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135 lines
4.2 KiB
Python
135 lines
4.2 KiB
Python
"""Chain that calls SerpAPI.
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Heavily borrowed from https://github.com/ofirpress/self-ask
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"""
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import os
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import sys
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from typing import Any, Dict, List, Optional
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from pydantic import BaseModel, Extra, root_validator
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from langchain.chains.base import Chain
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class HiddenPrints:
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"""Context manager to hide prints."""
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def __enter__(self) -> None:
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"""Open file to pipe stdout to."""
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self._original_stdout = sys.stdout
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sys.stdout = open(os.devnull, "w")
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def __exit__(self, *_: Any) -> None:
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"""Close file that stdout was piped to."""
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sys.stdout.close()
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sys.stdout = self._original_stdout
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class SerpAPIChain(Chain, BaseModel):
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"""Chain that calls SerpAPI.
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To use, you should have the ``google-search-results`` python package installed,
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and the environment variable ``SERPAPI_API_KEY`` set with your API key, or pass
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`serpapi_api_key` as a named parameter to the constructor.
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Example:
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.. code-block:: python
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from langchain import SerpAPIChain
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serpapi = SerpAPIChain()
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"""
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search_engine: Any #: :meta private:
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input_key: str = "search_query" #: :meta private:
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output_key: str = "search_result" #: :meta private:
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serpapi_api_key: Optional[str] = os.environ.get("SERPAPI_API_KEY")
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class Config:
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"""Configuration for this pydantic object."""
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extra = Extra.forbid
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@property
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def input_keys(self) -> List[str]:
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"""Return the singular input key.
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:meta private:
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"""
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return [self.input_key]
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@property
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def output_keys(self) -> List[str]:
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"""Return the singular output key.
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:meta private:
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"""
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return [self.output_key]
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@root_validator()
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def validate_environment(cls, values: Dict) -> Dict:
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"""Validate that api key and python package exists in environment."""
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serpapi_api_key = values.get("serpapi_api_key")
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if serpapi_api_key is None or serpapi_api_key == "":
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raise ValueError(
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"Did not find SerpAPI API key, please add an environment variable"
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" `SERPAPI_API_KEY` which contains it, or pass `serpapi_api_key` "
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"as a named parameter to the constructor."
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)
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try:
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from serpapi import GoogleSearch
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values["search_engine"] = GoogleSearch
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except ImportError:
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raise ValueError(
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"Could not import serpapi python package. "
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"Please it install it with `pip install google-search-results`."
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)
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return values
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def _run(self, inputs: Dict[str, Any]) -> Dict[str, str]:
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params = {
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"api_key": self.serpapi_api_key,
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"engine": "google",
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"q": inputs[self.input_key],
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"google_domain": "google.com",
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"gl": "us",
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"hl": "en",
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}
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with HiddenPrints():
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search = self.search_engine(params)
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res = search.get_dict()
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if "error" in res.keys():
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raise ValueError(f"Got error from SerpAPI: {res['error']}")
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if "answer_box" in res.keys() and "answer" in res["answer_box"].keys():
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toret = res["answer_box"]["answer"]
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elif "answer_box" in res.keys() and "snippet" in res["answer_box"].keys():
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toret = res["answer_box"]["snippet"]
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elif (
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"answer_box" in res.keys()
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and "snippet_highlighted_words" in res["answer_box"].keys()
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):
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toret = res["answer_box"]["snippet_highlighted_words"][0]
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elif "snippet" in res["organic_results"][0].keys():
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toret = res["organic_results"][0]["snippet"]
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else:
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toret = None
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return {self.output_key: toret}
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def search(self, search_question: str) -> str:
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"""Run search query against SerpAPI.
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Args:
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search_question: Question to run against the SerpAPI.
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Returns:
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Answer from the search engine.
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Example:
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.. code-block:: python
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answer = serpapi.search("What is the capital of Idaho?")
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"""
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return self({self.input_key: search_question})[self.output_key]
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