Send-SlackChat.ps1

<#
	{
		"info": {
			"Statement": "Code is poetry",
			"Author": "Joerg Hochwald",
			"Contact": "joerg.hochwald@outlook.com",
			"Link": "http://hochwald.net",
			"Support": "https://github.com/jhochwald/MyPowerShellStuff/issues"
		},
		"Copyright": "(c) 2012-2015 by Joerg Hochwald. All rights reserved."
	}

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	are permitted provided that the following conditions are met:

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	   conditions and the following disclaimer.

	2. Redistributions in binary form must reproduce the above copyright notice,
	   this list of conditions and the following disclaimer in the documentation and/or
	   other materials provided with the distribution.

	3. Neither the name of the copyright holder nor the names of its contributors may
	   be used to endorse or promote products derived from this software without
	   specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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#>

function Send-SlackChat {
<#
	.SYNOPSIS
		Sends a chat message to a Slack organization

	.DESCRIPTION
		The Post-ToSlack cmdlet is used to send a chat message to a Slack channel, group, or person.
		Slack requires a token to authenticate to an org.

	.PARAMETER Channel
		Slack Channel to post to

	.PARAMETER Message
		Chat message to post

	.PARAMETER token
		Slack API token

	.PARAMETER BotName
		Optional name for the bot

	.EXAMPLE
		PS C:\> Send-SlackChat -channel '#general' -message 'Hello everyone!' -botname 'The Borg' -token '1234567890'

		This will send a message to the "#General" channel using a specific token 1234567890, and the bot's name will be "The Borg".

	.EXAMPLE
		PS C:\> Send-SlackChat -channel '#general' -message 'Hello everyone!' -token '1234567890'

		This will send a message to the "#General" channel using a specific token 1234567890, and the bot's name will be default ("Build Bot").

	.NOTES
		Based on an idea of @ChrisWahl / Please note the Name change and the removal of some functions

	.LINK
		Validate or update your Slack tokens: https://api.slack.com/tokens
		Create a Slack token: https://api.slack.com/web
		More information on Bot Users: https://api.slack.com/bot-users
#>

	[CmdletBinding(ConfirmImpact = 'None',
				   SupportsShouldProcess = $true)]
	param
	(
		[Parameter(Mandatory = $true,
				   Position = 0,
				   HelpMessage = 'Slack Channel to post to')]
		[ValidateNotNullOrEmpty()]
		[string]
		$Channel,
		[Parameter(Mandatory = $true,
				   Position = 1,
				   HelpMessage = 'Chat message to post')]
		[ValidateNotNullOrEmpty()]
		[string]
		$Message,
		[Parameter(Mandatory = $false,
				   Position = 2,
				   HelpMessage = 'Slack API token')]
		[ValidateNotNullOrEmpty()]
		[string]
		$token,
		[Parameter(Mandatory = $false,
				   Position = 3,
				   HelpMessage = 'Optional name for the bot')]
		[Alias('Name')]
		[string]
		$BotName = 'Build Bot'
	)

	BEGIN {
		# Cleanup all variables...
		Remove-Variable -Name "uri" -Force -Confirm:$false -ErrorAction:SilentlyContinue -WarningAction:SilentlyContinue
		Remove-Variable -Name "body" -Force -Confirm:$false -ErrorAction:SilentlyContinue -WarningAction:SilentlyContinue
	}

	PROCESS {
		Set-Variable -Name "uri" -Value $("https://slack.com/api/chat.postMessage")

		# Build the body as per https://api.slack.com/methods/chat.postMessage
		Set-Variable -Name "body" -Value $(@{
			token = $token
			channel = $Channel
			text = $Message
			username = $BotName
			parse = 'full'
		})

		# Call the API
		try {
			Set-Variable -Name "post" -Value $(Invoke-RestMethod -Uri $uri -Body $body -UserAgent "Mozilla/5.0 (Windows NT; Windows NT 6.1; en-US) NET-Experts WindowsPowerShell Service $CoreVersion" -ErrorAction Stop -WarningAction SilentlyContinue)
		} catch {
			# Whoopsie! That should not happen...
			Write-Warning -message "Could not send notification to your Slack $Channel"
		}
	}

	END {
		# Cleanup all variables...
		Remove-Variable -Name "uri" -Force -Confirm:$false -ErrorAction:SilentlyContinue -WarningAction:SilentlyContinue
		Remove-Variable -Name "body" -Force -Confirm:$false -ErrorAction:SilentlyContinue -WarningAction:SilentlyContinue

		# Do a garbage collection
		if ((Get-Command run-gc -errorAction SilentlyContinue)) {
			run-gc
		}
	}
}