Georg Westenberger and Michael Emmerich,
Alkacon Software
Workshop track
Accessing the VFS repository
using CMIS
25.09.2012
● Introduction to CMIS
● What is CMIS?
● Demo 1: Uploading files
● CMIS Data Model
● OpenCms implementation of CMIS
● CMIS concepts in OpenCms
● Demo 2: Fetching resources from OpenCms
● Limitations of the CMIS implementation
● Demo 3: Searching with CMIS
2
Agenda
● Content Management Interoperability Services
● Standard for accessing content repositories
through a web service interface
● Defined in 2010 by web standards consortium
OASIS
● „Least common denominator“: not meant to
support all possible content repository
operations
3
What is CMIS?
● WebDAV
● Already supported by OpenCms
● JCR (Content Repository API for Java)
● Complex
● Java-centric
4
Previous standards
● Problem: Accessing different CMS repositories
● E.g. for content migration, aggregation
● Normally requires special programming effort for
every CMS repository you want to access
● Using CMIS to access CMS repositories:
Remote access to repositories
Using the same client software for different CMS
implementations
5
Purpose of CMIS
● Live Demo
6
Live Demo: Uploading Files
Demo
Demo Demo
Demo
デモ
● A repository contain objects
● Objects may be:
● Folders and documents arranged in a hierarchy
● Typed relationships between folders/documents (directed „links“)
● Policies
● Objects have a type
● Objects have properties defined by their type
● CMIS standard defines possible operations for reading/writing/creating/deleting these objects, changing properties, etc.
7
CMIS Data Model
● Protocols for accessing CMIS repositories:
● SOAP
● AtomPub
In principle accessible using any programming
language
8
Service bindings
● Uses Apache Chemistry
● Libraries for implementing CMIS clients or servers
● Provides servlets for SOAP and AtomPub bindings
● Service methods are implemented as Java
methods
● Servlets provide access to repositories
configured in opencms-importexport.xml
● Offline repository: read/write access to the Offline
project
● Online repository: read-only access to the Online
project
9
OpenCms CMIS implementation
● All basic CMIS file operations (create, update,
delete, etc.) are supported
● Folder navigation is supported
● The CMIS root folder always corresponds to the
OpenCms root folder
● OpenCms user accounts are used for all CMIS
operations
All changes through CMIS are made in the context
of the authenticated user
10
OpenCms CMIS implementation
● Files and folders have types cmis:document,
cmis:folder
● Standard resource attributes (Last modification
date, etc.) are represented as standard CMIS
properties
●
11
OpenCms CMIS implementation
cmis:objectId cmis:name
cmis:creationDate cmis:lastModificationDate
cmis:lastModifiedBy cmis:createdBy
cmis:path
● For each OpenCms property, there are two
CMIS properties, e.g. for the template property:
● opencms:template only contains the value directly
set on the resource itself
● opencms-inherited:template contains the property
value that is active for the resource, i.e. it may be
inherited from a parent folder
● The resource type can be read from the
property opencms-special:resource-type
12
OpenCms CMIS implementation
● Relations in OpenCms correspond directly to
CMIS relationships
● One type for every OpenCms relation type, e.g.
opencms:XML_WEAK
● Only relations not defined through XML content
are modifiable
13
OpenCms CMIS implementation
● Live Demo
14
Live Demo: Fetching resources from OpenCms
Demo
Demo Demo
Demo
デモ
● Demo program implemented using Apache Chemistry
● The main part:
Session session = getSession();
Folder origin = (Folder)session.getObjectByPath(cmisPath);
for (CmisObject child : origin.getChildren()) {
//…
if (child instanceof Folder) {
//…
} else if (child instanceof Document) {
Document document = (Document)child;
InputStream input = document.getContentStream().getStream();
writeStreamToFile(input, rfsFile);
}
}
15
Fetching resources from OpenCms
● CMIS has no concept of locking
Resources are implicitly locked/unlocked for each
operation
● The CMIS permission concept does not
translate well to the OpenCms permission
concept
● No negative permissions (deny)
● CMIS defines „allowable actions“ for a
document and the current user
You have to read the „allowable actions“ if you
want to check if you can perform an action
16
Limitations
● No support for multifiling (putting files in
multiple folders)
● Almost like OpenCms siblings, but this doesn‘t
work, since siblings can have different properties
● Versioning not supported
● Offline changes are not versioned, historic
versions are only created on publishing
● No support for search using the CMIS query
language
17
Limitations
● Solr queries can be used instead of the CMIS
query language
● This requires a Solr Index to be configured for
the repository
● Queries support all parameters supported by
the OpenCms Solr integration
● E.g. „fq=type:v8flower “
18
Search
● Live Demo
19
Live Demo: Searching with CMIS
Demo
Demo Demo
Demo
デモ
Session session = getSession();
for (QueryResult result : session.query(query, false)) {
String idString =
(String)(result.getPropertyValueById("cmis:objectId"));
ObjectId id = new ObjectIdImpl(idString);
CmisObject resultObject = session.getObject(id);
if (resultObject instanceof Document) {
Document resultDoc = (Document)resultObject;
//…
writeStreamToFile(resultDoc.getContentStream().getStream()
, new File(filename));
}
}
20
Searching through CMIS using Solr
● Any Questions?
21
Any Questions?
Fragen? Questions ?
Questiones?
¿Preguntas? 質問
Georg Westenberger
Michael Emmerich
Alkacon Software GmbH
http://www.alkacon.com
http://www.opencms.org
Thank you very much for your
attention! 22
