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Amazon S3 - HEAD Object

Metadata is a set of Key - Value pairs that provides some basic details about the file. If you want just retrieve the metadata of an Amazon S3 Object (Files stored on S3) , you can send an HTTP HEAD request to Amazon S3 server. You must have READ Permissions on the S3 Object to get a response for HEAD request. You can specify same options with HEAD Request as you can with an HTTP GET Request on S3 Objects. The only difference is that you will only receive the metadata of the Object, in response to HEAD Request, as opposed to getting the Object itself like you get in GET Request.

You can retrieve the metadata of an Amazon S3 Object by sending an HTTP HEAD request to Amazon S3 server. You have two options to retrieve the metadata of an Amazon S3 Object, you can consider one of the two options:

  1. Retrieve S3 Object Metadata using Amazon S3 REST API- HEAD Object API - If you are a programmer, you can write your own software program and use Amazon S3 REST or SOAP APIs. On this website, we will only provide reference to Amazon S3's REST APIs. You can read AWS documentation for details on SOAP APIs.
  2. Retrieve Object Metadata with HEAD Object using Bucket Explorer User Interface - The other way to retrieve the metadata of an Amazon S3 Object without having to write any code would be to use Bucket Explorer's UI. Using Bucket Explorer, you can perform such actions on Amazon S3 Object with mouse clicks.

If do not want to go through all the work involved in writing a program, however, you can use Bucket Explorer's interface to send requests with point and click and see the responses on the screen. The below sections describe both options for you:

Retrieve S3 Object Metadata using Amazon S3 REST API- HEAD Object API

By calling the HEAD Object REST API in your program, you can retrieve Metadata from an object without returning the object itself. HEAD Object request is only useful if you only want the object’s metadata. To authenticate the request, you must have READ access to the Object. You do not need to send request Parameters. You only need to specify common request headers.

Syntax:


HEAD / ObjectName HTTP/1.1
Host: BucketName .s3.amazonaws.com
Authorization: signatureValue
Date: date
 

Retrieve Object Metadata with HEAD Object using Bucket Explorer User Interface

You can retrieve the Object metadata with just mouse clicks, using Bucket Explorer, without having to write any program.

Object properties option displays the Meta information like object name, creation date, Last modified date, content type, content length, bucket name, request-id etc. about the selected object. You can add a new metadata  and edit or remove the existing metadata which were created by you previously.

Follow these steps to view the properties of an object:
  1. Select any file/folder whose properties you want to see.
  2. There are 2 options to see the properties:
    • Right click on the selected file, choose Properties option.
    • Or click on Properties button in toolbar of object panel.
  3. The window for the properties of object is displayed that shows the properties & their values if properties are present.

If you select a file, the properties displayed are:

Sr. No. Properties Sr. No. Properties Sr. No. Properties Sr. No. Properties
1. Object 2. Bucket 3. Owner ID 4. Owner Name
5. Size 6. Date 7. Last Modified Date 8. Type
9. id-2 10. request-id 11. Version-ID [1] 12. Etag
13. bucketexplorer-md5 14. md5-hash 15. bucketexplorer-filelastmodifieddate [2] 16. Storage-class
17. Server Side Encryption 18. Restore Last Version [3] 19. Custom Header Content-Type etc.    

Note: There are some options in above mentioned list that requires other requests like GET, List Request to get information about its property. For example: Server Side Encryption, Restore Last Version, etc.

At the end of Object Properties window, you can also  Update Metadata [4] .

If you select a folder, properties displayed are:

Sr. No. Properties Sr. No. Properties Sr. No. Properties
1. Object Name 2. Bucket Name 3. Total Virtual Folders
4. Total Files 5. Size of $Folder Name$ 6. Total Objects in $Folder Name$

Note:  Metadata of a folder can not be seen and updated.

  1. ˆ Version-ID: The combination of key and version id uniquely identifies an Object in a Bucket.
  2. ˆ bucketexplorer-filelastmodifieddate: This shows the date when the file was last modified in local system.
  3. ˆ Restore Last Version: You can restore the last version of the object, if available.
  4. ˆ Update Metadata:
    • List of Metadata attributes will also be seen below the properties. Metadata list can be updated by clicking on  Update Metadata button located below the list.
    • By clicking on Update Metadata, it will open a new window of update metadata where metadata can be added, edited or removed.