How to publish binary data

Firmware
1

I would like to publish 100 uint16_t values at once. I would like to publish them as binary value since then they fit into the 255 bytes of the data field:

optional data (up to 255 bytes)

Unfortunately the Particle.publish(const char *eventName, const char *data) only takes an ´const char *´ and no length and uses internally strlen() to calculate the length of the data which prevents sending binary data.

So the only way I found is encoding the binary data with a Base64 so I can send it as a string, but Base64 adds 33% overhead and with this my 100 uint16_t do not fit one publish anymore.

Is there another way to publish binary data without the overhead of an encoding?

2

You can also use Base85 but raw binary data can’t be transported via the cloud functions.
But TCP/UDP transport can send (unencrypted) binary data, but then you can also ignore the 255 byte limit.

Particle.variable() strings can only be requested not pushed, but a string variable can be as long as 622 characters.

1 Like
3

Thank you for the different options.

I will probably go with Base85 with the 25% overhead my 100 uint16_t values fit into the 255 bytes limit.

Raw TCP/UDP transport is no option since I have no server side that supports it.
The variable is no option since I need to push them from the device since the device will be most of the time offline to save power.