HEAD Object

Description

The HEAD object of QueryIO server fetches the metadata from an object. This is useful if user is only interested in metadata of object, since it does not return the object.

Requests

Syntax

• HEAD /queryio/<BucketName>/<ObjectName> HTTP/1.1
  Host: QueryIO.com
  authorization: <token>

• <BucketName>: Path of the bucket from which metadata object will be retrieved.
• <ObjectName>: Name of the object whose metadata will be retrieved.
• authorization: Token for authorization.

Request Headers

The HEAD operation in QueryIO Server uses following request headers:

Header Name	Description	Type	Defaults	Constraints	Required
If-Modified-Since	If the object has been modified after the specified time, it returns object.	String	None	None	No
If-Unmodified-Since	If the object has not been modified after the specified time, it return object.	String	None	None	No
If-Match	If the entity tag(ETag) of the object is same as the specified one, it returns the object.	String	None	None	No
If-None-Match	If the entity tag(ETag) of the object is different from the specified one, it returns the object.	String	None	None	No
fetch-metadata	Passing this argument as true will fetch metadata for files as response headers. Value: true or false	Boolean	-	-	No

Examples

Sample Request with the If-Modified-Since Header

The following request specifies the HTTP If-Modified-Since header to retrieve an object if it is modified after the given time.

• HEAD /queryio/NewBucket/myfile.txt HTTP/1.1
  Host: QueryIO.com
  authorization: iffo6l9hel2hfmbj2384joljgh9mqga58gb9if9593ucli9ke5s2e3854shhcmmm
  If-Modified-Since: 2012-05-17 12:00:00

Sample Response

• HTTP/1.1 206 Partial Content
  Content-Type: text/plain
  Content-Language: mi, en
  Expires: 2012-12-17 00:00:00
  Cache-Control: No-cache
  Content-Disposition: attachment
  Content-Encoding: x-gzip
  x-amz-request-id: 1350386026282911000_144715990
  x-amz-id-2: 1350386026282911000_144715990
  ETag: qs345tgfd5f27731c9771645a7853216
  Last-Modified: 2012-10-17 17:41:09

Sample Request with the If-Unmodified-Since Header

The following request specifies the HTTP If-Unmodified-Since header to retrieve an object if it is not modified after the given time.

• HEAD /queryio/NewBucket/myobject HTTP/1.1
  Host: QueryIO.com
  authorization: iffo6l9hel2hfmbj2384joljgh9mqga58gb9if9593ucli9ke5s2e3854shhcmmm
  If-Modified-Since: 2012-10-17 17:41:09

Sample Response

• HTTP/1.1 206 Partial Content
  Content-Type: text/plain
  Content-Language: mi, en
  Expires: 2012-12-17 00:00:00
  Cache-Control: No-cache
  Content-Disposition: attachment
  Content-Encoding: x-gzip
  x-amz-request-id: 1350386026282911000_144715990
  x-amz-id-2: 1350386026282911000_144715990
  ETag: qs345tgfd5f27731c9771645a7853216
  Last-Modified:  2012-05-17 12:00:09

Sample Request with the If-Match Header

The following request specifies the HTTP If-Match header to retrieve an object if its entity tag is same as specified.

• HEAD /queryio/NewBucket/aps.jpg HTTP/1.1
  Host: QueryIO.com
  Authorization: iffo6l9hel2hfmbj2384joljgh9mqga58gb9if9593ucli9ke5s2e3854shhcmmm
  If-Match: "881f7881ac1bc144a2672e45babb8839"

Sample Response

• HTTP/1.1 206 Partial Content
  Content-Type: text/plain
  Content-Language: mi, en
  Expires: 2012-12-17 00:00:00
  Cache-Control: No-cache
  Content-Disposition: attachment
  Content-Encoding: x-gzip
  x-amz-request-id: 1350386026282911000_144715990
  x-amz-id-2: 1350386026282911000_144715990
  ETag: qs345tgfd5f27731c9771645a7853216
  Last-Modified: 2012-10-11 02:10:00

Sample Request with the If-None-Match Header

The following request specifies the HTTP If-None-Match header to retrieve an object if its entity tag is not same as specified.

• HEAD /queryio/NewBucket/myfile.jpg HTTP/1.1
  Host: QueryIO.com
  Authorization: iffo6l9hel2hfmbj2384joljgh9mqga58gb9if9593ucli9ke5s2e3854shhcmmm
  If-None-Match: "881f7881ac1bc144a2672e45babb8839"

Sample Response

• HTTP/1.1 206 Partial Content
  Content-Type: text/plain
  Content-Language: mi, en
  Expires: 2012-12-17 00:00:00
  Cache-Control: No-cache
  Content-Disposition: attachment
  Content-Encoding: x-gzip
  x-amz-request-id: 1350386026282911000_144715990
  x-amz-id-2: 1350386026282911000_144715990
  ETag: qs345tgfd5f27731c9771645a7853216
  Last-Modified: 2012-7-16 23:00:45