Powershell – SQL Ryan

Setting default web proxy in Powershell

Powershell doesn’t seem to respect the default proxy settings carried through from the OS/Browser (possibly a bug like this one or this one, if you feel like reading). If you to fetch content from a website and your corporate network has a proxy in place, you’ll get an error like this one:

PS > Invoke-WebRequest "http://www.contoso.com"
Invoke-WebRequest:
Proxy Web Gateway - Notification
Request Blocked

(Insert scary message about trying to circumvent your corporate proxy here and you'll get in super-big trouble if this is malicious. For real, don't do it!) If you're not trying to break the rules, please contact your helpdesk for assistance.

URL: break_line("http://www.contoso.com/");

You can resolve this by specifying the proxy settings as parameters on your request:

PS > Invoke-WebRequest "http://www.contoso.com" -Proxy "http://proxy.yourcorp.com:8080" -ProxyUseDefaultCredentials
StatusCode        : 200
StatusDescription : OK
Content           : <html><head><title>Microsoft Corporation</title><meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7"></meta <meta http-equiv="Content-Type" content="text/html; charset=utf-8"></meta><meta name="...(and so on)...

However, you don’t have to specify that proxy settings on every single request – you can just set the default proxy settings in your Powershell session. The first line below sets the default proxy, and the second line tells it use the currently logged-in user to access the proxy (this isn’t necessary if your proxy doesn’t require login, but most do):

PS > [System.Net.Http.HttpClient]::DefaultProxy = New-Object System.Net.WebProxy('http://proxy.yourcorp.com:8080', $true)
PS > [System.Net.Http.HttpClient]::DefaultProxy.Credentials = [System.Net.CredentialCache]::DefaultCredentials

Once you’ve set those proxy settings for the default client, you can make a regular old web call without specifying the proxy details:

PS > Invoke-WebRequest "http://www.contoso.com"
StatusCode        : 200
StatusDescription : OK
Content           : <html><head><title>Microsoft Corporation</title><meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7"></meta <meta http-equiv="Content-Type" content="text/html; charset=utf-8"></meta><meta name="...(and so on)...

But if you’re the kind of person who doesn’t like setting your proxy settings every single time you launch Powershell, you’re in luck! Powershell, like other shells, has a default profile script that it runs when you log in and you can add the lines above to that script and they’ll execute by default every time you launch Powershell. When you try to open it, it will even create a blank script for you if one doesn’t already exist:

PS > notepad $PROFILE

Then just dump in the contents of the commands above, plus a little note to remind you that you set this up so if you have problems later, you’ll know where to check 🙂

# Set proxy settings manually since it doesn't pick it up from IE
[System.Net.Http.HttpClient]::DefaultProxy = New-Object System.Net.WebProxy('http://proxy.yourcorp.com:8080', $true)
[System.Net.Http.HttpClient]::DefaultProxy.Credentials = [System.Net.CredentialCache]::DefaultCredentials
Write-Output "Proxy configuration set via profile. To update, run 'notepad `$PROFILE' at the PS prompt."

Printing/Escaping a variable name in Powershell

In Powershell, if you include a variable name (like $PROFILE) in a statement that writes to the screen, it will be replaced with the contents of the variable:

PowerShell 7.4.1
PS C:\Users\Ryan> Write-Output "this is my profile: $PROFILE"
this is my profile: C:\Users\Ryan\OneDrive\Documents\PowerShell\Microsoft.PowerShell_profile.ps1

But what if you want to actually out the name of your variable instead of the contents? Like if you’re displaying an example statement to execute? In that case, you can escape it by using the backtick character (“`” – the backwards single-quote on in the upper left of your keyboard on the same key as the “~” tilde). In that case, your result will look like this:

PowerShell 7.4.1
PS C:\Users\Ryan> Write-Output "this is my profile: `$PROFILE"
this is my profile: $PROFILE

In my case, I was trying to print some instructions to the screen that included the $PROFILE, so that was the workaround.

Powershell command to get current sessions on an IIS site

After a Powershell session at SQL Saturday (Phoenix #131) this weekend, I’m now suddenly on the lookout for handy powershell commands. The first one lets you see the number of Active* sessions on your IIS site (* because HTTP is stateless, it’s really the number of connections that have been opened recently – not what’s currently active, which is likely next to zero. I tried browsing around on a test site and it showed only my one user connected).

To get the currently active user count, here’s the powershell:

# Ensure you use the server's actual name, not LOCALHOST, which won't work
$Servername = &quot;Your Server Name&quot;
$Sitename = &quot;Name of your IIS Site&quot;

Get-Counter &quot;\\$ServerName\web service($SiteName)\current connections&quot;