Hi Andreas, Andreas Kollegger schrieb: > Hi, > > I'd like to expose data stored in an external database as resource nodes > in Sling. Access to the database is already wrapped in an OSGi service > (MyService.java), and there is a Java model for the data (MyModel.java). > From what I can understand from reading the examples, searching the > mailing list and looking at documentation, the steps to integrate with > Sling could be: > > 1. MyResourceProvider implements ResourceProvider > - bridge to MyService for getting data rows > - provider.roots = /my/resources/ > - sub-path of root used to select row in table > (/my/resources/3245.html retrieves row index 3245 as Resource) > - listChildren() of root would list all database rows (probably add > query params to limit number of rows returned) > - getResource() returns a MyResourceWrapper
Makes perfect sense. > 2. MyResourceWrapper implements Resource > - wraps MyModel > - resourceType = my/Model > - adaptable to javax.jcr.Node (exposing columns as node properties) I would not adapt it to a Node. Rather I would adapt it to the MyModel class and propbably to ValueMap (or even PersistableValueMap) to get at the properties. > > That would take care of read access to the data. I can then easily add > scripts to render the data as appropriate. > > Write access is a little less clear to me. I'd like to have a servlet > which handles json, xml or form POSTs for anything submitted to the path > of my ResourceProvider. I think I need to do this: > > 1. MyResourceTypeProvider implements JcrResourceTypeProvider > - provider.roots = /my/resources > - any node below the root is returned as resourceType my/Model, > otherwise return null The problem exists mainly for non-existing resources (rows). Existing rows already map to the correct implementation (see above) and thus have the correct resource type. For non-existing resources, Ian Boston is preparing a patch providing a PathResourceTypeProvider which may be used to assign a special resource type to non-existing nodes much like the JcrResourceTypeProvider does for plain JCR Item based resources. So in your use case Ian's PathResourceTypeProvider would probably be appropriate. > > 2. MyPostServlet extends SlingAllMethodsServlet > - registered to handle nodes of type my/Model > - override doPost() to handle data based on content-type > - creates new database entries using MyService Makes perfect sense to me. We might want to inspect how much of the existing SlingPostServlet could be abstracted to support general resource creation, modification, removal, not just JCR Item based ones. > > That would allow the creation of a new database row by posting an > appropriate json or xml file to /my/resource/*.html . For the form data, > I'd conform to the SlingPostServlet interface to remain compatible with > generic node editing. > > Am I thinking about this correctly, or is their a more appropriate > Sling-Way? I think you are approach looks perfectly like the Sling way. Another approach could of course be to create a Jackrabbit PersistenceManager for your database and access your database through Jackrabbit. But I suspect that this would be more complicated. Regards Felix
