HTTP¶

AIS-catcher -H url [setting value] ...

Some cloud services collecting AIS data prefer messages to be periodically posted via the HTTP protocol, for example, APRS.fi. As per version 0.29, AIS-catcher can do this directly via the -H switch. For example:

AIS-catcher -r posterholt.raw -v 60 -H http://localhost:8000 INTERVAL 10 ID MyStation

will post JSON with the following layout every 10 seconds:

{
    "protocol": "jsonaiscatcher",
    "encodetime": "20221102171325",
    "stationid": "MyStation",
    "receiver":
        {
        "description": "AIS-catcher v0.39",
        "version": 39,
        "engine": "Base (non-coherent)",
        "setting": "droop ON fp_ds OFF "
        },
    "device":
        {
        "product": "FILE-RAW",
        "vendor": "",
        "serial": "",
        "setting": "rate 1536K file posterholt.raw format CU8"
        },
    "msgs": [ 
        {"class":"AIS","device":"AIS-catcher","rxtime":"20221102171324","scaled":true,"channel":"A","nmea":["!AIVDM,1,1,,A,13`fL1PP140KCELMBO7SS?wH0@Jv,0*50"],"ppm":0.000000,"type":1,"mmsi":244030470,"status":0,"status_text":"Under way using engine","speed":6.800000,"accuracy":false,"lon":5.964237,"lat":51.185970,"course":90.800003,"repeat":0,"second":44,"maneuver":0,"raim":false,"radio":67262}
    ]
}

We can use this functionality to submit data to APRS.fi directly without the need of middleware:

AIS-catcher -H http://aprs.fi/jsonais/post/secret-key ID callsign PROTOCOL aprs INTERVAL 30 -q

Where secret-key should be your password and callsign your callsign. The PROTOCOL setting instructs AIS-catcher to submit JSON in a form that is accepted by APRS.fi which is a multi-form HTTP message. The response from the server will be printed on screen, if you want to show this message only in case of an error, add RESPONSE OFF to the argument.

Another example of this HTTP feed functionality is to provide data to Chaos Consulting without the need to install any additional scripts. The Chaos Consulting server has been set up so that it can read the AIS-catcher JSON format as per above:

AIS-catcher -H https://ais.chaos-consulting.de/shipin/index.php USERPWD Station:Password GZIP on INTERVAL 5

Notice that this server requires authentication with a station name and password and accepts JSON with gzip encoding which significantly reduces bandwidth.

Important: to use and build AIS-catcher with HTTP support, please install the following libraries before running cmake:

sudo apt install libssl-dev zlib1g-dev

This step is only required if you want to ZIP content and post data to secure servers.

The supported protocol switches are AISCATCHER (default), MINIMAL (NMEA lines and metadata), LINES (one JSON message per line), APRS (to submit to APRS.fi).

Summary Settimgs¶

Key	Type	Default	Description
URL	string	-	Target HTTP endpoint URL
USERPWD	string	-	Authentication credentials
STATIONID	string	-	Station identifier
INTERVAL	integer	60	Post interval in seconds (1-86400)
TIMEOUT	integer	10	Connection timeout in seconds (1-30)
GZIP	boolean	false	Enable GZIP compression
RESPONSE	boolean	true	Show response messages
PROTOCOL	string	AISCATCHER	Protocol type (AISCATCHER/MINIMAL/AIRFRAMES/LIST/APRS)
LAT	float	0.0	Station latitude
LON	float	0.0	Station longitude
DEVICE_SETTING	string	N/A	Device settings

Note: filter and routing options can be set as per generic output settings