D2Sphere Key / Value Mapping Parser Specification

Introduction

Devices send key-value data in the format described here.

These data, even if following some special format definitions, come in in a typeless form. To visualize these data in the frontend, one of the key features of the mapping engine is to define the underlying format of the incoming data, e.g. key1="1.23" would suggest the type DOUBLE as the mapping type inside a mapping definition. Attaching a human readable name is another benefit from the mapping. So properly named in the mapping definition a key as e.g. _temp could be mapped to a more readable form as temperature.

The most interesting feature comes in with the description of an optional formula, which can convert any incoming values and formats on-the-fly to more meaningful values. The underlying framework used for these calculations is mXparser. D2Sphere uses a more or less the complete subset out of these features, even that some format restrictions come into place.

Specification

• The outgoing key can be named differently from the incoming one, e.g. _accl_x vs. formula $[N(0)]_accl$ * 10;

Restrictions

Even if the incoming value (or parts of it in case of a vecotr) can be used more than once inside the same formula, there is currently no support for different incoming values inside one formula!

Examples

$<sfal.data key1='value1' key2='value2' keyX='valueX'>" CRLF
$GPRMC CRLF (optional)
$ .... CRLF (optional)
$<end> CRLF