Function markdowns_to_safe_html

tensorboard/plugin_util.py:122–169

Convert multiple Markdown documents to one safe HTML document. One could also achieve this by calling `markdown_to_safe_html` multiple times and combining the results. Compared to that approach, this function may be faster, because HTML sanitization (which can be expensive) is perfo

(markdown_strings, combine)

def markdowns_to_safe_html(markdown_strings, combine):
    """Convert multiple Markdown documents to one safe HTML document.

    One could also achieve this by calling `markdown_to_safe_html`
    multiple times and combining the results. Compared to that approach,
    this function may be faster, because HTML sanitization (which can be
    expensive) is performed only once rather than once per input. It may
    also be less precise: if one of the input documents has unsafe HTML
    that is sanitized away, that sanitization might affect other
    documents, even if those documents are safe.

    Args:
      markdown_strings: List of Markdown source strings to convert, as
        Unicode strings or UTF-8--encoded bytestrings. Markdown tables
        are supported.
      combine: Callback function that takes a list of unsafe HTML
        strings of the same shape as `markdown_strings` and combines
        them into a single unsafe HTML string, which will be sanitized
        and returned.

    Returns:
      A string containing safe HTML.
    """
    unsafe_htmls = []
    total_null_bytes = 0

    for source in markdown_strings:
        # Convert to utf-8 whenever we have a binary input.
        if isinstance(source, bytes):
            source_decoded = source.decode("utf-8")
            # Remove null bytes and warn if there were any, since it probably means
            # we were given a bad encoding.
            source = source_decoded.replace("\x00", "")
            total_null_bytes += len(source_decoded) - len(source)
        unsafe_html = _MARKDOWN_STORE.markdown.convert(source)
        unsafe_htmls.append(unsafe_html)

    unsafe_combined = combine(unsafe_htmls)
    sanitized_combined = _CLEANER_STORE.cleaner.clean(unsafe_combined)

    warning = ""
    if total_null_bytes:
        warning = (
            "<!-- WARNING: discarded %d null bytes in markdown string "
            "after UTF-8 decoding -->\n"
        ) % total_null_bytes

    return warning + sanitized_combined


def context(environ):