Comunica SPARQL jQuery Widget

Try the Comunica SPARQL jQuery Widget online.

This jQuery widget is a browser-based user interface to the Comunica SPARQL client. It allows users to execute SPARQL queries over one or multiple heterogeneous interfaces, such as Triple Pattern Fragments interfaces.

The @comunica/web-client-generator allows this widget to be generated for any Comunica configuration.

Installation

This tool requires Node.JS 10.0 or higher and is tested on OSX and Linux.

The easiest way to use this tool is by installing it from NPM as follows:

$ npm install -g @comunica/web-client-generator

Alternatively, you can install from the latest GitHub sources:

$ git clone git@github.com:comunica/jQuery-Widget.js.git

Generate jQuery widget

After installation, the comunica-web-client-generator CLI tool allows you to generate a new widget.

If installed from the GitHub sources, use ./bin/generate.js instead of comunica-web-client-generator.

Generating the widget for the default Comunica SPARQL config can be done as follows:

$ comunica-web-client-generator

The output will be available in the build/ directory.

Provide a custom config

In order to override the default config, you can pass one as argument.

$ comunica-web-client-generator config/config-default.json

This assumes that your engine's dependencies are available in your working directory. If this is not the case, provide a path to your engine's directory via the -c option:

$ comunica-web-client-generator path/to/engine/config/config-default.json -c path/to/engine/

Change settings and queries

The default datasources and queries can be changed as follows:

$ comunica-web-client-generator -s settings.json -q queries

Examples for the settings.json file and the queries directory.

Show all available options

All available options for this command are:

$ comunica-web-client-generator -h
comunica-web-client-generator generates Comunica Web clients
  Usage:
    comunica-web-client-generator config/config-default.json
    comunica-web-client-generator config/config-default.json -d my-build/ -s my-settings.json
    comunica-web-client-generator config/config-default.json -q my-queries/
    comunica-web-client-generator config/config-default.json -w my-webpack.config.js

  Options:
    -d            Destination of the built output (defaults to build)
    -m            The compilation mode (defaults to production, can also be development)
    -c            Path to the main Comunica module (defaults to cwd)
    -q            Path to custom queries directory
    -s            Path to custom settings file
    -w            Path to custom Webpack config
    --help        Print this help message

Running in a Docker container

Run the pre-built container

docker run -p 3000:80 -it --rm comunica/jquery-widget.js

Run from git sources

Configure your widget by editing the settings.json file.

Next, edit the queries directory in which you should insert the queries that will be present by default in the widget.

Build the Docker container as follows:

docker build -t comunica-sparql-widget .

After that, you can run your newly created container by mounting your current folder to the Docker container:

docker run -p 3000:80 -it --rm comunica-sparql-widget

Settings and queries can be passed at runtime by mounting your custom queries.json to the Docker container:

# Compile queries.json from settings.json and the files in the queries folder
./bin/queries-to-json.js

# Provide the compiled queries.json at runtime
docker run -v $(pwd)/queries.json:/usr/share/nginx/html/queries.json -p 3000:80 -it --rm comunica-sparql-widget

Access on http://localhost:3000

For developers of this package

The following is only relevant for developers that contribute to this package.

Using the code

• Run yarn install to fetch dependencies and build the browser version of the client code.
• Run yarn run dev to run a local Web server (yarn run dev-prod for minified production output).
• Edit datasources in settings.json and queries in the queries folder, and run queries-to-json to compile both of them in a single JSON file.
• Run yarn run build to generate a production version in the build folder.

How the browser client works

The original Comunica SPARQL engine is written for the Node.js environment. The Webpack library makes it compatible with browsers.

The query engine itself runs in a background thread using Web Workers. The user interface (ldf-client-ui.js) instructs the worker (ldf-client-worker.js) to evaluate queries by sending messages, and the worker sends results back.

License

The Linked Data Fragments jQuery Widget was originally written by Ruben Verborgh and ported for Comunica SPARQL by Ruben Taelman.

This code is copyrighted by Ghent University – imec and released under the MIT license.