Re: [dam-cmis-profile-discuss] RE: Key Objectives For CMIS/DAM

["Mueller, Florian" <florian.mueller02@sap.com>]

Let me try to explain the CMIS 1.1 specification in a few sentences.

The CMIS specification is divided into two parts. The first part describes
the domain model (chapter 2) and the second part the bindings (chapters 3,
4, and 5). 

The domain model defines the six base types (document, folder,
relationship, policy, item, and secondary), their metadata and their
behavior (section 2.1). It also describes all CMIS operations (50+)
(section 2.2). The domain model does not say how a client and a server
communicate, though.

The CMIS bindings chapters define how the domain model is mapped to the
bytes on the wire. CMIS 1.1 defines three bindings:
- The Web Services binding, based on SOAP (chapter 3)
- The AtomPub binding, based on the Atom specification (chapter 4)
- The Browser binding, based on JSON and form data for JavaScript
applications in a web browsers (chapter 5)

The bindings are equivalent and a client can choose the binding that works
best in its environment. (There are only a few minor things you can't do
with the AtomPub binding.)
There are client libraries for many programming languages today that make
the bindings (almost) transparent to a developer. A developer uses the API
of the client library and eventually only needs to learn the domain model.

The domain model defines a set of mandatory data structures and operations
and several optional capabilities. A client can ask for the so-called
"repository info" to determine which capabilities the server provides.
The repository info has an extension point that would allow exposing
profile information. For example, a DAM server could provide information
about the DAM profile it supports and DAM specific capabilities. A DAM
client would be able to determine if the server supports the feature set
it needs.

A CMIS server is not allowed to expose another (seventh) base type, but it
can provide a hierarchy of types derived from the six CMIS base types.
These types can add more properties and may have a different behavior than
the parent type.
For example, a DAM profile could define that a server must provide a type
"dam:asset" that is derived from "cmis:document" (section 2.1.4). It would
inherit the properties of "cmis:document" and add new DAM specific
properties. The profile could also define that all objects that carry
content must be of the type "dam:asset" or a type derived from that. A
pure "cmis:document" object wouldn't exist in such a repository. The
repository would still be CMIS compliant and generic CMIS clients could
work with it.

I don't think there is anything to simplify if you start with the
mandatory CMIS capabilities and build the DAM features on top. Also the
Browser binding is a very simple and lean wire protocol. Find a few
examples here: [1]


I hope that helps,

Florian


[1] http://docs.oasis-open.org/cmis/CMIS/v1.1/os/examples/browser/






On 01.11.13 10:31, "Ralph Windsor" <ralph@daydream.co.uk> wrote:

>On point (1) of my message from last week, it seems to me that the
>cornerstone of any simplified variant of the CMIS protocol for DAM is a
>definition of the Objects to be stored (which are probably the assets in a
>typical DAM system in the vast majority of cases).  This should describe
>the
>core essential object properties which any compliant DAM systems need to
>be
>able to generate to allow more fully CMIS compliant tools to interpret
>them.
>
>I lack a full grasp of the CMIS protocol, is anyone on the list able to
>explain, in basic terms, how this works in CMIS and also cite any relevant
>sections from the CMIS spec?
>
>We'll almost certainly need to extend this with compatibility mappings
>between other protocols, but they can all come in later.  Right now, it's
>the real 'need to know' stuff we should  be interested in.
>
>
>
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