from __future__ import absolute_import, division, unicode_literals
from . import base
[docs]class Filter(base.Filter):
"""Injects ``<meta charset=ENCODING>`` tag into head of document"""
[docs] def __init__(self, source, encoding):
"""Creates a Filter
:arg source: the source token stream
:arg encoding: the encoding to set
"""
base.Filter.__init__(self, source)
self.encoding = encoding
def __iter__(self):
state = "pre_head"
meta_found = (self.encoding is None)
pending = []
for token in base.Filter.__iter__(self):
type = token["type"]
if type == "StartTag":
if token["name"].lower() == "head":
state = "in_head"
elif type == "EmptyTag":
if token["name"].lower() == "meta":
# replace charset with actual encoding
has_http_equiv_content_type = False
for (namespace, name), value in token["data"].items():
if namespace is not None:
continue
elif name.lower() == 'charset':
token["data"][(namespace, name)] = self.encoding
meta_found = True
break
elif name == 'http-equiv' and value.lower() == 'content-type':
has_http_equiv_content_type = True
else:
if has_http_equiv_content_type and (None, "content") in token["data"]:
token["data"][(None, "content")] = 'text/html; charset=%s' % self.encoding
meta_found = True
elif token["name"].lower() == "head" and not meta_found:
# insert meta into empty head
yield {"type": "StartTag", "name": "head",
"data": token["data"]}
yield {"type": "EmptyTag", "name": "meta",
"data": {(None, "charset"): self.encoding}}
yield {"type": "EndTag", "name": "head"}
meta_found = True
continue
elif type == "EndTag":
if token["name"].lower() == "head" and pending:
# insert meta into head (if necessary) and flush pending queue
yield pending.pop(0)
if not meta_found:
yield {"type": "EmptyTag", "name": "meta",
"data": {(None, "charset"): self.encoding}}
while pending:
yield pending.pop(0)
meta_found = True
state = "post_head"
if state == "in_head":
pending.append(token)
else:
yield token