`Arxiv` document loader (#3627)

It makes sense to use `arxiv` as another source of the documents for
downloading.
- Added the `arxiv` document_loader, based on the
`utilities/arxiv.py:ArxivAPIWrapper`
- added tests
- added an example notebook
- sorted `__all__` in `__init__.py` (otherwise it is hard to find a
class in the very long list)

docs/modules/indexes/document_loaders/examples/arxiv.ipynb

@@ -0,0 +1,177 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "bda1f3f5",
+   "metadata": {},
+   "source": [
+    "# Arxiv\n",
+    "\n",
+    "[arXiv](https://arxiv.org/) is an open-access archive for 2 million scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.\n",
+    "\n",
+    "This notebook shows how to load scientific articles from `Arxiv.org` into a document format that we can use downstream."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "1b7a1eef-7bf7-4e7d-8bfc-c4e27c9488cb",
+   "metadata": {},
+   "source": [
+    "## Installation"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "2abd5578-aa3d-46b9-99af-8b262f0b3df8",
+   "metadata": {},
+   "source": [
+    "First, you need to install `arxiv` python package."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b674aaea-ed3a-4541-8414-260a8f67f623",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "!pip install arxiv"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "094b5f13-7e54-4354-9d83-26d6926ecaa0",
+   "metadata": {
+    "tags": []
+   },
+   "source": [
+    "Second, you need to install `PyMuPDF` python package which transform PDF files from the `arxiv.org` site into the text fromat."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7cd91121-2e96-43ba-af50-319853695f86",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "!pip install pymupdf"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "95f05e1c-195e-4e2b-ae8e-8d6637f15be6",
+   "metadata": {},
+   "source": [
+    "## Examples"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "e29b954c-1407-4797-ae21-6ba8937156be",
+   "metadata": {},
+   "source": [
+    "`ArxivLoader` has these arguments:\n",
+    "- `query`: free text which used to find documents in the Arxiv\n",
+    "- optional `load_max_docs`: default=100. Use it to limit number of downloaded documents. It takes time to download all 100 documents, so use a small number for experiments.\n",
+    "- optional `load_all_available_meta`: default=False. By defaul only the most important fields downloaded: `Published` (date when document was published/last updated), `Title`, `Authors`, `Summary`. If True, other fields also downloaded."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9bfd5e46",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain.document_loaders.base import Document\n",
+    "from langchain.document_loaders import ArxivLoader"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "700e4ef2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "docs = ArxivLoader(query=\"1605.08386\", load_max_docs=2).load()\n",
+    "len(docs)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "8977bac0-0042-4f23-9754-247dbd32439b",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'Published': '2016-05-26',\n",
+       " 'Title': 'Heat-bath random walks with Markov bases',\n",
+       " 'Authors': 'Caprice Stanley, Tobias Windisch',\n",
+       " 'Summary': 'Graphs on lattice points are studied whose edges come from a finite set of\\nallowed moves of arbitrary length. We show that the diameter of these graphs on\\nfibers of a fixed integer matrix can be bounded from above by a constant. We\\nthen study the mixing behaviour of heat-bath random walks on these graphs. We\\nalso state explicit conditions on the set of moves so that the heat-bath random\\nwalk, a generalization of the Glauber dynamics, is an expander in fixed\\ndimension.'}"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "doc[0].metadata  # meta-information of the Document"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "46969806-45a9-4c4d-a61b-cfb9658fc9de",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'arXiv:1605.08386v1  [math.CO]  26 May 2016\\nHEAT-BATH RANDOM WALKS WITH MARKOV BASES\\nCAPRICE STANLEY AND TOBIAS WINDISCH\\nAbstract. Graphs on lattice points are studied whose edges come from a finite set of\\nallowed moves of arbitrary length. We show that the diameter of these graphs on fibers of a\\nfixed integer matrix can be bounded from above by a constant. We then study the mixing\\nbehaviour of heat-b'"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "doc[0].page_content[:400]  # all pages of the Document content\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

langchain/__init__.py

@@ -47,7 +47,7 @@ from langchain.prompts import (
     PromptTemplate,
 )
 from langchain.sql_database import SQLDatabase
-from langchain.utilities import ArxivAPIWrapper
+from langchain.utilities.arxiv import ArxivAPIWrapper
 from langchain.utilities.google_search import GoogleSearchAPIWrapper
 from langchain.utilities.google_serper import GoogleSerperAPIWrapper
 from langchain.utilities.powerbi import PowerBIDataset

langchain/document_loaders/__init__.py

@@ -2,6 +2,7 @@
 
 from langchain.document_loaders.airbyte_json import AirbyteJSONLoader
 from langchain.document_loaders.apify_dataset import ApifyDatasetLoader
+from langchain.document_loaders.arxiv import ArxivLoader
 from langchain.document_loaders.azlyrics import AZLyricsLoader
 from langchain.document_loaders.azure_blob_storage_container import (
     AzureBlobStorageContainerLoader,
@@ -90,78 +91,79 @@ from langchain.document_loaders.youtube import (
 PagedPDFSplitter = PyPDFLoader
 
 __all__ = [
-    "UnstructuredFileLoader",
+    "AZLyricsLoader",
-    "UnstructuredFileIOLoader",
+    "AirbyteJSONLoader",
-    "UnstructuredURLLoader",
+    "ApifyDatasetLoader",
-    "SeleniumURLLoader",
+    "ArxivLoader",
-    "PlaywrightURLLoader",
+    "AzureBlobStorageContainerLoader",
+    "AzureBlobStorageFileLoader",
+    "BSHTMLLoader",
+    "BigQueryLoader",
+    "BiliBiliLoader",
+    "BlackboardLoader",
+    "BlockchainDocumentLoader",
+    "CSVLoader",
+    "ChatGPTLoader",
+    "CoNLLULoader",
+    "CollegeConfidentialLoader",
+    "ConfluenceLoader",
+    "DataFrameLoader",
+    "DiffbotLoader",
     "DirectoryLoader",
-    "NotionDirectoryLoader",
+    "DiscordChatLoader",
-    "NotionDBLoader",
+    "DuckDBLoader",
-    "ReadTheDocsLoader",
+    "EverNoteLoader",
+    "FacebookChatLoader",
+    "GCSDirectoryLoader",
+    "GCSFileLoader",
+    "GitLoader",
+    "GitbookLoader",
+    "GoogleApiClient",
+    "GoogleApiYoutubeLoader",
     "GoogleDriveLoader",
-    "UnstructuredHTMLLoader",
+    "GutenbergLoader",
-    "BSHTMLLoader",
-    "UnstructuredPowerPointLoader",
-    "UnstructuredWordDocumentLoader",
-    "UnstructuredPDFLoader",
-    "UnstructuredImageLoader",
-    "ObsidianLoader",
-    "UnstructuredEmailLoader",
-    "OutlookMessageLoader",
-    "UnstructuredEPubLoader",
-    "UnstructuredMarkdownLoader",
-    "UnstructuredRTFLoader",
-    "RoamLoader",
-    "YoutubeLoader",
-    "S3FileLoader",
-    "TextLoader",
     "HNLoader",
-    "GitbookLoader",
+    "HuggingFaceDatasetLoader",
-    "S3DirectoryLoader",
-    "GCSFileLoader",
-    "GCSDirectoryLoader",
-    "WebBaseLoader",
-    "IMSDbLoader",
-    "AZLyricsLoader",
-    "CollegeConfidentialLoader",
     "IFixitLoader",
-    "GutenbergLoader",
+    "IMSDbLoader",
-    "PagedPDFSplitter",
+    "ImageCaptionLoader",
-    "PyPDFLoader",
+    "NotebookLoader",
-    "EverNoteLoader",
+    "NotionDBLoader",
-    "AirbyteJSONLoader",
+    "NotionDirectoryLoader",
+    "ObsidianLoader",
     "OnlinePDFLoader",
+    "OutlookMessageLoader",
     "PDFMinerLoader",
     "PDFMinerPDFasHTMLLoader",
+    "PagedPDFSplitter",
+    "PlaywrightURLLoader",
     "PyMuPDFLoader",
-    "TelegramChatLoader",
+    "PyPDFLoader",
+    "PythonLoader",
+    "ReadTheDocsLoader",
+    "RoamLoader",
+    "S3DirectoryLoader",
+    "S3FileLoader",
     "SRTLoader",
-    "FacebookChatLoader",
+    "SeleniumURLLoader",
-    "NotebookLoader",
-    "CoNLLULoader",
-    "GoogleApiYoutubeLoader",
-    "GoogleApiClient",
-    "CSVLoader",
-    "BlackboardLoader",
-    "ApifyDatasetLoader",
-    "WhatsAppChatLoader",
-    "DataFrameLoader",
-    "AzureBlobStorageFileLoader",
-    "AzureBlobStorageContainerLoader",
     "SitemapLoader",
-    "DuckDBLoader",
-    "BigQueryLoader",
-    "DiffbotLoader",
-    "BiliBiliLoader",
     "SlackDirectoryLoader",
-    "GitLoader",
+    "TelegramChatLoader",
+    "TextLoader",
     "TwitterTweetLoader",
-    "ImageCaptionLoader",
+    "UnstructuredEPubLoader",
-    "DiscordChatLoader",
+    "UnstructuredEmailLoader",
-    "ConfluenceLoader",
+    "UnstructuredFileIOLoader",
-    "PythonLoader",
+    "UnstructuredFileLoader",
-    "ChatGPTLoader",
+    "UnstructuredHTMLLoader",
-    "HuggingFaceDatasetLoader",
+    "UnstructuredImageLoader",
-    "BlockchainDocumentLoader",
+    "UnstructuredMarkdownLoader",
+    "UnstructuredPDFLoader",
+    "UnstructuredPowerPointLoader",
+    "UnstructuredRTFLoader",
+    "UnstructuredURLLoader",
+    "UnstructuredWordDocumentLoader",
+    "WebBaseLoader",
+    "WhatsAppChatLoader",
+    "YoutubeLoader",
 ]

langchain/document_loaders/arxiv.py

@@ -0,0 +1,31 @@
+from typing import List, Optional
+
+from langchain.docstore.document import Document
+from langchain.document_loaders.base import BaseLoader
+from langchain.utilities.arxiv import ArxivAPIWrapper
+
+
+class ArxivLoader(BaseLoader):
+    """Loads a query result from arxiv.org into a list of Documents.
+
+    Each document represents one Document.
+    The loader converts the original PDF format into the text.
+    """
+
+    def __init__(
+        self,
+        query: str,
+        load_max_docs: Optional[int] = 100,
+        load_all_available_meta: Optional[bool] = False,
+    ):
+        self.query = query
+        self.load_max_docs = load_max_docs
+        self.load_all_available_meta = load_all_available_meta
+
+    def load(self) -> List[Document]:
+        arxiv_client = ArxivAPIWrapper(
+            load_max_docs=self.load_max_docs,
+            load_all_available_meta=self.load_all_available_meta,
+        )
+        docs = arxiv_client.load(self.query)
+        return docs

langchain/utilities/arxiv.py

@@ -1,8 +1,13 @@
 """Util that calls Arxiv."""
-from typing import Any, Dict
+import logging
+from typing import Any, Dict, List
 
 from pydantic import BaseModel, Extra, root_validator
 
+from langchain.schema import Document
+
+logger = logging.getLogger(__name__)
+
 
 class ArxivAPIWrapper(BaseModel):
     """Wrapper around ArxivAPI.
@@ -12,12 +17,23 @@ class ArxivAPIWrapper(BaseModel):
     This wrapper will use the Arxiv API to conduct searches and
     fetch document summaries. By default, it will return the document summaries
     of the top-k results of an input search.
+
+    Parameters:
+        top_k_results: number of the top-scored document used for the arxiv tool
+        ARXIV_MAX_QUERY_LENGTH: the cut limit on the query used for the arxiv tool.
+        load_max_docs: a limit to the number of loaded documents
+        load_all_available_meta:
+          if True: the `metadata` of the loaded Documents gets all available meta info
+            (see https://lukasschwab.me/arxiv.py/index.html#Result),
+          if False: the `metadata` gets only the most informative fields.
     """
 
     arxiv_client: Any  #: :meta private:
     arxiv_exceptions: Any  # :meta private:
     top_k_results: int = 3
     ARXIV_MAX_QUERY_LENGTH = 300
+    load_max_docs: int = 100
+    load_all_available_meta: bool = False
 
     class Config:
         """Configuration for this pydantic object."""
@@ -36,6 +52,7 @@ class ArxivAPIWrapper(BaseModel):
                 arxiv.UnexpectedEmptyPageError,
                 arxiv.HTTPError,
             )
+            values["arxiv_result"] = arxiv.Result
         except ImportError:
             raise ValueError(
                 "Could not import arxiv python package. "
@@ -62,3 +79,64 @@ class ArxivAPIWrapper(BaseModel):
             return "\n\n".join(docs) if docs else "No good Arxiv Result was found"
         except self.arxiv_exceptions as ex:
             return f"Arxiv exception: {ex}"
+
+    def load(self, query: str) -> List[Document]:
+        """
+        Run Arxiv search and get the PDF documents plus the meta information.
+        See https://lukasschwab.me/arxiv.py/index.html#Search
+
+        Returns: a list of documents with the document.page_content in PDF format
+
+        """
+        try:
+            import fitz
+        except ImportError:
+            raise ValueError(
+                "PyMuPDF package not found, please install it with "
+                "`pip install pymupdf`"
+            )
+
+        try:
+            docs: List[Document] = []
+            for result in self.arxiv_search(  # type: ignore
+                query[: self.ARXIV_MAX_QUERY_LENGTH], max_results=self.load_max_docs
+            ).results():
+                try:
+                    doc_file_name: str = result.download_pdf()
+                    with fitz.open(doc_file_name) as doc_file:
+                        text: str = "".join(page.get_text() for page in doc_file)
+                        add_meta = (
+                            {
+                                "entry_id": result.entry_id,
+                                "published_first_time": str(result.published.date()),
+                                "comment": result.comment,
+                                "journal_ref": result.journal_ref,
+                                "doi": result.doi,
+                                "primary_category": result.primary_category,
+                                "categories": result.categories,
+                                "links": [link.href for link in result.links],
+                            }
+                            if self.load_all_available_meta
+                            else {}
+                        )
+                        doc = Document(
+                            page_content=text,
+                            metadata=(
+                                {
+                                    "Published": str(result.updated.date()),
+                                    "Title": result.title,
+                                    "Authors": ", ".join(
+                                        a.name for a in result.authors
+                                    ),
+                                    "Summary": result.summary,
+                                    **add_meta,
+                                }
+                            ),
+                        )
+                        docs.append(doc)
+                except FileNotFoundError as f_ex:
+                    logger.debug(f_ex)
+            return docs
+        except self.arxiv_exceptions as ex:
+            logger.debug("Error on arxiv: %s", ex)
+            return []

tests/integration_tests/document_loaders/test_arxiv.py

@@ -0,0 +1,55 @@
+from typing import List
+
+from langchain.document_loaders.arxiv import ArxivLoader
+from langchain.schema import Document
+
+
+def assert_docs(docs: List[Document]) -> None:
+    for doc in docs:
+        assert doc.page_content
+        assert doc.metadata
+        assert set(doc.metadata) == {"Published", "Title", "Authors", "Summary"}
+
+
+def test_load_success() -> None:
+    """Test that returns one document"""
+    loader = ArxivLoader(query="1605.08386", load_max_docs=2)
+
+    docs = loader.load()
+    assert len(docs) == 1
+    print(docs[0].metadata)
+    print(docs[0].page_content)
+    assert_docs(docs)
+
+
+def test_load_returns_no_result() -> None:
+    """Test that returns no docs"""
+    loader = ArxivLoader(query="1605.08386WWW", load_max_docs=2)
+    docs = loader.load()
+
+    assert len(docs) == 0
+
+
+def test_load_returns_limited_docs() -> None:
+    """Test that returns several docs"""
+    expected_docs = 2
+    loader = ArxivLoader(query="ChatGPT", load_max_docs=expected_docs)
+    docs = loader.load()
+
+    assert len(docs) == expected_docs
+    assert_docs(docs)
+
+
+def test_load_returns_full_set_of_metadata() -> None:
+    """Test that returns several docs"""
+    loader = ArxivLoader(query="ChatGPT", load_max_docs=1, load_all_available_meta=True)
+    docs = loader.load()
+    assert len(docs) == 1
+    for doc in docs:
+        assert doc.page_content
+        assert doc.metadata
+        assert set(doc.metadata).issuperset(
+            {"Published", "Title", "Authors", "Summary"}
+        )
+        print(doc.metadata)
+        assert len(set(doc.metadata)) > 4

tests/integration_tests/utilities/test_arxiv.py

@@ -1,6 +1,9 @@
 """Integration test for Arxiv API Wrapper."""
+from typing import List
+
 import pytest
 
+from langchain.schema import Document
 from langchain.utilities import ArxivAPIWrapper
 
 
@@ -9,22 +12,68 @@ def api_client() -> ArxivAPIWrapper:
     return ArxivAPIWrapper()
 
 
-def test_call(api_client: ArxivAPIWrapper) -> None:
+def test_run_success(api_client: ArxivAPIWrapper) -> None:
-    """Test that ArxivAPIWrapper returns correct answer"""
+    """Test that returns the correct answer"""
 
     output = api_client.run("1605.08386")
     assert "Heat-bath random walks with Markov bases" in output
 
 
-def test_several_docs(api_client: ArxivAPIWrapper) -> None:
+def test_run_returns_several_docs(api_client: ArxivAPIWrapper) -> None:
-    """Test that ArxivAPIWrapper returns several docs"""
+    """Test that returns several docs"""
 
     output = api_client.run("Caprice Stanley")
     assert "On Mixing Behavior of a Family of Random Walks" in output
 
 
-def test_no_result_call(api_client: ArxivAPIWrapper) -> None:
+def test_run_returns_no_result(api_client: ArxivAPIWrapper) -> None:
-    """Test that call gives no result."""
+    """Test that gives no result."""
 
     output = api_client.run("1605.08386WWW")
     assert "No good Arxiv Result was found" == output
+
+
+def assert_docs(docs: List[Document]) -> None:
+    for doc in docs:
+        assert doc.page_content
+        assert doc.metadata
+        assert set(doc.metadata) == {"Published", "Title", "Authors", "Summary"}
+
+
+def test_load_success(api_client: ArxivAPIWrapper) -> None:
+    """Test that returns one document"""
+
+    docs = api_client.load("1605.08386")
+    assert len(docs) == 1
+    assert_docs(docs)
+
+
+def test_load_returns_no_result(api_client: ArxivAPIWrapper) -> None:
+    """Test that returns no docs"""
+
+    docs = api_client.load("1605.08386WWW")
+    assert len(docs) == 0
+
+
+def test_load_returns_limited_docs() -> None:
+    """Test that returns several docs"""
+    expected_docs = 2
+    api_client = ArxivAPIWrapper(load_max_docs=expected_docs)
+    docs = api_client.load("ChatGPT")
+    assert len(docs) == expected_docs
+    assert_docs(docs)
+
+
+def test_load_returns_full_set_of_metadata() -> None:
+    """Test that returns several docs"""
+    api_client = ArxivAPIWrapper(load_max_docs=1, load_all_available_meta=True)
+    docs = api_client.load("ChatGPT")
+    assert len(docs) == 1
+    for doc in docs:
+        assert doc.page_content
+        assert doc.metadata
+        assert set(doc.metadata).issuperset(
+            {"Published", "Title", "Authors", "Summary"}
+        )
+        print(doc.metadata)
+        assert len(set(doc.metadata)) > 4