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viehlieb e37ad34901 Some checks failed continuous-integration/drone/push Build is failing Details mv lib to app/lib use :zeitwerk		2022-10-18 17:23:18 +02:00
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app	mv lib to app/lib use :zeitwerk	2022-10-18 17:23:18 +02:00
config	Add requeue action for printer jobs	2022-05-27 22:41:18 +02:00
db/migrate	Add Rails release to ActiveRecord::Migration	2020-09-05 14:40:11 +02:00
lib	Run rubocop --fix-layout and remove encoding comments	2021-03-02 09:12:19 +01:00
foodsoft_printer.gemspec	Remove deprecated test_files attributes from gemspec files	2022-05-27 22:41:18 +02:00
Rakefile	Auto correct rubocop style issues	2022-02-20 16:28:54 +01:00
README.md	Add a printer job queue via the printer plugin	2019-02-05 23:32:20 +01:00

README.md

FoodsoftPrinter

This plugin adds a printer queue to allow mebers to print PDF with one click. Usually a mini computer with a printer at a room in the foodcoop will wait for new printer jobs and prints them.

This plugin is not enabled by default. To install it, add uncomment the corresponding line in the Gemfile, or add:

gem 'foodsoft_printer', path: 'plugins/foodsoft_printer'

This plugin introduces the foodcoop config option printer_token, which takes a random string for authentication at the endpoint. Additionally a set of PDF files can be selected, which will be generated when a print is triggered.

The communication with the printer client happens via two endpoints, which both require the printer_token as Bearer token in the Authorization header.

/:foodcoop/printer/socket: main WebSocket communication
/:foodcoop/printer/:id: HTTP GET for documents

The main communication happens via JSON messages via an WebSocket connection, which sends an array of docuement ids to the client, which need to be printed. Addionally the docuemnt can be downloaded as PDF via a separate endpoint. The client can updated the status of the documents by sending an object with the following keys to the server:

id (NBR, REQUIRED): id of the document, which should be updated
state (ENUM): the current sate of the printing progress.
message (STR, REQUIRES state): detailed description of the current state (e.g. download progress)
finish (BOOL): when set to true the job will be marked as done

The following values are valid for the state property:

queued: the document is not yet ready for printing
ready: the document is ready to be downloaded
downloading: transfer of the document is in progress
pending: download completed, waiting for the printer
held: e.g., for "PIN printing"
processing: printing is in progress
stopped: out of paper, etc.)
cancelled: the user stopped the action
aborted: the printer stopped the action
completed: print was successful

Example: A server sending {"unfinished_jobs":[12,16]} via WebSocket indicates that the two documents 12 and 16 are ready for printing. The client will request the first document from /foodcoop/printer/12 and send it to the printer. The status can be updated by sending {"id":12,"state":"pending"} via WebSocket to the server. Sending {"id":12,"state":"completed","finish":true} as soon as when the printing succeded will mark the job done.

To use this plugin the webserver must support WebSockets. The current implementation uses socket hijack, which is not supported by thin. puma supports that, but might lead to other problems, since it's not well tested in combination with foodsoft. Please be careful when switching the webserver!

This plugin is part of the foodsoft package and uses the AGPL-3 license (see foodsoft's LICENSE for the full license text).