Ruby

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. Ruby

require 'chilkat'

success = false

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

rest = Chilkat::CkRest.new()

# 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 != true)
    print rest.lastErrorText() + "\n";
    exit
end

# Provide Azure Cloud credentials for the REST call.
azAuth = Chilkat::CkAuthAzureStorage.new()
azAuth.put_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.put_Account("chilkat")
azAuth.put_Scheme("SharedKey")
azAuth.put_Service("Blob")
# This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.put_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 = Chilkat::CkStringBuilder.new()
success = rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",sb)
if (success == false)
    # Examine the request/response to see what happened.
    print "response status code = " + rest.get_ResponseStatusCode().to_s() + "\n";
    print "response status text = " + rest.responseStatusText() + "\n";
    print "response header: " + rest.responseHeader() + "\n";
    print "---" + "\n";
    print "LastRequestStartLine: " + rest.lastRequestStartLine() + "\n";
    print "LastRequestHeader: " + rest.lastRequestHeader() + "\n";
    exit
end

# 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>

print sb.getAsString() + "\n";

# To see if we got Tags or an Error, then examine the XML.
xml = Chilkat::CkXml.new()
xml.LoadSb(sb,true)

# Examine the tag..
if (xml.TagEquals("Tags") == true)
    print "Blob exists!" + "\n";
else

    if (xml.ChildContentMatches("Code","BlobNotFound",true) == true)
        print "Blob does not exist." + "\n";
    else
        print "Some other error..." + "\n";
    end

end

print "Success." + "\n";