Enable-SPCORS.ps1

<# 
.Synopsis
    Modifies the web.config file for all servers for specific SharePoint web application. 
    
.Description
    Modifies the web.config file for all servers for specific SharePoint web application. 
    
.Example
    Add-SPCORSOrigin -Url http://domain.com
    
.Example
    Add-SPCORSOrigin (Get-SPWebApplication http://domain.com)
    
.Notes
    Name:      SP-EnableCORS
    Author:    Travis Smith
    LastEdit:  05/05/2014  

#>

# Adds SharePoint Snapin if needed and returns bool based on whether the Snapin was added.
Function Add-SPCORSSnapin {
    [CmdletBinding()]
    param()

    $SPSnapinAdded = $false;
    if ((Get-PSSnapin -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) -eq $null)
    {
        $SPSnapinAdded = $true;
        Write-Host "Need SharePoint Snapin. Adding SP Snapin"
        Add-PSSnapin -Name Microsoft.SharePoint.PowerShell

        #Wait until web.config modifications finished by timer job
        while( (Get-SPTimerJob | ? { $_.Name -eq "job-add-snapin"}) -ne $null ) {
            Write-Host "." -NoNewline
            Start-Sleep 1
        }
    }
    else
    {
        Write-Host "SharePoint Snapin already added."
    }
    Return $SPSnapinAdded
}

# Removes SharePoint Snapin
Function Remove-SPCORSSnapin
{
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory = $true, Position = 0)]
        [System.Boolean]
        [Alias('SnapinAdded')]
        $SPSnapinAdded
    )
    if ( $SPSnapinAdded ) 
    {
        Write-Host "Removing SharePoint Snapin."
        Remove-PSSnapin -Name Microsoft.SharePoint.PowerShell
    }
}

# Removes SPCORS WebConfig Modifications from Web Application
Function Remove-SPCORSWebMods
{
    [CmdletBinding()]
    Param
    (
        [Parameter(
            Mandatory = $true,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind] 
        $WebApplication,

        [Parameter(Mandatory = $false, Position = 1)]
        [System.String]
        [Alias('Owner')]
        $webModOwner
    )
    BEGIN {
        $SPSnapinAdded = Add-SPCORSSnapin
    }
    PROCESS {
        $webApp = $WebApplication.Read()

        if (!$webModOwner)
        {
            $webModOwner = "CrossSiteScripting"
        }

        Write-Host "Removing CORS $webModOwner modifications..." -ForegroundColor Magenta
        $oldMods = @();
        $webApp.WebConfigModifications | ? { $_.Owner -eq $webModOwner } | % { 
            $oldMods = $oldMods + $_
        }

        if ($oldMods)
        {
            Write-Host "Found CORS modifications..." -ForegroundColor Magenta
            $oldMods | % { 
                $webApp.WebConfigModifications.Remove($_) 
            }
        
            #update
            Write-Host "Updating WebConfigModifications $webModOwner removal..." -ForegroundColor Green
        
            # update the Web Application and apply all existing web.config modifications - this executes the "remove" actions from above
            Update-SPCORSWebApp $webApp

            #$webApp.Parent.ApplyWebConfigModifications()
            #$webApp.Update()
        }
        else
        {
            Write-Host "No CORS WebConfigModifications found." -ForegroundColor Yellow
        }
    }
    END {
        Remove-SPCORSSnapin $SPSnapinAdded        
    }
}

# Private Function
# Updates a Web Application with SP WebConfig Modification & waits until update is completed
Function Update-SPCORSWebApp
{
    [CmdletBinding()]
    param(
        [Parameter(
            Mandatory = $true,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]
        $WebApplication
    )
    PROCESS {
        $debugMessage=@"
        Previously when running this tool, we had an error on line 147, within the Update-SPCorsWebApp Function.  
        
        This is likely caused by the `$webapp the .Update() method not existing on this object.  
        
        Troubleshooting:
          - Ensure the needed binaries are installed to instantiate a [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind] object
          - Ensure that $webApp exists
"@
        $webApp = $WebApplication.Read()

        Write-Host "Web Application $($webApp.DisplayName) updating..."
        Write-debug $debugMessage
        $webApp.Update()
        $webApp.Parent.ApplyWebConfigModifications()
        #[Microsoft.SharePoint.Administration.SPWebService]::ContentService.ApplyWebConfigModifications()

        Write-Host "Web Application $($webApp.DisplayName) updated"

        Wait-SPCORS
    }
}

# Private Function
# Waits until Job with specific name (defaults to "job-webconfig-modification") is completed.
Function Wait-SPCORS
{
    [CmdletBinding()]
    param(
        [Parameter(
            Mandatory = $false,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]
        [Alias('Job')]
        $jobName
    )
    BEGIN {
        if (!$jobName)
        {
            $jobName = "job-webconfig-modification"
        }
    }
    PROCESS {
        
        #Wait until web.config modifications finished by timer job
        while( (Get-SPTimerJob | ? { $_.Name -eq $jobName}) -ne $null ) {
            Write-Host "." -NoNewline
            Start-Sleep 1
        }
    }
}

# Adds Cross-Site Scripting Origin WebConfig Modification
Function Add-SPCORSOrigin
{
    [CmdletBinding()]
    param(
        [Parameter(
            Mandatory = $false,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]
        $WebApplication,

        [Parameter(
            Mandatory = $false,
            Position = 1,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Alias('Url')]
        [System.String]
        $siteUrl,

        [Parameter(
            Mandatory = $false,
            Position = 2,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [System.String]
        $origin
    )
    BEGIN {
        $SPSnapinAdded = Add-SPCORSSnapin

        If ($WebApplication) {
            Write-Verbose "Reading Web Application"
            $webApp = $WebApplication.Read()
        } 
        Else
        {
            Write-Verbose "Getting Web Application by SiteUrl"
            If (!$siteUrl) {
                $siteUrl = Read-Host "Enter the URL of the Web Application"
            }
            $site = Get-SPSite $siteUrl
            $webApp = $site.WebApplication
        }

    }
    PROCESS {      

        # Remove old web.config modifications of MyAuthenticationProvider
        #Remove-SPCORSWebMods (Reference-Variable -Name webApp -Verbose) -Owner "CrossSiteScriptingOrigin"   

        # New web.config modifications for MyAuthenticationProvider
        $mod = New-Object Microsoft.SharePoint.Administration.SPWebConfigModification
        $mod.Path = "configuration/system.webServer/httpProtocol/customHeaders"
        $mod.Name = "add[@destination='$webApp.Url'][@name='Access-Control-Allow-Origin'][@value='$origin']"
        $mod.Sequence = 0
        $mod.Owner = "CrossSiteScriptingOrigin"

        ## SPWebConfigModificationType.EnsureChildNode -> 0 
        ## SPWebConfigModificationType.EnsureAttribute -> 1 
        ## SPWebConfigModificationType.EnsureSection -> 2 
        #0 = for the enum value "SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode"
        $mod.Type = 0
        $mod.Value = "<add name='Access-Control-Allow-Origin' value='$origin' />"
        
        Write-Host "Adding $($mod.Value)..."
        $webApp.WebConfigModifications.Add($mod)      

        # Update Web Application
        Update-SPCORSWebApp $webApp

    }
    END {
        Remove-SPCORSSnapin $SPSnapinAdded        
    }
}

# Adds Cross-Site Scripting Headers, Methods & Credentials
Function Add-SPCORS
{
    [CmdletBinding()]
    param(
        [Parameter(
            Mandatory = $false,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]
        $WebApplication,

        [Parameter(
            Mandatory = $false,
            Position = 1,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Alias('Url')]
        [System.String]
        $siteUrl
    )
    BEGIN {
        $SPSnapinAdded = Add-SPCORSSnapin

        If ($WebApplication) {
            Write-Verbose "Reading Web Application"
            $webApp = $WebApplication.Read()
        } 
        Else
        {
            Write-Verbose "Getting Web Application by SiteUrl"
            If (!$siteUrl) {
                $siteUrl = Read-Host "Enter the URL of the Web Application"
            }
            $site = Get-SPSite $siteUrl
            $webApp = $site.WebApplication
        }

    }
    PROCESS {

        # Remove old web.config modifications of MyAuthenticationProvider
        Remove-SPCORSWebApp $webApp

        Write-Verbose "Adding Access-Control-Request-Method"
        $mod1 = New-Object Microsoft.SharePoint.Administration.SPWebConfigModification
        $mod1.Path = "configuration/system.webServer/httpProtocol/customHeaders"
        $mod1.Name = "add[@name='Access-Control-Request-Method'][@value='GET,POST,HEAD,OPTIONS']"
        $mod1.Sequence = 0
        $mod1.Owner = "CrossSiteScripting"
        $mod1.Type = 0
        $mod1.Value = "<add name='Access-Control-Request-Method' value='GET,POST,HEAD,OPTIONS' />"
        $webapp.WebConfigModifications.Add($mod1)

        Write-Verbose "Adding Access-Control-Request-Headers"
        $mod2 = New-Object Microsoft.SharePoint.Administration.SPWebConfigModification
        $mod2.Path = "configuration/system.webServer/httpProtocol/customHeaders"
        $mod2.Name = "add[@name='Access-Control-Request-Headers'][@value='Content-Type,Authorization']"
        $mod2.Sequence = 0
        $mod2.Owner = "CrossSiteScripting"
        $mod2.Type = 0
        $mod2.Value = "<add name='Access-Control-Request-Headers' value='Content-Type,Authorization' />"
        $webapp.WebConfigModifications.Add($mod2)

        Write-Verbose "Adding Access-Control-Request-Credentials"
        $mod3 = New-Object Microsoft.SharePoint.Administration.SPWebConfigModification
        $mod3.Path = "configuration/system.webServer/httpProtocol/customHeaders"
        $mod3.Name = "add[@name='Access-Control-Allow-Credentials'][@value='true']"
        $mod3.Sequence = 0
        $mod3.Owner = "CrossSiteScripting"
        $mod3.Type = 0
        $mod3.Value = "<add name='Access-Control-Allow-Credentials' value='true' />"
        $webapp.WebConfigModifications.Add($mod3)

        Update-SPCORSWebApp $webapp
    }
    END {
        Remove-SPCORSSnapin $SPSnapinAdded        
    }
}

# Enables SPCORS by Adding Cross-Site Scripting Origin, Headers, Methods & Credentials
Function Enable-SPCORS
{
    [CmdletBinding()]
    param(
        [Parameter(
            Mandatory = $false,
            Position = 0,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Alias('Url')]
        [System.String]
        $siteUrl,
        [Parameter(
            Mandatory = $false,
            Position = 1,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]
        $WebApplication,
        [Parameter(
            Mandatory = $false,
            Position = 2,
            ValueFromPipeline = $true,
            ValueFromPipelinebyPropertyName = $true)]
        [System.String]
        $origin
    )
    BEGIN {
        $SPSnapinAdded = Add-SPCORSSnapin

        If ($WebApplication) {
            Write-Verbose "Reading Web Application"
            $webApp = $WebApplication.Read()
        } 
        Else
        {
            Write-Verbose "Getting Web Application by SiteUrl"
            If (!$siteUrl) {
                $siteUrl = Read-Host "Enter the URL of the Web Application"
            }
            $site = Get-SPSite $siteUrl
            $webApp = $site.WebApplication
        }

        If (!$origin) {
            $origin = "*";
        }
    }
    PROCESS {

        # Just in case...
        Set-Variable -Name webApp -Value $webApp

        Write-Verbose "Adding Origin CORS"
        Add-SPCORSOrigin $webApp $origin
        Write-Verbose "Adding Other CORS"
        Add-SPCORS $webApp

    }
    END {
        Remove-SPCORSSnapin $SPSnapinAdded        
    }
}