This section provides general information about SCSP INFO that applies to both named and unnamed objects.

INFO is a request to the storage cluster to provide information about a specific object. The INFO message is identical in semantics to the READ request, except that the object (if found) is not returned in the response. If the referenced content is found in the cluster, only the meta information about that object is returned in the form of response headers. The INFO request is formatted as an HTTP request using the HEAD method.

SCSP Method	HTTP Method	RFC 7231 Section

SCSP Method	HTTP Method	RFC 7231 Section
INFO	HEAD	4.3.2

Note

SCSP allows HEAD requests with mismatched Accept-Encoding headers to receive responses as if the encoding matched that of the object. Swarm relaxed this RFC restriction because a HEAD request returns no body contents, so there is nothing to encode.

INFO for Named Objects

HEAD /mybucket/samplefile.txt HTTP/1.1
  Host: cluster.example.com
  User-Agent: Swarm Client/0.1

INFO for Unnamed Objects

HEAD /06eec5e2c3f1aadcb41ef7fd52adc049 HTTP/1.1
  User-Agent: Swarm Client/0.1

Error

Error loading excerpt from "WRITE for Unnamed Objects".

INFO for Alias Objects

To INFO an alias object, optionally add the alias=yes query argument to the URI portion of the HTTP request line, as shown below.

HEAD /41A140B5271DC8D22FF8D027176A0821?alias=yes HTTP/1.1
  User-Agent: Swarm Client/0.1

Error

Error loading excerpt from "WRITE for Unnamed Objects".

Normal Responses to INFO

See https://perifery.atlassian.net/wiki/spaces/public/pages/2443820996 for a list of response headers.

The responses described in this section may be returned by the storage cluster in the case where the requested content was found. The content's meta-information can be returned directly by the node that received the request or the request may be redirected to another node in the cluster.

The following response indicates the requested object was located, but another node in the cluster services the request for meta-information. Additionally, all future requests of this storage cluster should be made through the new access node until another 301 response is received. There is no message-body, so the content length is always 0. The value of the Location header indicates which node in the cluster should receive the redirect.

301 Moved Permanently

The client is expected to send another INFO request using the exact URI contained in the Location header.

307 Temporary Redirect

The following response (307) is similar to the 301 response, except the client should continue to use the current node (the one generating this response) for future requests until further notice.

Normal Responses for Named Objects

The initial 401 Unauthorized response is a normal initial response to HTTP authentication. An initial 401 on an INFO on a domain is returned because access to a domain always requires administrator credentials.

The response for a named object is very similar to the response for a bucket except that Castor-System-CID is the identifier of the named object's parent (the bucket).

Normal Responses for Unnamed Objects

The following response indicates that the node that received the request found the requested content and is returning meta-information about the object in the headers of this response.

Error Responses to INFO

The responses in this section may be returned by the storage cluster when the specified content cannot be found or there is a problem with the INFO request.

The following response indicates a problem with the INFO request, such as missing mandatory headers, invalid message body, or any other violation of HTTP/1.1 by the HEAD request. The reason for the error is included in the status line.

Indicates the requested object cannot be located in this cluster: