Web Sockets

There are two WebSocket servers:

• Terminal WebSocket used to stream data to WebUI and exchange internal data

• Data WebSocket used to exchange data with external clients (not used by WebUI)

Terminal WebSocket

use subprotocol webui-v3 and port is web port +1 (e.g: 80+1=>81)

text mode

Reserved Messages between WebUI / ESP Format: (label):(message)

• from ESP to WebUI

  • currentID:(id) Sent when client is connecting, it is the last ID used and become the active ID

  • activeID:(id) Broadcast current active ID, when new client is connecting, client without this is (id) should close, ESP WS Server close all open WS connections but this one also

  • PING:<time left>:<time out> It is a response to PING from client to inform the time left if no activity (see below)

  • ERROR:(code):(message) If an error raise when doing upload, it informs client it must stop uploading because sometimes the http answer is not possible, or cannot cancel the upload, this is a workaround as there is no API in current webserver to cancel active upload

  • NOTIFICATION:(message) Forward the message sent by [ESP600] to webUI toast system

  • SENSOR: (value)[(unit)] (value2)[(unit2)] ... The sensor connected to ESP like DHT22

• from WebUI to ESP

  • PING:<current cookiesessionID / none > if any, or “none” if none

binary mode

Reserved

• from ESP to WebUI stream data from ESP to WebUI

• from WEBUI to ESP
  [-> File transfer from WebUI to ESP: not implemented yet]

Data WebSocket

use sub protocol arduino and port is any defined port (e.g: 8282)

text mode

This mode is used to transfer all G-code commands and their responses from the printer/CNC.

binary mode

This mode is used to transfer files to/from the ESP board.

It uses frames of 1024 bytes and can be increased after testing.

The frame format is: 2 bytes: for frame type 2 bytes: for frame size to check some integrity, currently as already part of frame no checksume is used x bytes : extra data according frame type

Frame types

Query status frame

type: client -> esp Status Request:

S	R	0	0

with hexadecimal values:

0x53	0x52	0	0

Response frame uses an inverted header: Response Status:

R	S	0	1	A

with hexadecimal values:

0x52	0x53	0	1	0x41

The first byte of the response indicates the state:

Code	Hexa	Meaning
B	0x42	busy
O	0x4F	idle/ok
E	0x45	error
A	0x41	abort
D	0x44	download ongoing
U	0x55	upload ongoing

Extra data may be added:

For Error:

error code and string, 1 byte : error code: 0->255 1 byte : string size 0->255 XX bytes for the string:

R	S	x	x	C	4	X	..	..

For Upload:

Upload information: 1 byte : path size 0->255 XX bytes : the path string 1 byte : the filename size 0->255 xx bytes : filename string 4 bytes : total file size 4 bytes : currently processed bytes 4 bytes : last packet id processed

R	S	x	x	U	X	..	..	X	..	..	S1	S1	S1	S1	S2	S2	S2	S2

For Download:

Download information: 1 byte : path size 0->255 XX bytes : the path string 1 byte : the filename size 0->255 xx bytes : filename string 4 bytes : total file size 4 bytes : currently processed bytes 4 bytes : last packet id processed

R	S	x	x	D	X	..	..	X	..	..	S1	S1	S1	S1	S2	S2	S2	S2

Start upload frame

Header is:

S	U	0	0

The content is: 1 byte : path size 0->255 XX bytes : the path string 1 byte : the filename size 0->255 xx bytes : filename string 4 bytes : total file size

S	U	x	x	D	X	..	..	X	..	..	S1	S1	S1	S1

If the answer is:

U	S	0	1	O

It means transfer can start.

Transfer upload frame

Header is:

U	P	x	x	ID	ID	ID	ID	..	..

4 bytes is packet id XXXX bytes is data

if packet is received the answer is

P	U	0	5	O	ID	ID	ID	ID

Start download frame

Header is:

S	D	0	0

The content is: 1 byte : path size 0->255 XX bytes : the path string 1 byte : the filename size 0->255 xx bytes : filename string 4 bytes : total file size

S	D	x	x	D	X	..	..	X	..	..	S1	S1	S1	S1

If the answer is:

D	S	0	1	O

It means transfer can start.

Transfer download frame

Header is:

D	P	x	x	ID	ID	ID	ID	..	..

4 bytes is packet id XXXX bytes is data

if packet is received the answer is:

P	D	0	5	O	ID	ID	ID	ID

Command frame

Header is:

C	M	0	1	X

Commands:

Code	Hexa	Meaning
A	0x41	abort

Abort command frame:

C	M	0	1	A