Dell DX6000 Руководство по установке и настройке - Страница 38

Appendix C. Enumerator API

DX Content Router provides a public HTTP 1.1 server interface component as part of the DX

Content Router Publisher service. The purpose of the HTTP interface is to enable a simple

standards based approach for building "plug-in like" DX Storage internal and 3rd party applications

that require some form of object enumeration. The DX Content Router Replicator service utilizes

this interface extensively to provide reliable object replication across Wide Area Networks. Some

other applications might include 3rd party object replication and/or backup applications, object

index/search engines, metadata query engines and virus scan applications. The base URL for any

enumerator is:

http://<publisherHost>:<publicationServerPort>/

C.1. Enumerator Types

Enumerator types are defined based on the type of data that should be returned with the response.

The default type is a Metadata enumerator. The list of supported types is:

• Metadata Enumerator: Metadata enumerators return the UUIDs and all associated metadata

for objects that match the specified filters. In the 2.1 and later releases, Metadata enumeration

includes all creates and updates regardless of subsequent deletes. Every event associated

with a mutable object (POST, COPY, APPEND, PUT, DELETE, etc) is included as a separate

enumeration item. In DX Content Router 2.2, metadata enumerators include metadata for both

named and unnamed DX Storage objects.

• UUID Enumerator: UUID enumerators return the UUIDs for all objects that match the specified

filters.

UUID enumeration includes the UUIDs for create events of immutable objects unless a

subsequent delete event has been registered by the Publisher for the same object. For mutable

objects, the alias UUIDs for creates and updates are included regardless of subsequent deletes in

order to ensure proper processing of all object revisions across different nodes and clusters. This

will result in the same alias UUID being enumerated multiple times if there are update or delete

events.

Only unnamed DX Storage objects are returned by the UUID enumerator in DX Content Router

2.2.

• Event Enumerator: Event enumerators return the UUIDs for objects that match the specified

filters as well as the last event associated with the UUID (create, update or delete). Only unnamed

DX Storage objects are returned by the Event enumerator in DX Content Router 2.2.

Note

Delete events are considered to match all channels and are sent to all subscribers. This

ensures delete events transmitted via a previous rule version are known to be deleted

even if they no longer match the current rules.

For a complete discussion of different DX Storage object types, including named, unnamed and

alias objects, please refer to the DX Storage Application Guide.

C.2. Enumerator Start

The Enumeration Start command instantiates an object enumerator for a given channel in Publisher,

and returns a unique identifier for this enumerator. The format of the request is as follows:

Version 2.2

December 2010