zulip/zerver/lib/markdown/fenced_code.py

448 lines
15 KiB
Python

"""
Fenced Code Extension for Python Markdown
=========================================
This extension adds Fenced Code Blocks to Python-Markdown.
>>> import markdown
>>> text = '''
... A paragraph before a fenced code block:
...
... ~~~
... Fenced code block
... ~~~
... '''
>>> html = markdown.markdown(text, extensions=['fenced_code'])
>>> print html
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Works with safe_mode also (we check this because we are using the HtmlStash):
>>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Include tilde's in a code block and wrap with blank lines:
>>> text = '''
... ~~~~~~~~
...
... ~~~~
... ~~~~~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code>
~~~~
</code></pre>
Removes trailing whitespace from code blocks that cause horizontal scrolling
>>> import markdown
>>> text = '''
... A paragraph before a fenced code block:
...
... ~~~
... Fenced code block \t\t\t\t\t\t\t
... ~~~
... '''
>>> html = markdown.markdown(text, extensions=['fenced_code'])
>>> print html
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Language tags:
>>> text = '''
... ~~~~{.python}
... # Some python code
... ~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code class="python"># Some python code
</code></pre>
Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
Contact: markdown@freewisdom.org
License: BSD (see ../docs/LICENSE for details)
Dependencies:
* [Python 2.4+](http://python.org)
* [Markdown 2.0+](http://packages.python.org/Markdown/)
* [Pygments (optional)](http://pygments.org)
"""
import re
from typing import Any, Dict, Iterable, List, Mapping, MutableSequence, Optional
import markdown
from django.utils.html import escape
from markdown.extensions.codehilite import CodeHilite, CodeHiliteExtension
from zerver.lib.exceptions import MarkdownRenderingException
from zerver.lib.tex import render_tex
# Global vars
FENCE_RE = re.compile("""
# ~~~ or ```
(?P<fence>
^(?:~{3,}|`{3,})
)
[ ]* # spaces
(
\\{?\\.?
(?P<lang>
[a-zA-Z0-9_+-./#]*
) # "py" or "javascript"
\\}?
) # language, like ".py" or "{javascript}"
[ ]* # spaces
(
\\{?\\.?
(?P<header>
[^~`]*
)
\\}?
) # header for features that use fenced block header syntax (like spoilers)
$
""", re.VERBOSE)
CODE_WRAP = '<pre><code{}>{}\n</code></pre>'
LANG_TAG = ' class="{}"'
def validate_curl_content(lines: List[str]) -> None:
error_msg = """
Missing required -X argument in curl command:
{command}
""".strip()
for line in lines:
regex = r'curl [-](sS)?X "?(GET|DELETE|PATCH|POST)"?'
if line.startswith('curl'):
if re.search(regex, line) is None:
raise MarkdownRenderingException(error_msg.format(command=line.strip()))
CODE_VALIDATORS = {
'curl': validate_curl_content,
}
class FencedCodeExtension(markdown.Extension):
def __init__(self, config: Mapping[str, Any] = {}) -> None:
self.config = {
'run_content_validators': [
config.get('run_content_validators', False),
'Boolean specifying whether to run content validation code in CodeHandler',
],
}
for key, value in config.items():
self.setConfig(key, value)
def extendMarkdown(self, md: markdown.Markdown, md_globals: Dict[str, Any]) -> None:
""" Add FencedBlockPreprocessor to the Markdown instance. """
md.registerExtension(self)
processor = FencedBlockPreprocessor(
md, run_content_validators=self.config['run_content_validators'][0])
md.preprocessors.register(processor, 'fenced_code_block', 25)
class BaseHandler:
def handle_line(self, line: str) -> None:
raise NotImplementedError()
def done(self) -> None:
raise NotImplementedError()
def generic_handler(processor: Any, output: MutableSequence[str],
fence: str, lang: str, header: str,
run_content_validators: bool=False,
default_language: Optional[str]=None) -> BaseHandler:
lang = lang.lower()
if lang in ('quote', 'quoted'):
return QuoteHandler(processor, output, fence, default_language)
elif lang == 'math':
return TexHandler(processor, output, fence)
elif lang == 'spoiler':
return SpoilerHandler(processor, output, fence, header)
else:
return CodeHandler(processor, output, fence, lang, run_content_validators)
def check_for_new_fence(processor: Any, output: MutableSequence[str], line: str,
run_content_validators: bool=False,
default_language: Optional[str]=None) -> None:
m = FENCE_RE.match(line)
if m:
fence = m.group('fence')
lang = m.group('lang')
header = m.group('header')
if not lang and default_language:
lang = default_language
handler = generic_handler(processor, output, fence, lang, header,
run_content_validators, default_language)
processor.push(handler)
else:
output.append(line)
class OuterHandler(BaseHandler):
def __init__(self, processor: Any, output: MutableSequence[str],
run_content_validators: bool=False,
default_language: Optional[str]=None) -> None:
self.output = output
self.processor = processor
self.run_content_validators = run_content_validators
self.default_language = default_language
def handle_line(self, line: str) -> None:
check_for_new_fence(self.processor, self.output, line,
self.run_content_validators, self.default_language)
def done(self) -> None:
self.processor.pop()
class CodeHandler(BaseHandler):
def __init__(self, processor: Any, output: MutableSequence[str],
fence: str, lang: str, run_content_validators: bool=False) -> None:
self.processor = processor
self.output = output
self.fence = fence
self.lang = lang
self.lines: List[str] = []
self.run_content_validators = run_content_validators
def handle_line(self, line: str) -> None:
if line.rstrip() == self.fence:
self.done()
else:
self.lines.append(line.rstrip())
def done(self) -> None:
text = '\n'.join(self.lines)
# run content validators (if any)
if self.run_content_validators:
validator = CODE_VALIDATORS.get(self.lang, lambda text: None)
validator(self.lines)
text = self.processor.format_code(self.lang, text)
text = self.processor.placeholder(text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
self.processor.pop()
class QuoteHandler(BaseHandler):
def __init__(self, processor: Any, output: MutableSequence[str],
fence: str, default_language: Optional[str]=None) -> None:
self.processor = processor
self.output = output
self.fence = fence
self.lines: List[str] = []
self.default_language = default_language
def handle_line(self, line: str) -> None:
if line.rstrip() == self.fence:
self.done()
else:
check_for_new_fence(self.processor, self.lines, line, default_language=self.default_language)
def done(self) -> None:
text = '\n'.join(self.lines)
text = self.processor.format_quote(text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
self.processor.pop()
class SpoilerHandler(BaseHandler):
def __init__(self, processor: Any, output: MutableSequence[str],
fence: str, spoiler_header: str) -> None:
self.processor = processor
self.output = output
self.fence = fence
self.spoiler_header = spoiler_header
self.lines: List[str] = []
def handle_line(self, line: str) -> None:
if line.rstrip() == self.fence:
self.done()
else:
check_for_new_fence(self.processor, self.lines, line)
def done(self) -> None:
if len(self.lines) == 0:
# No content, do nothing
return
else:
header = self.spoiler_header
text = '\n'.join(self.lines)
text = self.processor.format_spoiler(header, text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
self.processor.pop()
class TexHandler(BaseHandler):
def __init__(self, processor: Any, output: MutableSequence[str], fence: str) -> None:
self.processor = processor
self.output = output
self.fence = fence
self.lines: List[str] = []
def handle_line(self, line: str) -> None:
if line.rstrip() == self.fence:
self.done()
else:
self.lines.append(line)
def done(self) -> None:
text = '\n'.join(self.lines)
text = self.processor.format_tex(text)
text = self.processor.placeholder(text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
self.processor.pop()
class FencedBlockPreprocessor(markdown.preprocessors.Preprocessor):
def __init__(self, md: markdown.Markdown, run_content_validators: bool=False) -> None:
markdown.preprocessors.Preprocessor.__init__(self, md)
self.checked_for_codehilite = False
self.run_content_validators = run_content_validators
self.codehilite_conf: Dict[str, List[Any]] = {}
def push(self, handler: BaseHandler) -> None:
self.handlers.append(handler)
def pop(self) -> None:
self.handlers.pop()
def run(self, lines: Iterable[str]) -> List[str]:
""" Match and store Fenced Code Blocks in the HtmlStash. """
output: List[str] = []
processor = self
self.handlers: List[BaseHandler] = []
default_language = None
try:
default_language = self.md.zulip_realm.default_code_block_language
except AttributeError:
pass
handler = OuterHandler(processor, output, self.run_content_validators, default_language)
self.push(handler)
for line in lines:
self.handlers[-1].handle_line(line)
while self.handlers:
self.handlers[-1].done()
# This fiddly handling of new lines at the end of our output was done to make
# existing tests pass. Markdown is just kind of funny when it comes to new lines,
# but we could probably remove this hack.
if len(output) > 2 and output[-2] != '':
output.append('')
return output
def format_code(self, lang: str, text: str) -> str:
if lang:
langclass = LANG_TAG.format(lang)
else:
langclass = ''
# Check for code hilite extension
if not self.checked_for_codehilite:
for ext in self.md.registeredExtensions:
if isinstance(ext, CodeHiliteExtension):
self.codehilite_conf = ext.config
break
self.checked_for_codehilite = True
# If config is not empty, then the codehighlite extension
# is enabled, so we call it to highlite the code
if self.codehilite_conf:
highliter = CodeHilite(text,
linenums=self.codehilite_conf['linenums'][0],
guess_lang=self.codehilite_conf['guess_lang'][0],
css_class=self.codehilite_conf['css_class'][0],
style=self.codehilite_conf['pygments_style'][0],
use_pygments=self.codehilite_conf['use_pygments'][0],
lang=(lang or None),
noclasses=self.codehilite_conf['noclasses'][0])
code = highliter.hilite()
else:
code = CODE_WRAP.format(langclass, self._escape(text))
return code
def format_quote(self, text: str) -> str:
paragraphs = text.split("\n\n")
quoted_paragraphs = []
for paragraph in paragraphs:
lines = paragraph.split("\n")
quoted_paragraphs.append("\n".join("> " + line for line in lines if line != ''))
return "\n\n".join(quoted_paragraphs)
def format_spoiler(self, header: str, text: str) -> str:
output = []
header_div_open_html = '<div class="spoiler-block"><div class="spoiler-header">'
end_header_start_content_html = '</div><div class="spoiler-content" aria-hidden="true">'
footer_html = '</div></div>'
output.append(self.placeholder(header_div_open_html))
output.append(header)
output.append(self.placeholder(end_header_start_content_html))
output.append(text)
output.append(self.placeholder(footer_html))
return "\n\n".join(output)
def format_tex(self, text: str) -> str:
paragraphs = text.split("\n\n")
tex_paragraphs = []
for paragraph in paragraphs:
html = render_tex(paragraph, is_inline=False)
if html is not None:
tex_paragraphs.append(html)
else:
tex_paragraphs.append('<span class="tex-error">' +
escape(paragraph) + '</span>')
return "\n\n".join(tex_paragraphs)
def placeholder(self, code: str) -> str:
return self.md.htmlStash.store(code)
def _escape(self, txt: str) -> str:
""" basic html escaping """
txt = txt.replace('&', '&amp;')
txt = txt.replace('<', '&lt;')
txt = txt.replace('>', '&gt;')
txt = txt.replace('"', '&quot;')
return txt
def makeExtension(*args: Any, **kwargs: None) -> FencedCodeExtension:
return FencedCodeExtension(kwargs)
if __name__ == "__main__":
import doctest
doctest.testmod()