Script to Download Yammer Image Profile

<#
.SYNOPSIS
	This script downloads the profile image urls of all the users from Yammer, creates a csv file and uploads it to the YammerProfile document library.
	Example> 	.\Download-YammerProfile.ps1 -YammerToken 05fdIb1pNwIFEBg9k34EWw -SiteUrl http://mysharepoint/site
#>
param(
	[Parameter(Mandatory = $True, HelpMessage='Yammer Access Token - Refer to https://developer.yammer.com/authentication/ for how to generate an access token. Eg. 05fdIb1pNwIFEBg9k34EWw')]
	[string]$YammerToken,
	[Parameter(Mandatory = $True, HelpMessage='The url of the site that will store the Yammer user profile list. E.g. http://mysharepoint/site')]
	[string]$SiteUrl
)

Function Main() {
	$documentLibrary = "YammerProfiles"
	$csvFile = "YammerProfiles.csv"
	
	CreateEventLogSource "MePage"
	Log "Starting Download-YammerProfile.ps1"
	try {
		$spWeb = Get-SPWeb -Identity $SiteUrl
		CreateSharePointLibrary $spWeb $documentLibrary  "Downloaded cache of Yammer profile image urls" "DocumentLibrary"
		CreateYammerProfileCsv $YammerToken $csvFile
		$spWeb = Get-SPWeb -Identity $SiteUrl #Refresh reference to avoid timeout issue when it takes a long time to download from Yammer
		UploadToSharePoint $csvFile $spWeb $documentLibrary
		
		Log "Download-YammerProfile.ps1 completed succesfully"
	}
	catch {
		[string]$errDetail = $_.ToString()
		LogError "Error occured: $errDetail"
		Write-Error $_
	}
}

Function CreateYammerProfileCsv($token, $csvFile){
	$page = 0
	$userCount = 0
	if (Test-Path $csvFile){ Remove-Item $csvFile }
	do {
		$page++		
		$users = GetYammerUsers $token $page
		$userCount = $users.Length
		Log "Downloading Yammer Profiles Page: $page Users: $userCount"
		for($i = 1; $i -lt $users.Length; $i++) {
			$user = $users[$i];			
			if($user.mugshot_url_template.EndsWith("no_photo.png")) { continue } #Only store valid photos			
			for($e = 0; $e -lt $user.contact.email_addresses.Length; $e++) {				
				$email = $user.contact.email_addresses[$e];
				if($email.type -eq "primary"){ #We're only interested in the telstra.com email addresses	
					$output = $email.address.ToLowerInvariant() + "," + $user.mugshot_url_template
					Write-Host $user.mugshot_url_template $email.address
					Add-Content $csvFile $output
				}
			}
		}
		Start-Sleep -s 2 #Sleep for two seconds so we don't go over Yammer's rate count of 10 req / 10 sec
	}
	while ($userCount -gt 0) # -and $page -eq 1)
}

Function UploadToSharePoint($fileName, $spWeb, $documentLibraryName) {
	Log "Uploading $fileName to $spWeb/$documentLibraryName"
	#Read the contents into a memory stream to prevent the file getting locked
	[byte[]]$byteArray = Get-Content -encoding byte -path $fileName	
	[void][reflection.assembly]::LoadWithPartialName("System.IO")
	$stream = [System.IO.MemoryStream]$byteArray

	$spDoc = $spWeb.GetFolder($documentLibraryName)
	$spFile = $spDoc.Files.Add($fileName, $stream, $true)
}

Function CreateSharePointLibrary ($Web, $LibraryName, $Description, $LibraryTemplate) {  
	$spListCollection = $spWeb.Lists   
	$spLibrary=$spWeb.Lists.TryGetList($LibraryName)
	if($spLibrary -eq $null) {
		Log -f Yellow "$LibraryName document library does not exist. Creating..."
		$spListCollection.Add($LibraryName, $Description, $LibraryTemplate)
	}
}

Function LoadPSSnapIn {
	$snapin = Get-PSSnapin | Where-Object {$_.Name -eq 'Microsoft.SharePoint.Powershell'}
	if ($snapin -eq $null) {
		Write-Host "Loading SharePoint Powershell Snapin"
		Add-PSSnapin "Microsoft.SharePoint.Powershell"
	}
}

Function ConvertToJson($jsonString) {
	[System.Reflection.Assembly]::LoadWithPartialName("System.Web.Extensions")
	$ser = New-Object System.Web.Script.Serialization.JavaScriptSerializer
	return $ser.DeserializeObject($jsonString)
}

Function GetYammerUsers($token, $pageNumber) {
	$users = InvokeYammerGetRequest $token "users.json?page=$pageNumber"
	return $users
}

Function InvokeYammerGetRequest($token, $target) { 
	# Setup the request
	$yammerApiUrl = "https://www.yammer.com/api/v1/"
	$requestUrl = $yammerApiUrl + $target
	$webRequest = [System.Net.WebRequest]::Create($requestUrl)
	$webRequest.Method = "GET"
	$webRequest.Headers.Add("Authorization", "Bearer $token")

	# Execute the request
	[System.Net.WebResponse]$resp = $webRequest.GetResponse()
	$reqstream = $resp.GetResponseStream()
	$sr = new-object System.IO.StreamReader $reqstream
	$obj = ConvertToJson $sr.ReadToEnd()
	return $obj
}

Function CreateEventLogSource($sourceName) {			
	try {
		if(![System.Diagnostics.Eventlog]::SourceExists($sourceName))
		{
			Write-Host "Creating event log source $sourceName"
			New-Eventlog -LogName "Application" -Source $sourceName
		}
	}
	catch {
		Write-Host "Error creating event log source $sourceName"			
		Write-Host $_
	}
}

Function Log($message) {
	Write-Host $message
	WriteEventLog $message $false
}

Function LogError($message) {	
	WriteEventLog $message $true    
}

Function WriteEventLog($message, $isError) {
	try {
		if($isError) {
			Write-EventLog -logname Application -source MePage -eventid 4002 -EntryType Error -Message $message
		}
		else {
			Write-EventLog -logname Application -source MePage -eventid 4001 -EntryType Information -Message $message
		}
	}
	catch { #We don't want the script to error out because it couldn't write to event log		
		Write-Host "Error writing message to eventlog. Message = $message"
		Write-Host $_
	}
}

$ErrorActionPreference = "stop"
LoadPSSnapIn
return Main