Checking the internet connection

[N1c0_ds]

Based on another thread, here is a simple way to check if the device has a valid internet connection and show an appropriate error message.

You will need the HTTP library. Response is a Webresponse object and request is a webrequest object.

Let's say you want to download a file when your application starts:

Sub App_Start
 DownloadStuff
End Sub

If there is no response from the server, it will raise an error in your sub. When an error is raised, the execution of the sub stops. To avoid this, you must check if the connection is available by calling another thread.

Sub App_Start
 If CheckConnection=True Then
  DownloadStuff
 End If
End Sub

Sub CheckConnection(URL)
ErrorLabel(offline)
  Request.New1(URL)
  Response.New1
  Response.Value = Request.GetResponse
  Response.Close
   Return True
offline:
   Return False
End Sub

This way, when CheckConnection is called, it returns the connection status. However nothing will happen if there is no connection. No error message, nothing! Let's fix this by adding a new sub: NoConnection.

Sub App_Start
 If CheckConnection=True Then
  DownloadStuff
 End If
End Sub

Sub CheckConnection(URL)
ErrorLabel(offline)
  Request.New1(URL)
  Response.New1
  Response.Value = Request.GetResponse
  Response.Close
   Return True
offline:
   Return False
End Sub

Sub NoConnection
 MsgBox("Unable to download application")
End Sub

Now you get a nice error message if there is no connection. However, to avoid confusing the user if the problem is caused by an invalid URL or server downtime, it is good practice to distinguish the internet connection problems from the server problems.

Sub NoConnection
 If CheckConnection("http://google.com")=True Then
  MsgBox("Unable to find a valid data connection.")
 Else
  MsgBox("Unable to download file. The server might be experiencing difficulties.")
 End If
End Sub

Voilà!

 

[Erel]

Thank you for sharing this important tip