Retrieving Caller-ID Information

Most telephones and phone lines now support caller-ID, which displays an incoming caller’s name. Sometimes your phone displays only the caller’s phone number.

The GeoPhone web service offered by ServiceObjects lets you determine the person or business that corresponds to a specific phone number. For example, if you enter the phone number 510-523-8233, the service will return the owner, “Sybex Computer Books.”

The ASP.NET page GetCaller.aspx, which you can run from this book’s companion website, displays a form that prompts you to enter a phone number. After you enter the number and click the Get Caller button, the page will use the GeoPhone web service to retrieve the caller information, which the page will then display as shown in Figure 1.12. If the service cannot determine a number’s owner, the page will display a message so stating.

Behind the Scenes of the GeoPhone Web Service

The GeoPhone web service supports the following method:

PhoneInfo GetPhoneInfo(string PhoneNumber, string LicenseKey)

Figure 1.12: Using the GeoPhone web service to retrieve caller information

The GetPhoneInfo method returns a value of type PhoneInfo, which, depending on the phone listing the service discovers, may contain an array of contacts and an array of providers (the telephone companies that manage the numbers). Each entry within the contacts array contains name and address information.

The PhoneNumber parameter that you pass to the GetPhoneInfo method should not contain hyphens. To look up the number 800-555-1212, you would use the string 8005551212.

The GetPhoneInfo method requires that you pass a parameter that specifies your license key. If you visit the ServiceObjects website, you can download a trial key that lets you use the service for a specific period of time. If you need unlimited use of the service, you must purchase a license for service from ServiceObjects. The GetCaller.aspx ASP.NET page uses the license key 0, which provides a limited use of the service. The source code in Listing 1.5 implements the ASP.NET page GetCaller.aspx.

Listing 1.5 GetCaller.aspx

Public Class WebForm1     Inherits System.Web.UI.Page     Protected WithEvents Label1 As System.Web.UI.WebControls.Label     Protected WithEvents Label2 As System.Web.UI.WebControls.Label     Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox     Protected WithEvents TextBox2 As System.Web.UI.WebControls.TextBox     Protected WithEvents TextBox4 As System.Web.UI.WebControls.TextBox     Protected WithEvents Button1 As System.Web.UI.WebControls.Button     Protected WithEvents TextBox3 As System.Web.UI.WebControls.TextBox #Region " Web Form Designer Generated Code "     ' Code not shown #End Region     Private Sub Page_Load(ByVal sender As System.Object, ByVal e ÄAs System.EventArgs) Handles MyBase.Load         'Put user code to initialize the page here     End Sub     Private Sub Button1_Click(ByVal sender As System.Object, ÄByVal e As System.EventArgs) Handles Button1.Click         Dim Phone As New net.serviceobjects.ws.GeoPhone()         Dim PhoneInfo As net.serviceobjects.ws.PhoneInfo         Dim Contact As net.serviceobjects.ws.Contact         Dim Provider As net.serviceobjects.ws.Provider         Dim PhoneNumber As String         Dim ProcessingError As Boolean = False         PhoneNumber = TextBox1.Text & TextBox2.Text & TextBox3.Text         If (PhoneNumber.Length <> 10) Then             TextBox4.Text = "Invalid phone number" & PhoneNumber         Else             Try                 PhoneInfo = Phone.GetPhoneInfo(PhoneNumber, 0)             Catch Ex As Exception                 TextBox4.Text = "Error processing number " & Ex.Message                 ProcessingError = True             End Try             If (ProcessingError) Or (PhoneInfo Is Nothing) Then                 TextBox4.Text = "Error processing number"             Else                 TextBox4.Text = "Contact: "                 If (PhoneInfo.Contacts.Length = 0) Then                     TextBox4.Text &= "Unknown"                 Else                     For Each Contact In PhoneInfo.Contacts                         TextBox4.Text &= vbCrLf & Contact.Name                         TextBox4.Text &= vbCrLf & Contact.Address                         TextBox4.Text &= vbCrLf & Contact.City                         TextBox4.Text &= " " & Contact.State                         TextBox4.Text &= " " & Contact.Zip & vbCrLf                     Next                 End If             End If         End If     End Sub End Class

Within the button-click event handler, the following statement creates an object the program will use to interact with the GeoPhone web service:

Dim Phone As New net.serviceobjects.ws.GeoPhone()

After the user enters a phone number and clicks the Get Caller button, the code calls the GetPhoneInfo method within a Try-Catch block. If the web service is successful, the code will use a ForEach loop to display each element within the Contacts array.

To build the GetCaller.aspx ASP.NET page, perform these steps:

1. Within Visual Studio .NET, select the File menu New Project option. Visual Studio .NET will display the New Project dialog box.

2. Within the New Project dialog box Project Types list, click Visual Basic Projects. Then, within the Templates field, click ASP.NET Web Application. Finally, within the Location field, specify the name GetCaller. Select OK. Visual Studio .NET will display a page onto which you can drag and drop the program’s controls (label, buttons, and text box).

3. Using the Toolbox, drag and drop the label, buttons, and text boxes previously shown in Figure 1.12 onto the page. Using the Properties window, set the text box to support multiline operations.

4. Select the Project menu Add Web Reference option. Visual Studio .NET will display the Add Web Reference dialog box.

5. Within the Address field, type the URL http://ws.serviceobjects.net/gp/GeoPhone .asmx?WSDL and press Enter. The dialog box will load the file’s contents. Click the Add Reference button.

6. Select the View menu Code option. Visual Studio .NET will display the program’s source code. Enter the program statements previously shown.