community[patch]: fix bugs for bilibili Loader (#18036)

- **Description:** 
1. Fix the BiliBiliLoader that can receive cookie parameters, it
requires 3 other parameters to run. The change is backward compatible.
  2. Add test;      
  3. Add example in docs

- **Issue:** [#14213]

Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>

libs/community/langchain_community/document_loaders/bilibili.py

@@ -8,20 +8,55 @@ from langchain_core.documents import Document
 
 from langchain_community.document_loaders.base import BaseLoader
 
+# Pre-compile regular expressions for video ID extraction
+BV_PATTERN = re.compile(r"BV\w+")
+AV_PATTERN = re.compile(r"av[0-9]+")
+
 
 class BiliBiliLoader(BaseLoader):
-    """Load `BiliBili` video transcripts."""
+    """
+    Loader for fetching transcripts from BiliBili videos.
+    """
 
-    def __init__(self, video_urls: List[str]):
-        """Initialize with bilibili url.
+    def __init__(
+        self,
+        video_urls: List[str],
+        sessdata: str = "",
+        bili_jct: str = "",
+        buvid3: str = "",
+    ):
+        """
+        Initialize the loader with BiliBili video URLs and authentication cookies.
+        if no authentication cookies are provided, the loader can't get transcripts
+        and will only fetch videos info.
 
         Args:
-            video_urls: List of bilibili urls.
+            video_urls (List[str]): List of BiliBili video URLs.
+            sessdata (str): SESSDATA cookie value for authentication.
+            bili_jct (str): BILI_JCT cookie value for authentication.
+            buvid3 (str): BUVI3 cookie value for authentication.
         """
         self.video_urls = video_urls
+        self.credential = None
+        try:
+            from bilibili_api import video
+        except ImportError:
+            raise ImportError(
+                "requests package not found, please install it with "
+                "`pip install bilibili-api-python`"
+            )
+        if sessdata and bili_jct and buvid3:
+            self.credential = video.Credential(
+                sessdata=sessdata, bili_jct=bili_jct, buvid3=buvid3
+            )
 
     def load(self) -> List[Document]:
-        """Load Documents from bilibili url."""
+        """
+        Load and return a list of documents containing video transcripts.
+
+        Returns:
+            List[Document]: List of Document objects transcripts and metadata.
+        """
         results = []
         for url in self.video_urls:
             transcript, video_info = self._get_bilibili_subs_and_info(url)
@@ -31,6 +66,10 @@ class BiliBiliLoader(BaseLoader):
         return results
 
     def _get_bilibili_subs_and_info(self, url: str) -> Tuple[str, dict]:
+        """
+        Retrieve video information and transcript for a given BiliBili URL.
+        """
+        bvid = BV_PATTERN.search(url)
         try:
             from bilibili_api import sync, video
         except ImportError:
@@ -38,46 +77,50 @@ class BiliBiliLoader(BaseLoader):
                 "requests package not found, please install it with "
                 "`pip install bilibili-api-python`"
             )
-
-        bvid = re.search(r"BV\w+", url)
-        if bvid is not None:
-            v = video.Video(bvid=bvid.group())
+        if bvid:
+            v = video.Video(bvid=bvid.group(), credential=self.credential)
         else:
-            aid = re.search(r"av[0-9]+", url)
-            if aid is not None:
-                try:
-                    v = video.Video(aid=int(aid.group()[2:]))
-                except AttributeError:
-                    raise ValueError(f"{url} is not bilibili url.")
+            aid = AV_PATTERN.search(url)
+            if aid:
+                v = video.Video(aid=int(aid.group()[2:]), credential=self.credential)
             else:
-                raise ValueError(f"{url} is not bilibili url.")
+                raise ValueError(f"Unable to find a valid video ID in URL: {url}")
 
         video_info = sync(v.get_info())
         video_info.update({"url": url})
-        sub = sync(v.get_subtitle(video_info["cid"]))
 
-        # Get subtitle url
-        sub_list = sub["subtitles"]
+        # Return if no credential is provided
+        if not self.credential:
+            return "", video_info
+
+        # Fetching and processing subtitles
+        sub = sync(v.get_subtitle(video_info["cid"]))
+        sub_list = sub.get("subtitles", [])
         if sub_list:
-            sub_url = sub_list[0]["subtitle_url"]
+            sub_url = sub_list[0].get("subtitle_url", "")
             if not sub_url.startswith("http"):
                 sub_url = "https:" + sub_url
-            result = requests.get(sub_url)
-            raw_sub_titles = json.loads(result.content)["body"]
-            raw_transcript = " ".join([c["content"] for c in raw_sub_titles])
 
-            raw_transcript_with_meta_info = (
-                f"Video Title: {video_info['title']},"
-                f"description: {video_info['desc']}\n\n"
-                f"Transcript: {raw_transcript}"
-            )
-            return raw_transcript_with_meta_info, video_info
+            response = requests.get(sub_url)
+            if response.status_code == 200:
+                raw_sub_titles = json.loads(response.content).get("body", [])
+                raw_transcript = " ".join([c["content"] for c in raw_sub_titles])
+
+                raw_transcript_with_meta_info = (
+                    f"Video Title: {video_info['title']}, "
+                    f"description: {video_info['desc']}\n\n"
+                    f"Transcript: {raw_transcript}"
+                )
+                return raw_transcript_with_meta_info, video_info
+            else:
+                warnings.warn(
+                    f"Failed to fetch subtitles for {url}. "
+                    f"HTTP Status Code: {response.status_code}"
+                )
         else:
-            raw_transcript = ""
             warnings.warn(
-                f"""
-                No subtitles found for video: {url}.
-                Return Empty transcript.
-                """
+                f"No subtitles found for video: {url}. Returning empty transcript."
             )
-            return raw_transcript, video_info
+
+        # Return empty transcript if no subtitles are found
+        return "", video_info

libs/community/tests/integration_tests/document_loaders/test_bilibili.py

@@ -10,11 +10,6 @@ def test_bilibili_loader() -> None:
         ]
     )
     docs = loader.load()
-
     assert len(docs) == 2
-
-    assert len(docs[0].page_content) > 0
-    assert docs[1].metadata["owner"]["mid"] == 398095160
-
-    assert docs[1].page_content == ""
-    assert docs[1].metadata["owner"]["mid"] == 398095160
+    assert docs[0].metadata["aid"] == 34218168
+    assert docs[1].metadata["videos"] == 1