In this article I will show you how you can use Twitter API to Shutdown/Restart/Logoff your PC remotely using VB.net.
I have a very slow internet connection at home and most of the time Downloads takes hours to complete. I decided to write an application which will help me Shutdown my PC from a remote location. I wanted to use it to shutdown when I go out when some downloading is going on in my laptop. Instead of using a server and client architecture I decided to use Twitter API and use “My Timeline” to supply commands. One other reason to use Twitter is that I will be able to tweet from my mobile as well. I don't need to look for a computer with an internet connection when I am on the move.
Why Yedda Twitter framework?
The Twitter REST API methods allow developers to access core Twitter data. This includes update timelines, status data, and user information. It's very easy to connect to Twitter and get user time line using .net. But I dint wanted to reinvent wheel and decided to use an existing Twitter library. Yedda Twitter framework is the best open source Twitter library available in the internet. You can learn more and download the library from yedda's home page.
Designing the Interface
I wanted the interface to be as simple as possible. Below is the screenshot of TweetMyPC's interface which does not have more than 2 Text Boxes, 1 Check Box, Label and a Button.
The form also has a Notify Icon, Context Menu Strip and a Timer. Following are the names of all the controls in the form.
- From : frmTweetMyPc
- Text Boxes : txtUserName, txtPassword
- Button : btnSave
- Check Box : chkStartAutomatic
- Timer : tmrTweet (Interval : 10000)
- Label : lblSatus
There are few My.settings properties to store user information. These properties are shown below.
Add the following code which minimizes the Form on Load and Enable Timer to check for Tweets every 1 minute.
Me.WindowState = FormWindowState.Minimized Me.ShowInTaskbar = False tmrTweet.Enabled = True
The following code in Button's Click event will validate Twitter username, Password and save it to My.Settings.
If txtUserName.Text.Trim = "" Then lblSatus.Text = "Please enter Twitter Username" txtUserName.Focus() Exit Sub End If If txtPassword.Text.Trim = "" Then lblSatus.Text = "Please enter Twitter Password" txtPassword.Focus() Exit Sub End If lblSatus.Text = "" 'Check for valid Username and Password and then Save Settings Dim objTwitter As New Yedda.Twitter Dim Updates As XmlDocument Try 'Try Logging in Updates = objTwitter.GetUserTimelineAsXML(txtUserName.Text.Trim, txtPassword.Text.Trim) My.Settings.UserName = txtUserName.Text.Trim My.Settings.Password = txtPassword.Text.Trim Me.WindowState = FormWindowState.Minimized Me.ShowInTaskbar = False tmrTweet.Enabled = True Catch ex As Exception MsgBox("Failed to Login to Twitter with the values supplied. Please check your login details.") txtUserName.Focus() Exit Sub End Try
Yedda library is used to login to Twitter to check for valid username and password. The Label lblSatus is used to display any error messages.
Add the following code to the Checkbox's CheckChanged event which will add the required registry keys to start this app on Window's startup
If chkStartAutomatic.Checked = True Then My.Settings.AutomaticStart = True Dim regKey As RegistryKey regKey = Registry.CurrentUser.OpenSubKey("Software\Microsoft\Windows\CurrentVersion\Run", True) regKey.SetValue(Application.ProductName, Application.ExecutablePath) regKey.Close() Else My.Settings.AutomaticStart = False Dim regKey As RegistryKey regKey = Registry.CurrentUser.OpenSubKey("Software\Microsoft\Windows\CurrentVersion\Run", True) regKey.DeleteValue(Application.ProductName) regKey.Close() End If
The following code in Timer's Tick event will do the job of checking Twitter Timeline every one minute and Shutdown/Restart/Log off the system based on the Tweet.
If My.Settings.UserName.Trim = "" Then Exit Sub Else 'Check for new Tweet Dim objTwitter As New Yedda.Twitter Dim Updates As XmlDocument Dim node As XmlNode Try 'Try Logging in Updates = objTwitter.GetUserTimelineAsXML(My.Settings.UserName.Trim, My.Settings.Password.Trim) Catch ex As Exception MsgBox("Error : Failed to Login to Twitter with the values supplied. Please check your login details.") Exit Sub End Try Try node = Updates.SelectSingleNode("/statuses/status/id") If node.InnerText.Trim <> My.Settings.LastID.Trim Then 'Compare the Tweet ID to check for new tweets My.Settings.LastID = node.InnerText.Trim node = Updates.SelectSingleNode("/statuses/status/text") ProcessTweet(node.InnerText.Trim) End If Catch ex As Exception Exit Sub End Try End If
If the Tweet is new then we process the tweet.
Private Sub ProcessTweet(ByVal Tweet As String) If Tweet = "Shutdown" Then System.Diagnostics.Process.Start("shutdown", "-s -f -t 100") 'Shutdown ElseIf Tweet = "Logoff" Then System.Diagnostics.Process.Start("shutdown", "-l -f -t 100") 'Logoff ElseIf Tweet = "Restart" Then System.Diagnostics.Process.Start("shutdown", "-r -f -t 100") ' Restart End If End Sub
The Context Menu strip has two menu items. They are Edit Setting and Exit.
Add the following code the “Edit Settings” Client event and Notify Icon's Mouse Double Click Event.
tmrTweet.Enabled = False txtUserName.Text = My.Settings.UserName.Trim txtPassword.Text = My.Settings.Password.Trim If My.Settings.AutomaticStart = True Then chkStartAutomatic.Checked = True Me.WindowState = FormWindowState.Normal Me.ShowInTaskbar = True
TweetMyPC runs silently on startup. To Edit Settings double click/Right Click the notify icon.
Even though TweetMyPC is a simple app it has lot of interesting potential. Think about switching off your TV or washing machine using Twitter. It is possible with a little extra hardware and a simple .net program. TweetMyPC is free and open source. Feel free to download the sour code and add more functionality.
About The Author
Shoban Kumar is a Senior Software Engineer working for Allianz Cornhill India. Programming is his passion. He also writes about .net in http://www.dotnetcurry.com/ and an active participator in stackoverflow and speaker in Microsoft user group sessions. You also can follow him in Twitter.