PowerBuilder

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. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Rest
integer li_BTls
integer li_Port
integer li_BAutoReconnect
oleobject loo_AzAuth
oleobject loo_Sb
oleobject loo_Xml

li_Success = 0

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

loo_Rest = create oleobject
li_rc = loo_Rest.ConnectToNewObject("Chilkat.Rest")
if li_rc < 0 then
    destroy loo_Rest
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Connect to the Azure Storage Blob Service
li_BTls = 1
li_Port = 443
li_BAutoReconnect = 1
// In this example, the storage account name is "chilkat".
li_Success = loo_Rest.Connect("chilkat.blob.core.windows.net",li_Port,li_BTls,li_BAutoReconnect)
if li_Success <> 1 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    return
end if

// Provide Azure Cloud credentials for the REST call.
loo_AzAuth = create oleobject
li_rc = loo_AzAuth.ConnectToNewObject("Chilkat.AuthAzureStorage")

loo_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).
loo_AzAuth.Account = "chilkat"
loo_AzAuth.Scheme = "SharedKey"
loo_AzAuth.Service = "Blob"
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
loo_AzAuth.XMsVersion = "2021-08-06"
li_Success = loo_Rest.SetAuthAzureStorage(loo_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.
loo_Sb = create oleobject
li_rc = loo_Sb.ConnectToNewObject("Chilkat.StringBuilder")

li_Success = loo_Rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",loo_Sb)
if li_Success = 0 then
    // Examine the request/response to see what happened.
    Write-Debug "response status code = " + string(loo_Rest.ResponseStatusCode)
    Write-Debug "response status text = " + loo_Rest.ResponseStatusText
    Write-Debug "response header: " + loo_Rest.ResponseHeader
    Write-Debug "---"
    Write-Debug "LastRequestStartLine: " + loo_Rest.LastRequestStartLine
    Write-Debug "LastRequestHeader: " + loo_Rest.LastRequestHeader
    destroy loo_Rest
    destroy loo_AzAuth
    destroy loo_Sb
    return
end if

// 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>

Write-Debug loo_Sb.GetAsString()

// To see if we got Tags or an Error, then examine the XML.
loo_Xml = create oleobject
li_rc = loo_Xml.ConnectToNewObject("Chilkat.Xml")

loo_Xml.LoadSb(loo_Sb,1)

// Examine the tag..
if loo_Xml.TagEquals("Tags") = 1 then
    Write-Debug "Blob exists!"
else

    if loo_Xml.ChildContentMatches("Code","BlobNotFound",1) = 1 then
        Write-Debug "Blob does not exist."
    else
        Write-Debug "Some other error..."
    end if

end if

Write-Debug "Success."


destroy loo_Rest
destroy loo_AzAuth
destroy loo_Sb
destroy loo_Xml