from html import escape
from io import StringIO
[docs]class TextNode:
"""Text node to be used within HTML.
Attributes
----------
text : str
Wrapped text.
post_ws : bool
Whether to add whitespace after the tag when rendering in an inline
context.
"""
def __init__(self, text, post_ws=False):
self.text = text
self.post_ws = post_ws
[docs]class HtmlElement:
"""Lightweight class to represent an HTML element.
Attributes
----------
tag : str
HTML tag name (minus angle brackets).
children : list
List of child elements (``HtmlElement`` or strings).
attrs : dict
Mapping from attributes names (strings) to values (strings or bools).
inline : bool
Whether to render children in an inline context. If False each child
will be rendered on its own line. If True whitespace will only be added
before/after children according to the :attr:`post_ws` attribute of the
child.
classes : list
List of class names present in the "class" attribute. Assignable property.
post_ws : bool
Whether to add whitespace after the tag when rendering in an inline
context.
"""
def __init__(self, tag, children=None, attrs=None, inline=False, post_ws=False):
self.tag = tag
self.children = list(children or [])
self.attrs = dict(attrs or [])
self.inline = inline
self.post_ws = post_ws
@property
def classes(self):
s = self.attrs.get('class', '').strip()
return s.split() if s else []
@classes.setter
def classes(self, value):
if not isinstance(value, str):
value = ' '.join(value)
self.attrs['class'] = value
[docs] def add_class(self, classes):
current = self.classes
if isinstance(classes, str):
classes = classes.split()
for cls in classes:
if cls not in current:
current.append(cls)
self.classes = current
def __repr__(self):
return '<' + self.tag + (' ...' if self.attrs else '') + ('>...</' + self.tag if self.children else '/>')
def __str__(self):
return html_to_string(self)
def _write_html_recursive(stream, elem, indent, depth, inline=False):
inline = inline or elem.inline
# Opening tag and attrs
stream.write('<' + elem.tag)
for key, value in elem.attrs.items():
if isinstance(value, str):
stream.write(' %s="%s"' % (escape(key), escape(value)))
elif isinstance(value, bool):
if value:
stream.write(' %s' % escape(key))
else:
raise TypeError(type(value))
stream.write('>')
for child in elem.children:
if not inline:
stream.write('\n')
stream.write(indent * (depth + 1))
post_ws = False
if isinstance(child, str):
stream.write(escape(child))
elif isinstance(child, TextNode):
stream.write(escape(child.text))
post_ws = child.post_ws
elif isinstance(child, HtmlElement):
_write_html_recursive(stream, child, indent=indent, depth=depth + 1, inline=inline)
post_ws = child.post_ws
else:
raise TypeError(type(child))
if inline and post_ws:
stream.write(' ')
if elem.children and not inline:
stream.write('\n')
stream.write(indent * depth)
stream.write('</%s>' % elem.tag)
[docs]def write_html(stream, elem, indent='\t', inline=False):
_write_html_recursive(stream, elem, indent, depth=0, inline=inline)
[docs]def html_to_string(elem, **kwargs):
buf = StringIO()
write_html(buf, elem, **kwargs)
return buf.getvalue()