PowerShell

Azure Blob - Get Tags (Check if Blob Exists)

See more Azure Cloud Storage Examples

Gets the user-defined tags for a specified blob. This can also be used as a way to check to see if a blob exists. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$rest = New-Object Chilkat.Rest

# Connect to the Azure Storage Blob Service
$bTls = $true
$port = 443
$bAutoReconnect = $true
# In this example, the storage account name is "chilkat".
$success = $rest.Connect("chilkat.blob.core.windows.net",$port,$bTls,$bAutoReconnect)
if ($success -ne $true) {
    $($rest.LastErrorText)
    exit
}

# Provide Azure Cloud credentials for the REST call.
$azAuth = New-Object Chilkat.AuthAzureStorage
$azAuth.AccessKey = "AZURE_ACCESS_KEY"
# The account name used here should match the 1st part of the domain passed in the call to Connect (above).
$azAuth.Account = "chilkat"
$azAuth.Scheme = "SharedKey"
$azAuth.Service = "Blob"
# This causes the "x-ms-version: 2021-08-06" header to be automatically added.
$azAuth.XMsVersion = "2021-08-06"
$success = $rest.SetAuthAzureStorage($azAuth)

# Note: The application does not need to explicitly set the following
# headers: Content-Length, x-ms-date, Authorization.  These headers
# are automatically set by Chilkat.

# The Azure blob container is "test", the file is "helloWorld.txt"
# Add "?comp=tags" to get the user-defined tags instead of the actual blob content.
$sb = New-Object Chilkat.StringBuilder
$success = $rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",$sb)
if ($success -eq $false) {
    # Examine the request/response to see what happened.
    $("response status code = " + $rest.ResponseStatusCode)
    $("response status text = " + $rest.ResponseStatusText)
    $("response header: " + $rest.ResponseHeader)
    $("---")
    $("LastRequestStartLine: " + $rest.LastRequestStartLine)
    $("LastRequestHeader: " + $rest.LastRequestHeader)
    exit
}

# A typical blob with no tags will return this:

# <?xml version="1.0" encoding="utf-8"?>
# <Tags><TagSet/></Tags>

# If the blob does not exist, you get this:

# <?xml version="1.0" encoding="utf-8"?>
# <Error>
#     <Code>BlobNotFound</Code>
#     <Message>The specified blob does not exist.
# 	RequestId:fcfefdd9-301e-001a-2135-3a23d2000000
# 	Time:2023-02-06T14:17:00.7805577Z
#     </Message>
# </Error>

$($sb.GetAsString())

# To see if we got Tags or an Error, then examine the XML.
$xml = New-Object Chilkat.Xml
$xml.LoadSb($sb,$true)

# Examine the tag..
if ($xml.TagEquals("Tags") -eq $true) {
    $("Blob exists!")
}
else {

    if ($xml.ChildContentMatches("Code","BlobNotFound",$true) -eq $true) {
        $("Blob does not exist.")
    }
    else {
        $("Some other error...")
    }

}

$("Success.")