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44 lines
1.4 KiB
Python
44 lines
1.4 KiB
Python
import logging
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import os
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import subprocess
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from typing import Optional
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from django.conf import settings
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from zerver.lib.storage import static_path
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def render_tex(tex: str, is_inline: bool = True) -> Optional[str]:
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r"""Render a TeX string into HTML using KaTeX
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Returns the HTML string, or None if there was some error in the TeX syntax
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Keyword arguments:
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tex -- Text string with the TeX to render
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Don't include delimiters ('$$', '\[ \]', etc.)
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is_inline -- Boolean setting that indicates whether the render should be
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inline (i.e. for embedding it in text) or not. The latter
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will show the content centered, and in the "expanded" form
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(default True)
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"""
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katex_path = (
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static_path("webpack-bundles/katex-cli.js")
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if settings.PRODUCTION
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else os.path.join(settings.DEPLOY_ROOT, "node_modules/katex/cli.js")
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)
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if not os.path.isfile(katex_path):
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logging.error("Cannot find KaTeX for latex rendering!")
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return None
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command = ["node", katex_path]
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if not is_inline:
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command.extend(["--display-mode"])
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try:
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stdout = subprocess.check_output(
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command, input=tex, stderr=subprocess.DEVNULL, universal_newlines=True
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)
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# stdout contains a newline at the end
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return stdout.strip()
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except subprocess.CalledProcessError:
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return None
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