") { }
/// <summary>
/// Second constructor
/// </summary>
/// <param name="query">query</param>
/// <param name="sourceLanguage">source language</param>
/// <param name="targetLanguage">target language</param>
public TranslationRequest(string query, string sourceLanguage,
string targetLanguage)
: this(query, sourceLanguage, targetLanguage, "2.2") { }
/// <summary>
/// Third constructor
/// </summary>
/// <param name="query">query</param>
/// <param name="sourceLanguage">source language</param>
/// <param name="targetLanguage">target language</param>
/// <param name="version">api version</param>
public TranslationRequest(string query, string sourceLanguage,
string targetLanguage, string version)
{
_items = new List<BingParameter>();
_items.Add(new BingParameter
{
Name = "Sources",
Value = "Translation"
});
if (!Exists("Query"))
{
_query = query;
}
if (!Exists("Translation.SourceLanguage"))
{
_sourceLanguage = sourceLanguage;
}
if (!Exists("Translation.TargetLanguage"))
{
_targetLanguage = targetLanguage;
}
if (!Exists("Version"))
{
_version = version;
}
}
private void Add(string name, string val)
{
_items.Add(new BingParameter
{
Name = name,
Value = val
});
}
private bool Exists(string name)
{
bool result = false;
foreach (BingParameter f in _items)
{
if (f.Name.ToLower() == name.ToLower())
{
result = true;
break;
}
}
return result;
}
public ResponseHandler Response;
public string Query
{
set
{
if (!Exists("Query"))
{
_query = value;
Add("Query", value);
}
}
get { return _query; }
}
public string SourceLanguage
{
set
{
if (!Exists("Translation.SourceLanguage"))
{
_sourceLanguage = value;
Add("Translation.SourceLanguage", value);
}
}
get { return _sourceLanguage; }
}
public string TargetLanguage
{
set
{
if (!Exists("Translation.TargetLanguage"))
{
_targetLanguage = value;
Add("Translation.TargetLanguage", value);
}
}
get { return _targetLanguage; }
}
public string Version
{
set
{
if (!Exists("Version"))
{
_version = value;
Add("Version", value);
}
}
get { return _version; }
}
/// <summary>
/// Set/Get Items
/// </summary>
public List<BingParameter> List
{
get
{
return _items;
}
}
}
}
Usage
We will test our library by translating a phrase from English to Spanish. Create a console application, create a reference to our complied dll, and add the following code to test our library:
BingService bing = new BingService("ADD YOUR APPID HERE");
TranslationResponse response =TranslationRequest.ParseResponse(bing.Request(new TranslationRequest{
Query = "Welcome to my blog",
SourceLanguage = "en",
TargetLanguage = "es"
})
);
Console.WriteLine("{0} = {1}", response.SearchedTerms, response.TranslatedTerm);
Console.ReadLine();
Output:
Welcome to my blog = Bienvenido a mi blog
