ProblemSolution approach
basics
config
websocket
REST API
8mon.py
usage
options
example
8term.py
usage
options
keys
commands
weakness
Download
TODO
Screenshots
OctoPrint
is a neat software used as a web-operated printserver
for 3D printers
.
Sometimes, however, a commandline control is desired.
For command by command noninteractive work, 8control
suite was written in bash.
However, the commands do not provide the server's response. Which is occasionally needed.
The OctoPrint server comes with a powerful REST API accessible
over the HTTP protocol and extensively using JSON format for the data.
The production version API documentation is here.
There is also a websocket API. This is documented here.
Python was chosen for this level of complexity, as the startup time penalty is not worth the necessary cost of not spending too much time writing it all in C and bash is too weak.
Both 8mon and 8term use the same configuration file format as the 8control suite. The file is located at /etc/octocmd.conf and is in JSON format. An example is here:
"OctoAPI_KEY": "0C59XXXXXXXXXXXXXXXXXXXXXXXXXXXX",
"OctoPrint_URL": "http://printer:5000"
}
The API key can be provided by the Octoprint UI. The URL is the address of the machine. Can be domain name, can be a raw IP address.
The URL is converted to the websocket one by replacing http:// with ws://.
The websocket data come in the form of JSON blocks. A fairly large amount of data flows in, with every state change the server reports to the web browser interface.
The gcode logs, of Send and Recv streams, arrive in the ['current']['logs'] array.
The machine events arrive in the ['events'] array.
The data come in fixed intervals. More than one gcode line can come in the same event.
The websocket access is done via websockets library.
The API is needed for handling the login, and eventual other commands. The commands get submitted to the server via a HTTP request. The command responses are retrieved via websocket.
The API access is done via requests library.
8mon.py is the noninteractive websocket/REST client.
The command can provide monitoring of the gcode communication, the events, or the entire communication (which gets pretty spammy).
It can also send a command to the machine, and display its response.
CAVEAT: the code compares the command sent in with content of the Sent: line, then shows everything from that to Recv: ok. Octoprint rewrites/substitutes some G/M codes. In these cases, the code won't return data and will be killed by a timeout.
On startup, 8mon reads the config file, connects to the websocket of the server mentioned there, authorizes itself with the API key, subscribes to events and current streams on websocket, and shows the incoming data.
If told, also sends a command. The commands are converted to uppercase. (Beware, some commands like M117 and G7 have case-sensitive data. This will break them.)
Usage: ./8mon.py [-a] [-s] [-v] [-v] [-v] [-tTIMEOUT] [-C/config/file] [command] Parameters: -a show all messages -s show separators between messages -v increase verbosity, up to 2 times -t<num> timeout in seconds -C/file config file location, default /etc/octocmd.conf -h this help --help this help command gcode command to get the response
For easier parsing, there are no spaces between option and value.
8term.py is an interactive terminal for the gcode, the console somewhat equivalent of the "Terminal" window of the web interface. The terminal has color syntax highlighting.
The code uses the same general approach as 8mon does, with prompt_toolkit library
for general interactive screens, and pygments as lexer and syntax highlighter.
The modified gcode lexer and the associated color style were integrated to the main file, to avoid multifile dependencies and allow easy portability.
On startup, 8term reads the config file, connects to the websocket of the server mentioned there, authorizes itself with the API key, subscribes to events and current streams on websocket, and shows the incoming data on the top window.
The bottom window acts as the input console. A command entered there is sent via the REST API.
If the first command letter is lowercase, the command as a whole is converted to uppercase. Beware, some commands like M117 and G7 have case-sensitive data. This will break them. An uppercase G or M (or other letter) will signal to the software it should not translate case.
Command sent as parameter from the console will be uppercased regardless. (TODO: address.)
Usage: ./8term.py [-a] [-s] [-v] [-v] [-v] [-tTIMEOUT] [-C/config/file] [command] Parameters: -v increase verbosity, up to 2 times -C/file config file location, default /etc/octocmd.conf -h this help --help this help command gcode command to get the response
For easier parsing, there are no spaces between option and value.
The code gets slower at too many thousand gcode lines.
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