Google Search in C#: A step by step walk-through tutorial

In previous post, the implementation of Google book search in C# is discussed. In this post, the similar approach is used to implement Google Custom Search in C#.

Download the source project at Github here.

The code is very simple:

public static IList<Result> Search(string query)
{
    Console.WriteLine("Executing custom search for query: {0} ...", query);

    CseResource.ListRequest listRequest = Service.Cse.List(query);
    listRequest.Cx = cx;

    Search search = listRequest.Execute();
    return search.Items;
}

To get this code running, we need an instance variable called Service:

//API Key
private static string API_KEY = "AIzaSyCsqAm43dcaVHD6ycUEWTbCNtg4rD_aa8Y";

//The custom search engine identifier
private static string cx = "015598178761323117960:sbbkk2__0lo";

public static CustomsearchService Service = new CustomsearchService(
    new BaseClientService.Initializer
{
    ApplicationName = "ISBNBookCsutomSearch",
    ApiKey = API_KEY,
});

To get this code compile, you need to add reference to the Google Custom Search Library:

• You can use Nuget command: Install-Package Google.Apis.Customsearch.v1  or
• Right click on project reference >  Manage Nuget Packages > Search “Google.Apis.Customsearch.v1” in the top right corner > Install the found package

Compile and Run the below test code:

class Program
{
    static void Main(string[] args)
    {
        string query = "The University of Hong Kong";
        var results = GoogleSearch.Search(query);
        foreach (Result result in results)
        {
            Console.WriteLine("-----------------------------------");
            Console.WriteLine("Title: {0}", result.Title);
            Console.WriteLine("Link: {0}", result.Link);
        }
        Console.ReadKey();
    }
}

You should have a success in running Google search of your custom keyword!

Again, you might wonder what are the API KEY and cx? How to get these two strings?

• Goto Google Developer Console
• Create a project
• Click “Credentials” on the left Tab
• Click “Create new key” button on the right panel

 

 

• You are then offered an API KEY:

  

• To get the Custom Search engine ID (cx), follow below procedures:
• If you didn’t create a custom search engine yet, you can create one via Custom Search control panel

  

 
• You can find your Custom Search engine ID (cx) on the Basics tab of the Custom Search control panel.

  

• One last step: turn on the custom search api in your development console:

As you can see, the code is trivial, and the complexity is mostly due to Google configurations!

Happy coding and the code project can be found at Github here.