Add conversion for HTML to markdown

apprise/conversion.py

@@ -50,8 +50,7 @@ def convert_between(from_format, to_format, content):
  (NotifyFormat.MARKDOWN, NotifyFormat.HTML): markdown_to_html,
  (NotifyFormat.TEXT, NotifyFormat.HTML): text_to_html,
  (NotifyFormat.HTML, NotifyFormat.TEXT): html_to_text,
- # For now; use same converter for Markdown support
- (NotifyFormat.HTML, NotifyFormat.MARKDOWN): html_to_text,
+ (NotifyFormat.HTML, NotifyFormat.MARKDOWN): html_to_markdown,
  }
 
  convert = converters.get((from_format, to_format))
@@ -86,12 +85,23 @@ def html_to_text(content):
  return parser.converted
 
 
+def html_to_markdown(content):
+ """
+ Converts a content from HTML to markdown.
+ """
+
+ parser = HTMLMarkDownConverter()
+ parser.feed(content)
+ parser.close()
+ return parser.converted
+
+
 class HTMLConverter(HTMLParser, object):
  """An HTML to plain text converter tuned for email messages."""
 
  # The following tags must start on a new line
  BLOCK_TAGS = ('p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
- 'div', 'td', 'th', 'code', 'pre', 'label', 'li',)
+ 'div', 'td', 'th', 'pre', 'samp', 'label', 'li',)
 
  # the folowing tags ignore any internal text
  IGNORE_TAGS = (
@@ -200,3 +210,132 @@ def handle_endtag(self, tag):
 
  if tag in self.BLOCK_TAGS:
  self._result.append(self.BLOCK_END)
+
+
+class HTMLMarkDownConverter(HTMLConverter):
+ """An HTML to markdown converter tuned for email messages."""
+
+ # Escape markdown characters
+ MARKDOWN_ESCAPE = re.compile(r'([`*#])', re.DOTALL | re.MULTILINE)
+
+ # Detect Carriage Return
+ HAS_CR = re.compile(r'[\r*\n]+', re.DOTALL | re.MULTILINE)
+
+ def __init__(self, **kwargs):
+ super().__init__(**kwargs)
+
+ # Store href value
+ self._link = ""
+
+ self._preserver_cr = False
+
+ def handle_data(self, data, *args, **kwargs):
+ """
+ Store our data if it is not on the ignore list
+ """
+
+ # initialize our previous flag
+ if self._do_store:
+
+ # Tidy our whitespace
+ content = self.WS_TRIM.sub(' ', data) \
+ if not self._preserver_cr else data
+ content = self.MARKDOWN_ESCAPE.sub(r'\\\1', content)
+
+ # Add hyperlink
+ if self._link == "":
+ self._result.append(content)
+ else:
+ self._result.append("[" + content + "]" + self._link)
+
+ def handle_starttag(self, tag, attrs):
+ """
+ Process our starting HTML Tag
+ """
+ # Toggle initial states
+ self._do_store = tag not in self.IGNORE_TAGS
+ self._link = ""
+
+ if tag in self.BLOCK_TAGS:
+ self._result.append(self.BLOCK_END)
+
+ if tag == 'li':
+ self._result.append('- ')
+
+ elif tag == 'br':
+ self._result.append('\n')
+
+ elif tag == 'hr':
+ if self._result:
+ self._result[-1] = self._result[-1].rstrip(' ')
+
+ self._result.append('\n---\n')
+
+ elif tag == 'blockquote':
+ self._result.append('> ')
+
+ elif tag == 'h1':
+ self._result.append('# ')
+
+ elif tag == 'h2':
+ self._result.append('## ')
+
+ elif tag == 'h3':
+ self._result.append('### ')
+
+ elif tag == 'h4':
+ self._result.append('#### ')
+
+ elif tag == 'h5':
+ self._result.append('##### ')
+
+ elif tag == 'h6':
+ self._result.append('###### ')
+
+ elif tag in ('strong', 'b'):
+ self._result.append('**')
+
+ elif tag in ('em', 'i'):
+ self._result.append('*')
+
+ elif tag == 'code':
+ self._result.append('`')
+ self._preserver_cr = True
+
+ elif tag in ('pre', 'samp'):
+ self._result.append('```')
+ self._result.append(self.BLOCK_END)
+ self._preserver_cr = True
+
+ elif tag == 'a':
+ for name, link in attrs: # pragma: no branch
+ if name == 'href':
+ self._link = '(' + link + ')'
+ # Take an early exit for speed (in case there are more
+ # parameters - no need to waste time looking at them)
+ break
+
+ def handle_endtag(self, tag):
+ """
+ Edge case handling of open/close tags
+ """
+ self._do_store = True
+ self._link = ""
+
+ if tag in self.BLOCK_TAGS:
+ self._result.append(self.BLOCK_END)
+
+ if tag in ('strong', 'b'):
+ self._result.append('**')
+
+ elif tag in ('em', 'i'):
+ self._result.append('*')
+
+ elif tag == 'code':
+ self._result.append('`')
+ self._preserver_cr = False
+
+ elif tag in ('pre', 'samp'):
+ self._result.append('```')
+ self._result.append(self.BLOCK_END)
+ self._preserver_cr = False

test/test_conversion.py

@@ -107,6 +107,11 @@ def to_html(body):
  "<a href='#'>my link</a>") == \
  "test my link"
 
+ # a with missing href entry
+ assert to_html("<span></span<<span>test</span> "
+ "<a>my link</a>") == \
+ "test my link"
+
  # </p> missing
  assert to_html("<body><div>line 1 <b>bold</b></div> "
  " <a href='#'>my link</a>"
@@ -143,6 +148,126 @@ def to_html(body):
  assert to_html(object)
 
 
+def test_conversion_html_to_markdown():
+ """conversion: Test HTML to plain text
+ """
+
+ def to_markdown(body):
+ """
+ A function to simply html conversion tests
+ """
+ return convert_between(NotifyFormat.HTML, NotifyFormat.MARKDOWN, body)
+
+ assert to_markdown("No HTML code here.") == "No HTML code here."
+
+ clist = to_markdown("<ul><li>Lots and lots</li><li>of lists.</li></ul>")
+ assert "- Lots and lots" in clist
+ assert "- of lists." in clist
+
+ assert "> To be or not to be." == to_markdown(
+ "<blockquote>To be or not to be.</blockquote>")
+
+ cspace = to_markdown(
+ "<h2>Fancy heading</h2>"
+ "<p>And a paragraph too.<br>Plus line break.</p>")
+ assert "# Fancy heading" in cspace
+ assert "And a paragraph too.\nPlus line break." in cspace
+
+ assert to_markdown(
+ "<style>body { font: 200%; }</style>"
+ "<p>Some obnoxious text here.</p>") == "Some obnoxious text here."
+
+ assert to_markdown(
+ "<p>line 1</p>"
+ "<p>line 2</p>"
+ "<p>line 3</p>") == "line 1\nline 2\nline 3"
+
+ # Case sensitivity
+ assert to_markdown(
+ "<p>line 1</P>"
+ "<P>line 2</P>"
+ "<P>line 3</P>") == "line 1\nline 2\nline 3"
+
+ # double new lines (testing <br> and </br>)
+ assert to_markdown(
+ "some information<br/><br>and more information") == \
+ "some information\n\nand more information"
+
+ #
+ # Test bad tags
+ #
+
+ # first 2 entries are okay, but last will do as best as it can
+ assert to_markdown(
+ "<h1>Heading 1</h1>"
+ "<h2>Heading 2</h2>"
+ "<h3>Heading 3</h3>"
+ "<h4>Heading 4</h4>"
+ "<h5>Heading 5</h5>"
+ "<h6>Heading 6</h6>"
+ "<p>line 1</>"
+ "<p><em>line 2</em></gar>"
+ "<p>line 3>") == \
+ "# Heading 1\n## Heading 2\n### Heading 3\n" \
+ "#### Heading 4\n##### Heading 5\n###### Heading 6\n" \
+ "line 1\n*line 2*\nline 3>"
+
+ # Make sure we ignore fields that aren't important to us
+ assert to_markdown(
+ "<script>ignore this</script>"
+ "<p>line 1</p>"
+ "Another line without being enclosed") == \
+ "line 1\nAnother line without being enclosed"
+
+ # Test <code> and <pre>
+ assert to_markdown(
+ "<code>multi-line 1\nmulti-line 2</code>more content"
+ "<pre>multi-line 1\nmulti-line 2</pre>more content") == \
+ '`multi-line 1\nmulti-line 2`more content' \
+ '\n```\nmulti-line 1\nmulti-line 2\n```\nmore content'
+
+ # Test cases when there are no new lines (we're dealing with just inline
+ # entries); an empty entry as well
+ assert to_markdown("<span></span<<span>test</span> "
+ "<a href='#'>my link</a>") == \
+ "test [my link](#)"
+
+ # </p> missing
+ assert to_markdown("<body><div>line 1 <b>bold</b></div> "
+ " <a href='/link'>my link</a>"
+ "<p>3rd line</body>") == \
+ "line 1 **bold**\n[my link](/link)\n3rd line"
+
+ # <hr/> on it's own
+ assert to_markdown("<hr/>") == "---"
+ assert to_markdown("<hr>") == "---"
+
+ # We need to handle HTML Encodings
+ assert to_markdown("""
+ <html>
+ <title>ignore this entry</title>
+ <body>
+ Let&apos;s handle&nbsp;special html encoding
+ <hr/>
+ </body>
+ """) == "Let's handle special html encoding\n---"
+
+ # If you give nothing, you get nothing in return
+ assert to_markdown("") == ""
+
+ with pytest.raises(TypeError):
+ # Invalid input
+ assert to_markdown(None)
+
+ with pytest.raises(TypeError):
+ # Invalid input
+ assert to_markdown(42)
+
+ with pytest.raises(TypeError):
+ # Invalid input
+ assert to_markdown(object)
+
+
 def test_conversion_text_to():
  """conversion: Test Text to all types
  """