SPARQLfront

SPARQLfront is a PHP and javascript based frontend to RDF SPARQL endpoints.

It uses a modified version of ARC2 (a nice PHP RDF library) for most of the functionality, Skeleton to provide the basic HTML and stylesheets, and CodeMirror to provide syntax highlighting for SPARQL.

Demo

http://sparql.data.southampton.ac.uk/sparqlfront/

Getting started

Copy all of the SPARQLfront files into a directory that's visible on the web.

Most of the config is kept directly in index.php. Options you can set there there include:

• remote_store_endpoint - Set this to the URL of your triplestore's endpoint. SPARQL queries will be passed to this.
• endpoint_features - Set the operations allowed on this endpoint (load, insert, delete and dump disabled by default)
• endpoint_max_limit - [Optional] Max number of results that will be returned by a query.
• passthrough_sparqlxml - Set to true to pass any SPARQL XML returned by a store back to the user without being passed through ARC2. If set to false, results are parsed by ARC2, then serialised and sent back to user.
• sample_queries - Can set any number of sample queries to be displayed when javascript link on the endpoint is clicked.
• prefixes - Set namespace prefixes which will populate the query form when the Load Namespaces button is clicked.
• default_query - Text that is shown in the query form when page is loaded.
• output_formats - Formats listed in the Output format dropdown on the side of the page.

Changing styles and HTML

The HTML output can be modified by changing lib/template.php.

Stylesheets can be changed either inline in lib/template.php, or by editing anything in the stylesheets directory.

Modifications to ARC2

SPARQLfront uses an ARC2 fork that contains a few modifications. These include:

• Additional output formats (CSV and SQLite)
• JSON encoding bug fixed
• Added support for SPARQL 1.1 keyword GROUP_CONCAT and SAMPLE.
• Added RemoteStoreEndpoint class, which allows queries to be passed to any triplestore
• Added option to enable SPARQL XML output to be returned directly to client without passing through ARC2

Contact

Dave Challis

• Email: suicas@gmail.com
• Twitter: @davechallis