NAME

WebService::OpenSky - Perl interface to the OpenSky Network API

VERSION

version 0.4

SYNOPSIS

    use WebService::OpenSky;

    my $api = WebService::OpenSky->new(
        username => 'username',
        password => 'password',
    );

    my $states = $api->get_states;
    while ( my $vector = $states->next ) {
        say $vector->callsign;
    }

DESCRIPTION

This is a Perl interface to the OpenSky Network API. It provides a simple, object-oriented interface, but also allows you to fetch raw results for performance.

This is largely based on the official Python implementation, but with some changes to make it more user-friendly for Perl developers.

CONSTRUCTOR

Basic usage:

    my $open_sky = WebService::OpenSky->new;

This will create an instance of the API object with no authentication. This only allows you access to the get_states method.

If you want to use the other methods, you will need to provide a username and password:

    my $open_sky = WebService::OpenSky->new(
        username => 'username',
        password => 'password',
    );

You can get a username and password by registering for a free account on OpenSky Network.

Alternatively, you can set the OPENSKY_USERNAME and OPENSKY_PASSWORD environment variables, or create a .openskyrc file in your home directory with the following contents:

    [opensky]
    username = myusername
    password = s3cr3t

If you'd like that file in another directory, just pass the config argument:

    my $open_sky = WebService::OpenSky->new(
        config => '/path/to/config',
    );

All methods return objects. However, we don't inflate the results into objects until you ask for the next result. This is to avoid inflating all results if it's expensive. In that case, you can ask for the raw results:

    my $open_sky = WebService::OpenSky->new->get_states;
    my $raw = $open_sky->raw_response;

If you are debugging why something failed, pass the debug attribute to see a STDERR trace of the requests and responses:

    my $open_sky = WebService::OpenSky->new(
        debug => 1,
    );

In the unlikely event that you need to change the base URL, you can do so:

        my $open_sky = WebService::OpenSky->new(
                base_url => 'https://opensky-network.org/api/v2',
        );

The base url defaults to https://opensky-network.org/api.

METHODS

For more insight to all methods, see the OpenSky API documentation.

Note a key difference between the Python implementation and this one: the Python implementation returns <None> if results are not found. For this module, you will still receive the iterator, but it won't have any results. This allows you to keep a consistent interface without having to check for undef everywhere.

get_states

    my $states = $api->get_states;

Returns an instance of WebService::OpenSky::Response::States.

This API call can be used to retrieve any state vector of the OpenSky. Please note that rate limits apply for this call. For API calls without rate limitation, see get_my_states.

By default, the above fetches all current state vectors.

You can (optionally) request state vectors for particular airplanes or times using the following request parameters:

    my $states = $api->get_states(
        icao24 => 'abc9f3',
        time   => 1517258400,
    );

Both parameters are optional.

  • icao24

    One or more ICAO24 transponder addresses represented by a hex string (e.g. abc9f3). To filter multiple ICAO24 append the property once for each address. If omitted, the state vectors of all aircraft are returned.

  • time

    A Unix timestamp (seconds since epoch). Only state vectors after this timestamp are returned.

In addition to that, it is possible to query a certain area defined by a bounding box of WGS84 coordinates. For this purpose, add the following parameters:

    my $states = $api->get_states(
        bbox => {
            lomin => -0.5,     # lower bound for the longitude in decimal degrees
            lamin => 51.25,    # lower bound for the latitude in decimal degrees
            lomax => 0,        # upper bound for the longitude in decimal degrees
            lamax => 51.75,    # upper bound for the latitude in decimal degrees
        },
    );

You can also request the category of aircraft by adding the following request parameter:

    my $states = $api->get_states(
        extended => 1,
    );

Any and all of the above parameters can be combined.

    my $states = $api->get_states(
        icao24   => 'abc9f3',
        time     => 1517258400,
        bbox     => {
            lomin => -0.5,     # lower bound for the longitude in decimal degrees
            lamin => 51.25,    # lower bound for the latitude in decimal degrees
            lomax => 0,        # upper bound for the longitude in decimal degrees
            lamax => 51.75,    # upper bound for the latitude in decimal degrees
        },
        extended => 1,
    );

get_my_states

    my $states = $api->get_my_states;

Returns an instance of WebService::OpenSky::Response::States.

This API call can be used to retrieve state vectors for your own sensors without rate limitations. Note that authentication is required for this operation, otherwise you will get a 403 - Forbidden.

By default, the above fetches all current state vectors for your states. However, you can also pass arguments to fine-tune this:

    my $states = $api->get_my_states(
        time    => 1517258400,
        icao24  => 'abc9f3',
        serials => [ 1234, 5678 ],
    );
  • time

    The time in seconds since epoch (Unix timestamp to retrieve states for. Current time will be used if omitted.

  • <icao24>

    One or more ICAO24 transponder addresses represented by a hex string (e.g. abc9f3). To filter multiple ICAO24 append the property once for each address. If omitted, the state vectors of all aircraft are returned.

  • serials

    Retrieve only states of a subset of your receivers. You can pass this argument several time to filter state of more than one of your receivers. In this case, the API returns all states of aircraft that are visible to at least one of the given receivers.

get_arrivals_by_airport

    my $arrivals = $api->get_arrivals_by_airport('KJFK', $start, $end);

Returns an instance of WebService::OpenSky::Response::Flights.

Positional arguments:

  • airport

    The ICAO code of the airport you want to get arrivals for.

  • start

    The start time in seconds since epoch (Unix timestamp).

  • end

    The end time in seconds since epoch (Unix timestamp).

The interval between start and end time must be smaller than seven days.

get_departures_by_airport

Identical to get_arrivals_by_airport, but returns departures instead of arrivals.

get_flights_by_aircraft

    my $flights = $api->get_flights_by_aircraft($icao24, $start, $end);

Returns an instance of WebService::OpenSky::Response::Flights.

The first argument is the lower-case ICAO24 transponder address of the aircraft you want.

The second and third arguments are the start and end times in seconds since epoch (Unix timestamp). Their interval must be equal to or less than 30 days.

get_flights_from_interval

    my $flights = $api->get_flights_from_interval($start, $end);

Returns an instance of WebService::OpenSky::Response::Flights.

get_track_by_aircraft

        my $track = $api->get_track_by_aircraft( $icao24, $start );

Adds support for the experimental GET /tracks endpoint. Returns an instance of WebService::OpenSky::Response::FlightTrack.

Per the OpenSky documentation, this endpoint is experimental and may be removed or simply not working at any time.

limit_remaining

    my $limit = $api->limit_remaining;

Returns the number of API credits you have left. See https://openskynetwork.github.io/opensky-api/rest.html#limitations for more information.

If you have not yet made a request, this method will return undef.

delay_remaining($method)

        my $delay = $api->delay_remaining('get_states');

When you call either get_states or get_my_states, the your calls will be rate limited. This method returns the number of seconds you have to wait until you can make another request. You can sleep that many seconds before making a new call:

        sleep $api->delay_remaining('get_states');

If you attempt to make a request before the delay has expired, you will get a warning and no request will be made.

See limitations for more details.

EXAMPLES

Perl Wikipedia, OpenSky Network is ...

    The OpenSky Network is a non-profit association based in Switzerland that
    provides open access of flight tracking control data. It was set up as
    a research project by several universities and government entities with
    the goal to improve the security, reliability and efficiency of the
    airspace. Its main function is to collect, process and store air traffic
    control data and provide open access to this data to the public. Similar
    to many existing flight trackers such as Flightradar24 and FlightAware,
    the OpenSky Network consists of a multitude of sensors (currently around
    1000, mostly concentrated in Europe and the US), which are connected to
    the Internet by volunteers, industrial supporters, academic, and
    governmental organizations. All collected raw data is archived in a
    large historical database, containing over 23 trillion air traffic control
    messages (November 2020). The database is primarily used by researchers
    from different areas to analyze and improve air traffic control
    technologies and processes

Elon Musk's Jet

However, this data can be used to track the movements of certain aircraft. For example, Elon Musk's primary private jet (he has three, but this is the one he mainly uses), has the ICAO24 transponder address a835af. Running the following code ...

    use WebService::OpenSky;

    my $musks_jet = 'a835af';
    my $openapi   = WebService::OpenSky->new;

    my $days = shift @ARGV // 7;
    my $now  = time;
    my $then = $now - 86400 * $days;    # Max 30 days

    my $flight_data = $openapi->get_flights_by_aircraft( $musks_jet, $then, $now );
    say "Jet $musks_jet has " . $flight_data->count . " flights";

As of this writing, that prints out:

    Jet a835af has 6 flights

ETHICS

There are some ethical considerations to be made when using this module. I was ambivalent about writing it, but I decided to do so because I think it's important to be aware of the privacy implications. However, it's also important to be aware of the climate implications.

Others are using the OpenSky API to model the amount of carbon being released by the aviation industry, while others have used this public data to predict corporate mergers and acquisitions. There are a wealth of reasons why this data is useful, but not all of those reasons are good. Be good.

AUTHOR

Curtis "Ovid" Poe <curtis.poe@gmail.com>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2023 by Curtis "Ovid" Poe.

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)