Apply formating, light linting

printers

README.md

@@ -15,6 +15,7 @@ To make this project work, you will need :
 - A Thermal Printer :
     - I used *Adafruit's thermal printer* at first, but it broke down. You can get it [here](https://www.adafruit.com/product/597).
     - I then used an *EPSON TM-T2OIII*. It's expensive, but it's also high quality, and has better CUPS and specific library support.
+    - Sometime after, a friend leant me a *Brother QL-650TD* to add support for this type of printer.
 - A Raspberry Pi or any computer with USB or Serial.
 - Some electric wires.
 - Some knowledge of the command line,
@@ -37,13 +38,15 @@ You can also get some information from [here](https://learn.adafruit.com/mini-th
 
 LittlePrynter itself does not require any other software than the ones installed with it, i.e the ones listed in the `pyproject.toml` file.
 
-The version for the EPSON TM-T20III uses a library called `python-escpos`, which doesn't need a CUPS driver or anything else. It's included in the Python dependencies.
+The project supports EPSON label printers as well as Brother label printers, and you can try to adapt it for other printers. For example, using `adafruit-thermal`.
 
-The project only supports the EPSON printer, but you can try to adapt it for other printers. For example, using `adafruit-thermal`, or `brother-ql`.
+For the EPSON TM-T20III, LittlePrynter uses a library called `python-escpos`, which doesn't need a CUPS driver or anything else. It's included in the Python dependencies. For the Brother-QL, we use the `brother-ql` library, which is also included.
 
 ### Install & setup the project :
 
-Theses commands will copy the software on your computer, go into the directory, then activate a virtual environnement and install all of the project's dependecies.
+We use [Poetry](https://python-poetry.org/) to manage the Python environnement and packages. You will need to install it on your computer to install LittlePrynter.
+
+The following commands will copy the software on your computer, go into the directory, then activate a virtual environnement and install all of the project's dependecies.
 
 ```
 $ git clone https://git.n07070.xyz/n07070/LittlePrynter
@@ -69,6 +72,8 @@ $ flask run --cert=adhoc
 
 The `--cert=adhoc` argument will make LittlePrinter accessible in HTTPS with a [self-signed SSL certificate](https://en.wikipedia.org/wiki/Self-signed_certificate). This provides a free and easy way to use HTTPS, but does not provide any trust value. It is, on the other hand, a good way to access the webcam in developpement mode or on a local network, because a HTTPS connexion is required by browsers to access the needed APIs.
 
+You can also use the `run.sh` for this.
+
 This command should start a web server with which you can test your configuration. If you plan on exposing your printer to the Internet, and give it an IP / URL, _please, please, please_, don't run it this way. Look at Flask's documentation and read about running a production server. It's a little more work, but it will prevent your computer/server being hacked in too easily.
 
 Voilà !
@@ -79,6 +84,16 @@ Your contributions are very much welcome ! You can either request an account on
 
 Please also say if you had a printer to test your code, and which printer you've been using.
 
+### Code structure
+
+The app is written around the Flask framework. You can start by looking at the code in the `src/` folder, in the `main.py` file. There, you will see that a few classes are initialized. In general, they are two parts to the program :
+
+The Web pages and the API, which are the user-facing parts. This is with what the users will interact, and define how the program is going to be used. The web pages are renderer from the `include/` folder where Jinj2 templates are defined.
+
+The Worker and Printer Queue are the internal parts. When a new thing needs to be printed, usually sent from the Web or API interfaces, a new Task of the type of the document is created, and added to a print queue. Then, a Worker thread looks up the state of the queue every so often and picks jobs to execute on the printers connected to the system.
+
+The last part of the program is the Raspberry Pi class, that handles to Photomaton mode, which handles button presses, and LED indicator and a flash.
+
 ### Linting
 
 If you want to contribute code, please make sure to lint the project before commiting. This helps the code keep a general structure, and avoids some commons erros and mistakes.
@@ -120,7 +135,7 @@ If you liked this project, feel free to support my work !
 - [A link to buy one in Europe](https://rlx.sk/sk/various-boards/1829-mini-thermal-receipt-printer-adafruit-597.html)
 - [Another link to buy one, direct from factory](https://www.cashinotech.com/csn-a2-58mm-mini-panel-thermal-receipt-printer_p11.html)
 - [Diagnostickoeur](https://framagit.org/stickoeur/diagnostickoeur), another printer software mainly around Brother QL printers.
-
+- [FaxTheSystem](https://github.com/hackstub/faxthesystem/tree/main), another printer software, also around an Epson TM printer
 
 ## Licence
 

configuration/config.toml

@@ -1,13 +1,28 @@
 # Configuration file the LittlePrynter
 
 [defaults]
-signature = "Anonymous"
+signature = ""
+
 
 # Printer settings
 [printer]
-vendor_id = 0x04b8
-device_id = 0x0e28
 upload_folder = "src/static/uploads"
+# How long do we wait before giving up on waiting for a printer connexion
+waiting_time = 5
+
+[printer.epson]
+# Configurations for EPSON printers
+profile = "TM-T20III"
+label_type = 80 # 80 or 58 ( label width in mm )
+align_text = "center"
+text_max_length = 4096
+signature_max_length = 256
+
+[printer.brother]
+# Configurations for Brother printers
+label_type = "62" # See https://github.com/pklaus/brother_ql#usage for label types
+text_max_length = 4096
+signature_max_length = 256
 
 # Raspberry Pi Configuration
 [rpi]

configuration/config.toml.sample

@@ -5,8 +5,25 @@ signature = "Anonymous"
 
 # Printer settings
 [printer]
-vendor_id = "0x04b8"
+# Where do we upload the pictures and such
-device_id = "0x0e28"
+upload_folder = "src/static/uploads"
+
+# How long do we wait before giving up on waiting for a printer connexion
+waiting_time = 5
+
+[printer.epson]
+# Configurations for EPSON printers
+profile = "TM-T20III"
+label_type = 80 # 80 or 58 ( label width in mm )
+align_text = "center"
+text_max_length = 4096
+signature_max_length = 256
+
+[printer.brother]
+# Configurations for Brother printers
+label_type = 62 # See https://github.com/pklaus/brother_ql#usage for label types
+text_max_length = 4096
+signature_max_length = 256
 
 # Raspberry Pi Configuration
 [rpi]

poetry.lock

@@ -651,6 +651,18 @@ enabler = ["pytest-enabler (>=3.4)"]
 test = ["jaraco.test (>=5.4)", "pytest (>=6,!=8.1.*)", "zipp (>=3.17)"]
 type = ["pytest-mypy (>=1.0.1) ; platform_python_implementation != \"PyPy\""]
 
+[[package]]
+name = "iniconfig"
+version = "2.3.1"
+description = "brain-dead simple config-ini parsing"
+optional = false
+python-versions = ">=3.10"
+groups = ["main"]
+files = [
+    {file = "iniconfig-2.3.1-py3-none-any.whl", hash = "sha256:9121e2c1fdb355232495be3194c8dfe87ccc2d5dee45947b78e68f499790d7a7"},
+    {file = "iniconfig-2.3.1.tar.gz", hash = "sha256:67f4b9c50da0dedf52af349e7749a80a9057a5031199791b906c3bb3ae878960"},
+]
+
 [[package]]
 name = "isort"
 version = "8.0.1"
@@ -1137,6 +1149,18 @@ files = [
     {file = "platformdirs-4.9.6.tar.gz", hash = "sha256:3bfa75b0ad0db84096ae777218481852c0ebc6c727b3168c1b9e0118e458cf0a"},
 ]
 
+[[package]]
+name = "pluggy"
+version = "1.7.0"
+description = "plugin and hook calling mechanisms for python"
+optional = false
+python-versions = ">=3.10"
+groups = ["main"]
+files = [
+    {file = "pluggy-1.7.0-py3-none-any.whl", hash = "sha256:7dd7b0d8832ba3cb632c306926ded123429211b83641b35dc5c41ad2d34f9bec"},
+    {file = "pluggy-1.7.0.tar.gz", hash = "sha256:d1eaa46ebb595891b860ab086b4d09c8588af65ebd4361b8e8f4bb8920b90ba8"},
+]
+
 [[package]]
 name = "pycparser"
 version = "3.0"
@@ -1201,6 +1225,21 @@ files = [
     {file = "pycryptodomex-3.23.0.tar.gz", hash = "sha256:71909758f010c82bc99b0abf4ea12012c98962fbf0583c2164f8b84533c2e4da"},
 ]
 
+[[package]]
+name = "pygments"
+version = "2.21.0"
+description = "Pygments is a syntax highlighting package written in Python."
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "pygments-2.21.0-py3-none-any.whl", hash = "sha256:2363c69b61c4a97c838da3b130dcd6468f4848992b21a82f2a63ec34377137d9"},
+    {file = "pygments-2.21.0.tar.gz", hash = "sha256:610ca751c9bc2492b38eb9a38a7fbc93edbbb2d7182edaf34e66ae493dee5c8c"},
+]
+
+[package.extras]
+windows-terminal = ["colorama (>=0.4.6)"]
+
 [[package]]
 name = "pylint"
 version = "4.0.5"
@@ -1253,6 +1292,28 @@ files = [
 [package.extras]
 cp2110 = ["hidapi"]
 
+[[package]]
+name = "pytest"
+version = "9.2.0"
+description = "pytest: simple powerful testing with Python"
+optional = false
+python-versions = ">=3.10"
+groups = ["main"]
+files = [
+    {file = "pytest-9.2.0-py3-none-any.whl", hash = "sha256:07acdcf88ec174f907dc01af70bf52d49b014bbab03faeeade31c96b18c2e588"},
+    {file = "pytest-9.2.0.tar.gz", hash = "sha256:97c4f3b1f3c7414aa36465e09b8220f1d03627993bd51b1282e193753c80557b"},
+]
+
+[package.dependencies]
+colorama = {version = ">=0.4", markers = "sys_platform == \"win32\""}
+iniconfig = ">=2"
+packaging = ">=24"
+pluggy = ">=1.6,<2"
+pygments = ">=2.15"
+
+[package.extras]
+dev = ["argcomplete", "asynctest ; python_version < \"3.11\"", "attrs (>=23.1)", "coverage (>=7.5)", "hypothesis (>=6.75)", "mock", "numpy (>=1.26)", "pexpect (>=4.9)", "pytest-xdist (>=3.5)", "pyyaml", "requests", "setuptools", "xmlschema"]
+
 [[package]]
 name = "python-barcode"
 version = "0.16.1"
@@ -1882,5 +1943,5 @@ h11 = ">=0.16.0,<1"
 
 [metadata]
 lock-version = "2.1"
-python-versions = ">=3.14"
+python-versions = ">=3.13"
-content-hash = "18e1a5c8b085aa639b665279856f9e3c51a734a6a8d1d4dd135ca7e4f67e86ae"
+content-hash = "7f8ddfbcbf88df2634e01dd4daf62ad54d1b97c279e3c4b478822fb5d4485647"

pyproject.toml

@@ -7,7 +7,7 @@ authors = [
 ]
 license = "AGPLv3"
 readme = "README.md"
-requires-python = ">=3.14"
+requires-python = ">=3.13"
 dependencies = [
     "flask (>=3.1.3,<4.0.0)",
     "numpy (>=2.3.4)",
@@ -43,6 +43,7 @@ dependencies = [
     "pep8 (>=1.7.1,<2.0.0)",
     "pylint (>=4.0.5,<5.0.0)",
     "brother-ql-inventree (>=1.3,<2.0)",
+    "pytest (>=9.2.0,<10.0.0)",
 ]
 
 [tool.poetry]

run.sh

@@ -0,0 +1,2 @@
+eval $(poetry env activate)
+export FLASK_DEBUG=True; export FLASK_APP=src/main.py && flask run  --cert=adhoc --debug --no-debugger --host 0.0.0.0 --without-threads

src/main.py

@@ -1,7 +1,8 @@
 """
 Welcome to the LittlePrynter's source code.
-This program expose a web interface, with user authentification,
+This program expose a web interface,
 that makes it possible to print messages from the web.
+
 It also exposes a API, making it possible to print and interface
 with much of the printer's abilities.
 
@@ -10,12 +11,14 @@ Then we build the API around Flask,
 Then we build the web interface, using the simple Jinja2 templating.
 
 We support two modes :
+
 The first is a simple mode, where a computer, connected to a thermal printer,
 runs this program and exposes a web interface that makes use of the client's camera
-The seconde is booth mode, where a Raspberry Pi is connected to a thermal printer,
+
-a button and a flash.
+The seconde is booth mode, where a Raspberry Pi is connected to
-The web interface exists but may not be used, as the press of the button with take
+a thermal printer, a button and a flash.
- a picture and activate the flash while simply informing the web page.
+The web interface exists but it's not needed, as the press of the button
+takes a picture and activates the flash while simply informing the web page.
 """
 
 # Following are the librairies we import,
@@ -36,11 +39,11 @@ import werkzeug.exceptions
 from flask_socketio import SocketIO
 from flask_limiter import Limiter
 from flask_limiter.util import get_remote_address
-from printer import Printer  # The wrapper for the printer class
 from raspberry import Raspberry  # The Raspberry pi control Class
 from web import Web  # Wrapper for the web routes and API
 from print_queue import PrintQueue
 from worker import PrintWorker
+from printers import Printers
 
 # We create the main Flask object
 app = Flask(__name__)
@@ -73,11 +76,7 @@ except OSError as e:
 
 app.logger.debug("Config file loaded !")
 
-# Define the USB connections here.
-vendor_id = configuration_file["printer"]["vendor_id"]
-device_id = configuration_file["printer"]["device_id"]
 UPLOAD_FOLDER = str(configuration_file["printer"]["upload_folder"])
-
 try:
     os.mkdir(UPLOAD_FOLDER)
     app.logger.debug("Directory %s created successfully.", UPLOAD_FOLDER)
@@ -88,54 +87,54 @@ except PermissionError:
     sys.exit(77)
 
 # Output the config file
-if os.getenv("FLASK_DEBUG"):
+if not os.getenv("FLASK_DEBUG") is None and os.getenv("FLASK_DEBUG") is True:
     pprint.pprint(configuration_file)
 
 # We define the app module used by Flask
 app.secret_key = configuration_file["secrets"]["flask_secret_key"]
 app.config["UPLOAD_FOLDER"] = UPLOAD_FOLDER
 app.config["ALLOWED_EXTENSIONS"] = ALLOWED_EXTENSIONS
-app.config["MAX_CONTENT_LENGTH"] = 10 * 1000 * 1000  # Maximum 3Mb for a file upload
+app.config["MAX_CONTENT_LENGTH"] = 10 * 1000 * 1000  # Maximum 10Mb for a file upload
 app.config["TEMPLATES_AUTO_RELOAD"] = True
 
-# Printer connection
-# Uses the class defined in the printer.py file
-printer = Printer(app, 0x04B8, 0x0E28)
-# printers = Printer(app)
-# printers.discover_printers()
-# printers.init()
-printer.init_printer()
-
-# Find out if we are running on a Raspberry Pi
-rpi = Raspberry(
-    printer,
-    app,
-    socketio,
-    configuration_file["rpi"]["button_gpio_port_number"],
-    configuration_file["rpi"]["indicator_gpio_port_number"],
-    configuration_file["rpi"]["flash_gpio_port_number"],
-    configuration_file["rpi"]["flash"],
-)
-
-RASPBERRY_PI_CONNECTED = rpi.is_raspberry_pi()
-
 # Queue creation
 print_queue = PrintQueue(app)
 
-#  Web & API  routes
+# Find out if we are running on a Raspberry Pi
+rpi = Raspberry(print_queue, app, configuration_file)
+RASPBERRY_PI_CONNECTED = rpi.is_raspberry_pi()
+
+
+#  Web & API management
 web = Web(app, print_queue)
 
-# Start worker thread
+# Create a pool of printers
-worker = PrintWorker(app, print_queue, printer, socketio)
+try:
-worker.start()
+    # comment: Find all printers connected to the system
+    printers_pool = Printers(app, configuration_file)
+except Exception as e:
+    app.logger.error("Could not create a pool of printers because %s", str(e))
+    sys.exit(-1)
+# end try
 
+# Start worker thread
+try:
+    worker = PrintWorker(app, print_queue, printers_pool=printers_pool)
+    worker.start()
+except Exception as e:
+    app.logger.error("Could not start the worker because %s ", str(e))
+    sys.exit(-1)
+
+# The rate limit
 limiter = Limiter(
     get_remote_address, app=app, default_limits=["1500 per day", "500 per hour"]
 )
 
+
+app.logger.info("🖶 Welcome to LittlePrynter !")
+
+
 # General routes
-
-
 @app.route("/")
 @limiter.limit("1/second", override_defaults=False)
 def index():
@@ -153,8 +152,6 @@ def webcam():
 
 
 # Form treatement
-
-
 @app.route("/web/print/sms", methods=["POST"])
 @limiter.limit("6/minute", override_defaults=False)
 def web_print_sms():
@@ -176,16 +173,26 @@ def web_print_sms():
             "No signature found for this print, using default signature : %s ", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
+    try:
+        do_cut = bool(request.form["cut"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        do_cut = False
 
     try:
-        web.print_sms(txt, sign)
+        # Clamp value between 1 and
+        many = max(1, min(int(request.form["many"]), 20))
+    except werkzeug.exceptions.BadRequestKeyError:
+        many = 1
+
+    try:
+        web.print_sms(txt, sign, do_cut, many)
     except RuntimeError as e:
         app.logger.error("Whoops, we could not print an SMS because : %s ", str(e))
         flash("Whoops, we could not print an SMS because :" + str(e), "error")
         return redirect(url_for("index"))
 
     # end try
-    flash("The SMS has been printed !", "info")
+    flash("The SMS has been added to the print queue !", "info")
     return redirect(url_for("index"))
 
 
@@ -203,6 +210,9 @@ def web_print_img():
             "No signature found for this print, using default signature : %s", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
+    except werkzeug.exceptions.RequestEntityTooLarge as e:
+        flash("Whoops, image is too big: " + str(e), "error")
+        return redirect(url_for("index"))
 
     # check if the post request has the file part
     if "img" not in request.files:
@@ -219,15 +229,31 @@ def web_print_img():
         flash("Submitted file has no filename !", "error")
         return redirect(url_for("index"))
 
+    try:
+        do_cut = bool(request.form["cut"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        do_cut = False
+
+    try:
+        process_image = bool(request.form["process"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        process_image = False
+
+    try:
+        # Clamp value between 1 and
+        many = max(1, min(int(request.form["many"]), 20))
+    except werkzeug.exceptions.BadRequestKeyError:
+        many = 1
+
     try:
         app.logger.debug("Sending the image to the printer.")
-        web.print_image(file, sign)
+        web.print_image(file, sign, do_cut, process_image, many)
     except RuntimeError as e:
         app.logger.error("The image could not be printed because : %s ", str(e))
         flash("The image could not be printed because : " + str(e), "error")
         return redirect(url_for("index"))
 
-    flash("Picture printed !", "info")
+    flash("Picture added to the print queue !", "info")
     return redirect(url_for("index"))
 
 
@@ -266,9 +292,21 @@ def api_print_sms():
             "No signature found for this print, using default signature. : %s", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
+
+    try:
+        do_cut = bool(request.form["cut"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        do_cut = False
+
+    try:
+        # Clamp value between 1 and
+        many = max(1, min(int(request.form["many"]), 20))
+    except werkzeug.exceptions.BadRequestKeyError:
+        many = 1
+
     try:
         # comment: We try to print the SMS
-        web.print_sms(txt, sign)
+        web.print_sms(txt, sign, do_cut, many)
     except RuntimeError as e:
         return str(e), 500
     # end try
@@ -296,22 +334,39 @@ def api_print_image():
         return "No image submitted", 400
 
     file = request.files["img"]
-    # If the user does not select a file, the browser submits an
+    # If the user submits an empty file without a filename.
-    # empty file without a filename.
     if file.filename == "":
         app.logger.error("Submitted file has no filename !")
         return "Submitted file has no filename !", 400
 
+    try:
+        do_cut = bool(request.form["cut"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        do_cut = False
+
+    try:
+        process_image = bool(request.form["process"])
+    except werkzeug.exceptions.BadRequestKeyError:
+        process_image = False
+
+    try:
+        # Clamp value between 1 and
+        many = max(1, min(int(request.form["many"]), 20))
+    except werkzeug.exceptions.BadRequestKeyError:
+        many = 1
+
     try:
         app.logger.debug("Sending the image to the printer.")
-        web.print_image(file, sign)
+        web.print_image(file, sign, do_cut, process_image, many)
     except RuntimeError as e:
         return str(e), 500
 
     return "OK", 200
 
 
+# TODO: This might not depend on the Raspberry Pi
 @app.route("/api/camera/picture", methods=["GET"])
+@limiter.limit("6/minute", override_defaults=False)
 def camera_picture():
     """Returns a picture taken by the camera on a raspberry pi"""
     if RASPBERRY_PI_CONNECTED:
@@ -324,29 +379,53 @@ def camera_picture():
 
 
 @app.route("/api/queue", methods=["GET"])
+@limiter.limit("6/minute", override_defaults=False)
 def api_queue_status():
     """API endpoint for entire queue"""
     return jsonify(web.get_queue_state())
 
 
+@app.route("/api/queue/completed", methods=["GET"])
+@limiter.limit("6/minute", override_defaults=False)
+def api_queue_completed():
+    """API endpoint that returns the finished tasks"""
+    return jsonify(web.get_queue_completed())
+
+
 @app.route("/api/worker", methods=["GET"])
+@limiter.limit("6/minute", override_defaults=False)
 def api_worker_state():
     """API endpoint to get the worker state"""
     return jsonify(worker.current_state())
 
 
 @app.route("/api/worker/start")
+@limiter.limit("6/minute", override_defaults=False)
 def api_worker_start():
+    """
+    Enable to worker. This starts to process the print queue.
+    """
     worker.start_worker()
     return jsonify(worker.current_state())
 
 
 @app.route("/api/worker/stop")
+@limiter.limit("6/minute", override_defaults=False)
 def api_worker_stop():
+    """
+    Stops the print queue. This stops the processing of the print queue.
+    """
     worker.stop_worker()
     return jsonify(worker.current_state())
 
 
+@app.route("/api/printers")
+@limiter.limit("6/minute", override_defaults=False)
+def api_printers_info():
+    """Returns the current state of every printers"""
+    return jsonify(printers_pool.printers_info())
+
+
 ## Authentification
 
 
@@ -404,4 +483,4 @@ def camera_status():
 
 
 if __name__ == "__main__":
-    app.run(debug=True, use_reloader=False, host="0.0.0.0", ssl_context="adhoc")
+    app.run(use_reloader=False, host="0.0.0.0", ssl_context="adhoc")

src/print_queue.py

@@ -76,7 +76,21 @@ class PrintQueue:
         """Return current queue state"""
         with self._lock:
             self.app.logger.debug("Return current queue state")
-            return [{"task_id": t.task_id, "status": t.status} for t in self._queue]
+            return [
+                {
+                    "task_id": t.task_id,
+                    "status": t.status,
+                    "type": str(t.task_type),
+                    "content": str(t.get_print_data()),
+                }
+                for t in self._queue
+            ]
+
+    def get_queue_completed(self):
+        """Return completed queue elements"""
+        with self._lock:
+            self.app.logger.debug("Return completed queue elements")
+            return self._completed_tasks
 
     def get_status(self, task_id):
         """Get full status info for a task"""

src/printers.py

@@ -0,0 +1,215 @@
+"""
+A collection of Printers.
+
+It has methods to discover printers, and provides an interface for
+the methods expected from printers.
+"""
+
+from collections.abc import Set
+import time
+import threading
+import usb.core
+import usb.util
+from printer import Printer, EscPosPrinter, BrotherPrinter
+
+
+class Printers:
+    """
+    Finds and creates a set of Printer that can be used by the Workers to print.
+    """
+
+    def __init__(self, app, configuration_file):
+        """
+        Discovers printers connected to the computer
+        """
+        self.app = app
+        self.configuration_file = configuration_file
+        self.printers = list(self._discover_printers())
+        self._lock = threading.Lock()
+
+    def _discover_printers(self) -> Set[Printer]:
+        """
+        Gets connected USB printer devices using the pyusb library.
+
+        We analyse the USB devices, get the ones that match
+        the printer class ( 7 ) and for Brother and EPSON printers,
+        try to create a Printer object that can be used by the Worker class
+        to execute prints.
+
+        Returns a set of Printer
+        """
+
+        self.app.logger.debug("Discovering USB Devices connected to this system")
+
+        printers = set()
+
+        waiting_time_for_printer = self.configuration_file["printer"]["waiting_time"]
+
+        while True:
+            # Find all connected USB devices
+            # the find() fnc returns a generator
+            devices = list(
+                usb.core.find(find_all=True, custom_match=_FindClass(self.app, 7))
+            )
+
+            if devices:
+                break
+
+            if waiting_time_for_printer <= 0:
+                self.app.logger.warning(
+                    "No USB devices of class 7 ( printers ) found or pyusb could not access the bus."
+                )
+                raise RuntimeError(
+                    "No USB devices of class 7 ( printers ) found or pyusb could not access the bus."
+                )
+
+            self.app.logger.warning(
+                "No printers found; waiting for a printer to connect..."
+            )
+
+            time.sleep(1)
+            waiting_time_for_printer -= 1
+
+        for dev in devices:
+            # Attempt to get the manufacturer and product strings
+            try:
+                manufacturer = usb.util.get_string(dev, dev.iManufacturer)
+            except Exception:
+                manufacturer = "Unknown"
+
+            try:
+                product = usb.util.get_string(dev, dev.iProduct)
+            except Exception:
+                product = "Unknown"
+
+            self.app.logger.debug(
+                "Looking at %s %s (%s:%s)",
+                manufacturer,
+                product,
+                hex(dev.idVendor),
+                hex(dev.idProduct),
+            )
+
+            match (manufacturer):
+                case "EPSON":
+                    try:
+                        # We create a new EscPosPrinter()
+                        self.app.logger.debug("Trying to create a new EPSON printer")
+                        prid = dev.idProduct
+                        vendir = dev.idVendor
+                        escpos_printer = EscPosPrinter(
+                            self.app,
+                            vendir,
+                            prid,
+                            self.configuration_file["printer"]["epson"],
+                        )
+                    except Exception as e:
+                        raise e
+
+                    # If the object creation is successfull, we add it to the list of Printers
+                    printers.add(escpos_printer)
+                    self.app.logger.debug("Found a %s printer", manufacturer)
+                case "Brother":
+                    try:
+                        # We create a new BrotherPrinter()
+                        self.app.logger.debug("Trying to create a new BROTHER printer")
+
+                        brother_printer = BrotherPrinter(
+                            self.app,
+                            dev.idVendor,
+                            dev.idProduct,
+                            self.configuration_file["printer"]["brother"],
+                        )
+                    except Exception as e:
+                        self.app.logger.error(
+                            "Could not create a %s printer class with %s:%s",
+                            product,
+                            dev.idVendor,
+                            dev.idProduct,
+                        )
+                        raise e
+
+                    # If the object creation is successfull, we add it to the list of Printers
+                    printers.add(brother_printer)
+                    self.app.logger.debug("Found a %s printer", manufacturer)
+                case _:
+                    self.app.logger.debug(
+                        "Found a printer of unknown manufacturer : %s", manufacturer
+                    )
+            # end match
+
+        self.app.logger.debug("Found %s printers", len(printers))
+
+        if len(printers) < 1:
+            self.app.logger.warning(
+                "Not printers found ! Please plug in a Printer and restart the program."
+            )
+            raise RuntimeError("No printers found")
+
+        return printers
+
+    def acquire_available_printer(self, start_index=0):
+        """Atomically acquire and return an available printer, or None."""
+        printers = self.printers
+        if not printers:
+            self.app.logger.error("No printers available for acquisition")
+            return None
+
+        with self._lock:
+            # So don't always look at the first printer available if need be
+            # this allows for a round-robin lookup
+            for offset in range(len(printers)):
+                index = (start_index + offset) % len(printers)
+                printer = printers[index]
+
+                if not printer.used:
+                    printer.use_printer()
+                    return index, printer
+
+        return None
+
+    def printers_info(self):
+        """Return the current list of printers"""
+        printers_info_list = []
+        for i in self.printers:
+            printers_info_list.append(
+                [
+                    i.printer_type.name,
+                    "Used: " + str(i.used),
+                    "Ready: " + str(i.ready),
+                    i.printer_info,
+                ]
+            )
+
+        return printers_info_list
+
+
+class _FindClass:
+    """
+    Use by usb.core to modify the way USB devices are found
+    Taken from pyUSB documentation on Github
+    """
+
+    def __init__(self, app, class_):
+        self._class = class_
+        self.app = app
+
+    def __call__(self, device):
+        # first, let's check the device
+        self.app.logger.debug(
+            "Found a USB device of class %s", str(device.bDeviceClass)
+        )
+        if device.bDeviceClass == self._class:
+            return True
+        # ok, transverse all devices to find an
+        # interface that matches our class
+        for configuration in device:
+            # Every device can have one or more configuration,
+            interface = usb.util.find_descriptor(
+                configuration, bInterfaceClass=self._class
+            )
+            # each config can have several interfaces
+            if interface is not None:
+                return True
+
+        return False

src/raspberry.py

@@ -1,12 +1,21 @@
+"""
+This class executes when we are on a raspberry Pi.
+
+It handles the press of a button via GPIO,
+activates a flash and prints out the picture
+that was taken via a USB Webcam.
+"""
+
 import io  # To check if we are on a Raspberry Pi
 import subprocess
 import os
 from time import sleep, gmtime, strftime
-from flask_socketio import SocketIO
 from gpiozero import Button, LED, DigitalOutputDevice
 from PIL import Image
+from task import TextTask, ImageTask, CutTask
 
-class Raspberry():
+
+class Raspberry:
     """
     This class will manage three things :
     - Connecting to a USB webcam
@@ -14,32 +23,24 @@ class Raspberry():
     - Activating a flash ( or light )
     - Flash an indicator light
 
+    # pylint: disable=too-many-instance-attributes
+    # dede
     """
 
-    def __init__(
+    def __init__(self, print_queue, app, configuration_file):
-        self,
+        self.print_queue = print_queue
-        printer,
-        app,
-        socketio,
-        button_gpio_port_number,
-        indicator_gpio_port_number,
-        flash_gpio_port_number,
-        is_flash_present,
-    ):
-        self.printer = printer
-        self.socketio = socketio
         self.app = app
-
+        self.configuration_file = configuration_file
-        self.flash_gpio = flash_gpio_port_number
-        self.is_flash_present = is_flash_present
-        self.button_gpio = button_gpio_port_number
-        self.led_gpio = indicator_gpio_port_number
         self.image_path = self.app.config["UPLOAD_FOLDER"] + "/image.jpg"
 
-    def is_raspberry_pi(self, raise_on_errors=False):
+    def is_raspberry_pi(self):
+        """
+        Checking if we are on a Raspberry Pi by checking
+        information on the /proc/cpuinfo file
+        """
         # Check if we are running on a raspberry pi
         try:
-            with io.open("/proc/cpuinfo", "r") as cpuinfo:
+            with io.open("/proc/cpuinfo", "r", encoding="utf-8") as cpuinfo:
                 found = False
                 for line in cpuinfo:
                     if line.startswith("Hardware"):
@@ -59,8 +60,11 @@ class Raspberry():
                             return False
 
                 if not found:
-                    self.app.logger.error(
+                    self.app.logger.warning(
-                        "Couldn't get sufficient hardware information from /proc/cpuinfo, Unable to determine if we are on a Raspberry Pi."
+                        "Couldn't get sufficient hardware information from /proc/cpuinfo"
+                    )
+                    self.app.logger.warning(
+                        "Unable to determine if we are on a Raspberry Pi."
                     )
                     return False
         except IOError:
@@ -70,28 +74,41 @@ class Raspberry():
         self.app.logger.debug("It seems we are on a Raspberry Pi")
 
         try:
-            self.initialise_gpio()
+            self._initialise_gpio()
         except Exception as e:
             self.app.logger.debug("Could not init GPIO : " + str(e))
             raise e
         return True
 
-    def initialise_gpio(self):
+    def _initialise_gpio(self):
+        """
+        Set GPIO ports from configuration and activate them
+        to show the user it's working.
+        """
         self.app.logger.debug("Initializing GPIO")
 
-        self.led = LED(self.led_gpio)
+        self.led = LED(self.configuration_file["rpi"]["indicator_gpio_port_number"])
         self.app.logger.debug("Activated indicator LED")
         self.indicator_countdown(iters=3)
-        self.button = Button(self.button_gpio, pull_up=True, bounce_time=0.1)
+        self.button = Button(
+            self.configuration_file["rpi"]["button_gpio_port_number"],
+            pull_up=True,
+            bounce_time=0.1,
+        )
         self.button.when_pressed = self.on_button_pressed
         self.app.logger.debug("Activated button")
 
         # The "flash" is a relay-controlled device ( light bulb for example )
-        self.flash = DigitalOutputDevice(self.flash_gpio)
+        self.flash = DigitalOutputDevice(
+            self.configuration_file["rpi"]["flash_gpio_port_number"]
+        )
         self.flash_toggle()
         self.app.logger.debug("Activated flash")
 
     def indicator_countdown(self, iters=10, multi=10):
+        """
+        Activates the LED faster and faster to show a countdown
+        """
         for i in range(iters, 0, -1):
             self.led.on()
             sleep(i / multi)
@@ -99,7 +116,10 @@ class Raspberry():
             sleep(i / multi)
 
     def indicator_led(self, timing=0.2, l=5):
-        for i in range(l):
+        """
+        Turns on the indicator LED for a certain period of time
+        """
+        for _ in range(l):
             self.app.logger.debug("LED turned on")
             self.led.on()
             sleep(timing)
@@ -108,6 +128,9 @@ class Raspberry():
             sleep(timing)
 
     def flash_toggle(self):
+        """
+        Flashes the flash
+        """
         self.app.logger.debug("Flash turned on")
         self.flash.on()
         sleep(0.3)
@@ -115,6 +138,9 @@ class Raspberry():
         self.app.logger.debug("Flash turned off")
 
     def take_picture(self):
+        """
+        Takes a picture via the USB webcam
+        """
         # Validate if the image path is valid
         if not os.path.isdir(os.path.dirname(self.image_path)):
             self.app.logger.error(
@@ -140,7 +166,7 @@ class Raspberry():
                 f"Unable to take a picture. Error: {e.stderr.decode()}"
             )
             return False
-        except Exception as e:
+        except RuntimeError as e:
             # Catch any unexpected errors
             self.app.logger.error(f"Unexpected error while taking picture: {str(e)}")
             return False
@@ -160,6 +186,9 @@ class Raspberry():
         position="bottom_right",
         margin=10,
     ):
+        """
+        Takes an image and overlays it with a another picture.
+        """
         try:
             image = Image.open(image_path).convert("RGBA")
             logo = Image.open(logo_path).convert("RGBA")
@@ -186,7 +215,9 @@ class Raspberry():
                 y = image.height - logo.height - margin
             else:
                 raise ValueError(
-                    "Invalid position. Choose from 'bottom_right', 'top_left', 'top_right', or 'bottom_left'."
+                    "Invalid position."
+                    + "Choose from 'bottom_right', 'top_left', "
+                    + " 'top_right', or 'bottom_left'."
                 )
 
             # Composite the logo onto the image
@@ -197,13 +228,16 @@ class Raspberry():
                 output_path = image_path  # Overwrite the original image if no output path is given
             image.save(output_path)
 
-        except Exception as e:
+        except RuntimeError as e:
             self.app.logger.error(f"Error overlaying logo: {e}")
             return False
 
         return True
 
     def crop_to_square(self, image_path, output_path=None):
+        """
+        Crop an image so that it becomes a square
+        """
         try:
             image = Image.open(image_path)
             width, height = image.size
@@ -224,13 +258,17 @@ class Raspberry():
 
             image.save(output_path)
 
-        except Exception as e:
+        except RuntimeError as e:
             self.app.logger.error(f"Error cropping image to square: {e}")
             return False
 
         return True
 
     def on_button_pressed(self):
+        """
+        When a button press is detected, a picture is taken from the webcam
+        and added to the print queue.
+        """
         self.app.logger.debug("Button has been pressed")
         self.led.on()
         self.app.logger.debug("Counting down")
@@ -241,7 +279,7 @@ class Raspberry():
         try:
             self.flash.on()
             self.take_picture()
-        except Exception as e:
+        except RuntimeError as e:
             self.app.logger.error(
                 "Could not take a picture after the button press : " + str(e)
             )
@@ -250,15 +288,13 @@ class Raspberry():
         self.app.logger.debug("Printing picture")
         self.led.on()
         self.crop_to_square(self.image_path)
-        self.printer.print_img("src/static/images/extase-club.png", process=True)
+        self.print_queue.enqueue(ImageTask(self.image_path, signature="", process=True))
-        self.printer.print_img(self.image_path, process=True)
+        self.print_queue.enqueue(
-        self.printer.print_sms("")
+            TextTask(content="Imprimé par LittlePrynter", signature="")
-        self.printer.print_sms("With Love From Société.Vide", signature="", bold=True)
+        )
-        self.printer.print_sms("Printed by LittlePrynter", signature="")
+        time = strftime("%Y-%m-%d %H:%M", gmtime())
-        self.printer.print_sms("n07070.xyz", signature="")
+        self.print_queue.enqueue(TextTask(content=time, signature=""))
-        self.printer.print_sms(strftime("%Y-%m-%d %H:%M", gmtime()), signature="")
+        self.print_queue.enqueue(CutTask())
-        self.printer.qr("https://n07070.xyz/articles/littleprynter")
-        self.printer.cut()
         self.led.off()
-        self.app.logger.debug("Done printing picture")
+        self.app.logger.debug("Added a photomaton picture to the print queue")
         return True

src/task.py

@@ -14,11 +14,11 @@ to print at the same time.
 We can also delay and store printing tasks until a printer becomes
 available if none is online.
 """
+
 from abc import ABC, abstractmethod
 
 ## See https://docs.python.org/3/library/abc.html to learn more about this
 
-# from dataclasses import dataclass
 from enum import Enum
 import uuid
 
@@ -28,9 +28,11 @@ class TaskType(Enum):
     """
     The different tasks supported by the printers
     """
+
     TEXT = "text"
     IMAGE = "image"
     CUT = "cut"
+    QR = "qr"
 
 
 class PrintTask(ABC):
@@ -38,18 +40,15 @@ class PrintTask(ABC):
     A print task holds information about what we are looking to print.
     """
 
-    def __init__(self, task_type):
+    def __init__(self, task_type: TaskType):
         self.task_id = self._generate_id()
         self.task_type = task_type
         self.status = "pending"  # pending, processing, completed, failed
 
-        print("Created a new " + str(self.task_type) + " with ID " + self.task_id)
-
     @abstractmethod
     def get_print_data(self):
         """Return data formatted for printer"""
 
-
     def _generate_id(self):
         # Generate unique task ID
         return str(uuid.uuid4())
@@ -69,6 +68,18 @@ class TextTask(PrintTask):
         return {"txt": self.content, "sign": self.signature}
 
 
+class QRTask(TextTask):
+    """This task prints a QR-Code, the signature is ignore and is always the content itself"""
+
+    def __init__(self, content):
+        super().__init__(content, signature="")
+        self.content = content
+        self.signature = content
+
+    def get_print_data(self):
+        return {"txt": self.content, "sign": self.signature}
+
+
 class ImageTask(PrintTask):
     """
     This tasks represents a image content ( in the form of it's path ), and it's signature.

src/templates/api.html

@@ -5,6 +5,6 @@
     <title>LittlePrynter API</title>
   </head>
   <body>
-    "Welcome to the printing software's API. Please see the index page to get started.
+    Welcome to the printing software's API. Please see the index page to get started.
   </body>
 </html>

src/templates/base.html

@@ -53,7 +53,7 @@
         <hr>
 
         <footer class="row">
-        <p class=" text-center">Little Prynter is built by <a href="https://n07070.xyz/about-me/">n07070</a> because it's fun :) | <a href="https://git.n07070.xyz/n07070/littleprynter">Source code - AGPLv3</a></p>
+        <p class=" text-center">Little Prynter is built by <a href="https://n07070.xyz/about-me/">n07070</a> because it's fun :) | <a href="/api">API interface</a> | <a href="https://git.n07070.xyz/n07070/littleprynter">Source code - AGPLv3</a></p>
         </footer>
     </body>
             <script src="https://cdn.socket.io/4.0.0/socket.io.min.js"></script>

src/templates/footer.html

@@ -1,5 +0,0 @@
-<hr>
-<footer>Little Prynter is built by <a href="https://n07070.xyz/about-me/">n07070</a> because it's fun :) | <a href="https://git.n07070.xyz/n07070/littleprynter/src/branch/epson-tm-t20iii">Source code - AGPLv3</a></footer>
-</div>
-</body>
-</html>

src/templates/index.html

@@ -6,9 +6,23 @@
       <h3 class="card-header">Print a short message</h3>
       <div class="card-body">
         <form class="form-group" action="/web/print/sms" method="post">
-          <input class="form-control" type="text" name="txt" placeholder="200 chars or less " maxlength="200" required><br>
+          <textarea class="form-control" type="text" name="txt" placeholder="4096 caractères maximum " maxlength="4096"></textarea>
-          <input class="form-control" type="text" name="signature" placeholder="Signature or pseudo" maxlength="200"><br>
+          <br>
-          <input class="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">
+          <input class="form-control" type="text" name="signature" placeholder="Signature ou pseudo" maxlength="200"><br>
+          <div class="input-group">
+            <span class="input-group-text">Combien ?</span>
+            <input type="number" aria-label="how-many" class="form-control" name="many" max="20" min="1" value="1">
+            <input class="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">
+          </div>
+          <br>
+          <div class="form-check">
+            <input class="form-check-input" type="checkbox" value="True" id="flexCheckDefault" name="cut" checked>
+            <label class="form-check-label" for="flexCheckDefault">
+              Couper après impression ?
+            </label>
+          </div>
+
+
         </form>
       </div>
     </div>
@@ -20,8 +34,26 @@
       <div class="card-body">
         <form enctype="multipart/form-data" class="form-group" action="/web/print/img" method="post">
           <input class="form-control" type="file" name="img" required><br>
-          <input class="form-control" type="text" name="signature" placeholder="Signature or pseudo" maxlength="200"><br>
+          <input class="form-control" type="text" name="signature" placeholder="Signature ou pseudo" maxlength="200"><br>
-          <input class="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">
+          <div class="input-group">
+            <span class="input-group-text">Combien ?</span>
+            <input type="number" aria-label="how-many" class="form-control" name="many" max="20" min="1" value="1">
+            <input class="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">
+          </div>
+          <br>
+          <div class="form-check .form-check-inline">
+            <input class="form-check-input" type="checkbox" value="True" id="flexCheckDefault" name="cut" checked>
+            <label class="form-check-label" for="flexCheckDefault">
+              Couper après impression ?
+            </label>
+          </div>
+          <div class="form-check .form-check-inline">
+            <input class="form-check-input" type="checkbox" value="True" id="flexCheckDefault" name="process">
+            <label class="form-check-label" for="flexCheckDefault">
+              Traiter l'image ?
+            </label>
+          </div>
+
         </form>
       </div>
     </div>

src/templates/password.html

@@ -1,30 +0,0 @@
-<!DOCTYPE html>
-<html>
-    <head>
-        <meta charset="utf-8">
-        <title>Log in</title>
-        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
-        <link rel="stylesheet" href="{{ url_for('static',filename='css/style.css') }}">
-    </head>
-    <body class="container">
-        <div class="col-md-6 offset-md-3">
-            <h1>Login</h1>
-            {% with messages = get_flashed_messages(with_categories=true) %}
-              {% if messages %}
-                {% for category, message in messages %}
-                  <div class="alert alert-{{ category }}" role="alert">{{ message }}</div>
-                {% endfor %}
-              {% endif %}
-            {% endwith %}
-
-            <form action="/login" method="post">
-                <div class="form-group">
-                <input type="text" name="username" class="form-control" placeholder="Pseudo">
-                <input type="password" name="password" class="form-control" placeholder="Password">
-                <button type="submit" class="btn btn-primary">Submit</button>
-                </div>
-            </form>
-        </div>
-    </body>
-</html>

src/web.py

@@ -1,19 +1,22 @@
-from flask import flash
+"""
-from werkzeug.utils import secure_filename
+Manage all of the inputs from a web source
-import time
+"""
+
 import os
+from werkzeug.utils import secure_filename
 from task import TextTask, ImageTask, CutTask
 
 
-class Web(object):
+class Web:
-    """Web is the class that gets all of the information from web calls ( API and Web page ) and provides checks before sending stuff to printing"""
+    """Web is the class that gets all of the information from web calls
+    ( API and Web page ) and provides checks before sending stuff to printing"""
 
     def __init__(self, app, print_queue):
         super(Web).__init__()
         self.print_queue = print_queue
         self.app = app
 
-    def print_sms(self, texte, sign: str) -> bool:
+    def print_sms(self, texte, sign: str, do_cut: bool, many: int = 1) -> bool:
         """
         Get text and a signature, prints the text and cuts after that.
         """
@@ -25,15 +28,22 @@ class Web(object):
             # !! there is no garantee !! that both the SMS task and the Cut task
             # are added back to back, another task could be
             # inserted between the two.
-            sms = self.print_queue.enqueue(TextTask(content=texte, signature=sign))
+            for i in range(many):
-            cut = self.print_queue.enqueue(CutTask())
+                sms = self.print_queue.enqueue(TextTask(content=texte, signature=sign))
+                self.app.logger.info("Added a SMS task at position %s", sms)
+                if do_cut:
+                    cut = self.print_queue.enqueue(CutTask())
+                    self.app.logger.info("Added a CUT task at position %s", cut)
+
         except Exception as e:
             self.app.logger.error(e)
             raise RuntimeError("Could not add SMS to queue, " + str(e)) from e
-        self.app.logger.info("Added two new tasks at position %s and %s", sms, cut)
+
         return True
 
-    def print_image(self, image, sign: str) -> bool:
+    def print_image(
+        self, image, sign: str, do_cut: bool, process_image: bool, many: int = 1
+    ) -> bool:
         """
         Get an image and a signature, prints the image and cuts after that.
         """
@@ -41,40 +51,45 @@ class Web(object):
             file_uploaded = self.upload_file(image)
         except Exception as e:
             self.app.logger.error(e)
-            raise RuntimeError("Could not upload file") from e
+            raise RuntimeError("Could not upload file : " + str(e)) from e
 
         if file_uploaded:
             self.app.logger.debug("File has been uploaded, printing...")
             try:
-                img = self.print_queue.enqueue(
+                for i in range(many):
-                    ImageTask(
+                    img = self.print_queue.enqueue(
-                        os.path.join(
+                        ImageTask(
-                            self.app.config["UPLOAD_FOLDER"],
+                            os.path.join(
-                            secure_filename(image.filename),
+                                self.app.config["UPLOAD_FOLDER"],
-                        ),
+                                secure_filename(image.filename),
-                        signature=sign,
+                            ),
-                        process=True,
+                            signature=sign,
+                            process=process_image,
+                        )
                     )
-                )
+                    self.app.logger.info("Added a IMG task at position %s", img)
 
-                cut = self.print_queue.enqueue(CutTask())
+                    if do_cut:
+                        cut = self.print_queue.enqueue(CutTask())
+                        self.app.logger.info("Added a CUT task at position %s", cut)
             except Exception as e:
                 raise RuntimeError("Could not add IMG to queue" + str(e)) from e
 
-            self.app.logger.info("Added two new tasks at position %s and %s", img, cut)
-
         return True
 
-    def login(self, username: str, password: str) -> bool:
+    # def login(self, username: str, password: str) -> bool:
-        """Not implemented"""
+    #     """Not implemented"""
-        return
+    #     return
 
-    def logout(self, username: str, password: str) -> bool:
+    # def logout(self, username: str, password: str) -> bool:
-        """Not implemented"""
+    #     """Not implemented"""
-        return
+    #     return
 
     def allowed_file(self, filename) -> bool:
-        self.app.logger.debug("Is the filename allowed ?")
+        """
+        Check if the file extension is allowed
+        """
+        self.app.logger.debug("Checking if the file extension is allowed")
         return (
             "." in filename
             and filename.rsplit(".", 1)[1].lower()
@@ -82,8 +97,11 @@ class Web(object):
         )
 
     def upload_file(self, image) -> bool:
+        """
+        Save the file after executing checks on it
+        """
         self.app.logger.debug("Validating file")
-        if image:
+        if not image is None or not image == "":
             if self.allowed_file(image.filename):
                 filename = secure_filename(image.filename)
                 self.app.logger.debug("File valid")
@@ -91,24 +109,23 @@ class Web(object):
                     image.save(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
                 except OSError as e:
                     self.app.logger.error("Could not save file %s", e)
-                    return False
+                    raise RuntimeError(
+                        "An OS error occured while uploading this file : " + str(e)
+                    ) from e
 
                 self.app.logger.debug(
                     "File saved to "
                     + str(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
                 )
                 return True
-            else:
+
-                self.app.logger.error(
+        self.app.logger.error("Could not save file because the filename is forbidden")
-                    "Could not save file because the filename is forbidden"
+        raise RuntimeError("This file type is forbidden.")
-                )
-                return False
-        else:
-            self.app.logger.error(
-                "Could not save file, it seems to be null ? : " + str(filename)
-            )
-            return False
 
     def get_queue_state(self):
         """Return current queue state"""
         return self.print_queue.get_queue_state()
+
+    def get_queue_completed(self):
+        """Return completed queue elements"""
+        return self.print_queue.get_queue_completed()

src/worker.py

@@ -1,84 +1,158 @@
-# This is the main printing thread
+"""
-# As explained in the task file, this is where we command
+This is the main printing thread. A worker thread consums Tasks from
-# printing to happen.
+ a PrintQueue, while trying to find available printers.
+"""
 
 import threading
 import time
+import traceback
 
 
 class PrintWorker(threading.Thread):
-    def __init__(self, app, print_queue, printer, socketio=None):
+    """
+    A thread used to consume Tasks added to a Print Queue.
+
+    On initialisation, the worker will try to find Printers,
+    and on each print, if the choosen Printer becomes unavailable, it
+    will choose an available Printer from a list of Printers.
+
+    If a print fails, it's not retried, but will be added to a list of completed
+    tasks. TODO : Change that
+    """
+
+    def __init__(self, app, print_queue, printers_pool, printer_index=0):
         super().__init__(daemon=True)
         self.app = app
         self.print_queue = print_queue
-        self.printer = printer
+        self.printer = None
-        self.socketio = socketio  # Optional
+        self._lock = threading.Lock()
         self.running = True
         self.state = "idle"  # idle, printing, dead, drinking-a-beer
 
+        # All workers share the same pool of printers.
+        self.printers = printers_pool
+        self.printers_obj = self.printers.printers
+        # If we create several workers, we can assign an index
+        # so that we lookup the nth printer for the nth worker
+        self._printer_index = printer_index
+
+        self.app.logger.debug("Worker initialized.")
+        self.app.logger.debug("Printers connected:")
+        for printer in self.printers_obj:
+            self.app.logger.debug("Printer type: %s", printer.printer_type)
+            self.app.logger.debug("Printer state: %s", printer.ready)
+
         self.app.logger.debug("Ho great, I'm alive... I'm ready to work another day...")
 
+    def _acquire_available_printer(self):
+        result = self.printers.acquire_available_printer(
+            start_index=self._printer_index
+        )
+        if result is None:
+            return None
+
+        index, printer = result
+        # In case we need to lookup another printer, we don't
+        # look at the same printer in the printer list
+        self._printer_index = (index + 1) % len(self.printers_obj)
+        return printer
+
     def run(self):
         """Background thread that processes queue items"""
-        self.app.logger.info("Worker started working.")
+        self.app.logger.debug("Worker %s started working.", threading.get_ident())
+        self.app.logger.debug("Current threads : %s", threading.active_count())
+        self.app.logger.debug("Threads actives : %s ", threading.enumerate())
+
         while True:
-            if not self.running or not self.printer.ready:
+
+            # If the printer is dead or asleep, it can't work.
+            if not self.running:
                 time.sleep(0.2)
                 continue
 
-            try:
+            # If we have no available printer, we look at the list printers
-                task = self.print_queue.dequeue()
+            # we know about, and try to find one that is available.
-            except Exception as e:
+            # When we find a printer, we acquire it
-                self.app.logger.error("Could not get a new task ! %s ", str(e))
+            # When we are finished with a printer, we release it to the world.
-                raise RuntimeError(
-                    "We could not get a new task because " + str(e)
-                ) from e
 
-            if task:
+            # If we do not have a printer, we try to find one
+
+            while self.running and self.printer is None:
+                self.app.logger.debug(
+                    "Trying to find a available printer for the worker."
+                )
+                self.printer = self._acquire_available_printer()
+                self.app.logger.debug(
+                    "The worker got a %s printer and it's %s",
+                    self.printer.printer_type,
+                    "Ready" if self.printer.ready else "Not ready",
+                )
+
+                if self.printer is None:
+                    time.sleep(1)
+
+            self.printer.use_printer()
+
+            # If the printer is not ready, we wait for it to become ready.
+            while not self.printer.ready:
+                self.app.debug("Waiting for our printer to become ready...")
+                time.sleep(1)
+
+            if self.state != "idle":
+                self.app.logger("We are not idle, waiting...")
+                time.sleep(1)
+                continue
+
+            self.state = "printing"
+
+            with self._lock:
                 try:
-                    self.app.logger.info("Got a new task")
+                    task = self.print_queue.dequeue()
-                    self.app.logger.debug("Got task %s", task.task_id)
+                except Exception as e:
-                    self.state = "printing"
+                    self.app.logger.error("Could not get a new task ! %s ", str(e))
-                    task.status = "processing"
+                    self.state = "idle"
-                    self._emit_status(task.task_id, "processing")
+                    self.printer.free_printer()
+                    raise RuntimeError(
+                        "We could not get a new task because " + str(e)
+                    ) from e
 
-                    print_data = task.get_print_data()
+                if task:
                     try:
-                        self.printer.print_task(task.task_type, print_data)
+                        self.app.logger.info("Got a new task")
+                        self.app.logger.debug(
+                            "Got task %s %s", task.task_type, task.task_id
+                        )
+                        task.status = "processing"
+
+                        print_data = task.get_print_data()
+
+                        try:
+                            self.printer.print_task(task.task_type, print_data)
+                        except RuntimeError as e:
+                            self.state = "idle"
+                            self.app.logger.error("Could not print : %s", str(e))
+                            self.app.logger.error(traceback.format_exc())
+                            self.printer.free_printer()
+
+                        task.status = "completed"
+                        self.print_queue.mark_completed(task.task_id, "completed")
+                        self.app.logger.debug(
+                            "Finished printing task %s ", task.task_id
+                        )
+                        self.state = "idle"
+
                     except RuntimeError as e:
-                        self.app.logger.error("Could not print : %s", str(e))
+                        task.status = "failed"
-                        raise e
+                        self.state = "idle"
+                        self.print_queue.mark_completed(task.task_id, "failed")
+                        self.app.logger.error(
+                            "Could not print task %s because %s ", task.task_id, str(e)
+                        )
 
-                    task.status = "completed"
+                else:
-                    self.print_queue.mark_completed(task.task_id, "completed")
+                    # When they are no new tasks to handle, we put the thread to sleep.
-                    self._emit_status(task.task_id, "completed")
+                    self.state = "idle"
-
+                    time.sleep(0.1)
-                except RuntimeError as e:
-                    task.status = "failed"
-                    self.print_queue.mark_completed(task.task_id, "failed")
-                    self._emit_status(task.task_id, "failed", error=str(e))
-                    print(f"Print task {task.task_id} failed: {e}")
-            else:
-                # When they are no new tasks to handle, we put the thread to sleep.
-                self.state = "idle"
-                time.sleep(0.1)
-
-    def _emit_status(self, task_id, status, error=None):
-        """Emit status update via Socket.IO if available"""
-        if not self.socketio:
-            return
-
-        room = f"task_{task_id}"
-        data = {
-            "task_id": task_id,
-            "status": status,
-            "position": None,  # Task no longer in queue
-        }
-
-        if error:
-            data["error"] = error
-
-        self.socketio.emit("task_status", data, room=room)
 
     def stop_worker(self):
         """
@@ -86,6 +160,10 @@ class PrintWorker(threading.Thread):
         """
         self.app.logger.debug("Giving the worker a break")
         self.state = "drinking-a-beer"
+        # Free the printer during the worker break
+        # so it can be used by someone else
+        self.printer.free_printer()
+        self.printer = None
         self.running = False
 
     def start_worker(self):
@@ -104,4 +182,5 @@ class PrintWorker(threading.Thread):
             "is_running": self.running,
             "queue_size": len(self.print_queue),
             "state": self.state,
+            "printers": len(self.printers_obj),
         }