markdown: add linkify extension

app/utils/bleach_allowlist.py

@@ -16,7 +16,7 @@ markdown_tags = [
 markdown_attrs = {
     "*": ["id", "class"],
     "img": ["src", "alt", "title"],
-    "a": ["href", "alt", "title"],
+    "a": ["href", "alt", "title", "rel"],
     "form": ["action", "method", "enctype"],
     "input": ["id", "name", "type", "value"],
     "label": ["for"],

app/utils/filters/markdown.py

@@ -10,6 +10,7 @@ from app.utils.bleach_allowlist import markdown_tags, markdown_attrs
 from app.utils.markdown_extensions.pclinks import PCLinkExtension
 from app.utils.markdown_extensions.hardbreaks import HardBreakExtension
 from app.utils.markdown_extensions.escape_html import EscapeHtmlExtension
+from app.utils.markdown_extensions.linkify import LinkifyExtension
 
 
 @app.template_filter('md')
@@ -29,6 +30,7 @@ def md(text):
         EscapeHtmlExtension(),
         FootnoteExtension(UNIQUE_IDS=True),
         HardBreakExtension(),
+        LinkifyExtension(),
         TocExtension(baselevel=2),
         PCLinkExtension(),
     ]

app/utils/markdown_extensions/linkify.py

@@ -0,0 +1,56 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2013 Raitis Stengrevics
+# https://github.com/daGrevis/mdx_linkify
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from bleach.linkifier import Linker
+
+from markdown.postprocessors import Postprocessor
+from markdown.extensions import Extension
+
+
+class LinkifyExtension(Extension):
+    def __init__(self, **kwargs):
+        self.config = {
+            'linker_options': [{}, 'Options for bleach.linkifier.Linker'],
+        }
+        super(LinkifyExtension, self).__init__(**kwargs)
+
+    def extendMarkdown(self, md):
+        md.postprocessors.register(
+            LinkifyPostprocessor(
+                md,
+                self.getConfig('linker_options'),
+            ),
+            "linkify",
+            50,
+        )
+
+
+class LinkifyPostprocessor(Postprocessor):
+    def __init__(self, md, linker_options):
+        super(LinkifyPostprocessor, self).__init__(md)
+        linker_options.setdefault("skip_tags", ["code"])
+        self._linker_options = linker_options
+
+    def run(self, text):
+        linker = Linker(**self._linker_options)
+        return linker.linkify(text)