InfoAPI
Contents
What is infoAPI
The InfoAPI allows 3rd party applications and websites to get information about live tracks, like for example the position and height of a specific username thus allowing 3rd parties to construct usable and functional views on the livetrack database.
Restrictions
An API key and API secret are required to use the API. Currently i will only give these to developers of mobile applications to add extra value to their applications by querying useful info from the livetrack24.com
How to use
the url of the API is
http://www.livetrack24.com/api.php?....
and the parameters are
a=<APIKEY> c=<special CRC of the unencoded request text> m=<encoded request text>
We will see later what should be the contents of m variable, now we must
- compute the special CRC of the unencoded text
- encode the request text
Compute the special CRC of the unencoded text
Here is the php code to compute the CRC
function crc_16($data,$key) {
$crc = 0xFFFF;
for ($i = 0; $i < strlen($data); $i++)
{
$x = ( ($crc >> 8 ) ^ ( ord( $data [ $i ] ) + $key [ $i ] ) ) & 0xFF;
$x ^= $x >> 4;
$crc = ( ( $crc << 8 ) ^ ( $x << 12 ) ^ ( $x << 5 ) ^ $x ) & 0xFFFF;
}
return dechex($crc);
}
- $data is the clear text
- $key is your API secret (not the API key)
What you get from this function is a 4 char string that represents a 32 bit integer in hex format (ie 4E21 )
Encode the request text
Here is the function to encode your request text
function encryptWithApiKey($str,$key) {
$final="";
for($i=0; $i< strlen($str) ; $i++ ) {
$charcode= ord( $str$i );
$keypos= $i % strlen($key);
if ( $keypos > 0 )
$sign=( $key[ $keypos - 1 ] % 2 ) ? 1 : -1;
// if the previous digit from the key is odd, 1 , else -1
else
$sign=1;
$encryptedCode= $charcode + $key[ $keypos ] * $sign ;
$encryptedHex=dechex( $encryptedCode );
$final.= $encryptedHex;
}
return $final;
}
- $str is the clear request text
- $key is your API secret (not the API key)
What you get from this function is a char string with hex values, you must pass this as &m=.... to the API url
Example
Assume you have
- API key="R35G7852"
- API secret="3467257245748253452345214"
- Request text="7;1;0" -> this is a simple ping request to the server, it returns the server IP
What you should compute is
- crc should be bd26
- the encrypted message should be 3a3e2b3332
- so the api url is
http://www.livetrack24.com/api.php?a=R35G7852&c=bd26&m=3a3e2b3332
Using un-encoded requests for testing
For the period of testing, you can request an API key with unencoded access, you can use this to send un-encoded requests to the server with the following format:
Example
to use the previous exmaple
http://www.livetrack24.com/api.php?a=R35G7852&cm=7;1;0
to get the 30 most near tracks around lat/lon 40.2,23.1 in a radious of 100 km in the last 20000000 secs
http://www.livetrack24.com/api.php?a=R35G7852&cm=1;3;255;40.2;23.1;100;0;20000000;30
Operations
Get nearby tracks around a given point
Request text
1;<return type (only 3->json is supported>;<detail level 0-255 (not in effect currently, )>;<latitude of center in decimal format>;<longtitude of center in decimal format>;<search radius in km>;<activity type: 0->all, 1->3d (ie flights), 2->2D (ie run, bike)>;<return only tracks in the last X secs>;<return only latest X results, sorted by last fix>
Sample Request text
1;3;255;40.2;23.1;100;0;259200;30
<1=Get nearby tracks>;<3=return as json>;<255=max detail>;<latitude of center=40.2>;<longtitude of center=23.1>;<search in radius of 100 km>;<search in 2D and 3D activities>;<return only tracks in the last 259200 secs - 3 days>;<return only latest 30 results, sorted by last fix>
Returns
distance: distance (in m) of the last point of this track to the provided lat/lon bearing: bearing (0-360) of the last point of this track to the provided lat/lon username: the username of this track tm: timestamp of last fix we got (in UTC) trackID: the ID of the track, can be used to obtain more info for this track lat: latitude in decimal format of the last fix lon: langitude in decimal format of the last fix alt: altidute (in m) of the last fix cog: Course over ground (0-360) of the last fix sog: Speed over ground (in km/h) of the last fix
Get takeoffs around given point
Request text
1;<return type (0,1,2 currently supported)>;<detail level 0-255 (not in effect currently)>;<latitude of center in decimal format>;<longtitude of center in decimal format>;<search radius in km>;<return only X results>
Sample Request text
3;1;255;40.2;23.1;100;30
Get position of username(s) or userID(s)
Request text
2;2:<return type (0,1,2 currently supported)>;<detail level 0-255>;username1,username2...;userid1,userid2...;lat;lon;radious for nearby waypoints;limit for each category of waypoints
if you provide a set of lat/lon the output will also include the distance and bearing of the user in relation to the provided lat/lon
Returns
- to be completed-
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