JSON-RPC server for low end MCU's (a C++11 library)

[Євген Хуторний]

Dear Community,

Please let me share a library for implementing JSON-RPC API on low end MCUs.
Examples, coming with the library, illustrate how to create JSON-RPC API on Arduino Mega and Particle Photon boards.

Here is a code snippet from Arduino example:

/* class, implementing RPC call digitalWrite                                  */
class DigitalWrite : public Procedure {
public:
    typedef DigitalWrite self;
    /* micurpc calls this method to read procedure parameters                 */
    bool read_params(lexer& in) noexcept {
        return
            Params<self, uint8_t, uint8_t>::    /* defines parameter types    */
            Names<name::pin, name::val>::       /* defines parameter names    */
            FieldPointers<&self::pin,&self::val>/* binds parameters to members*/
            ::json().read(*this, in);           /* reads JSON                 */
    }
    /* micurpc calls this method to write result                              */
    bool write_result(ostream& out) const noexcept {
        /* result must be a JSON value (in its wide sense)                    */
        return write(val, out);
    }
    /* micurpc calls this method to run the procedure                         */
    void run(response::error_t& error) noexcept {
        if(! digitalPinIsOK(pin, error)) return;
        if( val != 0 && val != 1 ) {
            invalidParameter(error);
            return;
        }
        digitalWrite(pin, val);
        val = digitalRead(pin);
    }
    /* defines a literal name for this procedure                             */
    static cstring method() noexcept { return name::digitalWrite(); }
private:
    uint8_t pin = -1; /* invalid initial values indicated missing parameter  */
    uint8_t val = -1;
};

And some screenshots:

[Matt (MPCM)]

Very cool, thanks for sharing!