Using UDP to transfer files between mesh gateway and end-nodes

[armor]

I am looking into how best to transfer files - bitmap/.bmp - most likely 4K bytes in size from a gateway (could be Argon, Boron or Ethernet Xenon) to mesh end node devices. I am not sending files from the internet to the end node, only to the gateway and then I need a mechanism to safely transfer to the end nodes. This will be a broadcast type update. I can find software written in C for UDP file transfer but no libraries on Particle and wondered if the Community could provide any advice? Thanks

[ninjatill]

Have you seen this thread by @rickkas7? It may help...

Sending data with mesh devices

As it turns out, I misunderstood a few things about how data exchange works on mesh devices, and there are a lot more options for sending data from Xenons directly to the Internet, if you use UDP. In fact, you can communicate directly with IPv4 hosts on the Internet using UDP, directly from the Xenon! Particle.publish and Particle.subscribe The standard Particle.publish and Particle.subscribe functions work across the mesh network, and also allow communication with APIs (via webhooks and SSE) a…

[armor]

No I hadn’t - thanks for pointing it out to me! Unfortunately, it is not a solution for sending/receiving between mesh devices, at least as I understand the tutorial. I could use multiple mesh.publish() - splitting the file into packages that can be base64 encoded and fitted in 255 bytes. Just wondered if anyone else had thought how best to do this.

[ScruffR]

Rick also illustrates how to communicate via UDP in that post.
You want to look at the bidirectional UDP sample to cut out the need for a node server.

[armor]

@ScruffR I saw the bidirectional example - this requires a small node.js server. I am interested in a broadcast to the end node. I will ping Rick - using mesh.publish() is probably the best approach for now - is the data packet limited to 255 bytes or 622 bytes? Documentation says 255.

[ScruffR]

@armor

is the data packet limited to 255 bytes or 622 bytes? Documentation says 255.

Currently it still is 255 but I think that's going to change

Particle Device OS Updates: Comments

Yup, I can confirm that. As it seems the device OS fork for mesh devices was taken before the extension of the publish buffer. @rickkas7, can you forward that? Test code const char txt[] = "123456789112345678921234567893123456789412345678951234567896123456789712345678981234567899123456789A" "123456789112345678921234567893123456789412345678951234567896123456789712345678981234567899123456789B" "123456789112345678921234567893123456789412345678951234567896123456789712345678981234567899123456789…

[armor]

Thanks