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 the port depends on the firmware. Please refer to the firmware documentation

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 the port depends on the firmware. Please refer to the firmware documentation

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. (not implemented yet)

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

Response frame uses an inverted header: Response Status:

R S 0 1 A

with hexadecimal values:

0x52

0x53

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