Wednesday, April 9, 2014

The SSL Heartbleed bug: UPDATE NOW!

The OpenSSL "Heartbleed Bug (CVE-2014-0160)" (see, as it is being called, is a serious security hole in the Secure Sockel Layer (SSL) used for sending private documents over the internet. This bug is fixed for AllegroGraph and Allegro CL by our recent SSL module update. 

AllegroGraph Servers

Here are the specific steps to fix AllegroGraph servers:
  1. Download the following to your local machine running AllegroGraph:
  2. Find where AllegroGraph is installed and replace the file of the same name in that installation directory with the one downloaded in step #1.
  3. Restart the AllegroGraph server. That is, stop it with (AG directory is the directory where AllegroGraph is installed):
    [AC directory]/bin/agraph-control --config [AG directory]/lib/agraph.cfg stop 
    and restart it with
    [AG directory]/bin/agraph-control --config [AG directory]/lib/agraph.cfg start
Most AllegroGraph clients (AGWebview, etc.) run with non-Allegro CL software, which should be updated independently and the client restarted when the AllegroGraph server is restarted. If you are using the Lisp client, update Allegro CL as described above and then restart Allegro CL and connect it to the AllegroGraph server.

Tech Corner Article on

Friday, April 4, 2014

Gruff 5.2 (Now Available) - SPARQL Endpoint Connectivity

Gruff now connects directly to SPARQL Endpoints so you can view a Graph and issue SPARQL queries. The default uses:

When you're browsing DBPedia, the query view will have a "Sample" button just above the "Do Query" button.  It will paste in one of six (so far) sample queries that it rotates through.  These were selected for producing relatively interesting results and visual graphs.  (Please send us your favorite query and we might include it as a Gruff example.)

Gruff's Graphical query view now has a Sample button too, but only has one example query so far.

Current user will notice the command that was named "Display All Triples (up to a limit)" is now called "Display | Display Some Sample Triples".  It uses the same sample queries as the Sample button in the query view, and so generates the same visual graphs (in DBPedia only).

Also on the Display menu for DBPedia only, the commands to display a node by URI or by label will initially offer a suggestion of an interesting node.

We have employed a few strategies to make creating a visual graph from query results reasonably fast. Instead of asking the server for all of the triples of the nodes in the results, and then selecting from those, it instead deduces some triples that must exist in the store by plugging variable matches into triple patterns from the query.  This way it doesn't need to ask the server for the triples at all.  But it won't find anything for triple patterns in a UNION or the optional part of an OPTIONAL, for example.

This functionality is still in development so we welcome feedback.   If you'd like to unlock this capability please contact us - for the password.