Merge pull request 'Restructure the code and implement a printing queue' (#29) from restructure-printing-queue into master

Reviewed-on: #29

README.md

@@ -19,35 +19,42 @@ To make this project work, you will need :
 - Some electric wires.
 - Some knowledge of the command line,
 - Some knowledge of Python.
+    - You will need to install [Poetry](https://python-poetry.org/) to manage the depedencies of the projet.
 - 3h of your time, 5h if things need debugging.
-- `fswebcam`, `libjpeg-dev` ,`zlib1g-dev`,`libffi-dev`,`git`, `virtualenv`,`pip` and `python` >= 3.8.6.
+- You will need to following packages: `fswebcam`, `libjpeg-dev` ,`zlib1g-dev`,`libffi-dev`,`git`, `virtualenv`,`pip` and `python` >= 3.8.6.
 - A webcam for the webcam page to work. Will work on a smartphone. Not required.
 
 ## Context
 
+### Testing your printer
 For the EPSON TM-T20III, you can get the CUPS driver from [here](https://download.epson-biz.com/modules/pos/index.php?page=soft&scat=32). It's not specific to the printer I've been using, so you can try with other printers.
 
-With that, you can try out your printer and print normal text, images or pdf documents for example. LittlePrynter itself does not require any other software than the ones installed with it, i.e the ones listed in the `requirements.txt` file.
+With that, you can try out your printer and print normal text, images or pdf documents for example. For the Adafruit printer, start by following the guide [here](https://learn.adafruit.com/networked-thermal-printer-using-cups-and-raspberry-pi) to install the CUPS software needed to print images. If you want, you can install it via the command line, [following this guide](https://help.ubuntu.com/lts/serverguide/cups.html).
-
-For the Adafruit printer, start by following the guide [here](https://learn.adafruit.com/networked-thermal-printer-using-cups-and-raspberry-pi) to install the CUPS software needed to print images. If you want, you can install it via the command line, [following this guide](https://help.ubuntu.com/lts/serverguide/cups.html).
 
 You can also get some information from [here](https://learn.adafruit.com/mini-thermal-receipt-printer) and [here](https://learn.adafruit.com/instant-camera-using-raspberry-pi-and-thermal-printer) if you're stuck.
 
+### How LittlePrynter works
+
+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 only supports the EPSON printer, but you can try to adapt it for other printers using the `adafruit-thermal` branch, but I won't offer support for it.
+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`.
 
 ### 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.
+
 ```
 $ git clone https://git.n07070.xyz/n07070/LittlePrynter
-$ virtualenv LittlePrynter
 $ cd LittlePrynter
-$ source bin/activate
+$ eval "$(poetry env activate)"
-$ pip install -r requirements.txt
+$ poetry install
 ```
 
-> tip : when you're done, you can get out of the virtualenv either by closing your terminal, or by running `deactivate`.
+> tip : when you're done, you can get out of the poetry environnement either by closing your terminal, or by running `deactivate`.
+
+### Configure LittlePrynter
 
 You should see a folder named `configuration`. Enter it, and duplicate the file named `config.toml.sample`, and rename the copy to `config.toml`. Now, edit this file by following the comments in the file itself.
 
@@ -57,9 +64,11 @@ You can now start the web server with
 
 ```
 $ export FLASK_APP=src/main.py
-$ flask run
+$ 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.
+
 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 !
@@ -70,11 +79,21 @@ 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 about 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 in 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.
 
-To do so, you can run the following command :
+To do so, you can run the following command, which will modify your files to be in a certain coding style ;
 
 ```
 black src/
@@ -82,6 +101,12 @@ black src/
 
 Beware that this command *will* re-write files, so doing `git add <file>` and then `black src/` and then `git diff` to see what the linter has done is a good idea.
 
+Then, you can run another command, called Pylint ( [documentation](https://www.pylint.org/) ) which will rate your code. Try to get 10/10 : an excellent code works better and make you a better programmer !
+
+```
+pylint src/
+```
+
 ## Screenshots
 
 ![](src/static/images/homepage.png)
@@ -104,6 +129,7 @@ If you liked this project, feel free to support my work !
 - [Github repo with CUPS drivers for the Adafruit Thermal Printer ( zj-58 )](https://github.com/klirichek/zj-58)
 - [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.
 
 
 ## Licence

configuration/config.toml.sample

@@ -1,5 +1,8 @@
 # Configuration file the LittlePrynter
 
+[defaults]
+signature = "Anonymous"
+
 # Printer settings
 [printer]
 vendor_id = "0x04b8"

littleprynter.service

@@ -6,7 +6,7 @@ After=network.target
 Type=simple
 WorkingDirectory=/home/pi/littleprynter/
 Environment=FLASK_APP=src/main.py
-ExecStart=/home/pi/littleprynter/bin/flask run --host 0.0.0.0 --debug --no-reload
+ExecStart=/home/pi/littleprynter/bin/flask run --host 0.0.0.0 --no-reload
 
 [Install]
 WantedBy=multi-user.target

pip-selfcheck.json

@@ -1 +0,0 @@
-{"last_check":"2018-10-10T18:33:22Z","pypi_version":"18.1"}

pyproject.toml

@@ -0,0 +1,56 @@
+[project]
+name = "littleprynter"
+version = "0.1.0"
+description = "A web interface and API to print on thermal printers"
+authors = [
+    {name = "n07070",email = "contact@n07070.xyz"}
+]
+license = "AGPLv3"
+readme = "README.md"
+requires-python = ">=3.13"
+dependencies = [
+    "flask (>=3.1.3,<4.0.0)",
+    "numpy (>=2.3.4)",
+    "toml (>=0.10.2,<0.11.0)",
+    "flask-socketio (>=5.6.1,<6.0.0)",
+    "flask-limiter (>=4.1.1,<5.0.0)",
+    "gpiozero (>=2.0.1)",
+    "cryptography (>=48.0.0,<49.0.0)",
+    "pyusb (>=1.3.1,<2.0.0)",
+    "pyserial (>=3.5,<4.0)",
+    "qrcode (<9.0)",
+    "python-barcode (>=0.16.1)",
+    "setuptools (==81)",
+    "cffi (>=2.0.0,<3.0.0)",
+    "configobj (>=5.0.9,<6.0.0)",
+    "future (>=1.0.0,<2.0.0)",
+    "h11 (>=0.16.0,<0.17.0)",
+    "idna (>=3.15,<4.0)",
+    "itsdangerous (>=2.2.0,<3.0.0)",
+    "jinja2 (>=3.1.6,<4.0.0)",
+    "jsonpointer (>=3.1.1,<4.0.0)",
+    "jsonschema (>=4.26.0,<5.0.0)",
+    "limits (>=5.8.0,<6.0.0)",
+    "markupsafe (>=3.0.3,<4.0.0)",
+    "pillow (>=12.2.0,<13.0.0)",
+    "pycryptodomex (>=3.23.0,<4.0.0)",
+    "python-dateutil (>=2.9.0.post0,<3.0.0)",
+    "python-engineio (>=4.13.1,<5.0.0)",
+    "python-socketio (>=5.16.1,<6.0.0)",
+    "pyyaml (>=6.0.3,<7.0.0)",
+    "requests (>=2.34.2,<3.0.0)",
+    "python-escpos (>=3.1,<4.0)",
+    "pep8 (>=1.7.1,<2.0.0)",
+    "pylint (>=4.0.5,<5.0.0)",
+    "brother-ql-inventree (>=1.3,<2.0)",
+]
+
+[tool.poetry]
+package-mode = false
+
+
+[tool.poetry.dependencies]
+python-escpos = {allow-prereleases = true}
+[build-system]
+requires = ["poetry-core>=2.0.0,<3.0.0"]
+build-backend = "poetry.core.masonry.api"

requirements.txt

@@ -1,261 +0,0 @@
-appdirs==1.4.4
-apt-listchanges==4.8
-argcomplete==3.6.2
-arrow==1.3.0
-attrs==25.3.0
-babel==2.17.0
-bcrypt==4.2.0
-bidict==0.23.1
-blinker==1.9.0
-certifi==2025.1.31
-cffi==1.17.1
-chardet==5.2.0
-charset-normalizer==3.4.2
-click==8.3.0
-cloud-init==25.2
-colorzero==2.0
-configobj==5.0.9
-cryptography==43.0.0
-Deprecated==1.2.18
-distlib==0.3.9
-distro==1.9.0
-escpos==2.0.0
-filelock==3.18.0
-Flask==3.1.2
-Flask-Limiter==4.0.0
-Flask-SocketIO==5.5.1
-fqdn==1.5.1
-future==1.0.0
-gpiod==2.2.0
-gpiozero==2.0.1
-h11==0.16.0
-idna==3.10
-isoduration==20.11.0
-itsdangerous==2.2.0
-Jinja2==3.1.6
-jsonpatch==1.32
-jsonpointer==2.4
-jsonschema==4.19.2
-jsonschema-specifications==2023.12.1
-lgpio==0.2.2.0
-limits==5.6.0
-linkify-it-py==2.0.3
-markdown-it-py==3.0.0
-MarkupSafe==2.1.5
-mdurl==0.1.2
-numpy==2.3.4
-oauthlib==3.2.2
-olefile==0.47
-ordered-set==4.1.0
-packaging==25.0
-pillow==11.1.0
-platformdirs==4.3.7
-ply==3.11
-pycparser==2.22
-pycryptodomex==3.20.0
-Pygments==2.18.0
-PyJWT==2.10.1
-pyserial==3.5
-python-apt==3.0.0
-python-barcode==0.16.1
-python-dateutil==2.9.0
-python-engineio==4.12.3
-python-socketio==5.14.1
-pyusb==1.3.1
-PyYAML==6.0.2
-qrcode==8.2
-referencing==0.36.2
-requests==2.32.3
-rfc3339-validator==0.1.4
-rfc3986-validator==0.1.1
-rfc3987==1.3.8
-rich==13.9.4
-rpds-py==0.21.0
-rpi-keyboard-config==1.0
-rpi-lgpio==0.6
-setuptools==80.9.0
-simple-websocket==1.1.0
-six==1.17.0
-smbus2==0.4.3
-spidev==3.6
-ssh-import-id==5.10
-toml==0.10.2
-types-aiofiles==24.1
-types-antlr4-python3-runtime==4.13
-types-assertpy==1.1
-types-atheris==2.3
-types-aws-xray-sdk==2.14
-types-beautifulsoup4==4.12
-types-bleach==6.2
-types-boltons==24.1
-types-braintree==4.31
-types-cachetools==5.5
-types-caldav==1.3
-types-capturer==3.0
-types-cffi==1.16
-types-chevron==0.14
-types-click-default-group==1.2
-types-click-spinner==0.1
-types-colorama==0.4
-types-commonmark==0.9
-types-console-menu==0.8
-types-corus==0.10
-types-croniter==5.0.1
-types-dateparser==1.2
-types-decorator==5.1
-types-defusedxml==0.7
-types-Deprecated==1.2.15
-types-docker==7.1
-types-dockerfile-parse==2.0
-types-docutils==0.21
-types-editdistance==0.8
-types-entrypoints==0.4
-types-ExifRead==3.0
-types-fanstatic==1.4
-types-first==2.0
-types-flake8==7.1
-types-flake8-bugbear==24.12.12
-types-flake8-builtins==2.5
-types-flake8-docstrings==1.7
-types-flake8-rst-docstrings==0.3
-types-flake8-simplify==0.21
-types-flake8-typing-imports==1.16
-types-Flask-Cors==5.0
-types-Flask-Migrate==4.0
-types-Flask-SocketIO==5.4
-types-fpdf2==2.8.2
-types-gdb==15.0
-types-gevent==24.11
-types-google-cloud-ndb==2.3
-types-greenlet==3.1
-types-hdbcli==2.23
-types-html5lib==1.1
-types-httplib2==0.22
-types-humanfriendly==10.0
-types-hvac==2.3
-types-ibm-db==3.2.4
-types-icalendar==6.1
-types-influxdb-client==1.45
-types-inifile==0.4
-types-JACK-Client==0.5
-types-Jetson.GPIO==2.1
-types-jmespath==1.0
-types-jsonschema==4.23
-types-jwcrypto==1.5
-types-keyboard==0.13
-types-ldap3==2.9
-types-libsass==0.23
-types-lupa==2.2
-types-lzstring==1.0
-types-m3u8==6.0
-types-Markdown==3.7
-types-mock==5.1
-types-mypy-extensions==1.0
-types-mysqlclient==2.2
-types-nanoid==2.0.0
-types-netaddr==1.3
-types-netifaces==0.11
-types-networkx==3.4.2
-types-oauthlib==3.2
-types-objgraph==3.6
-types-olefile==0.47
-types-openpyxl==3.1.5
-types-opentracing==2.4
-types-paramiko==3.5
-types-parsimonious==0.10
-types-passlib==1.7
-types-passpy==1.0
-types-peewee==3.17.8
-types-pep8-naming==0.14
-types-pexpect==4.9
-types-pika-ts==1.3
-types-polib==1.2
-types-portpicker==1.6
-types-protobuf==5.29.1
-types-psutil==6.1
-types-psycopg2==2.9.10
-types-pyasn1==0.6
-types-pyaudio==0.2
-types-PyAutoGUI==0.9
-types-pycocotools==2.0
-types-pycurl==7.45.4
-types-pyfarmhash==0.4
-types-pyflakes==3.2
-types-pygit2==1.15
-types-Pygments==2.18
-types-pyinstaller==6.11
-types-pyjks==20.0
-types-PyMySQL==1.1
-types-pynput==1.7.7
-types-pyOpenSSL==24.1
-types-pyRFC3339==2.0.1
-types-PyScreeze==1.0.1
-types-pyserial==3.5
-types-pysftp==0.2
-types-pytest-lazy-fixture==0.6
-types-python-crontab==3.2
-types-python-datemath==3.0.1
-types-python-dateutil==2.9
-types-python-http-client==3.3.7
-types-python-jenkins==1.8
-types-python-jose==3.3
-types-python-nmap==0.7
-types-python-xlib==0.33
-types-pytz==2024.2
-types-pywin32==308
-types-pyxdg==0.28
-types-PyYAML==6.0
-types-qrbill==1.1
-types-qrcode==8.0
-types-regex==2024.11.6
-types-reportlab==4.2.5
-types-requests==2.32
-types-requests-oauthlib==2.0
-types-retry==0.9
-types-RPi.GPIO==0.7
-types-s2clientprotocol==5
-types-seaborn==0.13.2
-types-Send2Trash==1.8
-types-setuptools==75.6
-types-shapely==2.0
-types-simplejson==3.19
-types-singledispatch==4.1
-types-six==1.17
-types-slumber==0.7
-types-str2bool==1.1
-types-tabulate==0.9
-types-tensorflow==2.18.0
-types-TgCrypto==1.2
-types-toml==0.10
-types-toposort==1.10
-types-tqdm==4.67
-types-translationstring==1.4
-types-tree-sitter-languages==1.10
-types-ttkthemes==3.2
-types-ujson==5.10
-types-unidiff==0.7
-types-untangle==1.2
-types-usersettings==1.1
-types-uWSGI==2.0
-types-vobject==0.9.9
-types-waitress==3.0.1
-types-WebOb==1.8
-types-whatthepatch==1.0
-types-workalendar==17.0
-types-WTForms==3.2.1
-types-wurlitzer==3.1
-types-xdgenvpy==3.0
-types-xmltodict==0.14
-types-zstd==1.5
-types-zxcvbn==4.4
-typing_extensions==4.15.0
-uc-micro-py==1.0.3
-uritemplate==4.1.1
-urllib3==2.3.0
-viivakoodi==0.8.0
-virtualenv==20.31.2
-webcolors==1.13
-Werkzeug==3.1.3
-wheel==0.46.1
-wrapt==1.17.3
-wsproto==1.2.0

run.sh

@@ -1,7 +0,0 @@
-virtualenv .
-
-pip install -r requirements.txt
-
-export FLASK_APP=src/main.py
-export FLASK_ENV=development
-flask run --host 192.168.0.42 --debugger --eager-loading

src/main.py

@@ -39,11 +39,14 @@ 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
 
-# Variables
+# We create the main Flask object
-
 app = Flask(__name__)
-socketio = SocketIO(app)
+socketio = SocketIO(app, cors_allowed_origins="*")
+
+# Global variables
 ALLOWED_EXTENSIONS = {"png", "jpg", "jpeg", "gif", "webp"}
 
 # Load the configuration file
@@ -82,10 +85,10 @@ except FileExistsError:
     app.logger.debug("Directory %s already exists.", UPLOAD_FOLDER)
 except PermissionError:
     app.logger.error("Permission denied: Unable to create %s", UPLOAD_FOLDER)
-    exit(77)
+    sys.exit(77)
 
 # Output the config file
-if os.getenv("LIPY_DEBUG") is True:
+if os.getenv("FLASK_DEBUG"):
     pprint.pprint(configuration_file)
 
 # We define the app module used by Flask
@@ -113,19 +116,22 @@ rpi = Raspberry(
 
 RASPBERRY_PI_CONNECTED = rpi.is_raspberry_pi()
 
+# Queue creation
+print_queue = PrintQueue(app)
 
-#  Web & API  routes
+#  Web & API management
+web = Web(app, print_queue)
 
-web = Web(app, printer)
+# Start worker thread
-
+worker = PrintWorker(app, print_queue, printer, socketio)
-if __name__ == "__main__":
+worker.start()
-    app.run(debug=True, use_reloader=False, host="0.0.0.0", ssl_context="adhoc")
 
+# The rate limit
 limiter = Limiter(
     get_remote_address, app=app, default_limits=["1500 per day", "500 per hour"]
 )
 
-
+# General routes
 @app.route("/")
 @limiter.limit("1/second", override_defaults=False)
 def index():
@@ -142,6 +148,83 @@ def webcam():
     return render_template("webcam.html")
 
 
+# Form treatement
+@app.route("/web/print/sms", methods=["POST"])
+@limiter.limit("6/minute", override_defaults=False)
+def web_print_sms():
+    """Prints a short message on a printer"""
+    app.logger.debug("Printing an sms via web method")
+
+    try:
+        txt = request.form["txt"]
+    except werkzeug.exceptions.BadRequestKeyError as e:
+        app.logger.error("Whoops, we are missing the txt input field. : %s ", str(e))
+        flash("Whoops, no forms submitted or missing signature : " + str(e), "error")
+        return redirect(url_for("index"))
+
+    try:
+        # comment: We try to get a signature
+        sign = request.form["signature"]
+    except werkzeug.exceptions.BadRequestKeyError as e:
+        app.logger.warning(
+            "No signature found for this print, using default signature : %s ", str(e)
+        )
+        sign = configuration_file["defaults"]["signature"]
+
+    try:
+        web.print_sms(txt, sign)
+    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 added to the print queue !", "info")
+    return redirect(url_for("index"))
+
+
+@app.route("/web/print/img", methods=["POST"])
+@limiter.limit("1/second", override_defaults=False)
+def web_print_img():
+    """Prints an image on a printer"""
+    app.logger.debug("Printing an image with web method")
+
+    try:
+        # comment: We try to get a signature
+        sign = request.form["signature"]
+    except werkzeug.exceptions.BadRequestKeyError as e:
+        app.logger.warning(
+            "No signature found for this print, using default signature : %s", str(e)
+        )
+        sign = configuration_file["defaults"]["signature"]
+
+    # check if the post request has the file part
+    if "img" not in request.files:
+        app.logger.error("Whoops, no images submitted  : %s ", str(e))
+        app.logger.error("Error getting the files : %s", str(e))
+        flash("Whoops, no images submitted  : " + str(e), "error")
+        return redirect(url_for("index"))
+
+    file = request.files["img"]
+    # If the user does not select a file, the browser submits an
+    # empty file without a filename.
+    if file.filename == "":
+        app.logger.error("Submitted file has no filename !")
+        flash("Submitted file has no filename !", "error")
+        return redirect(url_for("index"))
+
+    try:
+        app.logger.debug("Sending the image to the printer.")
+        web.print_image(file, sign)
+    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 added to the print queue !", "info")
+    return redirect(url_for("index"))
+
+
 # API routes
 # The api has the following methods
 # api/print/{sms,img,letter,qr,barcode}
@@ -163,93 +246,115 @@ def api_index():
 @limiter.limit("6/minute", override_defaults=False)
 def api_print_sms():
     """Prints a short message on a printer"""
-    app.logger.debug("Printing an sms")
+    app.logger.debug("Printing an sms via API")
     try:
         txt = request.form["txt"]
     except werkzeug.exceptions.BadRequestKeyError as e:
         app.logger.error("Whoops, we are missing the txt input field. : %s ", str(e))
-        flash("Whoops, no forms submitted or missing signature : %s", str(e))
+        return str(e), 400
-        return redirect(url_for("index"))
-
     try:
         # comment: We try to get a signature
         sign = request.form["signature"]
     except werkzeug.exceptions.BadRequestKeyError as e:
         app.logger.warning(
-            "No signature found for this print, using default signature.", str(e)
+            "No signature found for this print, using default signature. : %s", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
-
+    try:
-    web.print_sms(txt, sign)
+        # comment: We try to print the SMS
-    return redirect(url_for("index"))
+        web.print_sms(txt, sign)
+    except RuntimeError as e:
+        return str(e), 500
+    # end try
+    return "OK", 200
 
 
 @app.route("/api/print/img", methods=["POST"])
 @limiter.limit("6/minute", override_defaults=False)
 def api_print_image():
     """Prints an image on a printer"""
-    app.logger.debug("Printing an image")
+    app.logger.debug("Printing an image via API")
 
     try:
         # comment: We try to get a signature
         sign = request.form["signature"]
     except werkzeug.exceptions.BadRequestKeyError as e:
         app.logger.warning(
-            "No signature found for this print, using default signature.", str(e)
+            "No signature found for this print, using default signature. %s", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
 
-    if request.method == "POST":
+    # check if the post request has the file part
-        # check if the post request has the file part
+    if "img" not in request.files:
-        if "img" not in request.files:
+        app.logger.error("Whoops, no images submitted.")
-            app.logger.error("Whoops, no images submitted  : %s ", str(e))
+        return "No image submitted", 400
-            app.logger.error("Error getting the files : %s", str(e))
-            flash("Whoops, no images submitted  : %s", str(e))
-            return redirect(url_for("index"))
 
-        file = request.files["img"]
+    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 == "":
-        if file.filename == "":
+        app.logger.error("Submitted file has no filename !")
-            app.logger.error("Submitted file has no filename !")
+        return "Submitted file has no filename !", 400
-            flash("Submitted file has no filename !")
-            return redirect(url_for("index"))
 
-        try:
+    try:
-            app.logger.debug("Sending the image to the printer.")
+        app.logger.debug("Sending the image to the printer.")
-            web.print_image(file, sign)
+        web.print_image(file, sign)
-        except Exception as e:
+    except RuntimeError as e:
-            app.logger.error("The image could not be printed because : %s ", str(e))
+        return str(e), 500
-            flash("The image could not be printed because : %s ", str(e))
-            return redirect(url_for("index"))
 
-    else:
+    return "OK", 200
-        app.logger.error("Method not allowed")
-        flash("Method not allowed")
-        return redirect(url_for("index"))
-
-    flash("Picture printed ! ")
-    return redirect(url_for("index"))
 
 
-@app.route("/api/camera/picture")
+@app.route("/api/camera/picture", methods=["GET"])
 def camera_picture():
-    """Returns a picture taken by the camera"""
+    """Returns a picture taken by the camera on a raspberry pi"""
     if RASPBERRY_PI_CONNECTED:
         try:
             return rpi.camera_picture()
-        except Exception as e:
+        except RuntimeError as e:
             return jsonify({"message": "Error getting the stream : " + e}), 500
     else:
         return jsonify({"message": "No camera present"}), 500
 
 
+@app.route("/api/queue", methods=["GET"])
+def api_queue_status():
+    """API endpoint for entire queue"""
+    return jsonify(web.get_queue_state())
+
+
+@app.route("/api/worker", methods=["GET"])
+def api_worker_state():
+    """API endpoint to get the worker state"""
+    return jsonify(worker.current_state())
+
+
+@app.route("/api/worker/start")
+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")
+def api_worker_stop():
+    """
+    Stops the print queue. This stops the processing of the print queue.
+    """
+    worker.stop_worker()
+    return jsonify(worker.current_state())
+
+
+## Authentification
+
+
 @app.route("/login")
 @limiter.limit("1/second", override_defaults=False)
 def login_page():
     """Unsued, logins"""
     # web.login(username,password)
-    return redirect(url_for("index"))
+    return redirect(url_for("index")), 501
 
 
 @app.route("/logout")
@@ -257,7 +362,7 @@ def login_page():
 def logout_page():
     """Unused, logout"""
     # web.logout(username, password)
-    return redirect(url_for("index"))
+    return redirect(url_for("index")), 501
 
 
 @app.errorhandler(429)
@@ -295,3 +400,7 @@ def camera_status():
         socketio.emit("camera_status", True)
     else:
         socketio.emit("camera_status", False)
+
+
+if __name__ == "__main__":
+    app.run(debug=True, use_reloader=False, host="0.0.0.0", ssl_context="adhoc")

src/print_queue.py

@@ -0,0 +1,135 @@
+"""
+This class has the method by which we manage the Tasks
+It's a printing queue, so we need to add, remove and get information on where
+the queue is
+"""
+
+from collections import deque
+
+# Because actually printing and adding new print job requests happen at
+# diffrent times, the print queue is managed by it's own thread.
+import threading
+
+from datetime import datetime
+from task import TaskType
+
+
+class PrintQueue:
+    """
+    A Double-ended Queue to manage the printing Tasks
+    """
+
+    def __init__(self, app):
+        self.app = app
+        self._queue = deque()
+        self._lock = threading.Lock()
+        self._completed_tasks = {}  # Store completed task info
+        self._task_counter = 0
+        self.app.logger.debug("Created a new PrintQueue")
+
+    def __len__(self) -> int:
+        return len(self._queue)
+
+    def enqueue(self, task):
+        """Add task to right of the queue and return position"""
+        with self._lock:
+            try:
+                self.app.logger.info("Add task %s to queue ", task.task_id)
+                self._queue.append(task)
+                position = self._queue.index(task)
+                # We return the current position of the task if it was added
+                self.app.logger.debug(
+                    "Added a new task %s to the queue at position %s",
+                    task.task_id,
+                    position,
+                )
+                return position
+            except Exception as e:
+                self.app.logger.error("Could not add a task to the queue : %s ", e)
+                raise e
+
+    def dequeue(self):
+        """Remove and return next task ( from the left of the queue ) (thread-safe)"""
+        with self._lock:
+            return self._queue.popleft() if len(self._queue) > 0 else None
+
+    def get_position(self, task):
+        """Get current position of task in queue (1-indexed)"""
+        with self._lock:
+            if task.task_id in self._completed_tasks:
+                return None  # Task already completed
+
+        try:
+            # Try to get the position of a Task
+            return self._queue.index(task)
+        except ValueError as e:
+            raise e
+        # end try
+
+    def is_empty(self):
+        """Check if queue is empty"""
+        with self._lock:
+            self.app.logger.debug("Checking if queue is empty")
+            return len(self._queue) == 0
+
+    def get_queue_state(self):
+        """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]
+
+    def get_status(self, task_id):
+        """Get full status info for a task"""
+        with self._lock:
+
+            if task_id in self._completed_tasks:
+                return self._completed_tasks[task_id]
+
+            # Check in queue if it exists
+            for index, task in enumerate(self._queue):
+                if task.task_id == task_id:
+                    # Depending on it's type, we return more info
+                    if task.task_type == TaskType.IMAGE:
+                        return {
+                            "task_id": task_id,
+                            "status": task.status,
+                            "type": task.task_type,
+                            "position": index,
+                            "in_queue": True,
+                            "content": task.content,
+                            "signature": task.signature,
+                        }
+
+                    if task.task_type == TaskType.TEXT:
+                        return {
+                            "task_id": task_id,
+                            "status": task.status,
+                            "type": task.task_type,
+                            "position": index,
+                            "in_queue": True,
+                            "image_path": str(task.image_path),
+                            "signature": task.signature,
+                            "process": str(task.process),
+                        }
+
+                    if task.task_type == TaskType.CUT:
+                        return {
+                            "task_id": task_id,
+                            "status": task.status,
+                            "type": task.task_type,
+                            "position": index,
+                            "in_queue": True,
+                        }
+
+            return None
+
+    def mark_completed(self, task_id, task_status):
+        """Mark task as completed and remove from queue"""
+        with self._lock:
+            self._completed_tasks[task_id] = {
+                "task_id": task_id,
+                "status": task_status,
+                "position": None,
+                "in_queue": False,
+                "completed_at": datetime.now().isoformat(),
+            }

src/printer.py

@@ -1,12 +1,18 @@
-# Importing the module to mage the connection to the printer.
+"""
-from escpos.printer import Usb, USBNotFoundError
+This class manages connexion to a Printer
-from time import sleep, gmtime, strftime
+"""
+# import brother_ql
+from time import sleep
 import os.path
-from PIL import Image, ImageEnhance, ImageOps
+
+from PIL import Image, ImageEnhance
 import numpy as np
 
+# Importing the module to manage the connection to the printer.
+import escpos.printer
 
-class Printer(object):
+
+class Printer():
     """
     # The connection is based on the ESC/POS library
 
@@ -27,7 +33,7 @@ class Printer(object):
     ready = False
 
     def __init__(self, app, device_id, vendor_id):
-        super(Printer, self).__init__()
+        super().__init__()
         self.app = app
         self.ready = False
         self.printer = None
@@ -38,7 +44,9 @@ class Printer(object):
         self.usb_args["idProduct"] = self.vendor_id
 
     def check_paper(self) -> bool:
-        # Let's check paper status
+        """
+        On printers that support it, we check that the printer has paper
+        """
         self.app.logger.debug("Checking paper status...")
         self.printer.open(self.usb_args)
         status = self.printer.paper_status()
@@ -46,7 +54,7 @@ class Printer(object):
             case 0:
                 self.app.logger.error("Printer has no more paper, aborting...")
                 self.printer.close()
-                raise Exception("No more paper in the printer")
+                raise RuntimeError("No more paper in the printer")
             case 1:
                 self.app.logger.warning(
                     "Printer needs paper to be changed very soon ! "
@@ -57,28 +65,42 @@ class Printer(object):
                 self.printer.close()
 
     def init_printer(self):
+        """
+        Check if the printer online ? Is the communication with the printer successfull ?
+        """
+
+        # TODO: This could happen directly when creating a new Printer class
+        if os.getenv("FLASK_DEBUG"):
+            waiting_elapsed = 3
+        else:
+            waiting_elapsed = 10
 
-        # Is the printer online ? Is the communication with the printer successfull ?
-        waiting_elapsed = 30
         self.app.logger.debug("Waiting for printer to get online...")
 
         while not self.ready:
             try:
                 # This also calls open(), which we need to close()
                 # or else the device will appear as busy.
-                p = Usb(self.device_id, self.vendor_id, 0, profile="TM-P80")
+                p = escpos.printer.Usb(
-            except USBNotFoundError as e:
+                    self.device_id, self.vendor_id, 0, profile="TM-P80"
-                self.app.logger.error(
+                )
-                    "The USB device is not plugged in, trying again : " + str(e)
+            except RuntimeError as e:
+                self.app.logger.error(
+                    "The USB device is not plugged in, trying again %s : %s",
+                    waiting_elapsed,
+                    str(e),
                 )
-                pass
 
             try:
                 if p.is_online():
                     self.ready = True
                     self.app.logger.debug("Printer online !")
-            except Exception as e:
+            except RuntimeError as e:
-                pass
+                self.app.logger.error(
+                    "Error while getting the printer online %s : %s",
+                    waiting_elapsed,
+                    str(e),
+                )
 
             sleep(1)
             waiting_elapsed -= 1
@@ -115,15 +137,24 @@ class Printer(object):
 
         return True
 
-    def print_sms(self, msg, signature="", bold=False):
+    def _print_sms(self, msg, signature="", bold=False):
+
+        if not isinstance(msg, str):
+            self.app.logger.error(
+                "It is not possible to print a " + str(type(msg)) + ", only strings."
+            )
+            raise ValueError
+
+        # We make sure that the signature is not something too goofy
         clean_msg = str(msg) + "\n"
         clean_signature = str(signature)
 
+        # Make checks on the size of the message being printed
         if len(clean_msg) > 4096:
             self.app.logger.warning(
                 "Could not print message of this length: " + str(len(clean_msg))
             )
-            raise Exception(
+            raise RuntimeError(
                 "Could not print message of this length :"
                 + str(len(clean_msg))
                 + ", needs to be below 4096 caracters long."
@@ -133,12 +164,14 @@ class Printer(object):
             self.app.logger.warning(
                 "Could not print signature of this length: " + str(len(clean_signature))
             )
-            raise Exception(
+            raise RuntimeError(
                 "Could not print signature of this length :"
                 + str(len(clean_signature))
                 + ", needs to be below 256 caracters long."
             )
 
+        # Do the actual printing
+        # We would pop the next element in the queue here, if it's a sms type
         try:
             self.printer.open(self.usb_args)
             self.printer.set(align="center", font="a", bold=bold)
@@ -148,18 +181,21 @@ class Printer(object):
             self.printer.close()
         except Exception as e:
             self.app.logger.error("Unable to print because : " + str(e))
+            raise RuntimeError(
+                "Unable to print a SMS, the printer couldn't do it."
+            ) from e
 
         self.app.logger.info("Printed text")
         return True
 
-    def print_img(self, path, sign="", center=True, process=False):
+    def _print_img(self, path, signature="", center=True, process=False):
-        clean_signature = str(sign)
+        clean_signature = str(signature)
 
-        if len(sign) > 256:
+        if len(signature) > 256:
             self.app.logger.warning(
                 "Could not print signature of this length: " + str(len(clean_signature))
             )
-            raise Exception(
+            raise ValueError(
                 "Could not print signature of this length :"
                 + str(len(clean_signature))
                 + ", needs to be below 256 caracters long."
@@ -167,45 +203,60 @@ class Printer(object):
 
         if not os.path.isfile(str(path)):
             self.app.logger.warning("File does not exist : " + str(path))
-            raise Exception(
+            raise OSError(
                 "The file path for this image :"
                 + str(path)
                 + " wasn't found. Please try again."
             )
-        else:
+
-            self.app.logger.debug("Printing file from " + str(path))
+        self.app.logger.debug("Printing file from " + str(path))
 
         if process:
             try:
                 self.app.logger.debug("Proccessing the image")
-                path = process_image(self, path)
+                path = _process_image(self, path)
-            except Exception as e:
+            except RuntimeError as e:
-                self.app.logger.error(str(e))
+                self.app.logger.error(
-                return False
+                    "Error while processing the image, aborting print : %s", str(e)
+                )
+                raise e
         else:
             self.app.logger.warning("Not proccessing the image")
 
         try:
             self.printer.open(self.usb_args)
             self.printer.image(path, center=center)
+            self.printer.textln(signature)
             self.printer.close()
             self.app.logger.debug("Printed an image : " + str(path))
-            os.remove(path)
-            self.app.logger.debug("Removed image : " + str(path))
         except Exception as e:
-            self.printer.close()
             self.app.logger.error(str(e))
-            return False
+            raise RuntimeError("Could not print the picture") from e
+        finally:
+            try:
+                os.remove(path)
+            except OSError as e:
+                raise e
+
+            self.app.logger.debug("Removed image : " + str(path))
+
+            try:
+                self.printer.close()
+            except Exception as e:
+                self.app.logger.error(
+                    "Could not close the printer connexion %s", str(e)
+                )
+                raise RuntimeError("Could not close the printer connexion. ") from e
 
         self.app.logger.info("Printed a picture")
         return True
 
-    def qr(self, content):
+    def _qr(self, content):
         try:
             self.printer.open(self.usb_args)
             self.printer.qr(content, center=True)
             self.printer.close()
-        except Exception as e:
+        except RuntimeError as e:
             self.printer.close()
             self.app.logger.error(str(e))
             return False
@@ -213,7 +264,7 @@ class Printer(object):
         self.app.logger.info("Printed a QR")
         return True
 
-    def cut(self):
+    def _cut(self):
         try:
             self.printer.open(self.usb_args)
             self.printer.cut()
@@ -226,8 +277,22 @@ class Printer(object):
         self.app.logger.info("Did a cut")
         return True
 
+    def print_task(self, task_type, data):
+        """Execute actual print based on task type"""
+        match (task_type.value):
+            case "text":
+                self._print_sms(data["txt"], signature=data["sign"])
+            case "image":
+                self._print_img(
+                    data["img"], signature=data["sign"], process=data["process"]
+                )
+            case "cut":
+                self._cut()
+            case _:
+                raise RuntimeError("This task type is not supported")
 
-def process_image(self, path):
+
+def _process_image(self, path):
     brightness_factor = 1.5  # Used only if image is too dark
     brightness_threshold = 100  # Brightness threshold (0–255)
     contrast_factor = 0.6  # Less than 1.0 = lower contrast
@@ -241,11 +306,12 @@ def process_image(self, path):
             original_img = original_img.convert("RGB")
 
         # Resize while maintaining aspect ratio
-        original_img.thumbnail((max_width, max_height), Image.LANCZOS)
+        original_img.thumbnail((max_width, max_height), Image.Resampling.LANCZOS)
         self.app.logger.debug("Resized the image")
 
         # # Convert to grayscale for dithering
-        # dithered_img = original_img.convert("L").convert("1")  # Dithering using default method (Floyd–Steinberg)
+        # dithered_img = original_img.convert("L").convert("1")
+        # Dithering using default method (Floyd–Steinberg)
         # self.app.logger.debug("Dithered the image")
 
         # Compute brightness of original image (grayscale average)
@@ -273,16 +339,9 @@ def process_image(self, path):
         # contrast_enhancer = ImageEnhance.Contrast(original_img)
         # original_img = contrast_enhancer.enhance(contrast_factor)
 
-        # Final resize check
-        if original_img.height > max_height:
-            raise ValueError("Image is too long, sorry! Keep it below 575×1000 pixels.")
-            self.app.logger.error(
-                "Image is too long, sorry! Keep it below 575×1000 pixels."
-            )
-            return False
-
         # Convert to JPEG and save
         jpeg_path = os.path.splitext(path)[0] + "_processed.jpg"
         original_img.save(jpeg_path, format="JPEG", quality=95, optimize=True)
+        self.app.logger.debug("Processed and saved image.")
 
     return jpeg_path

src/raspberry.py

@@ -1,13 +1,21 @@
-from flask_socketio import SocketIO
+"""
-from gpiozero import Button, LED, DigitalOutputDevice
+This class executes when we are on a raspberry Pi.
-from time import sleep, gmtime, strftime
+
-from PIL import Image
+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(object):
     """
     This class will manage three things :
     - Connecting to a USB webcam
@@ -19,7 +27,7 @@ class Raspberry(object):
 
     def __init__(
         self,
-        printer,
+        print_queue,
         app,
         socketio,
         button_gpio_port_number,
@@ -27,7 +35,7 @@ class Raspberry(object):
         flash_gpio_port_number,
         is_flash_present,
     ):
-        self.printer = printer
+        self.print_queue = print_queue
         self.socketio = socketio
         self.app = app
 
@@ -38,9 +46,13 @@ class Raspberry(object):
         self.image_path = self.app.config["UPLOAD_FOLDER"] + "/image.jpg"
 
     def is_raspberry_pi(self, raise_on_errors=False):
+        """
+        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"):
@@ -141,7 +153,7 @@ class Raspberry(object):
                 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
@@ -198,7 +210,7 @@ class Raspberry(object):
                 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
 
@@ -225,7 +237,7 @@ class Raspberry(object):
 
             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
 
@@ -242,7 +254,7 @@ class Raspberry(object):
         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)
             )
@@ -251,15 +263,11 @@ class Raspberry(object):
         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(TextTask(content="Imprimé par LittlePrynter", signature=""))
-        self.printer.print_sms("")
+        time = strftime("%Y-%m-%d %H:%M", gmtime())
-        self.printer.print_sms("With Love From Société.Vide", signature="", bold=True)
+        self.print_queue.enqueue(TextTask(content=time, signature=""))
-        self.printer.print_sms("Printed by LittlePrynter", signature="")
+        self.print_queue.enqueue(CutTask())
-        self.printer.print_sms("n07070.xyz", signature="")
-        self.printer.print_sms(strftime("%Y-%m-%d %H:%M", gmtime()), signature="")
-        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/static/js/webcam.js

@@ -193,7 +193,7 @@ function setup_events(){
     ev.preventDefault();
     try {
       await countDownToPicture();         // wait for countdown to finish
-      const data = await take_picture();  // take_picture can be async
+      var data = await take_picture();  // take_picture can be async
       print_picture(data);
     } catch (e) {
       alert("Failed to print a picture because : " + e);
@@ -212,6 +212,10 @@ function clear_canvas() {
 }
 
 function dataURLtoFile(dataurl, filename) {
+  if(dataurl === "") {
+    console.log("We didn't receive data");
+  }
+
   var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
       bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
   while(n--){
@@ -251,7 +255,12 @@ function print_picture(data){
     // headers:{
     //   'Content-Type': 'multipart/form-data'
     // }
-  }).then(function(response) { console.log('Success:', response); } , true)
+  }).then(function(response) {
+    console.log('Reponse:', response);
+    if(response.status != 200 ){
+      alert("The picture could not be printed be : " + response.statusText)
+    }
+  } , true)
   .catch(error => console.error('Error:', error), false);
 
 }

src/task.py

@@ -0,0 +1,98 @@
+"""
+Here we define the types of tasks
+We are using Abstract Base Classes,
+like this we can define types of tasks ( text, images, ... )
+that all work with the same basic options
+
+The tasks are going to be injected into a Queue.
+It's a usefull way of storing information in our
+program, while making sure that things are indeed printed.
+It's also a way to prevent two concurrent connexions creating
+a access conflict on a single printer, like two people wanting
+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 enum import Enum
+import uuid
+
+
+## You can expand this if you want to take other types of tasks into account
+class TaskType(Enum):
+    """
+    The different tasks supported by the printers
+    """
+    TEXT = "text"
+    IMAGE = "image"
+    CUT = "cut"
+
+
+class PrintTask(ABC):
+    """
+    A print task holds information about what we are looking to print.
+    """
+
+    def __init__(self, task_type):
+        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())
+
+
+class TextTask(PrintTask):
+    """
+    This tasks represents a texte content, and it's signature.
+    """
+
+    def __init__(self, content, signature):
+        super().__init__(TaskType.TEXT)
+        self.content = content
+        self.signature = signature
+
+    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.
+    """
+
+    def __init__(self, image_path, signature, process):
+        super().__init__(TaskType.IMAGE)
+        self.image_path = image_path
+        self.signature = signature
+        self.process = process
+
+    def get_print_data(self):
+        # Return image data in printer-compatible format
+        return {"img": self.image_path, "sign": self.signature, "process": self.process}
+
+
+class CutTask(PrintTask):
+    """
+    This class activates the cutter on the printer if it exists
+    """
+
+    def __init__(self):
+        super().__init__(TaskType.CUT)
+
+    # There is no print data,
+    # the task existence in itself is indication of what to do
+    def get_print_data(self):
+        return None

src/templates/index.html

@@ -5,7 +5,7 @@
     <div class="card">
       <h3 class="card-header">Print a short message</h3>
       <div class="card-body">
-        <form class="form-group" action="/api/print/sms" method="post">
+        <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>
           <input class="form-control" type="text" name="signature" placeholder="Signature or pseudo" maxlength="200"><br>
           <input class="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">
@@ -18,7 +18,7 @@
     <div class="card">
       <h3 class="card-header">Print an image</h3>
       <div class="card-body">
-        <form enctype="multipart/form-data" class="form-group" action="/api/print/img" method="post">
+        <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="btn btn-primary float-right" type="submit" value="Imprimer" name="imprimer">

src/user.py

@@ -1,41 +1,41 @@
-class User(object):
+# class User(object):
-    """docstring for User."""
+#     """docstring for User."""
 
-    def __init__(self, arg):
+#     def __init__(self, arg):
-        super(User, self).__init__()
+#         super(User, self).__init__()
-        self.arg = arg
+#         self.arg = arg
 
 
-#         @app.route('/login', methods=['POST','GET'])
+# #         @app.route('/login', methods=['POST','GET'])
-# @limiter.limit("100 per minute", error_message=error_handler_limiter)
+# # @limiter.limit("100 per minute", error_message=error_handler_limiter)
-def login():
+# def login():
-    if request.method == "POST":
+#     if request.method == "POST":
-        if not session.get("logged_in"):
+#         if not session.get("logged_in"):
-            if request.form["username"] and request.form["password"]:
+#             if request.form["username"] and request.form["password"]:
-                # Get the json
+#                 # Get the json
-                with open("users.json") as f:
+#                 with open("users.json") as f:
-                    users_file = json.load(f)
+#                     users_file = json.load(f)
-                for user in users_file["users"]:
+#                 for user in users_file["users"]:
-                    if users_file["users"][user] == request.form["password"]:
+#                     if users_file["users"][user] == request.form["password"]:
-                        session["logged_in"] = True
+#                         session["logged_in"] = True
-                        session["user"] = request.form["username"]
+#                         session["user"] = request.form["username"]
 
-                if not session.get("logged_in"):
+#                 if not session.get("logged_in"):
-                    flash("Mot de passe ou pseudo invalide.", "danger")
+#                     flash("Mot de passe ou pseudo invalide.", "danger")
-                    return redirect(url_for("login"))
+#                     return redirect(url_for("login"))
-                else:
+#                 else:
-                    return redirect(url_for("display_index_page"))
+#                     return redirect(url_for("display_index_page"))
-            else:
+#             else:
-                flash("Incorrect logins")
+#                 flash("Incorrect logins")
-                return render_template("password.html")
+#                 return render_template("password.html")
-        else:
+#         else:
-            return render_template("password.html")
+#             return render_template("password.html")
-    else:
+#     else:
-        return render_template("password.html")
+#         return render_template("password.html")
 
 
-@app.route("/logout")
+# @app.route("/logout")
-def logout():
+# def logout():
-    session["logged_in"] = False
+#     session["logged_in"] = False
-    flash("Tu est déconnecté", "info")
+#     flash("Tu est déconnecté", "info")
-    return redirect(url_for("login"))
+#     return redirect(url_for("login"))

src/web.py

@@ -1,56 +1,78 @@
-from flask import Flask, request, flash
+from flask import flash
 from werkzeug.utils import secure_filename
-from printer import Printer
 import time
 import os
+from task import TextTask, ImageTask, CutTask
 
 
 class Web(object):
-    """docstring for 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"""
 
-    def __init__(self, app, printer):
+    def __init__(self, app, print_queue):
         super(Web).__init__()
-        self.printer = printer
+        self.print_queue = print_queue
         self.app = app
 
-    def print_sms(self, texte, sign: str):
+    def print_sms(self, texte, sign: str) -> bool:
-        # TODO: verify the texte before printing it here ?
+        """
+        Get text and a signature, prints the text and cuts after that.
+        """
         self.app.logger.debug("Printing : " + str(texte) + " from " + str(sign))
+
         try:
-            self.printer.print_sms(texte, sign)
+            # We create two new tasks and add them directly to the queue
-            self.printer.cut()
+            # TODO: this might need to be improved because
+            # !! 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))
+            cut = self.print_queue.enqueue(CutTask())
         except Exception as e:
             self.app.logger.error(e)
-            flash("Error while printing the SMS : " + str(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
 
-        flash("You message " + str(texte) + " has been printed :)")
+    def print_image(self, image, sign: str) -> bool:
-
+        """
-    def print_image(self, image, sign):
+        Get an image and a signature, prints the image and cuts after that.
-        self.app.logger.debug("Uploading file")
+        """
         try:
-            self.app.logger.debug("Uploading file from " + str(sign))
+            file_uploaded = self.upload_file(image)
-            if self.upload_file(image):
+        except Exception as e:
-                self.app.logger.debug("File has been uploaded, printing...")
+            self.app.logger.error(e)
-                self.printer.print_img(
+            raise RuntimeError("Could not upload file") from e
-                    os.path.join(
+
-                        self.app.config["UPLOAD_FOLDER"],
+        if file_uploaded:
-                        secure_filename(image.filename),
+            self.app.logger.debug("File has been uploaded, printing...")
-                    ),
+            try:
-                    sign=sign,
+                img = self.print_queue.enqueue(
-                    process=True,
+                    ImageTask(
+                        os.path.join(
+                            self.app.config["UPLOAD_FOLDER"],
+                            secure_filename(image.filename),
+                        ),
+                        signature=sign,
+                        process=True,
+                    )
                 )
-                self.printer.cut()
-        except Exception as e:
-            self.app.logger.error(e)
-            flash("Could not upload file." + str(e))
 
-        flash("Your image has been printed :)")
+                cut = self.print_queue.enqueue(CutTask())
+            except Exception as e:
+                raise RuntimeError("Could not add IMG to queue" + str(e)) from e
 
-    def login(username: str, password: str) -> bool:
+            self.app.logger.info("Added two new tasks at position %s and %s", img, cut)
-        pass
 
-    def logout(username: str, password: str) -> bool:
+        return True
-        pass
+
+    def login(self, username: str, password: str) -> bool:
+        """Not implemented"""
+        return
+
+    def logout(self, username: str, password: str) -> bool:
+        """Not implemented"""
+        return
 
     def allowed_file(self, filename) -> bool:
         self.app.logger.debug("Is the filename allowed ?")
@@ -62,22 +84,32 @@ class Web(object):
 
     def upload_file(self, image) -> bool:
         self.app.logger.debug("Validating file")
-        if image and self.allowed_file(image.filename):
+        if image:
-            filename = secure_filename(image.filename)
+            if self.allowed_file(image.filename):
-            self.app.logger.debug("File valid")
+                filename = secure_filename(image.filename)
-            try:
+                self.app.logger.debug("File valid")
-                image.save(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
+                try:
-                self.app.logger.debug("File saved")
+                    image.save(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
-            except Exception as e:
+                except OSError as e:
-                self.app.logger.error("Could not save file")
+                    self.app.logger.error("Could not save file %s", e)
-                flash(str(e), "error")
+                    return False
-                return False
 
-            self.app.logger.debug(
+                self.app.logger.debug(
-                "File saved to "
+                    "File saved to "
-                + str(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
+                    + str(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
-            )
+                )
-            return True
+                return True
+            else:
+                self.app.logger.error(
+                    "Could not save file because the filename is forbidden"
+                )
+                return False
         else:
-            self.app.logger.error("Could not save file " + str(filename))
+            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()

src/worker.py

@@ -0,0 +1,107 @@
+# This is the main printing thread
+# As explained in the task file, this is where we command
+# printing to happen.
+
+import threading
+import time
+
+
+class PrintWorker(threading.Thread):
+    def __init__(self, app, print_queue, printer, socketio=None):
+        super().__init__(daemon=True)
+        self.app = app
+        self.print_queue = print_queue
+        self.printer = printer
+        self.socketio = socketio  # Optional
+        self.running = True
+        self.state = "idle"  # idle, printing, dead, drinking-a-beer
+
+        self.app.logger.debug("Ho great, I'm alive... I'm ready to work another day...")
+
+    def run(self):
+        """Background thread that processes queue items"""
+        self.app.logger.info("Worker started working.")
+        while True:
+            if not self.running or not self.printer.ready:
+                time.sleep(0.2)
+                continue
+
+            try:
+                task = self.print_queue.dequeue()
+            except Exception as e:
+                self.app.logger.error("Could not get a new task ! %s ", str(e))
+                raise RuntimeError(
+                    "We could not get a new task because " + str(e)
+                ) from e
+
+            if task:
+                try:
+                    self.app.logger.info("Got a new task")
+                    self.app.logger.debug("Got task %s", task.task_id)
+                    self.state = "printing"
+                    task.status = "processing"
+                    self._emit_status(task.task_id, "processing")
+
+                    print_data = task.get_print_data()
+                    try:
+                        self.printer.print_task(task.task_type, print_data)
+                    except RuntimeError as e:
+                        self.app.logger.error("Could not print : %s", str(e))
+                        raise e
+
+                    task.status = "completed"
+                    self.print_queue.mark_completed(task.task_id, "completed")
+                    self._emit_status(task.task_id, "completed")
+
+                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):
+        """
+        Give the worker a break
+        """
+        self.app.logger.debug("Giving the worker a break")
+        self.state = "drinking-a-beer"
+        self.running = False
+
+    def start_worker(self):
+        """
+        Get the worker back to it
+        """
+        self.app.logger.debug("Time to work !")
+        self.state = "idle"
+        self.running = True
+
+    def current_state(self):
+        """
+        Return the worker state
+        """
+        return {
+            "is_running": self.running,
+            "queue_size": len(self.print_queue),
+            "state": self.state,
+        }