Checking the existence of an annotation

Content Platform Tenant Management Help

File Size
4269 KB
Part Number

You use the HTTP HEAD method to check whether an object or specific version of an object has a specific annotation.

Access permission

To check for the existence of an annotation, you need browse permission.

Request header

HEAD /rest/directory/file?type=custom-metadata&annotation=annotation HTTP/1.1
Parameter Required Description
directory Yes Folder name.
file Yes Name of the file, including file extension.
type Yes Use the value custom-metadata.
annotation No Use a value of the name of the annotation. You can omit this parameter for the default annotation.Used in conjunction with the type parameter.
version No To check whether an annotation exists for a specific object version, in addition to specifying the request elements listed above, specify this URL query parameter.

Response headers

The list below describes the request-specific response headers for this operation.

Always text/xml.
The size of the annotation, in bytes.
The ETag of the object or version enclosed in double quotation marks ("). This header is returned only if the object has an ETag.
The change time for the object, in milliseconds since January 1, 1970, at 00:00:00 UTC, followed by an integer that is unique for the change time. For example: 1336483100178.00.
The change time for the object in this format:
In this format, Z represents the offset from UTC and is specified as:
For example, 2020-09-18T09:18:20-0400 represents the start of the 20th second into 9:18 AM, September 18, 2020, EDT.
The cryptographic hash algorithm HCP uses, along with the cryptographic hash value stored for the object, in this format:
X-HCP-Hash: hash-algorithmhash-value
You can use the returned hash value to verify that the stored data is the same as the data you sent. To perform the verification, compare this value with a hash value that you generate from the original data.
header is not returned for multipart objects.
The size of the object data, in bytes.
The path to the target object as specified when the symbolic link was created.
This header is returned only if the URL specifies a symbolic link to an object.
If this header is returned, the X-HCP-ACL value is always false.
The object entity type.

If HCP does not find the specified annotation, it returns an X-HCP-ErrorMessage header with the message No annotation exists with name annotation-name.

Status codes

The table below describes the HTTP status codes that have specific meaning for this request.

Code Meaning Description
200 OK The specified object has the requested annotation.
204 No Content The specified object does not have the requested annotation.
404 Not Found

One of:

  • HCP could not find an object or version at the specified URL. The specified object or version does not exist, or the request specified the current version of an object that has been deleted.
  • Any component of the URL except for the last component in the path is a symbolic link to a directory.

Example: Checking the existence of an annotation

Here’s a sample HTTP HEAD request that checks the existence of the report_data annotation for an object named Q1_2012.ppt in the quarterly_rpts directory.

Request with curl command line

curl -k -iI -H "Authorization: HCP bXl1c2Vy:3f3c6784e97531774380db177774ac8d"

Request in Python using PycURL

import pycurl
import StringIO
cin = StringIO.StringIO()
curl = pycurl.Curl()
curl.setopt(pycurl.HTTPHEADER, ["Authorization: HCP
curl.setopt(pycurl.URL, " \
  /rest/quarterly_rpts/Q1_2012.ppt?type=custom-metadata \
curl.setopt(pycurl.SSL_VERIFYPEER, 0)
curl.setopt(pycurl.SSL_VERIFYHOST, 0)
curl.setopt(pycurl.HEADER, 1)
curl.setopt(pycurl.NOBODY, 1)
curl.setopt(pycurl.WRITEFUNCTION, cin.write)
print curl.getinfo(pycurl.RESPONSE_CODE)
print cin.getvalue()

Request headers

HEAD /rest/quarterly_rpts/Q1_2012.ppt?type=custom-metadata
&annotation=report_data HTTP/1.1
Authorization: HCP bXl1c2Vy:3f3c6784e97531774380db177774ac8d

Response headers

HTTP/1.1 200 OK
X-HCP-Time: 1352396298
X-RequestId: 47306C879E376245
ETag: "8d604138ffb0f308a8552a3752e5a1be"
Content-Type: text/xml
Content-Length: 35643
X-HCP-Type: annotation
X-HCP-Size: 35643
X-HCP-ChangeTimeMilliseconds: 1352322160000.00
X-HCP-ChangeTimeString: 2012-11-07T16:02:40-0500
X-HCP-Hash: SHA-256 F8C7D88D139D14D115BA5300CD352338B8A1D344046DB2...