Performing a Conditioned Download

If you have any questions during development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see API Reference.

When downloading an object, you can specify one or more conditions. Only when the conditions are met, the object will be downloaded. Otherwise, an error code will be returned and the download will fail.

You can set the following conditions:

• The ETag of an object is the MD5 check value of the object.
• If a request includes IfUnmodifiedSince or IfMatch and the specified condition is not met, the object download will fail and an exception will be thrown with error code 412 Precondition Failed returned.
• If a request includes IfModifiedSince or IfNoneMatch and the specified condition is not met, the object download will fail and an exception will be thrown with error code 304 Not Modified returned.

Sample code:

// Import the dependency library.
require 'vendor/autoload.php';
// Import the SDK code library during source code installation.
// require 'obs-autoloader.php';
// Declare the namespace.
use Obs\ObsClient;
// Create an instance of ObsClient.
$obsClient = new ObsClient ( [ 
      //Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
      //Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
      'key' => getenv('ACCESS_KEY_ID'),
      'secret' => getenv('SECRET_ACCESS_KEY'),
      'endpoint' => 'https://your-endpoint',
      'signature' => 'obs'
] );

$resp = $obsClient -> getObject([
       'Bucket' => 'bucketname',
       'Key' => 'objectname',
       'IfModifiedSince' => 'Thu, 31 Dec 2015 16:00:00 GMT'
]);

printf("RequestId:%s\n", $resp['RequestId']);
printf("Object Content:\n");
echo $resp ['Body'];