Request and response types

The Cloud Block Storage API supports both the JSON and XML data serialization formats.

The request format is specified by using the Content-Type header and is required for operations that have a request body.

The response format can be specified in requests either by using the Accept header or by adding an .xml or .json extension to the request URI. A response can be serialized using a format that is different from the request. If no response format is specified, JSON is the default. If conflicting formats are specified by using both an Accept header and a query extension, the query extension takes precedence.

JSON and XML response formats

Format	Accept header	Query extension	Default
JSON	application/json	.json	Yes
XML	application/xml	.xml	No

In the request example below, notice that Content-Type is set to application/json, but application/xml is requested via the Accept header.

Example: Request with headers (listing volume types)

GET /v1/441446/types HTTP/1.1
Host: dfw.blockstorage.api.rackspacecloud.com
X-Auth-Token: eaaafd18-0fed-4b3a-81b4-663c99ec1cbb
Content-Type: application/json
Accept: application/xml

An XML response format is returned.

Example: XML response with headers

HTTP/1.1 200 OK
Date: Fri, 20 Jul 2012 20:32:13 GMT
Content-Length: 187
Content-Type: application/xml
X-Compute-Request-Id: req-8e0295cd-a283-46e4-96da-cae05cbfd1c7

<?xml version='1.0' encoding='UTF-8'?>
<volume_types>
    <volume_type id="1" name="SATA">
        <extra_specs/>
    </volume_type>
    <volume_type id="2" name="SSD">
        <extra_specs/>
    </volume_type>
</volume_types>