community[minor]: Add Scrapfly Loader community integration (#22036)

Added [Scrapfly](https://scrapfly.io/) Web Loader integration. Scrapfly
is a web scraping API that allows extracting web page data into
accessible markdown or text datasets.

- __Description__: Added Scrapfly web loader for retrieving web page
data as markdown or text.
- Dependencies: scrapfly-sdk
- Twitter: @thealchemi1st

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/community/langchain_community/document_loaders/scrapfly.py

@@ -0,0 +1,69 @@
+"""Scrapfly Web Reader."""
+import logging
+from typing import Iterator, List, Literal, Optional
+
+from langchain_core.document_loaders import BaseLoader
+from langchain_core.documents import Document
+from langchain_core.utils import get_from_env
+
+logger = logging.getLogger(__file__)
+
+
+class ScrapflyLoader(BaseLoader):
+    """Turn a url to llm accessible markdown with `Scrapfly.io`.
+
+    For further details, visit: https://scrapfly.io/docs/sdk/python
+    """
+
+    def __init__(
+        self,
+        urls: List[str],
+        *,
+        api_key: Optional[str] = None,
+        scrape_format: Literal["markdown", "text"] = "markdown",
+        scrape_config: Optional[dict] = None,
+        continue_on_failure: bool = True,
+    ) -> None:
+        """Initialize client.
+
+        Args:
+            urls: List of urls to scrape.
+            api_key: The Scrapfly API key. If not specified must have env var
+                SCRAPFLY_API_KEY set.
+            scrape_format: Scrape result format, one or "markdown" or "text".
+            scrape_config: Dictionary of ScrapFly scrape config object.
+            continue_on_failure: Whether to continue if scraping a url fails.
+        """
+        try:
+            from scrapfly import ScrapflyClient
+        except ImportError:
+            raise ImportError(
+                "`scrapfly` package not found, please run `pip install scrapfly-sdk`"
+            )
+        if not urls:
+            raise ValueError("URLs must be provided.")
+        api_key = api_key or get_from_env("api_key", "SCRAPFLY_API_KEY")
+        self.scrapfly = ScrapflyClient(key=api_key)
+        self.urls = urls
+        self.scrape_format = scrape_format
+        self.scrape_config = scrape_config
+        self.continue_on_failure = continue_on_failure
+
+    def lazy_load(self) -> Iterator[Document]:
+        from scrapfly import ScrapeConfig
+
+        scrape_config = self.scrape_config if self.scrape_config is not None else {}
+        for url in self.urls:
+            try:
+                response = self.scrapfly.scrape(
+                    ScrapeConfig(url, format=self.scrape_format, **scrape_config)
+                )
+                yield Document(
+                    page_content=response.scrape_result["content"],
+                    metadata={"url": url},
+                )
+            except Exception as e:
+                if self.continue_on_failure:
+                    logger.error(f"Error fetching data from {url}, exception: {e}")
+                else:
+                    raise e