C++ API for Duet 3 Mainboard 6HC

ElevenJune

@T3P3Tony I have a question just to be sure I understood well. I will soon start the development of a control App and want to be sure before beginning to code.

I will develop a C++ software, can it communicate with the Duet 3 in these configurations :

Duet 3 6HC In Standalone mode. I plug a RJ45 cable between the Duet and a PC (no Raspberry Pi or other SBC is involved) and can use the HTTP Requests to communicate with the card (https://github.com/Duet3D/RepRapFirmware/wiki/HTTP-requests). My software exchanges directly with RepRapFirmware
Duet 3 6HC connected to an Raspberry Pi 4 (a SBC) through SPI. I run the Duet Web Server on the Raspberry and can there use the RESTful API (https://github.com/Duet3D/DuetSoftwareFramework#rest-api) to communicate with the card. I can deploy my software on the Raspeberry Pi or on a more powerful PC (not a SBC) that I will connect to the Raspberry with RJ45. My software exchanges with Duet Web Server , like Duet Web Control exchanges with Duet Web Server

Is this right please ?

There is the third option where I can develop my own C++ API communicating with the card through SBC and use it as part of my C++ software. I do not plan on choosing this one.

I really thank you in advance !

T3P3Tony

@ElevenJune said in C++ API for Duet 3 Mainboard 6HC:

@T3P3Tony I have a question just to be sure I understood well. I will soon start the development of a control App and want to be sure before beginning to code.

I will develop a C++ software, can it communicate with the Duet 3 in these configurations :

Duet 3 6HC In Standalone mode. I plug a RJ45 cable between the Duet and a PC (no Raspberry Pi or other SBC is involved) and can use the HTTP Requests to communicate with the card (https://github.com/Duet3D/RepRapFirmware/wiki/HTTP-requests). My software exchanges directly with RepRapFirmware

Yes, configure a fixed IP on the Duet and your laptop within the same range

Duet 3 6HC connected to an Raspberry Pi 4 (a SBC) through SPI. I run the Duet Web Server on the Raspberry and can there use the RESTful API (https://github.com/Duet3D/DuetSoftwareFramework#rest-api) to communicate with the card. I can deploy my software on the Raspeberry Pi or on a more powerful PC (not a SBC) that I will connect to the Raspberry with RJ45. My software exchanges with Duet Web Server , like Duet Web Control exchanges with Duet Web Server

That is also possible. If you are deploying to the Same raspberry pi then I have not tested connection to the Webserver restful API using 127.0.0.1, you might need to use the external facing IP.

Is this right please ?

There is the third option where I can develop my own C++ API communicating with the card through SBC and use it as part of my C++ software. I do not plan on choosing this one.

I really thank you in advance !

ElevenJune

@T3P3Tony Thanks a lot ! This is clear for me !

ElevenJune

@T3P3Tony I have a new question regarding a command
How does the M291 command (to display a message) works ?
If this command is in a G-Code being executed, how can I retrieve the message ? How will the REST API will notify me of this please ?

ElevenJune

Concerning the REST API, can I access a statut Response like the one proposed by RepRapFirmware please ? https://github.com/Duet3D/RepRapFirmware/wiki/JSON-responses
I can't find any info on this.

dc42

That's one for @chrishamm, however there is some documentation here https://github.com/Duet3D/DuetSoftwareFramework/blob/master/README.md.

ElevenJune

@dc42 Thank you for your answer ! My question is regarding this request : https://github.com/Duet3D/DuetSoftwareFramework/blob/master/README.md#get-machinestatus
Do you know where I can find the status response that I will receive when using this request please ?

MintyTrebor

@ElevenJune: When getting status information I think you may benefit from understanding the JSON Machine Model, as most of the information returned via status requests will be either the full Machine Model, a subset, or a patch - depending on the api and commands you use. There is a Machine Model plugin for DWC which is a great way of navigating the model to find where keys/values are.

For example you mentioned a M291 msg: When triggered, an M291 command will populate the Machine Model keys:

state.messageBox.title

state.messageBox.message

So the command : M291 P"This Is A Test Msg" R"My Msg"
Would result in:

state.messageBox.title : "My Msg"

state.messageBox.message : "This Is A Test Msg"

The values will auto clear once the msg has been acknowledged or timed-out.
(Note: There are other keys set by M291 but I have excluded them for brevity)

(I actually use these keys specifically in my NodeDSF project to trigger events. I would normally point you at my code to give you an idea, but its node.js/javascript so I'm not sure it would be much help.)

Hope this helps!

ElevenJune

@MintyTrebor Thanks for your reply ! Unfortunately I will be programming in C++ so I cannot use this Machine Model. Do you know how I can access this type of information with the REST API to later use it in C++ please ?

MintyTrebor

@ElevenJune If your using the rest api to query the status then you will have to use the machine model. The HTTP GET /machine/status request you can send returns a JSON object which is the Machine Model. If you go the websocket route, it will still be JSON and the machine model. I don't think there is any way around it with the rest api.

ElevenJune

@MintyTrebor Thanks for your reply.
Is MachineModel a Json structure that will be returned with the request ? Or is it a something like a JavaScript class ? I don't understand.

MintyTrebor

Is MachineModel a Json structure that will be returned with the request ?
Yes.
The easiest way of seeing it is by entering:

http://[your sbc/dsf ip address]/machine/status

into your browser.

It should just return the full JSON Machine Model as text (if using firefox it will automatically parse for you).

For the avoidance of confusion - the returned data is just text with an enforced structural pattern (JSON)

ElevenJune

@MintyTrebor Thanks for your reply and your patience, I got a bit confused while reading the last messages !
This is what I am looking for. I don't have received my Duet card yet so I can't try the request, would you have a link showing the content of the Machine Model or an example of it please ?

MintyTrebor

https://duet3d.dozuki.com/Wiki/Object_Model_of_RepRapFirmware

will get you started.

ElevenJune

@MintyTrebor This is what I needed ! Thank you
If this the structure to use when I want to retrieve info during printing (like position, % of completion, speed, etc) or is there a other one ?