[Building Sakai] Writing an EntityProvider

[Jim Eng]

Hi Aaron,

I hope you (or anyone else who reads this message) can help me with an  
issue I'm having in writing an EntityProvider to serve up JSON views  
of ContentEntity objects (ContentCollection's and ContentResources's).

On a sakai instance running my laptop, I have a resource with this  
resourceId:

/group/d6759b23-39e1-48a3-beb7-fc0cc54cc18a/pothole.jpg

The prefix of the entity provider is "resources-list-item", so the URL  
to request this item from the direct servlet is:

http://localhost:8080/direct/resources-list-item/group/d6759b23-39e1-48a3-beb7-fc0cc54cc18a/pothole.jpg.json

When this request arrives at EntityHandlerImpl.handleEntityAccess(),  
the path is shown in the debugger as:

/resources-list-item/group/d6759b23-39e1-48a3-beb7-fc0cc54cc18a/ 
pothole.jpg.json

It appears that EntityHandlerImpl.handleEntityAccess() correctly  
identifies the format as "json" and creates an EntityReference object  
with prefix of "resources-list-item", but it assigns an entityId of  
"group" in the EntityReference.  That is the EntityReference passed to  
my EntityProvider's getEntity() method. This results in an error and I  
do not get any JSON.

Have I done something wrong, or is there a problem upstream from my  
code?

I'm also wondering how to deal with entityId's that being and end with  
a slash. EntityID's for ContentCollection's and ContentResources's  
generally begin with a slash, and have one or more internal slashes.   
For ContentCollection's, they end with a slash.  I'm wondering how to  
create a URL to identify such entityId's to the direct servlet so my  
EntityProvider can get the full entityId, including leading and  
trailing slashes.  Is that possible?

Thanks.

Jim