This library converts KAF to NAF and NAF to KAF. It also contains a webservice for doing exactly this.

It uses slightly altered distributions of the VUA_pylib and KafNafParserPy but it keeps the external libraries contained, so that shouldn’t influence anything on your system.

Confused by some terminology?

This software is part of a larger collection of natural language processing tools known as “the OpeNER project”. You can find more information about the project at the OpeNER portal. There you can also find references to terms like KAF (an XML standard to represent linguistic annotations in texts), component, cores, scenario’s and pipelines.

Quick Use Example

Installing the kaf-naf-parser can be done by executing:

gem install opener-kaf-naf-parser

Please bare in mind that all components in OpeNER take KAF as an input and output KAF by default.

It ships with 3 command line tools and a webservice:


It works like this:

cat some_kaf.kaf | kaf-to-naf > output.naf
cat some_naf.naf | naf-to-kaf > output.kaf

cat some_kaf.kaf | kaf-naf-parser --tonaf > output.naf

The webservice can be started like this:


And can then be accessed at: http://localhost:9292

Easiest way to install the gem:

gem install opener-kaf-naf-parser


Last but not least the kaf-naf-parser comes shipped with a daemon that can read jobs (and write) jobs to and from Amazon SQS queues. For more information type:

kaf-naf-parser-daemon -h

Description of dependencies

The working part of this OpeNER component is the KafNafParserPy Python library. More documentation on this library can be found here and at KafNafParserPy Github Page.

This component runs best if you run it in an environment suited for OpeNER components. You can find an installation guide and helper tools in the OpeNER installer and an installation guide on the Opener Website.

At least you need the following system setup:

Dependencies for normal use:

  • Ruby 1.9.3 or newer
  • Python 2.6

Where to go from here

Report problem/Get help

If you encounter problems, please email or leave an issue in the issue tracker.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request


Command Line Interface


Provide subexamples
cat some_kaf.kaf | kaf-to-naf > output.naf
cat some_naf.naf | naf-to-kaf > output.kaf

cat some_kaf.kaf | kaf-naf-parser --tonaf > output.naf


You can launch a webservice by executing:


After launching the server, you can reach the webservice at http://localhost:9292.

The webservice takes several options that get passed along to Puma, the webserver used by the component. The options are:

    -b, --bind URI                   URI to bind to (tcp://, unix://, ssl://)
    -C, --config PATH                Load PATH as a config file
        --control URL                The bind url to use for the control server
                                     Use 'auto' to use temp unix server
        --control-token TOKEN        The token to use as authentication for the control server
    -d, --daemon                     Daemonize the server into the background
        --debug                      Log lowlevel debugging information
        --dir DIR                    Change to DIR before starting
    -e, --environment ENVIRONMENT    The environment to run the Rack app on (default development)
    -I, --include PATH               Specify $LOAD_PATH directories
    -p, --port PORT                  Define the TCP port to bind to
                                     Use -b for more advanced options
        --pidfile PATH               Use PATH as a pidfile
        --preload                    Preload the app. Cluster mode only
        --prune-bundler              Prune out the bundler env if possible
    -q, --quiet                      Quiet down the output
    -R, --restart-cmd CMD            The puma command to run during a hot restart
                                     Default: inferred
    -S, --state PATH                 Where to store the state details
    -t, --threads INT                min:max threads to use (default 0:16)
        --tcp-mode                   Run the app in raw TCP mode instead of HTTP mode
    -V, --version                    Print the version information
    -w, --workers COUNT              Activate cluster mode: How many worker processes to create
        --tag NAME                   Additional text to display in process listing
    -h, --help                       Show help


The daemon has the default OpeNER daemon options. Being:

Usage: kaf-naf-parser-daemon <start|stop|restart> [options]

When calling kaf-naf-parser without <start|stop|restart> the daemon will start as a foreground process

Daemon options:
    -i, --input QUEUE_NAME           Input queue name
    -o, --output QUEUE_NAME          Output queue name
        --batch-size COUNT           Request x messages at once where x is between 1 and 10
        --buffer-size COUNT          Size of input and output buffer. Defaults to 4 * batch-size
        --sleep-interval SECONDS     The interval to sleep when the queue is empty (seconds)
    -r, --readers COUNT              number of reader threads
    -w, --workers COUNT              number of worker thread
    -p, --writers COUNT              number of writer / pusher threads
    -l, --logfile, --log FILENAME    Filename and path of logfile. Defaults to STDOUT
    -P, --pidfile, --pid FILENAME    Filename and path of pidfile. Defaults to /var/run/
        --pidpath DIRNAME            Directory where to put the PID file. Is Overwritten by --pid if that option is present
        --debug                      Turn on debug log level
        --relentless                 Be relentless, fail fast, fail hard, do not continue processing when encountering component errors

Environment Variables

These daemons make use of Amazon SQS queues and other Amazon services. The access to these services and other environment variables can be configured using a .opener-daemons-env file in the home directory of the current user.

It is also possible to provide the environment variables directly to the deamon.

For example:

AWS_REGION='eu-west-1' kaf-naf-parser start [other options]

We advise to have the following environment variables available:

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 261712.