Source code for langchain.chains.api.openapi.chain

"""Chain that makes API calls and summarizes the responses to answer a question."""
from __future__ import annotations

import json
from typing import Any, Dict, List, NamedTuple, Optional, cast

from import APIOperation
from langchain_community.utilities.requests import Requests
from langchain_core.callbacks import CallbackManagerForChainRun, Callbacks
from langchain_core.language_models import BaseLanguageModel
from langchain_core.pydantic_v1 import BaseModel, Field
from requests import Response

from langchain.chains.api.openapi.requests_chain import APIRequesterChain
from langchain.chains.api.openapi.response_chain import APIResponderChain
from langchain.chains.base import Chain
from langchain.chains.llm import LLMChain

class _ParamMapping(NamedTuple):
    """Mapping from parameter name to parameter value."""

    query_params: List[str]
    body_params: List[str]
    path_params: List[str]

[docs]class OpenAPIEndpointChain(Chain, BaseModel): """Chain interacts with an OpenAPI endpoint using natural language.""" api_request_chain: LLMChain api_response_chain: Optional[LLMChain] api_operation: APIOperation requests: Requests = Field(exclude=True, default_factory=Requests) param_mapping: _ParamMapping = Field(alias="param_mapping") return_intermediate_steps: bool = False instructions_key: str = "instructions" #: :meta private: output_key: str = "output" #: :meta private: max_text_length: Optional[int] = Field(ge=0) #: :meta private: @property def input_keys(self) -> List[str]: """Expect input key. :meta private: """ return [self.instructions_key] @property def output_keys(self) -> List[str]: """Expect output key. :meta private: """ if not self.return_intermediate_steps: return [self.output_key] else: return [self.output_key, "intermediate_steps"] def _construct_path(self, args: Dict[str, str]) -> str: """Construct the path from the deserialized input.""" path = self.api_operation.base_url + self.api_operation.path for param in self.param_mapping.path_params: path = path.replace(f"{{{param}}}", str(args.pop(param, ""))) return path def _extract_query_params(self, args: Dict[str, str]) -> Dict[str, str]: """Extract the query params from the deserialized input.""" query_params = {} for param in self.param_mapping.query_params: if param in args: query_params[param] = args.pop(param) return query_params def _extract_body_params(self, args: Dict[str, str]) -> Optional[Dict[str, str]]: """Extract the request body params from the deserialized input.""" body_params = None if self.param_mapping.body_params: body_params = {} for param in self.param_mapping.body_params: if param in args: body_params[param] = args.pop(param) return body_params
[docs] def deserialize_json_input(self, serialized_args: str) -> dict: """Use the serialized typescript dictionary. Resolve the path, query params dict, and optional requestBody dict. """ args: dict = json.loads(serialized_args) path = self._construct_path(args) body_params = self._extract_body_params(args) query_params = self._extract_query_params(args) return { "url": path, "data": body_params, "params": query_params, }
def _get_output(self, output: str, intermediate_steps: dict) -> dict: """Return the output from the API call.""" if self.return_intermediate_steps: return { self.output_key: output, "intermediate_steps": intermediate_steps, } else: return {self.output_key: output} def _call( self, inputs: Dict[str, Any], run_manager: Optional[CallbackManagerForChainRun] = None, ) -> Dict[str, str]: _run_manager = run_manager or CallbackManagerForChainRun.get_noop_manager() intermediate_steps = {} instructions = inputs[self.instructions_key] instructions = instructions[: self.max_text_length] _api_arguments = self.api_request_chain.predict_and_parse( instructions=instructions, callbacks=_run_manager.get_child() ) api_arguments = cast(str, _api_arguments) intermediate_steps["request_args"] = api_arguments _run_manager.on_text( api_arguments, color="green", end="\n", verbose=self.verbose ) if api_arguments.startswith("ERROR"): return self._get_output(api_arguments, intermediate_steps) elif api_arguments.startswith("MESSAGE:"): return self._get_output( api_arguments[len("MESSAGE:") :], intermediate_steps ) try: request_args = self.deserialize_json_input(api_arguments) method = getattr(self.requests, self.api_operation.method.value) api_response: Response = method(**request_args) if api_response.status_code != 200: method_str = str(self.api_operation.method.value) response_text = ( f"{api_response.status_code}: {api_response.reason}" + f"\nFor {method_str.upper()} {request_args['url']}\n" + f"Called with args: {request_args['params']}" ) else: response_text = api_response.text except Exception as e: response_text = f"Error with message {str(e)}" response_text = response_text[: self.max_text_length] intermediate_steps["response_text"] = response_text _run_manager.on_text( response_text, color="blue", end="\n", verbose=self.verbose ) if self.api_response_chain is not None: _answer = self.api_response_chain.predict_and_parse( response=response_text, instructions=instructions, callbacks=_run_manager.get_child(), ) answer = cast(str, _answer) _run_manager.on_text(answer, color="yellow", end="\n", verbose=self.verbose) return self._get_output(answer, intermediate_steps) else: return self._get_output(response_text, intermediate_steps)
[docs] @classmethod def from_url_and_method( cls, spec_url: str, path: str, method: str, llm: BaseLanguageModel, requests: Optional[Requests] = None, return_intermediate_steps: bool = False, **kwargs: Any, # TODO: Handle async ) -> "OpenAPIEndpointChain": """Create an OpenAPIEndpoint from a spec at the specified url.""" operation = APIOperation.from_openapi_url(spec_url, path, method) return cls.from_api_operation( operation, requests=requests, llm=llm, return_intermediate_steps=return_intermediate_steps, **kwargs, )
[docs] @classmethod def from_api_operation( cls, operation: APIOperation, llm: BaseLanguageModel, requests: Optional[Requests] = None, verbose: bool = False, return_intermediate_steps: bool = False, raw_response: bool = False, callbacks: Callbacks = None, **kwargs: Any, # TODO: Handle async ) -> "OpenAPIEndpointChain": """Create an OpenAPIEndpointChain from an operation and a spec.""" param_mapping = _ParamMapping( query_params=operation.query_params, body_params=operation.body_params, path_params=operation.path_params, ) requests_chain = APIRequesterChain.from_llm_and_typescript( llm, typescript_definition=operation.to_typescript(), verbose=verbose, callbacks=callbacks, ) if raw_response: response_chain = None else: response_chain = APIResponderChain.from_llm( llm, verbose=verbose, callbacks=callbacks ) _requests = requests or Requests() return cls( api_request_chain=requests_chain, api_response_chain=response_chain, api_operation=operation, requests=_requests, param_mapping=param_mapping, verbose=verbose, return_intermediate_steps=return_intermediate_steps, callbacks=callbacks, **kwargs, )