Add shop ribbon color styling to links in product and content descriptions

- Modify protect_links function to apply shop theme_link_color to all links
- Add custom CSS validation using regex patterns for security
- Support hex colors (#fff, #ffffff), rgb(), rgba(), hsl(), hsla(), and named colors
- Reject malicious inputs like javascript: schemes
- Add style attribute to allowed attributes for anchor tags
- Pass shop reference through cleaner object for color access

make_post_sell/lib/render.py

@@ -13,6 +13,8 @@ def make_cleaner_from_shop(shop):
     """Given a Shop return a bleach Cleaner object."""
     cleaner = default_cleaner()
     cleaner.link_protection = True
+    # Store shop reference for link color styling
+    cleaner.shop = shop
     if shop.domain_name:
         apex_domain_name = shop.domain_name.split(".")[-2:]
         cleaner.whitelist_domains.append("makepostsell.com")

make_post_sell/lib/sanitize_html.py

@@ -10,6 +10,8 @@ from bleach.callbacks import nofollow, target_blank
 
 from bleach_allowlist import markdown_tags, markdown_attrs, all_styles
 
+# We implement our own CSS validation in protect_links() for security
+
 from bs4 import BeautifulSoup
 
 import miniuri
@@ -58,6 +60,11 @@ def default_cleaner(tag_acl=None):
     attrs["img"].append("width")
     attrs["img"].append("style")
     attrs["span"] = ["class"]
+    
+    # Allow style attribute on anchor tags for link color styling
+    if "a" not in attrs:
+        attrs["a"] = []
+    attrs["a"].append("style")
 
     # Allow both whitelist and blacklist tag_name/attr/attr_value
     # to get past bleach.
@@ -78,6 +85,8 @@ def default_cleaner(tag_acl=None):
                 # attributes for the given tag_name.
                 attrs[tag_name].append(attr_name)
 
+    # We allow style attributes and validate CSS in protect_links function
+    # This provides targeted validation for the specific CSS we add (color property)
     cleaner = Cleaner(tags=tags, attributes=attrs)
 
     # doesn't do anything, but i used to be able to pass it via constructor.
@@ -172,6 +181,23 @@ def protect_links(soup, cleaner):
     for a_tag in soup.find_all("a"):
         uri = miniuri.Uri(a_tag.attrs.get("href", ""))
 
+        # Add shop ribbon color styling to all links
+        if hasattr(cleaner, 'shop') and cleaner.shop:
+            link_color = cleaner.shop.theme_link_color
+            if link_color:
+                # Validate that the color looks like a valid CSS color
+                # Allow hex colors (#fff, #ffffff), rgb(), rgba(), hsl(), hsla(), and named colors
+                import re
+                color_pattern = r'^(#[0-9a-fA-F]{3}|#[0-9a-fA-F]{6}|rgb\([^)]+\)|rgba\([^)]+\)|hsl\([^)]+\)|hsla\([^)]+\)|[a-zA-Z]+)$'
+                if re.match(color_pattern, link_color.strip()):
+                    # Get existing style or create new one
+                    existing_style = a_tag.attrs.get("style", "")
+                    if existing_style and not existing_style.endswith(";"):
+                        existing_style += ";"
+                    # Add color styling with validation
+                    new_style = f"{existing_style}color:{link_color.strip()};"
+                    a_tag.attrs["style"] = new_style
+
         if uri.hostname in cleaner.whitelist_domains:
             # domain in whitelist or relative URI so remove rel="nofollow".
             a_tag.attrs.pop("rel", None)