OpenAI Functions Server

This is a server application that integrates with OpenAI's GPT-4 model to provide chat and function capabilities. It includes endpoints for chat completions, function calls, and text completions.

Getting Started

1. Clone the repository:

git clone https://github.com/princepspolycap/openai-functions-server.git

2. Install the dependencies:

cd openai-functions-server
npm install

3. Create a .env file in the root directory of the project, and add your OpenAI API key:

OPENAI_API_KEY=your-api-key

4. Build the TypeScript files:

npm run build

5. Start the server:

npm run start

The server will start running at http://localhost:3000.

Endpoints

• POST /api/function: Call a function using the OpenAI API.
• POST /api/chat: Get a chat completion from the OpenAI API.
• POST /api/completion: Get a text completion from the OpenAI API.

Function Call Documentation

How to Call Functions with Chat Models Using a TypeScript Server

This document covers how to use the OpenAI Chat Completions API in combination with external functions to extend the capabilities of GPT models in a TypeScript server environment.

The functions parameter in the Chat Completion API can be used to provide function specifications. The purpose of this is to enable models to generate function arguments that adhere to the provided specifications. Note that the API will not actually execute any function calls. It is up to developers to execute function calls using model outputs.

If the functions parameter is provided, then by default, the model will decide when it is appropriate to use one of the functions. The API can be forced to use a specific function by setting the function_call parameter to {"name": "<insert-function-name>"}. The API can also be forced to not use any function by setting the function_call parameter to "none". If a function is used, the output will contain "finish_reason": "function_call" in the response, as well as a function_call object that has the name of the function and the generated function arguments.

How to Generate Function Arguments

First, let's define a function specification for a hypothetical weather API. We'll pass these function specifications to the Chat Completions API in order to generate function arguments that adhere to the specification.

const functions = [
    {
        "name": "get_current_weather",
        "description": "Get the current weather",
        "parameters": {
            "type": "object",
            "properties": {
                "location": {
                    "type": "string",
                    "description": "The city and state, e.g., San Francisco, CA"
                },
                "format": {
                    "type": "string",
                    "enum": ["celsius", "fahrenheit"],
                    "description": "The temperature unit to use. Infer this from the user's location."
                }
            },
            "required": ["location", "format"]
        }
    },
    {
        "name": "get_n_day_weather_forecast",
        "description": "Get an N-day weather forecast",
        "parameters": {
            "type": "object",
            "properties": {
                "location": {
                    "type": "string",
                    "description": "The city and state, e.g., San Francisco, CA"
                },
                "format": {
                    "type": "string",
                    "enum": ["celsius", "fahrenheit

"],
                    "description": "The temperature unit to use. Infer this from the user's location."
                },
                "days": {
                    "type": "number",
                    "minimum": 1,
                    "maximum": 7,
                    "description": "The number of days to forecast"
                }
            },
            "required": ["location", "format", "days"]
        }
    }
];

To generate function arguments, you can follow these steps:

1. Call the Chat Completions API and pass the functions parameter along with the prompt to generate a response.

const prompt = "What's the weather like in San Francisco?";
const maxTokens = 100;

const response = await openai.complete({
    engine: 'text-davinci-003',
    prompt,
    maxTokens,
    functions
});

2. Extract the function call from the API response.

const functionCall = response.choices[0].function_call;

3. Use the extracted function call to execute the corresponding function with the generated arguments.

if (functionCall) {
    const functionName = functionCall.name;
    const functionArguments = functionCall.arguments;

    switch (functionName) {
        case 'get_current_weather':
            // Call the get_current_weather function with the generated arguments
            const currentWeather = await getCurrentWeather(functionArguments);
            // Process the currentWeather response
            break;
        case 'get_n_day_weather_forecast':
            // Call the get_n_day_weather_forecast function with the generated arguments
            const nDayForecast = await getNDayWeatherForecast(functionArguments);
            // Process the nDayForecast response
            break;
        default:
            // Handle unrecognized function name
            break;
    }
} else {
    // No function call generated by the model, process the regular chat response
}

4. Implement the actual function calls (getCurrentWeather, getNDayWeatherForecast, etc.) using external APIs or any other relevant logic.

Remember to handle any errors that may occur during the execution of function calls.

License

MIT License

Copyright (c) 2023 Princeps Polycap

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.