Enable Cache On Azure CDN - azure

Question

I am setting up Azure CDN, and having trouble setting the Cache-Control header.
I used Cloudberry Explorer to setup a sync between my server folders and the CDN. This is working well. All my files were copied to the CDN with no problem.
Under Tools > Http Headers > Edit Http Header I set the value for Cache-Control to be: public,max-age=604800
However, this does not appear to be having any effect (according to both Fiddler and Page Speed).
Any tips on setting the Cache-Control header for the Azure CDN would be GREATLY appreciated.

Answer 1

I had this issue myself and needed to update the Cache-Control header on thousands of files. To prevent caching issues in sites, I re-deploy these files with every release to a new path.
I was able to patch together some different suggestions online and ultimately landed on the following solution, which I currently use for deploying one of my production apps.
You need two files, and the script assumes they're in the same directory on your computer:
A text file with a listing of the files in the container (see example below)
The PowerShell script
The Text File (file-list.txt)
The file should be in the example format below with the full file path as deployed to the CDN container. Note this uses forward slashes, and should not include the container name since it will be included in the script. The name of this text file will be included in the PowerShell script below.
v12/app/app.js
v12/app/app.min.js
v12/app/app.min.js.map
v12/app/account/signup.js
v12/app/account/signup.min.js
... (and so on)
The Script (cdn-cache-control.ps1)
The full script is below. You'll need to replace the constants like STORAGE_ACCOUNT_NAME, STORAGE_KEY, and you may need to update the path to the Azure SDK DLL if you have a different version. There are also 2 possible implementations of $blobClient; I repurposed some of this code from a source online, and the un-commented one works for me.
The key difference between what I have here and what you'll find online is the inclusion of $blob.FetchAttributes(). Without explicitly calling this method, a majority of the blob properties like Content-Type, Last Modified Date, and others will be loaded into memory as empty/default values, then when $blob.SetProperties() is called these empty values will blow away the existing ones in the CDN, causing files to load without a Content-Type among other things.
Add-Type -Path "C:\Program Files\Microsoft SDKs\Azure\.NET SDK\v2.9\bin\Microsoft.WindowsAzure.StorageClient.dll"
$accountName = "STORAGE_ACCOUNT_NAME"
$accountKey = "STORAGE_KEY"
$blobContainerName = "STORAGE_CONTAINER_NAME"
$storageCredentials = New-Object Microsoft.WindowsAzure.StorageCredentialsAccountAndKey -ArgumentList $accountName,$accountKey
$storageAccount = New-Object Microsoft.WindowsAzure.CloudStorageAccount -ArgumentList $storageCredentials,$true
#$blobClient = $storageAccount.CreateCloudBlobClient()
$blobClient = [Microsoft.WindowsAzure.StorageClient.CloudStorageAccountStorageClientExtensions]::CreateCloudBlobClient($storageAccount)
$cacheControlValue = "max-age=31556926"
echo "Setting cache control: $cacheControlValue"
Get-Content "file-list.txt" | foreach {
$blobName = "$blobContainerName/$_".Trim()
$blob = $blobClient.GetBlobReference($blobName)
$blob.FetchAttributes()
$blob.Properties.CacheControl = $cacheControlValue
$blob.SetProperties()
echo $blobName
}
It was tricky to find information about mass-setting the Cache-Control header but I've run this script for multiple production releases with great success. I've verified the configuration of the header as well, and routinely run Google's PageSpeed Insights against my site to verify.