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https://github.com/rkrehn/csharpchatgpt

How to use ChatGPT in C#
https://github.com/rkrehn/csharpchatgpt

chatgpt chatgpt-api chatgpt-app chatgpt-bot chatgpt3 csharp csharp-code openai openai-api openai-chatgpt tutorial

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How to use ChatGPT in C#

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README 

        
# About

I see there are quite a few NuGet packages for Visual Studio to implement ChatGPT. The reality is that it's a lot easier than people may realize. This guide is designed to teach people how to use it using a basic "I want one response". This code is used in my [OutlookGPT](https://github.com/rkrehn/OutlookGPT) plugin.



# Requirements (from NuGet)



* Microsoft.AspNet.WebApi.Client

* System.Text.Json

* Newtonsoft.Json (not required, but recommended)



# Setup



1. First add the following lines at the top of your project where declare 'using":



```C

using System.Net.Http;

using System.Net;

using System.Text;

using Newtonsoft.Json;

```



2. Declare your API key (insert your [OpenAI API key](https://platform.openai.com/account/api-keys) in the quotes)



```C

string apiKey = "[api key]";

```



# Calling the Chat



Setting the TLS to 1.2 will ensure a secure connection. The next part is calling the API from the Chat Completions. Finally, we'll create the client and add a header with your API key from above.



```C

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

string requestUrl = $"https://api.openai.com/v1/chat/completions";

HttpClient client = new HttpClient();

client.DefaultRequestHeaders.Add("Authorization", $"Bearer {apikey}");

```



# Setting up the request



The following code creates the JSON request to OpenAI. You can review all the options you can include here: [https://platform.openai.com/docs/api-reference/chat/create](https://platform.openai.com/docs/api-reference/chat/create).



It's worth noting that only the "model" and the "messages" are required in the body. There are [many models](https://platform.openai.com/docs/models), but I'm using **gpt-3.5-turbo** in this example. Likewise, there are a few roles you can use such as system, user, assistance, or function. Typically, the **system** role defines what you want to accomplish. In our example, we'll tell ChatGPT **sytem** role that is acting as a travel agent (used on my [ReisPlan](https://www.reisplan.net) site).



I'm using max_tokens at 1024 to prevent a high cost. The **gpt-3.5-turbo** model can only support 4,096 tokens. I also use a [temperature](https://platform.openai.com/docs/guides/gpt/how-should-i-set-the-temperature-parameter) of 0.7, which gives a good sense of creativity, without being too consistent. Generally, temperature should be between 0.05 and 1, where 1 is very creative and 0.05 is very consistent.



```C

  var requestJson = new

  {

      messages = new[]

      {

          new

          {

              role = "system",

              content = "You are a travel agent. Please provide a detailed itinerary based on the user's input."

          },

          new

          {

              role = "user",

              content = "I am traveling to Denver, CO for three days and I like beer."

          }

      },

      max_tokens = 1024,

      temperature = 0.7,

      model = "gpt-3.5-turbo"

  };

```



Next, build a **HTTP content** using the serialized **requestJson** variable that we created above:



```C

StringContent content = new StringContent(JsonConvert.SerializeObject(requestJson), Encoding.UTF8, "application/json");

```



# Receiving the response



This next part is sending the message over to OpenAI and retrieving a JSON response.



```C

// Send the request and receive the response

HttpResponseMessage response = client.PostAsync(requestUrl, content).Result;

string responseJson = response.Content.ReadAsStringAsync().Result;

```



Then, we'll deserialize the response into a readable format.



```C

// Extract the completed text from the response

dynamic responseObject = JsonConvert.DeserializeObject(responseJson);

```



You will receive a JSON response like this in the responseObject (don't copy this):



```JSON

{

  "id": "chatcmpl-123",

  "object": "chat.completion",

  "created": 1677652288,

  "model": "gpt-3.5-turbo-0613",

  "choices": [{

    "index": 0,

    "message": {

      "role": "assistant",

      "content": "\n\nSure, I can recommend you check out Livin the Dream brewery in Littleton and Denver Beer Co in Englewood.",

    },

    "finish_reason": "stop"

  }],

  "usage": {

    "prompt_tokens": 9,

    "completion_tokens": 12,

    "total_tokens": 21

  }

}

```



* choices[0] is the first response

* message is the node within the choices[0]

* content is the response you're looking for



The **completedText** string below is created from those three nodes above in the responseObject:



```C

string completedText = responseObject.choices[0].message.content;

```



**completedText** will look like:



> Sure, I can recommend you check out Livin the Dream brewery in Littleton and Denver Beer Co in Englewood.



# Everything together



Now, put it together in all its glory:



```C

// setup variables and HTTPClient

string apiKey = "[api key]";

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

string requestUrl = $"https://api.openai.com/v1/chat/completions";

HttpClient client = new HttpClient();

client.DefaultRequestHeaders.Add("Authorization", $"Bearer {apikey}");



// build JSON request

  var requestJson = new

  {

      messages = new[]

      {

          new

          {

              role = "system",

              content = "You are a travel agent. Please provide a detailed itinerary based on the user's input."

          },

          new

          {

              role = "user",

              content = "I am traveling to Denver, CO for three days and I like beer."

          }

      },

      max_tokens = 1024,

      temperature = 0.7,

      model = "gpt-3.5-turbo"

  };



StringContent content = new StringContent(JsonConvert.SerializeObject(requestJson), Encoding.UTF8, "application/json");



// Send the request and receive the response

HttpResponseMessage response = client.PostAsync(requestUrl, content).Result;

string responseJson = response.Content.ReadAsStringAsync().Result;



// Extract the completed text from the response

dynamic responseObject = JsonConvert.DeserializeObject(responseJson);

string completedText = responseObject.choices[0].message.content;

```



> Sure, I can recommend you check out Livin the Dream brewery in Littleton and Denver Beer Co in Englewood.