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117 lines
3.7 KiB
Python
117 lines
3.7 KiB
Python
"""Loader that fetches a sitemap and loads those URLs."""
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import itertools
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import re
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from typing import Any, Callable, Generator, Iterable, List, Optional
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from langchain.document_loaders.web_base import WebBaseLoader
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from langchain.schema import Document
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def _default_parsing_function(content: Any) -> str:
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return str(content.get_text())
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def _batch_block(iterable: Iterable, size: int) -> Generator[List[dict], None, None]:
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it = iter(iterable)
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while item := list(itertools.islice(it, size)):
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yield item
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class SitemapLoader(WebBaseLoader):
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"""Loader that fetches a sitemap and loads those URLs."""
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def __init__(
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self,
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web_path: str,
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filter_urls: Optional[List[str]] = None,
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parsing_function: Optional[Callable] = None,
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blocksize: Optional[int] = None,
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blocknum: int = 0,
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):
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"""Initialize with webpage path and optional filter URLs.
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Args:
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web_path: url of the sitemap
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filter_urls: list of strings or regexes that will be applied to filter the
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urls that are parsed and loaded
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parsing_function: Function to parse bs4.Soup output
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blocksize: number of sitemap locations per block
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blocknum: the number of the block that should be loaded - zero indexed
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"""
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if blocksize is not None and blocksize < 1:
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raise ValueError("Sitemap blocksize should be at least 1")
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if blocknum < 0:
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raise ValueError("Sitemap blocknum can not be lower then 0")
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try:
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import lxml # noqa:F401
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except ImportError:
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raise ValueError(
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"lxml package not found, please install it with " "`pip install lxml`"
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)
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super().__init__(web_path)
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self.filter_urls = filter_urls
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self.parsing_function = parsing_function or _default_parsing_function
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self.blocksize = blocksize
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self.blocknum = blocknum
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def parse_sitemap(self, soup: Any) -> List[dict]:
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"""Parse sitemap xml and load into a list of dicts."""
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els = []
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for url in soup.find_all("url"):
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loc = url.find("loc")
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if not loc:
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continue
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if self.filter_urls and not any(
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re.match(r, loc.text) for r in self.filter_urls
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):
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continue
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els.append(
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{
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tag: prop.text
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for tag in ["loc", "lastmod", "changefreq", "priority"]
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if (prop := url.find(tag))
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}
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)
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for sitemap in soup.find_all("sitemap"):
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loc = sitemap.find("loc")
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if not loc:
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continue
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soup_child = self.scrape_all([loc.text], "xml")[0]
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els.extend(self.parse_sitemap(soup_child))
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return els
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def load(self) -> List[Document]:
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"""Load sitemap."""
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soup = self.scrape("xml")
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els = self.parse_sitemap(soup)
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if self.blocksize is not None:
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elblocks = list(_batch_block(els, self.blocksize))
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blockcount = len(elblocks)
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if blockcount - 1 < self.blocknum:
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raise ValueError(
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"Selected sitemap does not contain enough blocks for given blocknum"
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)
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else:
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els = elblocks[self.blocknum]
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results = self.scrape_all([el["loc"].strip() for el in els if "loc" in el])
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return [
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Document(
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page_content=self.parsing_function(results[i]),
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metadata={**{"source": els[i]["loc"]}, **els[i]},
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)
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for i in range(len(results))
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]
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