Add util functions to generate qr codes for urls

changelog.d/2887.added.md

@@ -0,0 +1 @@
+Add functionality to create QR codes to a given url

python/nav/web/utils.py

@@ -14,12 +14,17 @@
 # along with NAV. If not, see <http://www.gnu.org/licenses/>.
 #
 """Utils for views"""
+import base64
+import io
+import os
 
 from django.http import HttpResponse
-
-
 from django.views.generic.list import ListView
 
+import qrcode
+from PIL import ImageDraw, ImageFont
+import qrcode.image.pil
+
 
 def get_navpath_root():
  """Returns the default navpath root
@@ -51,6 +56,7 @@ def require_param(parameter):
 
  Will check both GET and POST querydict for the parameter.
  """
+
  # pylint: disable=missing-docstring
  def wrap(func):
  def wrapper(request, *args, **kwargs):
@@ -64,3 +70,59 @@ def wrapper(request, *args, **kwargs):
  return wrapper
 
  return wrap
+
+
+def generate_qr_code(url: str, name: str = "") -> io.BytesIO:
+ """
+ Generate a QR code from a given url, and, if given, adds the name below as a
+ caption
+
+ Returns the generated image as a bytes buffer
+ """
+ # Creating QR code
+ qr = qrcode.QRCode(box_size=10)
+ qr.add_data(url)
+ img = qr.make_image()
+ draw = ImageDraw.Draw(img)
+
+ # Adding the name as caption
+ if name:
+ img_width, img_height = img.size
+ font_path = os.path.join(os.path.dirname(__file__), "static/fonts/OS600.woff")
+ if len(name) < 25:
+ font = ImageFont.truetype(font_path, 25)
+ elif len(name) < 50:
+ font = ImageFont.truetype(font_path, 15)
+ else:
+ font = ImageFont.truetype(font_path, 10)
+ caption_width = font.getlength(name)
+ draw.text(
+ ((img_width - caption_width) / 2, img_height - 40),
+ text=name,
+ font=font,
+ fill="black",
+ )
+
+ file_object = io.BytesIO()
+ img.save(file_object, "PNG")
+ img.close()
+
+ return file_object
+
+
+def convert_bytes_buffer_to_bytes_string(bytes_buffer: io.BytesIO) -> str:
+ return base64.b64encode(bytes_buffer.getvalue()).decode('utf-8')
+
+
+def generate_qr_codes_as_byte_strings(url_dict: dict[str, str]) -> list[str]:
+ """
+ Takes a dict of the form {name:url} and returns a list of generated QR codes as
+ byte strings
+ """
+ qr_code_byte_strings = []
+ for name, url in url_dict.items():
+ qr_code_byte_buffer = generate_qr_code(url=url, name=name)
+ qr_code_byte_strings.append(
+ convert_bytes_buffer_to_bytes_string(bytes_buffer=qr_code_byte_buffer)
+ )
+ return qr_code_byte_strings

requirements/base.txt

@@ -9,7 +9,9 @@ pyaml
 twisted~=23.8.0 # last version that still supports Python 3.7
 
 networkx==2.6.3
+# Cannot be removed as long as qrcode is included 
 Pillow>3.3.2
+qrcode>7.4
 pyrad==2.1
 sphinx==5.3.0
 sphinxcontrib-programoutput==0.17

tests/unittests/web/qrcode_test.py

@@ -0,0 +1,16 @@
+import io
+
+from nav.web.utils import generate_qr_code, generate_qr_codes_as_byte_strings
+
+
+def test_generate_qr_code_returns_byte_buffer():
+ qr_code = generate_qr_code(url="www.example.com", name="buick.lab.uninett.no")
+ assert isinstance(qr_code, io.BytesIO)
+
+
+def test_generate_qr_codes_as_byte_strings_returns_list_of_byte_strings():
+ qr_codes = generate_qr_codes_as_byte_strings(
+ {"buick.lab.uninett.no": "www.example.com"}
+ )
+ assert isinstance(qr_codes, list)
+ assert isinstance(qr_codes[0], str)