powershell v2 : WebClient/UploadString never connect - powershell

Question

with powershell v2 and pushbullet, I try to send push notification when a file in modified
$folder = 'c:\path\to\file'
$filter = '*.*'
$user = "pushbullet_token"
$url = "https://api.pushbullet.com/v2/pushes"
$fsw = New-Object IO.FileSystemWatcher $folder, $filter
$fsw.IncludeSubdirectories = $true
$fsw.NotifyFilter = [IO.NotifyFilters]'FileName, LastWrite'
$onCreated = Register-ObjectEvent $fsw Created -SourceIdentifier FileCreated -Action {
$name = $Event.SourceEventArgs.Name
$path = $Event.SourceEventArgs.FullPath
Out-File -FilePath c:\path\to\file\outlog.txt -Append -InputObject "$path"
$title = $path
Add-Type -AssemblyName System.Web
$title = [System.Web.HttpUtility]::UrlEncode($title)
$data = "type=note&title=" + $title + "&body=body"
$webclient = new-object System.Net.WebClient
$webclient.Credentials = new-object System.Net.NetworkCredential($user, "")
Out-File -FilePath c:\path\to\file\outlog.txt -Append -InputObject "$data"
$result = $webclient.UploadString($url, "POST", $data)
Out-File -FilePath c:\path\to\file\outlog.txt -Append -InputObject "$result"
}
#Unregister-Event FileCreated
for check the script a outlog.txt file is write, but only the two first messages are writen and the notification never is submitted.
when I launch uploadstring manually
$user = "pushbullet_token"
$url = "https://api.pushbullet.com/v2/pushes"
$data = "type=note&title=title&body=body"
$webclient = new-object System.Net.WebClient
$webclient.Credentials = new-object System.Net.NetworkCredential($user, "")
$result = $webclient.UploadString($url, "POST", $data)
work ok.

Answer 1

The global variable $url is not available inside your event handler script block. Change your Register-ObjectEvent like so:
$onCreated = Register-ObjectEvent $fsw Created -SourceIdentifier FileCreated -MessageData $url -Action {
$name = $Event.SourceEventArgs.Name
$path = $Event.SourceEventArgs.FullPath
$url = $Event.MessageData
...
}

Answer 2

The call to $webclient.UploadString(...) in the event handler is throwing an exception, which terminates the EventJob context it's running in. You can verify this by typing:
Get-Job
and looking for the failed job. You can then do Recieve-Job on the failed job to get the error message. Its probably an authentication error. By putting a valid authentication token, I was able to get your code to work.
If you want to have event handler continue even in the event of an error you'll have to use a try/catch, for example:
$result = try { $webclient.UploadString($url, "POST", $data) }
catch { $_.Exception.InnerException.Response }