parse_node.py

"""
ParseNode Module
"""

import re
from typing import List, Optional, Tuple
from urllib.parse import urljoin

from langchain_community.document_transformers import Html2TextTransformer
from langchain_core.documents import Document

from ..helpers import default_filters
from ..utils.split_text_into_chunks import split_text_into_chunks
from .base_node import BaseNode


class ParseNode(BaseNode):
    """
    A node responsible for parsing HTML content from a document.
    The parsed content is split into chunks for further processing.

    This node enhances the scraping workflow by allowing for targeted extraction of
    content, thereby optimizing the processing of large HTML documents.

    Attributes:
        verbose (bool): A flag indicating whether to show print statements during execution.

    Args:
        input (str): Boolean expression defining the input keys needed from the state.
        output (List[str]): List of output keys to be updated in the state.
        node_config (dict): Additional configuration for the node.
        node_name (str): The unique identifier name for the node, defaulting to "Parse".
    """

    url_pattern = re.compile(
        r"[http[s]?:\/\/]?(www\.)?([-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b[-a-zA-Z0-9()@:%_\+.~#?&\/\/=]*)"
    )
    relative_url_pattern = re.compile(r"[\(](/[^\(\)\s]*)")

    def __init__(
        self,
        input: str,
        output: List[str],
        node_config: Optional[dict] = None,
        node_name: str = "ParseNode",
    ):
        super().__init__(node_name, "node", input, output, 1, node_config)

        self.verbose = (
            False if node_config is None else node_config.get("verbose", False)
        )
        self.parse_html = (
            True if node_config is None else node_config.get("parse_html", True)
        )
        self.parse_urls = (
            False if node_config is None else node_config.get("parse_urls", False)
        )

        self.llm_model = node_config.get("llm_model")
        self.chunk_size = node_config.get("chunk_size")

    def execute(self, state: dict) -> dict:
        """
        Executes the node's logic to parse the HTML document content and split it into chunks.

        Args:
            state (dict): The current state of the graph. The input keys will be used to fetch the
                            correct data from the state.

        Returns:
            dict: The updated state with the output key containing the parsed content chunks.

        Raises:
            KeyError: If the input keys are not found in the state, indicating that the
                        necessary information for parsing the content is missing.
        """

        self.logger.info(f"--- Executing {self.node_name} Node ---")

        input_keys = self.get_input_keys(state)
        input_data = [state[key] for key in input_keys]
        docs_transformed = input_data[0]
        source = input_data[1] if self.parse_urls else None

        if self.parse_html:
            docs_transformed = Html2TextTransformer(
                ignore_links=False
            ).transform_documents(input_data[0])
            docs_transformed = docs_transformed[0]

            link_urls, img_urls = self._extract_urls(
                docs_transformed.page_content, source
            )

            chunks = split_text_into_chunks(
                text=docs_transformed.page_content,
                chunk_size=self.chunk_size - 250,
            )
        else:
            docs_transformed = docs_transformed[0]

            try:
                link_urls, img_urls = self._extract_urls(
                    docs_transformed.page_content, source
                )
            except Exception:
                link_urls, img_urls = "", ""

            chunk_size = self.chunk_size
            chunk_size = min(chunk_size - 500, int(chunk_size * 0.8))

            if isinstance(docs_transformed, Document):
                chunks = split_text_into_chunks(
                    text=docs_transformed.page_content,
                    chunk_size=chunk_size,
                )
            else:
                chunks = split_text_into_chunks(
                    text=docs_transformed, chunk_size=chunk_size
                )

        state.update({self.output[0]: chunks})
        state.update({"parsed_doc": chunks})
        state.update({"content": chunks})

        if self.parse_urls:
            state.update({self.output[1]: link_urls})
            state.update({self.output[2]: img_urls})

        return state

    def _extract_urls(self, text: str, source: str) -> Tuple[List[str], List[str]]:
        """
        Extracts URLs from the given text.

        Args:
            text (str): The text to extract URLs from.

        Returns:
            Tuple[List[str], List[str]]: A tuple containing the extracted link URLs and image URLs.
        """
        if not self.parse_urls:
            return [], []

        image_extensions = default_filters.filter_dict["img_exts"]
        url = ""
        all_urls = set()

        for group in ParseNode.url_pattern.findall(text):
            for el in group:
                if el != "":
                    url += el
            all_urls.add(url)
            url = ""

        url = ""
        for group in ParseNode.relative_url_pattern.findall(text):
            for el in group:
                if el not in ["", "[", "]", "(", ")", "{", "}"]:
                    url += el
            all_urls.add(urljoin(source, url))
            url = ""

        all_urls = list(all_urls)
        all_urls = self._clean_urls(all_urls)
        if not source.startswith("http"):
            all_urls = [url for url in all_urls if url.startswith("http")]
        else:
            all_urls = [urljoin(source, url) for url in all_urls]

        images = [
            url
            for url in all_urls
            if any(url.endswith(ext) for ext in image_extensions)
        ]
        links = [url for url in all_urls if url not in images]

        return links, images

    def _clean_urls(self, urls: List[str]) -> List[str]:
        """
        Cleans the URLs extracted from the text.

        Args:
            urls (List[str]): The list of URLs to clean.

        Returns:
            List[str]: The cleaned URLs.
        """
        cleaned_urls = []
        for url in urls:
            if not ParseNode._is_valid_url(url):
                url = re.sub(r".*?\]\(", "", url)
                url = re.sub(r".*?\[\(", "", url)
                url = re.sub(r".*?\[\)", "", url)
                url = re.sub(r".*?\]\)", "", url)
                url = re.sub(r".*?\)\[", "", url)
                url = re.sub(r".*?\)\[", "", url)
                url = re.sub(r".*?\(\]", "", url)
                url = re.sub(r".*?\)\]", "", url)
            url = url.rstrip(").-")
            if len(url) > 0:
                cleaned_urls.append(url)

        return cleaned_urls

    @staticmethod
    def _is_valid_url(url: str) -> bool:
        """
        CHecks if the URL format is valid.

        Args:
            url (str): The URL to check.

        Returns:
            bool: True if the URL format is valid, False otherwise
        """
        if re.fullmatch(ParseNode.url_pattern, url) is not None:
            return True
        return False