nasg/pandoc.py

__author__ = "Peter Molnar"
__copyright__ = "Copyright 2017-2019, Peter Molnar"
__license__ = "apache-2.0"
__maintainer__ = "Peter Molnar"
__email__ = "mail@petermolnar.net"

import subprocess
import logging
import hashlib
import os
import settings


class Pandoc(str):
    in_format = "html"
    in_options = []
    out_format = "plain"
    out_options = []
    columns = None

    @property
    def hash(self):
        return str(hashlib.sha1(self.source.encode()).hexdigest())

    @property
    def cachefile(self):
        return os.path.join(
            settings.tmpdir, "%s_%s.pandoc" % (self.__class__.__name__, self.hash)
        )

    @property
    def cache(self):
        if not os.path.exists(self.cachefile):
            return False
        with open(self.cachefile, "rt") as f:
            self.result = f.read()
            return True

    def __init__(self, text):
        self.source = text
        if self.cache:
            return
        conv_to = "--to=%s" % (self.out_format)
        if len(self.out_options):
            conv_to = "%s%s" % (conv_to, "".join(self.out_options))

        conv_from = "--from=%s" % (self.in_format)
        if len(self.in_options):
            conv_from = "%s%s" % (conv_from, "".join(self.in_options))

        is_pandoc_version2 = False
        try:
            version = subprocess.check_output(["pandoc", "-v"])
            if version.startswith(b"pandoc 2"):
                is_pandoc_version2 = True
        except OSError:
            print("Error: pandoc is not installed!")

        cmd = ["pandoc", "-o-", conv_to, conv_from, "--no-highlight"]
        if is_pandoc_version2:
            # Only pandoc v2 and higher support quiet param
            cmd.append("--quiet")

        if self.columns:
            cmd.append(self.columns)

        p = subprocess.Popen(
            tuple(cmd),
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
        )

        stdout, stderr = p.communicate(input=text.encode())
        if stderr:
            logging.warning("Error during pandoc covert:\n\t%s\n\t%s", cmd, stderr)
        r = stdout.decode("utf-8").strip()
        self.result = r
        with open(self.cachefile, "wt") as f:
            f.write(self.result)

    def __str__(self):
        return str(self.result)

    def __repr__(self):
        return str(self.result)


class PandocMD2HTML(Pandoc):
    in_format = "markdown"
    in_options = [
        "+footnotes",
        "+pipe_tables",
        "+strikeout",
        # 'superscript',
        # 'subscript',
        "+raw_html",
        "+definition_lists",
        "+backtick_code_blocks",
        "+fenced_code_attributes",
        "+shortcut_reference_links",
        "+lists_without_preceding_blankline",
        "+autolink_bare_uris",
        "-smart",
    ]
    out_format = "html5"
    out_options = []


class PandocHTML2MD(Pandoc):
    in_format = "html"
    in_options = []
    out_format = "markdown"
    out_options = [
        "+footnotes",
        "+pipe_tables",
        "+strikeout",
        "+raw_html",
        "+definition_lists",
        "+backtick_code_blocks",
        "+fenced_code_attributes",
        "+shortcut_reference_links",
        "+lists_without_preceding_blankline",
        "+autolink_bare_uris",
        "-smart",
    ]


class PandocMD2TXT(Pandoc):
    in_format = "markdown"
    in_options = [
        "+footnotes",
        "+pipe_tables",
        "+strikeout",
        "+raw_html",
        "+definition_lists",
        "+backtick_code_blocks",
        "+fenced_code_attributes",
        "+shortcut_reference_links",
        "+lists_without_preceding_blankline",
        "+autolink_bare_uris",
        "-smart",
    ]
    out_format = "markdown"
    out_options = [
        "+footnotes",
        "+pipe_tables",
        "+strikeout",
        "+raw_html",
        "+definition_lists",
        "+backtick_code_blocks",
        "+fenced_code_attributes",
        "+shortcut_reference_links",
        "+lists_without_preceding_blankline",
        "+autolink_bare_uris",
        "-smart",
    ]
    columns = "--columns=80"


class PandocHTML2TXT(Pandoc):
    in_format = "html"
    in_options = []
    out_format = "plain"
    out_options = []
    columns = "--columns=80"