Introduction

Setting Cache-Control on Azure Blobs can help reduce bandwidth and improve the performance by preventing consumers from having to continuously download resources.

Cache-Control allows you to specify a relative amount of time to cache data after it is received. It is strongly recommended if you need the control over the completed cache.

We used to set the cache-control property of blob files through azure portal or windows azure storage explore. However, if you want to set the cache-control property for each file in your blob, such method will be a waste of time. Besides, you may also need to change this property overtimes. A better way to do this is creating a C# program using Azure Storage Client assembly and setting it.

However, this blog considers using PowerShell script to do the same work because it’s more convenient to change the property. This example is to help us set storage blob cache-control properties by PowerShell script. One thing to be noticed is that we still need to use "Microsoft.WindowsAzure.StorageClient.dll" to access the blobs.

Scenario

You need to set storage blob cache-control property or easily check cache-control property through PowerShell script.

Requirements

• PowerShell Version > 3.0
• Windows Azure PowerShell > 1.0.0

Example

#set Properties 
$blobRef.Properties.CacheControl = $cacheControlValue 
$blobRef.SetProperties() 

Script

The content of the script is reproduced at below. - Download and install the latest PowerShell. Then, connect it to your subscription.
ps1 Import-AzurePublishSettingsFile -Environment AzureChinaCloud E:\PublishSettings\CIETest03-12-9-2015-credentials.publishsettings - Set the value of Properties and Metadata
```ps1

connection info

$StorageName="your storage account name"

$StorageKey="storage Key”

$ContainerName="containername"

$BlobUri="https://yourstorageaccountname.blob.core.chinacloudapi.cn/"+$ContainerName

get all the blob under your container

$StorageCtx = New-AzureStorageContext -StorageAccountName $StorageName -StorageAccountKey $StorageKey

$blobs = Get-AzureStorageBlob -Container $ContainerName -Context $StorageCtx

creat CloudBlobClient

Add-Type -Path "C:\Program Files\Microsoft SDKs\Windows Azure.NET SDK\v2.3\ref\Microsoft.WindowsAzure.StorageClient.dll"

$storageCredentials = New-Object Microsoft.WindowsAzure.StorageCredentialsAccountAndKey -ArgumentList $StorageName,$StorageKey

$blobClient = New-Object Microsoft.WindowsAzure.StorageClient.CloudBlobClient($BlobUri,$storageCredentials)

set Properties and Metadata

$cacheControlValue = "public, max-age=60480"

foreach ($blob in $blobs)

{

#set Metadata

$blobRef = $blobClient.GetBlobReference($blob.Name)

$blobRef.Metadata.Add("abcd","abcd")

$blobRef.SetMetadata()

#set Properties

$blobRef.Properties.CacheControl = $cacheControlValue

$blobRef.SetProperties()

} ```

• Test result:

  • Before running the script: The Cache Control is empty and the METADATA is empty too.
    
  • Run script:
    Type Command Get-AzureAccount
    The Command Line will provide you with the AzureAccount infomation.
    And Then Type Command E:\TSG\readiness\Cognitive Services Readiness\setcachecontrol.ps1
  • Result:
    The cache Control has been created, And The METADATA

See Also

• Using Azure PowerShell with Azure Storage
• Set blob Properties