get_openapi_chain#

langchain.chains.openai_functions.openapi.get_openapi_chain(spec: OpenAPISpec | str, llm: BaseLanguageModel | None = None, prompt: BasePromptTemplate | None = None, request_chain: Chain | None = None, llm_chain_kwargs: Dict | None = None, verbose: bool = False, headers: Dict | None = None, params: Dict | None = None, **kwargs: Any) → SequentialChain[source]#

Deprecated since version 0.2.13: This function is deprecated and will be removed in langchain 1.0. See API reference for replacement: https://api.python.langchain.com/en/latest/chains/langchain.chains.openai_functions.openapi.get_openapi_chain.html

Create a chain for querying an API from a OpenAPI spec.

Note: this class is deprecated. See below for a replacement implementation.

The benefits of this implementation are:

  • Uses LLM tool calling features to encourage properly-formatted API requests;

  • Includes async support.

from typing import Any

from langchain.chains.openai_functions.openapi import openapi_spec_to_openai_fn
from langchain_community.utilities.openapi import OpenAPISpec
from langchain_core.prompts import ChatPromptTemplate
from langchain_openai import ChatOpenAI

# Define API spec. Can be JSON or YAML
api_spec = """
{
"openapi": "3.1.0",
"info": {
    "title": "JSONPlaceholder API",
    "version": "1.0.0"
},
"servers": [
    {
    "url": "https://jsonplaceholder.typicode.com"
    }
],
"paths": {
    "/posts": {
    "get": {
        "summary": "Get posts",
        "parameters": [
        {
            "name": "_limit",
            "in": "query",
            "required": false,
            "schema": {
            "type": "integer",
            "example": 2
            },
            "description": "Limit the number of results"
        }
        ]
    }
    }
}
}
"""

parsed_spec = OpenAPISpec.from_text(api_spec)
openai_fns, call_api_fn = openapi_spec_to_openai_fn(parsed_spec)
tools = [
    {"type": "function", "function": fn}
    for fn in openai_fns
]

prompt = ChatPromptTemplate.from_template(
    "Use the provided APIs to respond to this user query:\n\n{query}"
)
llm = ChatOpenAI(model="gpt-4o-mini", temperature=0).bind_tools(tools)

def _execute_tool(message) -> Any:
    if tool_calls := message.tool_calls:
        tool_call = message.tool_calls[0]
        response = call_api_fn(name=tool_call["name"], fn_args=tool_call["args"])
        response.raise_for_status()
        return response.json()
    else:
        return message.content

chain = prompt | llm | _execute_tool

response = chain.invoke({"query": "Get me top two posts."})
Parameters:

  • spec (Union[OpenAPISpec, str]) – OpenAPISpec or url/file/text string corresponding to one.

  • llm (Optional[BaseLanguageModel]) – language model, should be an OpenAI function-calling model, e.g. ChatOpenAI(model=”gpt-3.5-turbo-0613”).

  • prompt (Optional[BasePromptTemplate]) – Main prompt template to use.

  • request_chain (Optional[Chain]) – Chain for taking the functions output and executing the request.

  • llm_chain_kwargs (Optional[Dict])

  • verbose (bool)

  • headers (Optional[Dict])

  • params (Optional[Dict])

  • kwargs (Any)

Return type:

SequentialChain

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