Resolve upstream issue with void tags in Dash Markdown (#224)

examples/example-markdown.md

@@ -7,6 +7,10 @@
 Hi from a Markdown text file containing Norwegian letters (æ ø å), some
 **bold** letters, _italic_ letters. _You can also **combine** them._
 
+---
+
+Horizontal line splitting two paragraphs.
+
 #### An unordered list
 
 * Item 1

setup.py

@@ -32,11 +32,9 @@
     },
     entry_points={"console_scripts": ["webviz=webviz_config.command_line:main"]},
     install_requires=[
-        # Pinning dash to the 1.7-series as long as
-        # https://github.com/plotly/dash-core-components/issues/746 is open
-        "dash==1.7",
         "bleach>=3.1",
         "cryptography>=2.4",
+        "dash>=1.7",
         "flask-caching>=1.4",
         "flask-talisman>=0.6",
         "jinja2>=2.10",

webviz_config/plugins/_markdown.py

@@ -1,3 +1,4 @@
+import re
 from pathlib import Path
 from typing import List
 from xml.etree import ElementTree  # nosec
@@ -175,6 +176,11 @@ def __init__(self, markdown_file: Path):
             styles=Markdown.ALLOWED_STYLES,
         )
 
+        # Workaround for upstream issue https://github.com/plotly/dash-core-components/issues/746,
+        # where we convert void html tags from <tag> to <tag/>.
+        self.html = re.sub("<img (.*?[^/])>", r"<img \1/>", self.html)
+        self.html = self.html.replace("<br>", "<br/>").replace("<hr>", "<hr/>")
+
     def add_webvizstore(self) -> List[tuple]:
         return [(get_path, [{"path": self.markdown_file}])]