My program accesses the local Nitro server (API Jan for Windows – https://jan.ai/api-reference#tag/chat/post/chat/completions). I’m trying to write a POST request for the “Create chat completion” API request. This is communication with the AI model. Everything works fine in Python and I get the answer. On Delphi 11.3 I get some strange blocks instead of response. But they contain the necessary data (each block contains 1 word). Although I have to receive the JSON and highlight the response in a “content” object. Here is my code.

procedure TForm2.Button1Click(Sender: TObject);
var
  IdHTTP: TIdHTTP;
  RequestData: TStringStream;
  ResponseData: string;
  JsonResponse: TJSONObject;
begin
  IdHTTP := TIdHTTP.Create;
  RequestData := TStringStream.Create;
  try
    IdHTTP.Request.ContentType := 'application/json';
    RequestData.WriteString('{"messages":[{"content":"You are a helpful assistant.","role":"system"},{"content":"How are you?","role":"user"}],"model":'+
    '"tinyllama-1.1b","stream":true,"max_tokens":2048,"stop":["hello","Hello","HELLO","hELLO"],"frequency_penalty":0,"presence_penalty":0,"temperature":0.7,"top_p":0.95}');
    ResponseData := IdHTTP.Post('http://localhost:1337/v1/chat/completions', RequestData);
    Memo2.Lines.Add(ResponseData);
    JsonResponse := TJSONObject.ParseJSONValue(ResponseData) as TJSONObject;
  finally
    IdHTTP.Free;
    RequestData.Free;
  end;
end;

I sent an array, stream, HTTP 200 response OK, but this is the best I could get. Unfortunately, I can’t send screenshots, but the HTTP analyzer for Delphi and the code for Python work correctly, but the answer in Delphi is not JSON.

Here is a valid Python query that works in my case.

import requests

url = "http://localhost:1337/v1/chat/completions"

payload = {
    "messages": [
        {
            "content": "You are a helpful assistant.",
            "role": "system"
        },
        {
            "content": "Hello!",
            "role": "user"
        }
    ],
    "model": "tinyllama-1.1b",
    "stream": True,
    "max_tokens": 2048,
    "stop": ["hello", "Hello", "HELLO", "hELLO"],
    "frequency_penalty": 0,
    "presence_penalty": 0,
    "temperature": 0.7,
    "top_p": 0.95
}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.json())

And I get this correct answer. But in Delphi the answer is as in the screenshot.

{
  "choices": [
    {
      "finish_reason": null,
      "index": 0,
      "message": {
        "content": "Hello user. What can I help you with?",
        "role": "assistant"
      }
    }
  ],
  "created": 1700193928,
  "id": "ebwd2niJvJB1Q2Whyvkz",
  "model": "_",
  "object": "chat.completion",
  "system_fingerprint": "_",
  "usage": {
    "completion_tokens": 500,
    "prompt_tokens": 33,
    "total_tokens": 533
  }
}