Serving a HTML Page from Azure PowerShell Function

The new PowerShell language (experimental) support in Azure Function is really handy. Especially if you want to use the Azure PowerShell cmdlets to retrieve any kind of Azure Resources and diplay them in a HTML page. Hosting the cmdlet in Azure Function eliminates the need of a local installed Azure PowerShell module.

Here is a simple PowerShell Function that returns a Hello world HTML page:

# POST method: $req
$requestBody = Get-Content $req -Raw | ConvertFrom-Json
$name = $requestBody.name

# GET method: each querystring parameter is its own variable
if ($req_query_name)
{
    $name = $req_query_name
}

$html = @'

<header>This is title</header>


Hello world


'@

Out-File -Encoding Ascii -FilePath $res -inputObject $html

Invoking the script in a browser doesn’t give us the desired result. The content gets interpreted as XML instead of HTML:

xmlresult

The reason for that is that the Content-Type is set to applicaton/xml:

xmlresponse

The output of an Azure PowerShell function is a file (called $res by default) – so how can we change the content type to text/html?

It turns out (thanks to Mikhail) that we can construct a Repsonse Object using a JSON string (here the node definition) where we can set the content and the content type:

$resp = [string]::Format('{{ "status": 200, "body": "{0}", "headers": {{
"content-type": "text/html" }} }}', $html)
Out-File -Encoding Ascii -FilePath $res -inputObject $resp

If we invoke the function in the browser again we get the desired result:
htmlresponse

And the content-type is set to text/html:
htmldebug

Note that if your HTML contains JSON characters like double quotes or backslashes you will have to escape them. Example:

$html -replace '"', '\"'

Configure Azure Cloud Shell to use a profile hosted on GitHub

You may have noticed that you can run the Azure Cloud Shell without the portal as a separate component on https://shell.azure.com/

The shell is really handy since it can be used from everywhere. Today I want to show you how you can load a remote profile that is hosted on GitHub in the Azure Cloud Shell.

A PowerShell profile is used to add aliases, functions or variables to a session every time you start the shell.

The Azure Cloud Shell uses a fileshare stored on your storage account to persist files. This is also true for your profile. You can determine your profile path by entering:

$profile

You will see a path similar to this:

profile

This doesn’t mean that the profile exists, its just the path where Azure Cloud Shell tries to load your profile when you start it. You can determine whether the file actually exists using the Test-Path cmdlet:

Test-Path $profile

The cmdlet should return false if you didn’t already created a profile:

Capture

You could create a profile using the New-Item cmdlet and go to your file share to edit it. But you may like to have a history where you can compare the changes you made. You may also want to use the same profile for different accounts. So how can we connect a profile that is stored in a GitHub repository?

Lets start with adding the actual profile to our GitHub repository. My profile.ps1 contains a single function to print Hello World:

function Show-HelloWorld
{
    Write-Host "hello, world!"
}

Next we have to load the profile. For that purpose I have created another file called Set-Profile.ps1:

$profilePath = 'https://raw.githubusercontent.com/mjisaak/azure/master/profile.ps1'

$downloadString = '{0}?{1}' -f $profilePath, (New-Guid)
Invoke-Expression ((New-Object System.Net.WebClient).DownloadString($profilePath))

The $profilePath contains the URL to the previous created profile.ps1. I do append a query string to the path containg a random guid to prevent the web client from caching the file. This is particularly usefull when we update the profile.ps1 in the GitHub repository and want to load these changes without restarting the shell by dot sourcing the profile.
In line 4,  I download the profile.ps1 as a string and execute it using the Invoke-Expression cmdlet to load it to the runspace.

The last step we need to do is to set the content of the Set-Profile.ps1 to the actual PowerShell profile. We can do this by executing the following snippet in the Azure Cloud Shell:

(New-Object System.Net.WebClient).DownloadString('https://raw.githubusercontent.com/mjisaak/azure/master/Set-Profile.ps1') |
  Set-Content $profile -Force

The snippet is using the web client again but instead of executing the code,  it pipes the string to the Set-Content cmdlet to override the profile. I can verfiy that by retrieving the content of $profile. This should output the content of my Set-Profile.ps1:

Capture4

Finally to load the profile we can either restart the PowerShell session or dot source the profile as mentioned earlier:

. $profile

And now we can use all the aliases, variables and function we have defined in the profile that is stored on GitHub:

helloworld

Rename Azure Storage Blob using PowerShell

At the time of writing this there is no API to rename an Azure Storage blob in one operation. You have to copy the blob and delete the original one after the copy process completes.

You can vote for the feature here: Rename blobs without needing to copy them

Until then you can use my convenience Rename-AzureStorageBlob cmdlet:


function Rename-AzureStorageBlob
{
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$true, ValueFromPipeline=$true, Position=0)]
        [Microsoft.WindowsAzure.Commands.Common.Storage.ResourceModel.AzureStorageBlob]$Blob,

        [Parameter(Mandatory=$true, Position=1)]
        [string]$NewName
    )

  Process {
    $blobCopyAction = Start-AzureStorageBlobCopy `
        -ICloudBlob $Blob.ICloudBlob `
        -DestBlob $NewName `
        -Context $Blob.Context `
        -DestContainer $Blob.ICloudBlob.Container.Name

    $status = $blobCopyAction | Get-AzureStorageBlobCopyState 

    while ($status.Status -ne 'Success')
    {
        $status = $blobCopyAction | Get-AzureStorageBlobCopyState
        Start-Sleep -Milliseconds 50
    }

    $Blob | Remove-AzureStorageBlob -Force
  }
}

It accepts the blob as pipeline input so you can pipe the result of the Get-AzureStorageBlob to it and just provide a new name:

$connectionString= 'DefaultEndpointsProtocol=https;AccountName....'
$storageContext = New-AzureStorageContext -ConnectionString $connectionString

Get-AzureStorageBlob -Container 'MyContainer' -Context $storageContext -Blob 'myBlob.txt'|
    Rename-AzureStorageBlob -NewName 'MyNewBlob.txt'

You can also download the script from my GitHub repository.