def highlight(html, highlights, show_tags=False):
"""Highlight part of an HTML documents.
:param highlights: Iterable of (start, end, tags) triples, which are
computed over UTF-8 bytes and don't count HTML tags
:param show_tags: Whether to show the tag names within brackets after each
highlight
"""
# Build a list of starting points and ending points
starts = []
ends = []
for hl in highlights:
starts.append((hl[0], 'start', []))
if len(hl) == 2:
ends.append((hl[1], 'end', []))
else:
ends.append((hl[1], 'end', hl[2]))
# This relies on the fact that 'end' < 'start'
events = sorted(ends + starts)
events = iter(events)
soup = BeautifulSoup(html, 'html5lib')
pos = 0
node = soup
highlighting = 0
try:
event_pos, event_type, tags = next(events)
except StopIteration:
event_pos = event_type = tags = None
while node is not None:
if getattr(node, 'contents', None):
# Move down
node = node.contents[0]
continue
if isinstance(node, NavigableString):
# Move through text
nb = len(node.string.encode('utf-8'))
while event_pos is not None:
if event_pos == pos and event_type == 'start':
# Start highlighting at beginning of text node
highlighting += 1
try:
event_pos, event_type, tags = next(events)
except StopIteration:
event_pos = None
elif pos + nb > event_pos:
# Next event falls inside of this text node
if event_type == 'start' and highlighting:
# Keep highlighting (can't highlight *more*)
highlighting += 1
elif (
event_type == 'end'
and not show_tags
and highlighting > 1
):
# Keep highlighting (no need to put labels)
highlighting -= 1
else: # 'end' and (show_tags or highlighting becomes 0)
# Split it
char_idx = byte_to_str_index(
node.string,
event_pos - pos,
)
left = node.string[:char_idx]
right = node.string[char_idx:]
# Left part
newnode = NavigableString(left)
if highlighting:
# Optionally highlight left part
span = soup.new_tag(
'span',
attrs={'class': 'highlight'},
)
span.append(newnode)
newnode = span
node.replace_with(newnode)
node = newnode
if event_type == 'start':
highlighting += 1
else:
highlighting -= 1
if show_tags:
# Add tag labels
comment = soup.new_tag(
'span',
attrs={'class': 'taglist'},
)
comment.string = ' [%s]' % ', '.join(tags)
node.insert_after(comment)
node = comment
# Right part
newnode = NavigableString(right)
node.insert_after(newnode)
node = newnode
nb -= event_pos - pos
pos = event_pos
# Next loop will highlight right part if needed
try:
event_pos, event_type, tags = next(events)
except StopIteration:
event_pos = None
elif highlighting: # and pos + nb <= event_pos:
# Highlight whole text node
newnode = soup.new_tag(
'span',
attrs={'class': 'highlight'},
)
node.replace_with(newnode)
newnode.append(node)
node = newnode
if pos + nb == event_pos and event_type == 'end':
if show_tags:
comment = soup.new_tag(
'span',
attrs={'class': 'taglist'},
)
comment.string = ' [%s]' % ', '.join(tags)
newnode.insert_after(comment)
node = comment
highlighting -= 1
try:
event_pos, event_type, tags = next(events)
except StopIteration:
event_pos = None
break
else: # not highlighting and pos + nb <= event_pos
# Skip whole text node
break
pos += nb
# Move up until there's a sibling
while not node.next_sibling and node.parent:
node = node.parent
if not node.parent:
break
# Move to next node
node = node.next_sibling
# Remove everything but body
body = soup.body
soup.clear()
soup.append(body)
# Remove the body tag itself to only have the contents
soup.body.unwrap()
# Back to text
return str(soup)
def highlight(html, highlights):
"""Highlight part of an HTML documents.
:param highlights: Iterable of (start, end) pairs, which are computed over
UTF-8 bytes and don't count HTML tags
"""
highlights = iter(highlights)
soup = BeautifulSoup(html, 'html5lib')
pos = 0
node = soup
highlighting = False
try:
start, end = next(highlights)
while True:
if getattr(node, 'contents', None):
node = node.contents[0]
else:
if isinstance(node, NavigableString):
nb = len(node.string.encode('utf-8'))
while True:
if not highlighting and start == pos:
highlighting = True
elif not highlighting and pos + nb > start:
parent = node.parent
left = node.string[:start - pos]
right = node.string[start - pos:]
idx = parent.index(node)
node.replace_with(NavigableString(left))
node = NavigableString(right)
parent.insert(idx + 1, node)
nb -= start - pos
pos = start
# Code below will do the actual highlighting
highlighting = True
elif highlighting and pos + nb <= end:
newnode = soup.new_tag(
'span',
attrs={'class': 'highlight'},
)
node.replace_with(newnode)
newnode.append(node)
node = newnode
if pos + nb == end:
highlighting = False
start, end = next(highlights)
break
elif highlighting:
parent = node.parent
left = node.string[:end - pos]
rest = node.string[end - pos:]
idx = parent.index(node)
newnode = NavigableString(left)
node.replace_with(newnode)
node = newnode
newnode = soup.new_tag(
'span',
attrs={'class': 'highlight'},
)
node.replace_with(newnode)
newnode.append(node)
node = NavigableString(rest)
parent.insert(idx + 1, node)
nb -= end - pos
pos = end
highlighting = False
start, end = next(highlights)
else:
break
pos += nb
while not node.next_sibling:
if not node.parent:
raise StopIteration
node = node.parent
node = node.next_sibling
except StopIteration:
# Remove everything but body
body = soup.body
soup.clear()
soup.append(body)
# Remove the body tag itself to only have the contents
soup.body.unwrap()
# Back to text
return str(soup)
