======================
 Container Operations
======================

A container is a mechanism for storing data objects. An account may
have many containers, but container names must be unique. This API enables a 
client to create a container, set access controls and metadata, 
retrieve a container's contents, and delete a container. Since this API 
makes requests related to information in a particular user's account, all 
requests in this API must be authenticated unless a container's access control
is deliberately made publicly accessible (i.e., allows anonymous requests).

.. note:: The Amazon S3 API uses the term 'bucket' to describe a data container.
   When you hear someone refer to a 'bucket' within the Swift API, the term 
   'bucket' may be construed as the equivalent of the term 'container.'
   
One facet of object storage is that it does not support hierarchical paths
or directories. Instead, it supports one level consisting of one or more
containers, where each container may have objects. The RADOS Gateway's
Swift-compatible API supports the notion of 'pseudo-hierarchical containers,'
which is a means of using object naming to emulate a container (or directory)
hierarchy without actually implementing one in the storage system. You may 
name objects with pseudo-hierarchical names 
(e.g., photos/buildings/empire-state.jpg), but container names cannot
contain a forward slash (``/``) character.


Create a Container
==================

To create a new container, make a ``PUT`` request with the API version, account,
and the name of the new container. The container name must be unique, must not
contain a forward-slash (/) character, and should be less than 256 bytes. You 
may include access control headers and metadata headers in the request. The 
operation is idempotent; that is, if you make a request to create a container
that already exists, it will return with a HTTP 202 return code, but will not
create another container.


Syntax
~~~~~~

::

	PUT /{api version}/{account}/{container} HTTP/1.1
	Host: {fqdn}
	X-Auth-Token: {auth-token}
	X-Container-Read: {comma-separated-uids}
	X-Container-Write: {comma-separated-uids}
	X-Container-Meta-{key}: {value}


Headers
~~~~~~~

``X-Container-Read``

:Description: The user IDs with read permissions for the container. 
:Type: Comma-separated string values of user IDs.
:Required: No

``X-Container-Write``

:Description: The user IDs with write permissions for the container.
:Type: Comma-separated string values of user IDs.
:Required: No

``X-Container-Meta-{key}``

:Description:  A user-defined meta data key that takes an arbitrary string value.
:Type: String
:Required: No


HTTP Response
~~~~~~~~~~~~~

If a container with the same name already exists, and the user is the
container owner then the operation will succeed. Otherwise the operation
will fail.

``409``

:Description: The container already exists under a different user's ownership.
:Status Code: ``BucketAlreadyExists``




List a Container's Objects
==========================

To list the objects within a container, make a ``GET`` request with the 
API version, account, and the name of the container.  You can specify query 
parameters to filter the full list, or leave out the parameters to return a list 
of the first 10,000 object names stored in the container.


Syntax
~~~~~~

::

   GET /{api version}/{container} HTTP/1.1
  	Host: {fqdn}
	X-Auth-Token: {auth-token}


Parameters
~~~~~~~~~~

``format``

:Description: Defines the format of the result. 
:Type: String
:Valid Values: ``json`` | ``xml``
:Required: No

``prefix``

:Description: Limits the result set to objects beginning with the specified prefix.
:Type: String
:Required: No

``marker``

:Description: Returns a list of results greater than the marker value.
:Type: String
:Required: No

``limit``

:Description: Limits the number of results to the specified value.
:Type: Integer
:Valid Range: 0 - 10,000
:Required: No

``delimiter``

:Description: The delimiter between the prefix and the rest of the object name.
:Type: String
:Required: No

``path``

:Description: The pseudo-hierarchical path of the objects.
:Type: String
:Required: No

``allow_unordered``

:Description: Allows the results to be returned unordered to reduce computation overhead. Cannot be used with ``delimiter``.
:Type: Boolean
:Required: No
:Non-Standard Extension: Yes


Response Entities
~~~~~~~~~~~~~~~~~

``container``

:Description: The container. 
:Type: Container

``object``

:Description: An object within the container.
:Type: Container

``name``

:Description: The name of an object within the container.
:Type: String

``hash``

:Description: A hash code of the object's contents.
:Type: String

``last_modified``

:Description: The last time the object's contents were modified.
:Type: Date

``content_type``

:Description: The type of content within the object.
:Type: String



Update a Container's ACLs
=========================

When a user creates a container, the user has read and write access to the
container by default. To allow other users to read a container's contents or
write to a container, you must specifically enable the user. 
You may also specify ``*`` in the ``X-Container-Read`` or ``X-Container-Write``
settings, which effectively enables all users to either read from or write
to the container. Setting ``*`` makes the container public. That is it 
enables anonymous users to either read from or write to the container.

.. note:: If you are planning to expose public read ACL functionality
	  for the Swift API, it is strongly recommended to include the
	  Swift account name in the endpoint definition, so as to most
	  closely emulate the behavior of native OpenStack Swift. To
	  do so, set the ``ceph.conf`` configuration option ``rgw
	  swift account in url = true``, and update your Keystone
	  endpoint to the URL suffix ``/v1/AUTH_%(tenant_id)s``
	  (instead of just ``/v1``).


Syntax
~~~~~~

::

   POST /{api version}/{account}/{container} HTTP/1.1
   Host: {fqdn}
	X-Auth-Token: {auth-token}
	X-Container-Read: *
	X-Container-Write: {uid1}, {uid2}, {uid3}

Request Headers
~~~~~~~~~~~~~~~

``X-Container-Read``

:Description: The user IDs with read permissions for the container. 
:Type: Comma-separated string values of user IDs.
:Required: No

``X-Container-Write``

:Description: The user IDs with write permissions for the container.
:Type: Comma-separated string values of user IDs.
:Required: No


Add/Update Container Metadata
=============================

To add metadata to a container, make a ``POST`` request with the API version, 
account, and container name. You must have write permissions on the 
container to add or update metadata.

Syntax
~~~~~~

::

   POST /{api version}/{account}/{container} HTTP/1.1
   Host: {fqdn}
	X-Auth-Token: {auth-token}
	X-Container-Meta-Color: red
	X-Container-Meta-Taste: salty
	
Request Headers
~~~~~~~~~~~~~~~

``X-Container-Meta-{key}``

:Description:  A user-defined meta data key that takes an arbitrary string value.
:Type: String
:Required: No


Enable Object Versioning for a Container
========================================

To enable object versioning a container, make a ``POST`` request with
the API version, account, and container name. You must have write
permissions on the container to add or update metadata.

.. note:: Object versioning support is not enabled in radosgw by
	  default; you must set ``rgw swift versioning enabled =
	  true`` in ``ceph.conf`` to enable this feature.

Syntax
~~~~~~

::

   POST /{api version}/{account}/{container} HTTP/1.1
   Host: {fqdn}
	X-Auth-Token: {auth-token}
	X-Versions-Location: {archive-container}

Request Headers
~~~~~~~~~~~~~~~

``X-Versions-Location``

:Description: The name of a container (the "archive container") that
	      will be used to store versions of the objects in the
	      container that the ``POST`` request is made on (the
	      "current container"). The archive container need not
	      exist at the time it is being referenced, but once
	      ``X-Versions-Location`` is set on the current container,
	      and object versioning is thus enabled, the archive
	      container must exist before any further objects are
	      updated or deleted in the current container.

	      .. note:: ``X-Versions-Location`` is the only
                        versioning-related header that radosgw
                        interprets. ``X-History-Location``, supported
                        by native OpenStack Swift, is currently not
                        supported by radosgw.
:Type: String
:Required: No (if this header is passed with an empty value, object
	   versioning on the current container is disabled, but the
	   archive container continues to exist.)


Delete a Container
==================

To delete a container, make a ``DELETE`` request with the API version, account,
and the name of the container. The container must be empty. If you'd like to check 
if the container is empty, execute a ``HEAD`` request against the container. Once 
you have successfully removed the container, you will be able to reuse the container name.

Syntax
~~~~~~

::

	DELETE /{api version}/{account}/{container} HTTP/1.1
	Host: {fqdn}
	X-Auth-Token: {auth-token}    


HTTP Response
~~~~~~~~~~~~~

``204``

:Description: The container was removed.
:Status Code: ``NoContent``

