Add util function to generate qr code for url

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 +70,50 @@ def wrapper(request, *args, **kwargs):
         return wrapper
 
     return wrap
+
+
+def generate_qr_code(url: str, name: str = "") -> qrcode.image.pil.PilImage:
+    """
+    Generate a QR code from a given url, and, if given, adds the name below as a
+    caption
+
+    Returns the generated image as a PilImage object
+    """
+    # 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_dir = os.path.dirname(__file__)
+        if len(name) < 25:
+            font = ImageFont.truetype(
+                os.path.join(font_dir, "static/fonts/OS600.woff"), 25
+            )
+        elif len(name) < 50:
+            font = ImageFont.truetype(
+                os.path.join(font_dir, "static/fonts/OS600.woff"), 15
+            )
+        else:
+            font = ImageFont.truetype(
+                os.path.join(font_dir, "static/fonts/OS600.woff"), 10
+            )
+        caption_width = font.getlength(name)
+        draw.text(
+            ((img_width - caption_width) / 2, img_height - 40),
+            text=name,
+            font=font,
+            fill="black",
+        )
+
+    return img
+
+
+def convert_pil_object_to_bytes_string(pil_image: qrcode.image.pil.PilImage) -> str:
+    file_object = io.BytesIO()
+    pil_image.save(file_object, "PNG")
+    pil_image.close()
+    return base64.b64encode(file_object.getvalue()).decode('utf-8')

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/generate_qr_code_test.py

@@ -0,0 +1,11 @@
+import qrcode.image.pil
+from nav.web.utils import convert_pil_object_to_bytes_string, generate_qr_code
+
+import qrcode
+
+
+def test_generate_qr_code_returns_string():
+    qr_code = generate_qr_code(url="www.example.com", name="buick.lab.uninett.no")
+    assert isinstance(qr_code, qrcode.image.pil.PilImage)
+    qr_code_bytes_string = convert_pil_object_to_bytes_string(qr_code)
+    assert isinstance(qr_code_bytes_string, str)