(Perl) Download Object from Google Cloud Storage

Demonstrates how to download an object from Google Cloud Storage to a file.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

# This example uses a previously obtained access token having permission for the 
# scope "https://www.googleapis.com/auth/cloud-platform"

# In this example, Get Google Cloud Storage OAuth2 Access Token, 
# the service account access token was saved to a text file.  This example fetches the access token from the file..
$sbToken = chilkat::CkStringBuilder->new();
$sbToken->LoadFile("qa_data/tokens/googleCloudStorageAccessToken.txt","utf-8");

# Send a GET equivalent to this curl command.

# curl -X GET \
#     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
#     -o "[SAVE_TO_LOCATION]" \
#     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?alt=media"

$http = chilkat::CkHttp->new();

$http->put_AuthToken($sbToken->getAsString());

# Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
$http->SetUrlVar("bucket_name","chilkat-ocean");
$http->SetUrlVar("object_name","starfish.jpg");
$url = "https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media";

# If there is an error response, then we didn't actually download the file data,
# but instead we downloaded an error response..
$fileData = chilkat::CkBinData->new();
$success = $http->DownloadBd($url,$fileData);
if ($success == 0) {
    print $http->lastErrorText() . "\r\n";
    exit;
}

$sbErrorResponse = chilkat::CkStringBuilder->new();
$responseCode = $http->get_LastStatus();
if ($responseCode == 401) {
    print "If invalid credentials, then it is likely the access token expired." . "\r\n";
    print "Your app should automatically fetch a new access token and re-try." . "\r\n";
}

if ($responseCode != 200) {
    # Get the error response
    $sbErrorResponse->AppendBd($fileData,"utf-8",0,0);
    print "Error response code = " . $responseCode . "\r\n";
    print "Error:" . "\r\n";
    print $sbErrorResponse->getAsString() . "\r\n";
    exit;
}

print "Success." . "\r\n";

# Save the downloaded data to a file.
$success = $fileData->WriteFile("qa_output/starfish.jpg");