topic Re: CMIS needs to support aspects in Alfresco Archive

CMIS needs to support aspects

jpotts — Wed, 18 Nov 2009 01:36:22 GMT

Currently (CMIS 1.0cd04), you can query for properties defined in an aspect, which is good. But full support for aspects is going to be critical for Alfresco-based CMIS implementations. Without it, CMIS clients cannot discover properties defined in aspects by interrogating getType, which I would thi

Re: CMIS needs to support aspects

dennisnk — Wed, 18 Nov 2009 07:39:26 GMT

If you want to be sure OASIS receives the feedback, submit a comment to the TC comment list: http://www.oasis-open.org/committees/comments/index.php?wg_abbrev=cmis. The public review should be ongoing until December 22.

Dennis

Re: CMIS needs to support aspects

darryl_staflund — Tue, 12 Jan 2010 04:54:21 GMT

Hi there,

My colleagues and I at work have been discussing this issue and it seems at the very least as though discussions are taking place on the support of aspects in CMIS. Take a look at the following link:

http://wiki.oasis-open.org/cmis/Mixin_Proposal

Important is the section that summarizes John Newton and David Caruana's discussions on possible CMIS mixin implementations:

1. Pool of Properties
———————-
In this proposal, a mixin would be implemented as a list of properties associated with an object but not its type. It's easy to implement, it maps to Sharepoint, and can map existing Aspects to optional properties. However, these properties don't have any specific structure so aspects would be hard to detect. As such, it would have limited use beyond a few aspects.

2. Separate Object (Different Id?) Connected with Association
————————————————————–
In this proposal, a mixin would be modeled as a separate object with a different Id (?) that is connected to a base type with an association. This would work well with existing models, and would not require an extension to the CMIS query language. However, the queries used to join objects with aspects would be complex requiring a full join (hence performance would suffer), and constraints would be needed to avoid linking an aspect instance to more than one object at a time. Filters would also be needed on Type discovery to separate them from core types.

3. Aspects as Children of Objects
———————————-
In this proposal, aspects would be modeled as children, similar to items in a folder. Patterns used to add and remove items to and from folders could be adopted to work with aspects, and no major changes to the CMIS content model would be needed. However, queries could become quite complex, Id handling could be messy, and a new folder-like hierarchy would be introduced into the system.

4. New Type with No Separate Id with Implicit Association
———————————————————-
In this proposal, aspects would be implemented as objects without IDs having foreign key relationships with the IDs of the objects that they depend on. In this model, queries are simple, the model is simple, and properties are handled well. However, a new Aspect type would need to be added to CMIS and ECM's that don't support aspects would need to find some way of supporting it.

My personal hope is that (4) is incorporated into the CMIS standard – but as an optional extension instead of a mandatory requirement. Seems to me like this would be the best of both worlds. We'll have to see what happens.

Darryl

Re: CMIS needs to support aspects

kbryd — Tue, 12 Jan 2010 15:33:06 GMT

Does anyone know how to access attributes defined in aspects in current Alfresco version (3.2r2)? There is that query on some Wiki page but it does not work unfortunately (joins are not supported) and while I agree that full aspects support is not trivial to implement there are some aspects for which it would be nice to have at least read only access (cm:titled for example or any other custom aspect).

I was even thinking about branching CMIS code from Alfresco and implement the 1) option from above list so at least I could have access to aspects from my application now and not in 2011 🙂

Jeff, could you shed some light on that issue?

Thanks!
Karol

Re: CMIS needs to support aspects

darryl_staflund — Tue, 12 Jan 2010 16:36:29 GMT

The Wiki page in question is:

http://wiki.alfresco.com/wiki/CMIS

where a join example is provided in the 'Query Language' section.

However, on the following Wiki page:

http://wiki.alfresco.com/wiki/Full_Text_Search_Query_Syntax

it appears as though aspect properties can be accessed by attaching the 'aspect:' prefix to an Alfresco FTS expression embedded inside of the CMIS 'contains()' predicate. I might be wrong on this last point though, for where the following row entry is found:

Description: ASPECT
Type: Special
Example: ASPECT:"qname"
FTS: Yes
CMIS contains(): No

I am not sure if 'No' in the 'CMIS contains()' columns means that this particular FTS expression won't work in the CMIS 'contains()' prefix, or whether the CMIS 'contains()' prefix doesn't offer similar native CMIS functionality. I am guessing the former, but I haven't sat down to give it a try yet.
Darryl

Re: CMIS needs to support aspects

kbryd — Tue, 12 Jan 2010 21:43:09 GMT

Problem with queries and CMIS is that by default joins are not supported. In the CMISQueryServiceImpl class there is following code fragment:


        public CMISJoinEnum getJoinSupport()
        {
            return CMISJoinEnum.NO_JOIN_SUPPORT;
        }

=============

        CMISJoinEnum joinSupport = getJoinSupport();
        if(options.getQueryMode() == CMISQueryOptions.CMISQueryMode.CMS_WITH_ALFRESCO_EXTENSIONS)
        {
            joinSupport = CMISJoinEnum.INNER_JOIN_SUPPORT;
        }‍‍‍‍‍‍‍‍‍‍‍‍‍

So, to enable joins you have to pass CMISQueryOptions.CMISQueryMode.CMS_WITH_ALFRESCO_EXTENSIONS to the method, BUT, there is no way to do it from the CMIS client 😞
What's worse there is no way to enable it from Spring configuration files, the only way to do it is by changing the class and recompiling it. I will try it tomorrow.

Karol

Re: CMIS needs to support aspects

kbryd — Mon, 18 Jan 2010 21:31:28 GMT

Small update. I have enabled joins in HEAD and recompiled it but unfortunately queries like:

SELECT D.*, O.* FROM CMIS:DOCUMENT AS D JOIN CM:OWNABLE AS O ON D.cmis:objectId = O.cmis:objectId‍

return 0 rows…So it looks like this is not the right path. At least with that Alfresco version.

So, instead I have modified remote api module and implemented 1) option from the list above and it seems that it works. I have modified getProperties() in ObjectServicePort so it adds one more 'internal' property named
cmis:attached_aspects which contains IDs of those aspects (like cm:titled, cmwnable etc.), getProperties() also retrieves properties from those aspects and adds them to the properties list which is returned to the client.

From the client perspective I can query for aspect details because they are present in the dictionary as Policy objects. Property updates are also working correctly.

Even though this is a hacky solution it seems to work and until a real solution is implemented can be used without any major problems (I hope so 🙂

Re: CMIS needs to support aspects

a_evagelopoulos — Fri, 09 Jul 2010 11:22:47 GMT

Hello.
I use Alfresco 3.3 Community and i am facing that problem(CMIS getTypeDefinition service doesn't work for custom aspects). i call the following cmis service 'http://localhost:8080/alfresco/service/cmis/type/D:myContentType'
First of all that works fine in Alfresco 3.0 labs and when i call the service 'http://localhost:8080/alfresco/service/api/type/D/myContentType' i do get my custom aspects. I can't understand why something that works in draft edition doesn't work in final release?
1. Is there any other way to get my custom aspects for my custom content-type in the Alfresco 3.3 Community edition?
2. Is this "problem" solved in 3.3 Enterprise edition?
3. Is there any way to get the typedefinition right from the PHP SDK?

Below i send you the xml code of my custom model

<?xml version="1.0" encoding="UTF-8"?>
<!– Definition of new Model –>
<model name="exaeAnakoinoseis:exaeAnakoinoseismodel" xmlns="http://www.alfresco.org/model/dictionary/1.0">

   <!– Optional meta-data about the model –>
   <description>Exae Anakoinoseis Model</description>
   <author>Stolis</author>
   <version>1.0</version>

   <!– Imports are required to allow references to definitions in other models –>
   <imports>
      <!– Import Alfresco Dictionary Definitions –>
      <import uri="http://www.alfresco.org/model/dictionary/1.0" prefix="d" />
      <!– Import Alfresco Content Domain Model Definitions –>
      <import uri="http://www.alfresco.org/model/content/1.0" prefix="cm" />
      <import uri="http://www.alfresco.org/model/system/1.0" prefix="sys" />
   </imports>

   <!– Introduction of new namespaces defined by this model –>
   <namespaces>
      <namespace uri="http://www.exae.gr/ermhs2/modelAnakoinoseis/content/1.0" prefix="exaeAnakoinoseis" />
   </namespaces>
   
   <constraints>
      <constraint name="exaeAnakoinoseis:agora-eisagoghs-list" type="LIST">
         <parameter name="allowedValues">
            <list>
               <value>Χ.Α.</value>
               <value>ΕΝ.Α</value>
            </list>
         </parameter>
      </constraint>
   </constraints>
   
   <!– TYPES –>
   
   <types>
      <!– Enterprise-wide generic document type –>
      <type name="exaeAnakoinoseis:doc">
         <parent>cm:content</parent>
         
         <associations>
               <child-association name="exaeAnakoinoseis:attachment">
                  <title>attachment</title>
                  <source>
                     <mandatory>true</mandatory>
                     <many>false</many>
                  </source>
                  <target>
                     <class>exaeAnakoinoseis:doc</class>
                     <mandatory>false</mandatory>
                     <many>true</many>
                  </target>
                  <duplicate>false</duplicate>
               </child-association>
            </associations>
            
      </type>      
      
      <type name="exaeAnakoinoseis:k1-03-001">
         <title>Ανακοινωση για εισαγωγή Μετόχων στο Χ.Α/ΕΝ.Α για πρώτη φορά με δημόσια Προσφορά</title>
         <parent>exaeAnakoinoseis:doc</parent>
         <mandatory-aspects>
            <aspect>exaeAnakoinoseis:hmnia-eisagogis-metoxon-aspect</aspect>
            <aspect>exaeAnakoinoseis:arithmos-metoxon-aspect</aspect>
            <aspect>exaeAnakoinoseis:kodikos-metoxhs-oasis-aspect</aspect>
            <aspect>exaeAnakoinoseis:kodikos-isin-aspect</aspect>
            <aspect>exaeAnakoinoseis:drasthriothta-aspect</aspect>
         </mandatory-aspects>
      </type>   
      <type name="exaeAnakoinoseis:k1-03-003">
         <title>Ανακοινωση για εισαγωγή Μετόχων στο Χ.Α/ΕΝ.Α για πρώτη φορά χωρίς δημόσια Προσφορά</title>
         <parent>exaeAnakoinoseis:doc</parent>
         <mandatory-aspects>
            <aspect>exaeAnakoinoseis:hmnia-eisagogis-metoxon-aspect</aspect>
            <aspect>exaeAnakoinoseis:arithmos-metoxon-aspect</aspect>
            <aspect>exaeAnakoinoseis:kodikos-metoxhs-oasis-aspect</aspect>
            <aspect>exaeAnakoinoseis:kodikos-isin-aspect</aspect>
            <aspect>exaeAnakoinoseis:drasthriothta-aspect</aspect>
         </mandatory-aspects>
      </type>      
   </types>
   
   
   <!– ASPECTS –>
   
   <aspects>
      <aspect name="exaeAnakoinoseis:hmnia-eisagogis-metoxon-aspect">
         <title></title>
         <properties>
            <property name="exaeAnakoinoseis:agora-eisagoghs">
               <type>d:text</type>
               <multiple>true</multiple>
               <constraints>
                  <constraint ref="exaeAnakoinoseis:agora-eisagoghs-list"></constraint>
               </constraints>
            </property>
            <property name="exaeAnakoinoseis:hmnia-eisagoghs-metoxon">
               <type>d:date</type>
            </property>
         </properties>
      </aspect>
      <aspect name="exaeAnakoinoseis:arithmos-metoxon-aspect">
         <title>Αριθμός Μετοχών</title>
         <properties>
            <property name="exaeAnakoinoseis:arithmos-metoxon">
               <type>d:long</type>
            </property>
         </properties>
      </aspect>
      <aspect name="exaeAnakoinoseis:kodikos-metoxhs-oasis-aspect">
         <title>Κωδικός Μετοχών στο Όασης</title>
         <properties>
            <property name="exaeAnakoinoseis:kodikos-metoxhs-oasis">
               <type>d:text</type>
            </property>
         </properties>
      </aspect>
      <aspect name="exaeAnakoinoseis:kodikos-isin-aspect">
         <title>Κωδικός ISIN</title>
         <properties>
            <property name="exaeAnakoinoseis:kodikos-isin">
               <type>d:text</type>
            </property>
         </properties>
      </aspect>
      <aspect name="exaeAnakoinoseis:drasthriothta-aspect">
         <title>Δραστηριότητα</title>
         <properties>
            <property name="exaeAnakoinoseis:drasthriothta">
               <type>d:text</type>
            </property>
         </properties>
      </aspect>
   </aspects>
</model>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: CMIS needs to support aspects

gclaussn — Sat, 10 Jul 2010 14:28:59 GMT

Aspects are Alfresco specific. They are not defined within the CMIS specification!

best regards, gclaussn

Re: CMIS needs to support aspects

mrogers — Sun, 11 Jul 2010 09:53:08 GMT

Alfresco has proposed extending the CMIS specification to include Aspects since its clear that there is a need for them, however they are not part of CMIS 1.0. Which is why the Alfresco CMIS interface not longer shows them.

I think Alfresco can be switched to a "less strict" CMIS mode that does have some non standard extensions such as aspects.

Re: CMIS needs to support aspects

nikes — Thu, 28 Oct 2010 08:46:36 GMT

How to switch to "less strict" mode for Aspect support?

From wiki pages I found that we can use JOIN query. But Alfresco CMIS doesn't support JOIN operation.

Any inputs?

Nikesh

Re: CMIS needs to support aspects

jpotts — Thu, 16 Dec 2010 15:21:48 GMT

If you look at the Web Quick Start code you can see how Alfresco grabs aspect props:

    private final static String COMMON_ASSET_SELECT_CLAUSE = "SELECT d.cmisbjectId, d.cmisbjectTypeId, d.cmis:name, d.cmis:contentStreamLength, "
            + "d.cmis:contentStreamMimeType, d.cmis:lastModificationDate, t.cm:title, t.cm:description, wa.wsarentSections, wa.wsublishedTime, "
            + "wa.ws:derivedCommentCount, wa.ws:derivedAverageRating, wa.ws:tags, a.cm:author ";

    private final static String COMMON_ASSET_FROM_CLAUSE = "FROM cmis:document AS d "
            + "JOIN ws:webasset AS wa ON d.cmisbjectId = wa.cmisbjectId "
            + "JOIN cm:author AS a ON d.cmisbjectId = a.cmisbjectId "
            + "JOIN cm:titled AS t ON d.cmisbjectId = t.cmisbjectId ";

Unfortunately, the query returns zero rows if the aspect isn't present, so if you add your own aspect and aspect props to this query, it works, but only if all documents you are interested in have the aspect applied.