ASP.NET web client for Google Web API

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Introduction

Recently I got an opportunity to explore the Google Web API which can be downloaded from the Google site. So I decided to code the web-client which is very easy and interesting too!  The article focuses on developing the Web-Client with which you can search items from your site itself.

Installation & Setup

You must download the google web api first! Then follow the instructions below. 

1. Create the folder like "Net" within "wwwroot" folder and make that folder web application.
2. Create "bin" sub-folder within the "Net" folder.
3. Make GoogleProxy.cs using the WSDL tool and compile GoogleProxy.cs into the .net assembly using csc command to generate the proxy. 
   1. >wsdl /l:cs /o:GoogleProxy.cs "http://localhost/Net/GoogleSearch.wsdl">http://localhost/Net/GoogleSearch.wsdl
/n:GoogleWebService
      This generates the GoogleProxy.cs. "GoogleSearch.wsdl" is found in the API you have downloaded.
   2. >csc /out:GoogleProxy.dll /t:library /r:system.dll, system.web.dll,
system.xml.dll, system.web.services.dll GoogleProxy.cs
      This generates the .net assembly, GoogleProxy.dll. Copy the dll file into "bin" folder. Your ASP.NET page will ultimately call the web-callable methods and properties exposed by this dll.
4. Write GoogleClient.aspx file to create the UI and to consume the services exposed by google web api, to be precise GoogleProxy.dll in our case.
5. Browse http://localhost/Net/GoogleClient.aspx. That's it!

Why proxy?

A proxy resides on the consumer's machine and acts as a rely between the consumer and the web service. When we build the proxy, we use WSDL file to create a map that tells the consumer what methods are available and how to call them. The consumer then calls the web method that is mapped in the proxy, which in turn, makes calls to the actual web service over the Internet. The proxy handles all of the network-related work and sending of data, as well as managing the underlying WSDL so the consumer doesn't have to. When we reference the web service in the consumer application, it looks as if it's part of the consumer application itself.

Using the code

The code is pretty straight forward.

<%@ Page Language="C#" %>
<@ import Namespace="GoogleWebService" >
//Remember,GoogleWebService is the namespace you named while creating the proxy!
<script runat="server">

    string key="licence key you got from google";
    /* I have declared the key string variable as global variable 
       since the key variable is to be passed every time you call the methods.
    */ 
    
    void Page_Load()
    {
        lblSpellSug.Text="";     
        //Label to display the Spelling Suggestion

        lblResultCount.Text="";  
        //Label to display the Estimated total result count

        lblSearchTime.Text="";   
        //Label to display the server time to return the search results, 

        //measured in seconds.

    }
    
    void btnSearch_Click(Object sender, EventArgs e) {
    //creating the instance of  the GoogleSearch class to invoke required methods

    GoogleSearchService obj=new GoogleSearchService();
    
    //spelling checking and suggesting if entered wrong

    string suggestion=obj.doSpellingSuggestion(key,Request.Form["txtPhrase"]);
    if (suggestion!=null)
        {
            lblSpellSug.Text="Suggestion: "+ suggestion;
        }
    
    //searching the phrase.....

    //Regarding the parameters refer to the Google API

    GoogleSearchResult res=obj.doGoogleSearch(key, Request.Form["txtPhrase"], 
                                              0, 10, false,"",false,"","","");
    lblResultCount.Text="Est. Total Result Count: " + 
                         Convert.ToString(res.estimatedTotalResultsCount); 
    //to display the total estimated result count

    lblSearchTime.Text= "Search Time: " + Convert.ToString(res.searchTime) + 
                        "sec";//search Time

    
    //displaying the results Returned by the Search in tabular using the Table control.

    ResultElement[] result=res.resultElements;
    foreach(ResultElement r in result)
        {
            ResultTable.CellSpacing=1;
            ResultTable.CellPadding=2;
    
            //formatting the Server control Table

            TableRowCollection trCol=ResultTable.Rows; 
            //ResultTable is the instance created for Table class

            //creating new Table Row and adding to the TableRowCollection

            TableRow tr=new TableRow();
            trCol.Add(tr);

            TableCellCollection tcCol=tr.Cells;
            //creating new Table Cell, assigning the title and the summary 

            //of the search result.

            TableCell tc=new TableCell();
            tc.Text="<a href="+ r.URL +">"+  r.title + "</a>" + "<BR>" +  r.summary;
            tcCol.Add(tc);
    
    
        }
    
    }
</script>

Conclusion

Let's share the solution.