Merge pull request pklaus#18 from DL6ER/new/random

Add {{random[:len]}} and add optional [start] for {{counter}}

Author: DL6ER

README.md

@@ -96,6 +96,15 @@ Additional printer support comes from [matmair/brother_ql-inventree](https://git
 -   Dockerized
 -   Devcontainer for ease of development/contributing
 
+### Supported templates
+
+-   `{{counter[:start]}}` — Inserts the current counter value (automatically increments when printing multiple labels at the same time).
+-   `{{datetime:<format>}}` — Inserts the current date and time, e.g. `%H:%M:%S %d.%m.%Y` (see [strftime](https://strftime.org/)).
+-   `{{uuid}}` — Inserts a random UUID (Universally Unique Identifier).
+-   `{{short-uuid}}` — Inserts a shortened version of a UUID.
+-   `{{env:var}}` — Inserts the value of the environment variable `var`.
+-   `{{random[:<len>]}}` — Inserts a random string of optional length `len` (defaulting to 64).
+
 ## Docker Compose
 
 You may also use the example [`docker-compose.yml`](./docker-compose.yml) file provided in this repository to quickly get started with Docker Compose:

app/labeldesigner/label.py

@@ -8,6 +8,8 @@
 from barcode.writer import ImageWriter
 import datetime
 import re
+import random
+import string
 
 logger = logging.getLogger(__name__)
 
@@ -90,6 +92,7 @@ def __init__(
             border_distance=(0, 0),
             border_color=(0, 0, 0),
             timestamp=0,
+            counter=0,
             red_support=False):
         self._width = width
         self._height = height
@@ -109,7 +112,7 @@ def __init__(
         self._border_roundness = border_roundness
         self._border_distance = border_distance
         self._border_color = border_color
-        self._counter = 1
+        self._counter = counter
         self._timestamp = timestamp
         self._red_support = red_support
 
@@ -125,7 +128,7 @@ def want_text(self, img):
         # We always want to draw text (even when empty) when no image is
         # provided to avoid an error 500 because we created no image at all
         return img is None or self._label_content not in (LabelContent.QRCODE_ONLY,) and len(self.text) > 0 and len(self.text[0]['text']) > 0
-    
+
     @property
     def need_image_text_distance(self):
         return self._label_content in (LabelContent.TEXT_QRCODE,
@@ -170,13 +173,17 @@ def label_type(self, value):
         self._label_type = value
 
     def process_templates(self):
-        # Loop over text lines and replace
-        # {{datetime:x}} by current datetime in specified format x
-        # {{counter}} by an incrementing counter
+        # Loop over text lines and replace templates
         self.text = self.input_text.copy()
         for line in self.text:
-            # Replace {{counter}} with current counter value
-            line['text'] = line['text'].replace("{{counter}}", str(self._counter))
+            if len(line['text']) > 500:
+                logger.warning("Text line is very long (> 500 characters), this may lead to long processing times.")
+
+            # Replace {{counter[:offset]}} with current label counter (x is an optional offset defaulting to 1)
+            def counter_replacer(match):
+                offset = int(match.group(1)) if match.group(1) else 1
+                return str(self._counter + offset)
+            line['text'] = re.sub(r"\{\{counter(?:\:(\d+))?\}\}", counter_replacer, line['text'])
 
             # Replace {{datetime:x}} with current datetime formatted as x
             def datetime_replacer(match):
@@ -186,9 +193,7 @@ def datetime_replacer(match):
                 else:
                     now = datetime.datetime.now()
                 return now.strftime(fmt)
-            # Performance issue mitigation
-            if len(line['text']) < 100:
-                line['text'] = re.sub(r"\{\{datetime:([^}]+)\}\}", datetime_replacer, line['text'])
+            line['text'] = re.sub(r"\{\{datetime:([^}]+)\}\}", datetime_replacer, line['text'])
 
             # Replace {{uuid}} with a new UUID
             if "{{uuid}}" in line['text']:
@@ -202,12 +207,13 @@ def datetime_replacer(match):
             def env_replacer(match):
                 var_name = match.group(1)
                 return os.getenv(var_name, "")
-            # Performance issue mitigation
-            if len(line['text']) < 100:
-                line['text'] = re.sub(r"\{\{env:([^}]+)\}\}", env_replacer, line['text'])
+            line['text'] = re.sub(r"\{\{env:([^}]+)\}\}", env_replacer, line['text'])
 
-        # Increment counter
-        self._counter += 1
+            # Replace {{random[:len]}} with random string of optional length <len>
+            def random_replacer(match):
+                length = int(match.group(1)) if match.group(1) else 64
+                return ''.join(random.choices(string.ascii_letters + string.digits + string.punctuation, k=length))
+            line['text'] = re.sub(r"\{\{random(?:\:(\d+))?\}\}", random_replacer, line['text'])
 
     def generate(self, rotate = False):
         # Process possible templates in the text

app/labeldesigner/printer.py

@@ -45,15 +45,12 @@ def label_size(self):
     def label_size(self, value):
         self._label_size = value
 
-    def add_label_to_queue(self, label, count, cut_once=False, high_res: bool = False):
-        for cnt in range(0, count):
-            cut = (cut_once == False) or (cut_once and cnt == count-1)
-
-            self._printQueue.append(
-                {'label': label,
-                 'cut': cut,
-                 'high_res': high_res
-                 })
+    def add_label_to_queue(self, label, cut: bool = True, high_res: bool = False):
+        self._printQueue.append(
+            {'label': label,
+             'cut': cut,
+             'high_res': high_res
+             })
 
     def process_queue(self) -> bool:
         qlr = BrotherQLRaster(self._model)

app/labeldesigner/routes.py

@@ -115,7 +115,6 @@ def print_label():
             if isinstance(level, int):
                 current_app.logger.setLevel(level)
         printer = create_printer_from_request(request)
-        label = create_label_from_request(request)
         print_count = int(request.values.get('print_count', 1))
         if print_count < 1:
             raise ValueError("print_count must be greater than 0")
@@ -127,9 +126,15 @@ def print_label():
         # Generate error 400 response
         return make_response(jsonify(return_dict), 400)
 
-    printer.add_label_to_queue(label, print_count, cut_once, high_res)
-
     try:
+        for i in range(print_count):
+            label = create_label_from_request(request, i)
+            # Cut only if we
+            # - always cut, or
+            # - we cut only once and this is the last label to be generated
+            cut = (cut_once == False) or (cut_once and i == print_count-1)
+            printer.add_label_to_queue(label, cut, high_res)
+
         status = printer.process_queue()
     except Exception as e:
         return_dict['message'] = str(e)
@@ -159,7 +164,7 @@ def parse_text_form(input):
         return []
     return json.loads(input)
 
-def create_label_from_request(request):
+def create_label_from_request(request, counter: int = 0):
     d=request.values
     label_size = d.get('label_size', "62")
     kind = [label.form_factor for label in ALL_LABELS if label.identifier == label_size][0]
@@ -312,5 +317,6 @@ def get_uploaded_image(image):
         border_roundness=context['border_roundness'],
         border_distance=(context['border_distanceX'], context['border_distanceY']),
         border_color=border_color,
-        timestamp=context['timestamp']
+        timestamp=context['timestamp'],
+        counter=counter
     )

app/labeldesigner/templates/labeldesigner.html

@@ -356,12 +356,13 @@ <h6>Additional Font Options:</h6>
                             <li><code>{{'{{datetime:%H:%M:%S %d.%m.%Y'}}}}</code> — Inserts the current date and time when printing.
                                 You can customize the format using <a href="https://strftime.org/" target="_blank"
                                     rel="noopener">strftime</a> options.</li>
-                            <li><code>{{'{{counter'}}}}</code> — Inserts an up-counting number, increasing for every printed label.
+                            <li><code>{{'{{counter[:start]}}'}}</code> — Inserts an up-counting number. You can optionally specify a <code>start</code> value (defaulting to 1) to start counting from a different number.
+                                When printing multiple labels at once, the counter automatically increments for each label.
                             </li>
                             <li><code>{{'{{uuid'}}}}</code> — Inserts a random UUID (Universally Unique Identifier).</li>
                             <li><code>{{'{{short-uuid'}}}}</code> — Inserts a shortened version of a UUID.</li>
-                            <li><code>{{'{{env:var}}'}}</code> — Inserts the value of the environment variable <code>var</code>.
-                            </li>
+                            <li><code>{{'{{env:var}}'}}</code> — Inserts the value of the environment variable <code>var</code>.</li>
+                            <li><code>{{'{{random[:len]}}'}}</code> — Inserts a random string of optional length <code>len</code> (defaulting to 64).</li>
                         </ul>
                         <span class="text-muted">Templates are replaced at print time.</span>
                     </div>

tests/template.png

@@ -392,7 +392,7 @@ def test_generate_template(client):
         {
             'family': 'DejaVu Sans',
             'style': 'Book',
-            'text': '{{datetime:%d.%m.%Y %H:%M:%S}} COUNTER: {{counter}}',
+            'text': '{{datetime:%d.%m.%Y %H:%M:%S}} COUNTER: {{counter}} {{counter:5}}',
             'size': '30',
             'align': 'left'
         },