changedetection.io/changedetectionio/html_tools.py

from bs4 import BeautifulSoup
from inscriptis import get_text
from inscriptis.model.config import ParserConfig
from jsonpath_ng.ext import parse
from typing import List
import json
import re

# HTML added to be sure each result matching a filter (.example) gets converted to a new line by Inscriptis
TEXT_FILTER_LIST_LINE_SUFFIX = "<br>"

# 'price' , 'lowPrice', 'highPrice' are usually under here
# all of those may or may not appear on different websites
LD_JSON_PRODUCT_OFFER_SELECTOR = "json:$..offers"

class JSONNotFound(ValueError):
    def __init__(self, msg):
        ValueError.__init__(self, msg)
        
# Given a CSS Rule, and a blob of HTML, return the blob of HTML that matches
def include_filters(include_filters, html_content, append_pretty_line_formatting=False):
    soup = BeautifulSoup(html_content, "html.parser")
    html_block = ""
    r = soup.select(include_filters, separator="")

    for element in r:
        # When there's more than 1 match, then add the suffix to separate each line
        # And where the matched result doesn't include something that will cause Inscriptis to add a newline
        # (This way each 'match' reliably has a new-line in the diff)
        # Divs are converted to 4 whitespaces by inscriptis
        if append_pretty_line_formatting and len(html_block) and not element.name in (['br', 'hr', 'div', 'p']):
            html_block += TEXT_FILTER_LIST_LINE_SUFFIX

        html_block += str(element)

    return html_block

def subtractive_css_selector(css_selector, html_content):
    soup = BeautifulSoup(html_content, "html.parser")
    for item in soup.select(css_selector):
        item.decompose()
    return str(soup)


def element_removal(selectors: List[str], html_content):
    """Joins individual filters into one css filter."""
    selector = ",".join(selectors)
    return subtractive_css_selector(selector, html_content)


# Return str Utf-8 of matched rules
def xpath_filter(xpath_filter, html_content, append_pretty_line_formatting=False):
    from lxml import etree, html

    tree = html.fromstring(bytes(html_content, encoding='utf-8'))
    html_block = ""

    r = tree.xpath(xpath_filter.strip(), namespaces={'re': 'http://exslt.org/regular-expressions'})
    #@note: //title/text() wont work where <title>CDATA..

    for element in r:
        # When there's more than 1 match, then add the suffix to separate each line
        # And where the matched result doesn't include something that will cause Inscriptis to add a newline
        # (This way each 'match' reliably has a new-line in the diff)
        # Divs are converted to 4 whitespaces by inscriptis
        if append_pretty_line_formatting and len(html_block) and (not hasattr( element, 'tag' ) or not element.tag in (['br', 'hr', 'div', 'p'])):
            html_block += TEXT_FILTER_LIST_LINE_SUFFIX

        if type(element) == etree._ElementStringResult:
            html_block += str(element)
        elif type(element) == etree._ElementUnicodeResult:
            html_block += str(element)
        else:
            html_block += etree.tostring(element, pretty_print=True).decode('utf-8')

    return html_block


# Extract/find element
def extract_element(find='title', html_content=''):

    #Re #106, be sure to handle when its not found
    element_text = None

    soup = BeautifulSoup(html_content, 'html.parser')
    result = soup.find(find)
    if result and result.string:
        element_text = result.string.strip()

    return element_text

#
def _parse_json(json_data, json_filter):
    if 'json:' in json_filter:
        jsonpath_expression = parse(json_filter.replace('json:', ''))
        match = jsonpath_expression.find(json_data)
        return _get_stripped_text_from_json_match(match)

    if 'jq:' in json_filter:

        try:
            import jq
        except ModuleNotFoundError:
            # `jq` requires full compilation in windows and so isn't generally available
            raise Exception("jq not support not found")

        jq_expression = jq.compile(json_filter.replace('jq:', ''))
        match = jq_expression.input(json_data).all()

        return _get_stripped_text_from_json_match(match)

def _get_stripped_text_from_json_match(match):
    s = []
    # More than one result, we will return it as a JSON list.
    if len(match) > 1:
        for i in match:
            s.append(i.value if hasattr(i, 'value') else i)

    # Single value, use just the value, as it could be later used in a token in notifications.
    if len(match) == 1:
        s = match[0].value if hasattr(match[0], 'value') else match[0]

    # Re #257 - Better handling where it does not exist, in the case the original 's' value was False..
    if not match:
        # Re 265 - Just return an empty string when filter not found
        return ''

    # Ticket #462 - allow the original encoding through, usually it's UTF-8 or similar
    stripped_text_from_html = json.dumps(s, indent=4, ensure_ascii=False)

    return stripped_text_from_html

# content - json
# json_filter - ie json:$..price
# ensure_is_ldjson_info_type - str "product", optional, "@type == product" (I dont know how to do that as a json selector)
def extract_json_as_string(content, json_filter, ensure_is_ldjson_info_type=None):
    stripped_text_from_html = False

    # Try to parse/filter out the JSON, if we get some parser error, then maybe it's embedded <script type=ldjson>
    try:
        stripped_text_from_html = _parse_json(json.loads(content), json_filter)
    except json.JSONDecodeError:

        # Foreach <script json></script> blob.. just return the first that matches json_filter
        s = []
        soup = BeautifulSoup(content, 'html.parser')

        if ensure_is_ldjson_info_type:
            bs_result = soup.findAll('script', {"type": "application/ld+json"})
        else:
            bs_result = soup.findAll('script')


        if not bs_result:
            raise JSONNotFound("No parsable JSON found in this document")

        for result in bs_result:
            # Skip empty tags, and things that dont even look like JSON
            if not result.string or not '{' in result.string:
                continue
                
            try:
                json_data = json.loads(result.string)
            except json.JSONDecodeError:
                # Just skip it
                continue
            else:
                stripped_text_from_html = _parse_json(json_data, json_filter)
                if ensure_is_ldjson_info_type:
                    # Could sometimes be list, string or something else random
                    if isinstance(json_data, dict):
                        # If it has LD JSON 'key' @type, and @type is 'product', and something was found for the search
                        # (Some sites have multiple of the same ld+json @type='product', but some have the review part, some have the 'price' part)
                        if json_data.get('@type', False) and json_data.get('@type','').lower() == ensure_is_ldjson_info_type.lower() and stripped_text_from_html:
                            break
                elif stripped_text_from_html:
                    break

    if not stripped_text_from_html:
        # Re 265 - Just return an empty string when filter not found
        return ''

    return stripped_text_from_html

# Mode     - "content" return the content without the matches (default)
#          - "line numbers" return a list of line numbers that match (int list)
#
# wordlist - list of regex's (str) or words (str)
def strip_ignore_text(content, wordlist, mode="content"):
    ignore = []
    ignore_regex = []

    # @todo check this runs case insensitive
    for k in wordlist:

        # Is it a regex?
        if k[0] == '/':
            ignore_regex.append(k.strip(" /"))
        else:
            ignore.append(k)

    i = 0
    output = []
    ignored_line_numbers = []
    for line in content.splitlines():
        i += 1
        # Always ignore blank lines in this mode. (when this function gets called)
        if len(line.strip()):
            regex_matches = False

            # if any of these match, skip
            for regex in ignore_regex:
                try:
                    if re.search(regex, line, re.IGNORECASE):
                        regex_matches = True
                except Exception as e:
                    continue

            if not regex_matches and not any(skip_text.lower() in line.lower() for skip_text in ignore):
                output.append(line.encode('utf8'))
            else:
                ignored_line_numbers.append(i)



    # Used for finding out what to highlight
    if mode == "line numbers":
        return ignored_line_numbers

    return "\n".encode('utf8').join(output)


def html_to_text(html_content: str, render_anchor_tag_content=False) -> str:
    """Converts html string to a string with just the text. If ignoring
    rendering anchor tag content is enable, anchor tag content are also
    included in the text

    :param html_content: string with html content
    :param render_anchor_tag_content: boolean flag indicating whether to extract
    hyperlinks (the anchor tag content) together with text. This refers to the
    'href' inside 'a' tags.
    Anchor tag content is rendered in the following manner:
    '[ text ](anchor tag content)'
    :return: extracted text from the HTML
    """
    #  if anchor tag content flag is set to True define a config for
    #  extracting this content
    if render_anchor_tag_content:

        parser_config = ParserConfig(
            annotation_rules={"a": ["hyperlink"]}, display_links=True
        )

    # otherwise set config to None
    else:
        parser_config = None

    # get text and annotations via inscriptis
    text_content = get_text(html_content, config=parser_config)

    return text_content


# Does LD+JSON exist with a @type=='product' and a .price set anywhere?
def has_ldjson_product_info(content):
    try:
        pricing_data = extract_json_as_string(content=content, json_filter=LD_JSON_PRODUCT_OFFER_SELECTOR, ensure_is_ldjson_info_type="product")
    except JSONNotFound as e:
        # Totally fine
        return False
    x=bool(pricing_data)
    return x


def workarounds_for_obfuscations(content):
    """
    Some sites are using sneaky tactics to make prices and other information un-renderable by Inscriptis
    This could go into its own Pip package in the future, for faster updates
    """

    # HomeDepot.com style <span>$<!-- -->90<!-- -->.<!-- -->74</span>
    # https://github.com/weblyzard/inscriptis/issues/45
    if not content:
        return content

    content = re.sub('<!--\s+-->', '', content)

    return content