R43ples (Revision for triples) is an open source Revision Management Tool for the Semantic Web.

It provides different revisions of named graphs via a SPARQL interface. All information about revisions, changes, commits, branches and tags are stored in additional named graphs beside the original graph in an attached external triple store.

This project provides an enhanced SPARQL endpoint for revision management of named graphs. R43ples uses an internal Jena TDB is attached to an existing SPARQL endpoint of a triplestore and acts as another endpoint both for normal SPARQL queries as well as for revision-enhanced SPARQL queries, named R43ples queries. The R43ples endpoint allows to specify revisions which should be queried for each named graph used inside a SPARQL query. The whole revision information is stored in additional graphs in the attached Jena TDB.

The website of R43ples contains further project information including Javadocs. A running test server should be available under http://eatld.et.tu-dresden.de:9998/r43ples/sparql

• JDK 1.7
• Maven

sudo apt-get install maven default-jdk

Releases are stored on GitHub. They just have to be unzipped and started with Java

java -jar r43ples-*-with-dependencies.jar

There are also debian packages available.

Maven is used for compiling

mvn compile exec:exec

Packages (JAR with dependencies for the webservice, a console client and a debian package) can be be built with:

mvn package

There is a configuration file named resources/r43ples.conf. The most important ones are the following:

• triplestore.type - type of attached triplestore (can be tdb, virtuoso, http or http_virtuoso)
• triplestore.uri - URI or path under which R43ples can access the attached triplestore
• triplestore.user - user of attached triplestore if necessary
• triplestore.password - password of attached triplestore if necessary
• revision.graph - named graph which is used by R43ples to store revision graph information
• sdd.graph - named graph for storing the SDD
• service.host - host which provides R43ples
• service.port - port which should provide R43ples
• service.path - path of host which should provide R43ples

The logging configuration is stored in resources/log4j.properties

SPARQL endpoint is available at:

[uri]:[port]/r43ples/sparql

The endpoint directly accepts SPARQL queries with HTTP GET or HTTP POST parameters for query and format:

[uri]:[port]/r43ples/sparql?query=[]&format=[]

The formats can be specified as URL Path Parameter format, as HTTP post paramter format or as HTTP header parameter Accept:

• text/turtle
• application/json
• application/rdf+xml
• text/html
• text/plain

There are some additional keywords which can be used to control the revisions of graphs:

• Create graph

    CREATE GRAPH <graph>
  

• Select query

    SELECT *
    WHERE {
    	GRAPH <graph> REVISION "23" {?s ?p ?o}
    }
  

• Update query

    USER "mgraube" MESSAGE "test commit"
    INSERT {
        GRAPH <test> REVISION "2" {
            <a> <b> <c> .
        }
    }
  

• Branching

    USER "mgraube"
    MESSAGE "test commit"
    BRANCH GRAPH <test> REVISION "2" TO "unstable"
  

• Tagging

    USER "mgraube"
    MESSAGE "test commit"
    TAG GRAPH <test> REVISION "2" TO "v0.3-alpha"
  

• Merging

    USER "mgraube"
    MESSAGE "merge example"
    MERGE GRAPH <test> BRANCH "branch-1" INTO "branch-2"
  

There is a new option for R43ples which improves the performance. The necessary revision is not temporarily generated anymore. The SPARQL query is rewritten in such a way that the branch and the change sets are directly joined inside the query. This includes the order of the change sets. It is currently under development and further research.

The option can be enabled by passing an additional parameter "join_option=true"

It currently supports:

• Multiple Graphs
• Multiple TriplePath
• FILTER
• MINUS

For more details, have a look into the doc/ directory.

Following libraries are used in R43ples:

• Jersey for RestFul web services in Java
• Grizzly as web server
• Jena ARQ for processing SPARQL results
• Jena TDB as triplestore
• jQuery as JavaScript framework
• Bootstrap as HTML, CSS and JS framework
• Mustache as template engine