Unable to upload G-code from OrcaSlicer to ESP3DLib (HTTP 400 error on v3)

[anlaco]

Hi everyone,

I'm trying to send G-code files directly from OrcaSlicer to my 3D printer running ESP3DLib. Unfortunately, the upload fails every time.

I've tested with both ESP3DLib v1 and v3, but in both cases the file transfer from OrcaSlicer doesn't work. With v3, I consistently get an HTTP 400 Bad Request error as soon as the slicer tries to upload the file.

Has anyone managed to use OrcaSlicer successfully with ESP3DLib?
Are there any known compatibility issues or specific upload requirements (e.g. endpoint, headers, field names) that need to be addressed?

Any help would be greatly appreciated. Thanks!

[luc-github]

how do you set upload path in orca?

[anlaco]

I suppose they've used the same method that's used by the web interface upload — that's what I noticed the first time I checked. They should at least provide a generic option for file upload via pull requests. I'm going to try configuring something to make it work with esp3dlib v3, although I'm not entirely sure why this method is considered obsolete.

[luc-github]

but to be clear:
in ESP3D 2.X
handler is /upload_serial because it does not allow direct SD Upload but only M28/M29 protocol which now dropped
in ESP3DLib 1.X
handler is /upload because upload_serial make no sense
in ESP3DLib 3.X and ESP3D 3.X:
handler is /sdfiles because /upload is used by MKS protocol and because it allows direct access to SD according hardware configuration.

Since 3.X ESP3DLib and ESP3D share same code at 99% so be sure you communicate right version when you share your fix

I have tested orca slicer and indeed it is set the ip only, because of Temperatures queries I guess, not only upload

[anlaco]

Hi, thank you very much for your work and for sharing all this valuable information.

I'm quite new to ESP3D and still trying to understand how everything works, so I hope you don't mind if I ask a few questions to clarify my doubts.

I’m currently using ESP3DLib only, because I work directly with an ESP32 DevKit board. I’m using version 1.x of the library since it’s the one that comes integrated with Marlin.

Looking at the code, it seems that the correct upload handler in V1 is /upload, but I’m not completely sure about this and would appreciate your confirmation.

Also, I don’t fully understand what the MKS protocol refers to, or why the behaviour changes depending on the hardware — for example, why /sdfiles works with some setups but not others.

Lastly, regarding temperature queries, I’ve noticed Orca Slicer sets the printer’s IP, but I’m not sure how temperature readings affect the upload or communication flow.

Thanks again for your dedication and for helping the community — I really appreciate it.

[luc-github]

Ho boy you are right - I wrote wrong orz... ESP3DLib V1 handler is /upload - at that ime no mks protocole was yet supported...too many version

the MKS protocol upload is serial upload but not using M28/M29 commands and it is specific to MKS boards but faster (~110KB/s) than M28/M29 protocol (~0.4KB/s)

The /SDFILES is present when esp board is directly connected to SD Card reader which is the case if you use ESP3DLib or in some hardware configurations, Direct SD connected to ESP like in ESP32Cam or when using multiplexer SD card sharing solution: https://esp3d.io/ESP3D/Version_3.X/documentation/sdtransfer/

Lastly, regarding temperature queries, I’ve noticed Orca Slicer sets the printer’s IP, but I’m not sure how temperature readings affect the upload or communication flow

It does not really but IP is same for getting current temperatures / positions or for doing file upload

I hope it clarify - with V3 I have tried to make everything clear - so soon v3 should be the reference

[anlaco]

Thank you very much for the clarification!

I’m currently designing educational kits, and my plan is to use a board with an ESP32 chip, running Marlin with ESP3DLib, and using OrcaSlicer as the front-end for students and makers.

For now, I’ll stick with V1, as it works well in my current setup. However, I’ll definitely start studying V3, especially since it looks like it will become the main reference moving forward.

I truly appreciate all the work you've put into this project. If I ever get any financial benefit from these kits, I’ll make sure to donate a part to support your amazing work.

Thanks again!