Skip to content

g2core REST Interface

Jump to bottom Edit New page
Alden Hart edited this page Nov 16, 2016 · 9 revisions

PRELIMINARY
This page is used for discussion of the g2core REST interface.
Please also see the companion page g2core REST Resources. This is a design page; we expect that we will use Swagger to ultimately document the REST API.

The g2core REST API, which is the top layer of the three nested APIs:

  • g2core REST API - exposed via node-g2core-server module
  • g2core NodeJS API - exposed via node-g2core-api module
  • g2core firmware API - exposed via serial and USB from the g2core firmware

#Background The g2core REST API is a RESTful API that allows control of a CNC machine and associated "print jobs". The conceptual model has these layers:

  1. Host Functions - e.g communications setup, managing files, other non-CNC things
  2. Machine Setup - job-agnostic machine configuration and actions (e.g. homing)
  3. Job Setup and Mgmt - job and material setup, pre-job operations, job queuing, etc.
  4. Job Runtime - job start and stop, pause/resume, status reporting, feedback...

1. Host Functions

These functions are the domain of the host operating system and don't involve the CNC machine at all. In general the g2core REST API tries not to concern itself with host functions, but some functions such as receiving, storing, and locating files are necessary to upload and manage files over the REST interface. The API may implement:

  • File and filesystem primitives such as get, view, edit, write, store
  • Advanced viewers such as 3d rendering

Additional host functions are not the domain of this API, may include:

  • Communications functions such as wireless setup and connectivity.
  • CAD/CAM and other modeling and design

2. Machine Setup

Machine setup reads and writes parameters and initiates actions to configure the CNC machine independently of any given job. They may be done once and once only, periodically, or before or after a job. These may include:

  • Machine Configuration exposes machines settings generally not changed on a per-job basis. E.g. communications settings, reporting levels, machine startup defaults. All settings exist at the same level, so it's up the the UI to determine which to show to users, which are "expert", and which should be hidden (if any). Machine configuration is implemented as synchronous REST calls to various machine resources.

  • Machine Operations includes actions such as homing, axis tramming or automatic bed leveling that may be run on power up, periodically, or before a job is run. Machine operations are implemented as long-running asynchronous REST calls bundled in an operation resource that provides a control context for the duration of the operation.

3. Job Setup and Management

Job setup and management handles commands to prepare a job for runtime. It operates on job resources, and the job queue (job list), which orders the jobs to be run.

The model for job management is borrowed from commercial printing operations. A 'job jacket' is a container for a job. It includes one or more 'print files', a 'master' JSON doc with job metadata and a declarative control specification, and any other files that make up the job bundle such as multi-file prints, runtime logs, etc. (In implementation the jacket can be a directory containing a bunch of files).

The API implements:

  • Fetch and manipulate job files
  • Preview/check job file
  • Queue and order jobs for execution
  • Define job parameters - e.g. filament type and size

4. Job Runtime

Job runtime scopes those things that happen while the job is running. It is differentiated from job setup because there are commands that can only be executing during job runtime (e.g. feedholds), and other commands that should not be executed during runtime (e.g. machine configuration). The REST interface implements the following runtime state changes:

  • Start/stop job (including running the Gcode)
  • Pause and resume job (feedhold / cycle start)
  • In-job manual operations (tool change, filament restock)
  • Report job progress
  • Job exception reporting, handling, and job recovery

A Note on Formats: Most of the functions above are accessed using REST/JSON, with the Gcode commands being the exception. We call the Gcode a 'tape' because it's pre-planned motion that executes linearly, does not loop or branch (g2core does not support O codes), and can be controlled like a tape machine. It can be stopped, started, sped up and slowed down, paused and resumed. You may be able to do things in the pauses such as manual tool changes, but that doesn't change the tape itself. Tapes used to actually be paper tapes, just like phones used to have dials and dial tones.

#Examples

##Info

GET /info

REQUEST:
  GET /info HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"fv":0.99,"fb":100.12,"fbs":"100.12-14-g375c-dirty","fbc":"settings_makeblock.h","hp":3,"hv":0,"id":"0084-7bd6-29c6-8ce","msg":"SYSTEM READY"}

Machine

The machine REST endpoint is used to query machine state and to query and set machine parameters in the machine resource. It is intended for JSON commands that execute synchronously, as most queries and configuration settings do. The API can handle single values, JSON objects, or composite JSON documents consisting of multiple values and/or objects. Examples are provided for each.

To send Gcode or to invoke long-running JSON commands that require asynchronous handling see operation.

GET /machine

Return machine objects and/or attributes by a JSON specification in the request body. The following calling styles are supported:

(body omitted)              no body provided. Return entire machine
{ }                         key is empty object. Return entire machine
{"stat":null}               key is freestanding; not part of an object (system state)
{"x":null}                  key is an object (X axis)
{"x":{"vm":null}}           key is part of an object (X axis max velocity)
{"xvm":null}                key is flattened version of above (may be deprecated later)
{"x.vm":null}               key is flattened version of above (planned for future)
{"x":null,"y":null}         key described multiple objects (X and Y axes)
{"x":null,"y":{"jm":null}}  key is mixed objects and attributes
{"posx":null,"posy":null,"posz":null,"vel":null,"stat":null} key has multiple attributes

REQUEST:
  GET /info HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
{"value":
{
"sys":{"fb":100.12,"fbs":"100.12-14-g375c-dirty", "fbc":"settings_makeblock.h","fv":0.99,"hp":3,"hv":0, "id":"0084-7bd6-29c6-4ad", "jt":0.75,"ct":0.1,"sl":0,"lim":0,"saf":1,"m48e":1,"mfoe":0,"mfo":1,"mtoe":0,"mto":1,"mt":2,"spep":1,"spdp":0,"spph":1,"spdw":1,"ssoe":0,"sso":1,"cofp":1,"comp":1,"coph":0,"tv":1,"ej":1,"jv":2,"qv":0,"sv":1,"si":250,"gpl":0,"gun":1,"gco":1,"gpa":2,"gdi":0},
"x":{"am":1,"vm":40000,"fr":40000,"tn":0,"tm":420,"jm":5000,"jh":20000,"hi":1,"hd":0,"sv":3000,"lv":100,"lb":4,"zb":2},
"y":{"am":1,"vm":40000,"fr":40000,"tn":0,"tm":420,"jm":5000,"jh":20000,"hi":3,"hd":0,"sv":3000,"lv":100,"lb":4,"zb":2},
"z":{"am":1,"vm":1200,"fr":1200,"tn":-95,"tm":0,"jm":500,"jh":1000,"hi":6,"hd":1,"sv":800,"lv":25,"lb":4,"zb":2},
"a":{"am":0,"vm":393701,"fr":393701,"tn":-1,"tm":-1,"jm":49213,"jh":49213,"ra":5.821,"hi":0,"hd":0,"sv":196850,"lv":39370.08,"lb":5,"zb":2},
"b":{"am":0,"vm":393701,"fr":393701,"tn":-1,"tm":-1,"jm":49213,"jh":49213,"ra":5.821,"hi":0,"hd":0,"sv":196850,"lv":39370.08,"lb":5,"zb":2},
"c":{"am":0,"vm":393701,"fr":393701,"tn":-1,"tm":-1,"jm":49213,"jh":49213,"ra":5.821,"hi":0,"hd":0,"sv":196850,"lv":39370.08,"lb":5,"zb":2},
"1":{"ma":0,"sa":1.8,"tr":36.576,"mi":8,"su":43.74453,"po":0,"ep":1,"pm":2,"pl":0.4},
"2":{"ma":1,"sa":1.8,"tr":36.576,"mi":8,"su":43.74453,"po":0,"ep":1,"pm":2,"pl":0.4},
"3":{"ma":2,"sa":1.8,"tr":1.25,"mi":8,"su":1280,"po":0,"ep":1,"pm":2,"pl":0.4},
"4":{"ma":3,"sa":1.8,"tr":360,"mi":8,"su":4.44444,"po":0,"ep":1,"pm":0,"pl":0},
"do1":{"mo":1},
"do2":{"mo":1},
"do3":{"mo":1},
"do4":{"mo":1},
"do5":{"mo":1},
"do6":{"mo":1},
"do7":{"mo":1},
"do8":{"mo":1},
"do9":{"mo":1},
"di1":{"mo":0,"ac":0,"fn":0},
"di2":{"mo":0,"ac":0,"fn":0},
"di3":{"mo":0,"ac":0,"fn":0},
"di4":{"mo":0,"ac":0,"fn":0},
"di5":{"mo":0,"ac":0,"fn":0},
"di6":{"mo":0,"ac":0,"fn":0},
"di7":{"mo":0,"ac":0,"fn":0},
"di8":{"mo":0,"ac":0,"fn":0},
"di9":{"mo":0,"ac":0,"fn":0},
"he1":{"e":false,"p":9,"i":0.12,"d":400,"st":0,"t":-1,"op":0,"tr":-1,"at":false,"an":0,"fp":1,"fm":0.4,"fl":40,"fh":40},
"he2":{"e":false,"p":9,"i":0.12,"d":400,"st":0,"t":-1,"op":0,"tr":-1,"at":false,"an":0,"fp":1,"fm":0.4,"fl":40,"fh":40},
"he3":{"e":false,"p":9,"i":0.12,"d":400,"st":0,"t":-1,"op":0,"tr":-1,"at":false,"an":0,"fp":1,"fm":0.4,"fl":40,"fh":40},
"g54":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g55":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g56":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g57":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g58":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g59":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g92":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g28":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
"g30":{"x":0,"y":0,"z":0,"a":0,"b":0,"c":0},
}
}

Return top level objects in a machine

REQUEST:
  GET /info?shallow=true HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":{"sys":true,"x":true,"y":true,"z":true,"a":true,"b":true,"c":true,"1":true,"2":true,"3":true,"4":true,"do1":true,"do2":true,"do3":true,"do4":true,"do5":true,"do6":true,"do7":true,"do8":true,"do9":true,"di1":true,"di2":true,"di3":true,"di4":true,"di5":true,"di6":true,"di7":true,"di8":true,"di9":true,"he1":true,"he2":true,"he3":true,"g54":true,"g55":true,"g56":true,"g57":true,"g58":true,"g59":true,"g92":true,"g28":true,"g30":true}}

Response prettified:

{
	"value": {
		"sys": true,
		"x": true,
		"y": true,
		"z": true,
		"a": true,
		"b": true,
		"c": true,
		"1": true,
		"2": true,
		"3": true,
		"4": true,
		"do1": true,
		"do2": true,
		"do3": true,
		"do4": true,
		"do5": true,
		"do6": true,
		"do7": true,
		"do8": true,
		"do9": true,
		"di1": true,
		"di2": true,
		"di3": true,
		"di4": true,
		"di5": true,
		"di6": true,
		"di7": true,
		"di8": true,
		"di9": true,
		"he1": true,
		"he2": true,
		"he3": true,
		"g54": true,
		"g55": true,
		"g56": true,
		"g57": true,
		"g58": true,
		"g59": true,
		"g92": true,
		"g28": true,
		"g30": true
	}
}

GET /machine/{key}

A {key} can be any of the following. The examples illustrate these cases.

  • /machine/stat - key is freestanding; not part of an object (system state)
  • /machine/x/vm - key is part of an object (X axis max velocity)
  • /machine/xvm - flattened version of the above (may be deprecated in the future)
  • /machine/x.vm - flattened version of the above planned for future
  • /machine/x - key is entire object

Get the value of a single {key} of ct (chordal tolerance) as an example, which is a numeric type.

REQUEST:
  GET /machine/ct HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":0.01}

Get the value of a single {key} x/jm (max jerk in the X axis), which is a numeric type.

REQUEST:
  GET /machine/x/jm HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":1200}

Same as above using flattened notation xjm

REQUEST:
  GET /machine/xjm HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":1200}

Get the value of a single object {key} using the pos object as an example.

REQUEST:
  GET /machine/pos HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":{"pos":{"x":0,"y":0,"z":0,"a":0,"b":0}}}

PUT /machine/{key}

Using a {key} of xjm as an example, which is a numeric type.

REQUEST:
  GET /machine/xjm HTTP/1.1
  {"value":1200}

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":1200}

Using a {key} of g54 as an example, which is an object type.

REQUEST:
  GET /machine/pos HTTP/1.1
  {"value":{"g54":{"x":0,"y":0,"z":0,"a":0,"b":0}}}

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"value":{"g54":{"x":0,"y":0,"z":0,"a":0,"b":0}}}

Status Reports

GET /status_report

See status report resource for operation.

Question: Is it useful for status_report to report back the operation ID and/or job ID it is reporting on?

Use a status report with no filter to return all keys configured in the status report

REQUEST:
  GET /status_report HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"line":101,"posx":10,"posy":20,"posz":-1,"posa":0,"posb":0,"posc":0,"feed":1000,"vel":1000,"momo":0,"stat":5}

Use a status report filter with null values to select which keys to return

REQUEST:
  GET /status_report HTTP/1.1
  {"posx":null,"posy":null,"posz":null,"vel":null,"stat":null}

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"posx":10,"posy":20,"posz":-1,"vel":1000,"stat":5}}

Use a status report filter with non-null values to return only keys that have different values (have changed)

REQUEST:
  GET /status_report HTTP/1.1
  {"posx":10,"posy":20,"posz":-1,"vel":1000,"stat":5}

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"posx":10.2}

Operations

Enums:

  • Operation types (optype)
    • run - run arbitrary Gcode, JSON or a mix
    • sendfile - send a file
  • Operation states (opstate)
    • pend
    • run
    • done
    • error

POST /operation

Start a new RUN operation to execute multiple Gcode lines

The following are all valid ways to invoke a RUN operation:

  • ``

Option 1 - pipe delimited string

REQUEST:
  POST /operation HTTP/1.1
  {"optype":"run","value":"G28.2 z0 | G28.2 x0 y0"}
  {"optype":"run", "value":["G28.2 z0","G28.2 x0 y0"]}

Option 2 - array type

REQUEST:
  POST /operation HTTP/1.1
  {"optype":"run"},
  {"value":["G28.2 z0","G28.2 x0 y0"]}

Option 3 - multiple Value keys. Can you even do this? Do they remain ordered?)

REQUEST:
  POST /operation HTTP/1.1
  {"optype":"run"},
  {"value":"G28.2 z0"
  {"value":"G28.2 x0 y0"} 
RESPONSE:
  HTTP/1.x 201 RESOURCE HAS BEEN CREATED
  Content-Type: application/json; charset=UTF-8
  42

GET /operation/{id}

Get a current operation

REQUEST:
  GET /operation/42 HTTP/1.1

RESPONSE:
  HTTP/1.x 200 OK
  Content-Type: application/json; charset=UTF-8
  {"opstate":"run"},
  {"value":"??? What does it really return?"}

PUT /operation/{id}

Jobs

POST /job

GET /job/{id}

PUT /job/{id}

Error Responses

All error responses look like this:

HTTP/1.x 404 NOT FOUND
Content-Type: application/json; charset=UTF-8
{"status":{"code":100,"description":"Unrecognized command or config name","additional_description":"xyzzy is not supported at the current time"}}

Commonly Used HTTP Response Codes

Defines the use of HTTP response codes and the mapping from g2core stat codes to HTTP codes

Success Codes

  • 200 OK
    • STAT_OK 0
  • 201 Created
  • 202 Accepted

Exception Codes

  • 400 Bad Request

    • Syntax errors 101-103, 111-116, 200-203, 207-209
    • Gcode specification errors 130-181
    • Homing errors 240-247
    • Probing errors 250-254

  • 404 Not Found

    • STAT_UNRECOGNIZED_NAME 100
    • STAT_NO_SUCH_DEVICE 11

  • 405 Method Not Allowed

    • STAT_PARAMETER_IS_READ_ONLY 104
    • STAT_PARAMETER_CANNOT_BE_READ 105
    • STAT_COMMAND_NOT_ACCEPTED 106
    • Soft limit errors 220-233

  • 408 Request Timeout

    • from host

  • 410 Gone

    • STAT_SHUTDOWN 5
    • STAT_PANIC 6
    • STAT_ALARM 18
    • STAT_COMMAND_REJECTED_BY_ALARM 204
    • STAT_COMMAND_REJECTED_BY_SHUTDOWN 205
    • STAT_COMMAND_REJECTED_BY_PANIC 206

  • 413 Request Entity Too Large

    • STAT_FILE_SIZE_EXCEEDED 10
    • STAT_INPUT_EXCEEDS_MAX_LENGTH 107

  • 416 Requested Range Not Satisfiable

    • STAT_INPUT_LESS_THAN_MIN_VALUE 108
    • STAT_INPUT_EXCEEDS_MAX_VALUE 109
    • STAT_INPUT_VALUE_RANGE_ERROR 110

  • 500 Internal Server Error

    • Internal errors 7-9, 12-17, 19-36, 88-99

  • 501 Not Implemented

    • from host

  • 504 Gateway Timeout 0 from host

Add a custom footer

Getting Started Pages

  1. Home
  2. What is g2core?
  3. Who uses g2core?
  4. Jerk-Controlled Motion
  5. Getting Started with g2core
  6. Connecting to g2core
  7. Configuring g2core
  8. Flashing g2core
  9. Troubleshooting

Reference Pages

  1. Gcodes
  2. Mcodes
  3. Text Mode
  4. JSON Communications
  5. GPIO Digital IO
  6. Alarms & Exceptions
  7. Power Management
  8. Coordinate Systems
  9. Status Reports
  10. Status Codes
  11. G2 Communications
  12. Tool Offsets and Selection
  13. Probing
  14. Feedhold, Resume, Job Kill
  15. Marlin Compatibility
  16. 9 Axis UVW Operation
  17. gQuintic Specs

Discussion Topics

  1. Roadmap
  2. GPIO for 1.X Releases
  3. Toolheads
  4. Raster Streaming Prototol
  5. g2core REST Interface
  6. Gcode Parsing
  7. G2 3DP Dialect
  8. Consensus Gcode
  9. Digital DRO
  10. Overview of Motion Processing

Developer Pages

  1. Development & Contribution
  2. Branching and Release - DRAFT
  3. Getting Started with g2core Development
  4. Project Structure & Motate
  5. Compiling G2
  6. OSX w/Xcode
  7. OSX/Linux Command Line
  8. Windows10 w/AtmelStudio7
  9. Debugging G2 on OSX
  10. Board and Machine Profiles
  11. Arduino Due Pinout
  12. Arduino DUE External Interfaces
  13. Diagnostics
  14. Debugging w/Motate Pins
  15. Development Troubleshooting
  16. g2core Communications
  17. Git Procedures
  18. Windows 10 / VMware 8 Issues
  19. Dual Endpoint USB Internals
  20. G2core License
  21. VSCode Setup
  22. Compatibility Axioms
  23. Wiki History
Clone this wiki locally