Classic ASP

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. Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<body>
<%
success = 0

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

set rest = Server.CreateObject("Chilkat.Rest")

'  Connect to the Azure Storage Blob Service
bTls = 1
port = 443
bAutoReconnect = 1
'  In this example, the storage account name is "chilkat".
success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect)
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
    Response.End
End If

'  Provide Azure Cloud credentials for the REST call.
set azAuth = Server.CreateObject("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.
set sb = Server.CreateObject("Chilkat.StringBuilder")
success = rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",sb)
If (success = 0) Then
    '  Examine the request/response to see what happened.
    Response.Write "<pre>" & Server.HTMLEncode( "response status code = " & rest.ResponseStatusCode) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "response status text = " & rest.ResponseStatusText) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "response header: " & rest.ResponseHeader) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "---") & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "LastRequestStartLine: " & rest.LastRequestStartLine) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "LastRequestHeader: " & rest.LastRequestHeader) & "</pre>"
    Response.End
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>

Response.Write "<pre>" & Server.HTMLEncode( sb.GetAsString()) & "</pre>"

'  To see if we got Tags or an Error, then examine the XML.
set xml = Server.CreateObject("Chilkat.Xml")
success = xml.LoadSb(sb,1)

'  Examine the tag..
If (xml.TagEquals("Tags") = 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Blob exists!") & "</pre>"
Else

    If (xml.ChildContentMatches("Code","BlobNotFound",1) = 1) Then
        Response.Write "<pre>" & Server.HTMLEncode( "Blob does not exist.") & "</pre>"
    Else
        Response.Write "<pre>" & Server.HTMLEncode( "Some other error...") & "</pre>"
    End If

End If

Response.Write "<pre>" & Server.HTMLEncode( "Success.") & "</pre>"

%>
</body>
</html>