Move clean_html() & foreground_color() to utilities.html

netbox/utilities/html.py

@@ -1,12 +1,46 @@
 import re
 
+import nh3
 from django.utils.html import escape
 
+from .constants import HTML_ALLOWED_ATTRIBUTES, HTML_ALLOWED_TAGS
+
 __all__ = (
+    'clean_html',
+    'foreground_color',
     'highlight',
 )
 
 
+def clean_html(html, schemes):
+    """
+    Sanitizes HTML based on a whitelist of allowed tags and attributes.
+    Also takes a list of allowed URI schemes.
+    """
+    return nh3.clean(
+        html,
+        tags=HTML_ALLOWED_TAGS,
+        attributes=HTML_ALLOWED_ATTRIBUTES,
+        url_schemes=set(schemes)
+    )
+
+
+def foreground_color(bg_color, dark='000000', light='ffffff'):
+    """
+    Return the ideal foreground color (dark or light) for a given background color in hexadecimal RGB format.
+
+    :param dark: RBG color code for dark text
+    :param light: RBG color code for light text
+    """
+    THRESHOLD = 150
+    bg_color = bg_color.strip('#')
+    r, g, b = [int(bg_color[c:c + 2], 16) for c in (0, 2, 4)]
+    if r * 0.299 + g * 0.587 + b * 0.114 > THRESHOLD:
+        return dark
+    else:
+        return light
+
+
 def highlight(value, highlight, trim_pre=None, trim_post=None, trim_placeholder='...'):
     """
     Highlight a string within a string and optionally trim the pre/post portions of the original string.