Quick Powershell tip concerning Out-String and Send-MailMessage

Recently I wrote a script at work to generate a report about the load on a set of servers. The gathered statistics were mailed around everything nice and dandy. But after a few weeks something strange happened the body of the mail message containing a nice table got turned into gibberish.

Cause

I really didn’t understand want went wrong all of a sudden, so I started to inspect the output of the script. And low and behold the trouble was caused by the fact that Out-String by default puts only 80 characters in a line. Quoting the documentation:

-Width <int> Specifies the number of characters in each line of output. Any additional characters are truncated, not wrapped. If you omit this parameter, the width is determined by the characteristics of the host. The default for the PowerShell.exe host is 80 (characters).

If you’re lucky the line breaks end up outside of your tags which was the case for me the first couple of times the script ran. But if Out-String happens to break the line inside an HTML tag, your output gets garbled.

Solution

I thought this would be easy to fix just specify [int]::MaxValue for the -Width parameter to Out-String. Trying that in a PowerShell console gave: Hum, seems like the [int]::MaxValue doesn’t get evaluated before it is interpreted by Out-String so some extra parenthesis should do the trick.

End result

The paragraph of code that I use to send around an HTML table containing the load statistics hence becomes something like this:

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$messageParameters = @{
    Subject = "Weekly load report"
    Body = (Get-LoadStatistics | ConvertTo-Html -Head $head | 
        Out-String -Width ([int]::MaxValue))
    From = "donotreply@devnull.org"
    To = "fred.flinstone@bedrock.com"
    SmtpServer = "my.smtpserver"
}
Send-MailMessage @messageParameters -BodyAsHtml

I hope this helps anybody using the Power to send nice reports.