(Delphi DLL) Conversation with Streaming Responses

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Note: This example requires Chilkat v11.2.0 or greater.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Ai, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
ai: HCkAi;
systemMsg: PWideChar;
developerMsg: PWideChar;
conversationName: PWideChar;
sbEventName: HCkStringBuilder;
sbDelta: HCkStringBuilder;
sbFullResponse: HCkStringBuilder;
finished: Boolean;
abortFlag: Boolean;
maxWaitMs: Integer;
result: Integer;
result: Integer;

begin
success := False;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

ai := CkAi_Create();

// The provider can be "openai", "google", "claude", "deepseek", "xai", or "perplexity".
// Support for additional providers will be added in future versions of Chilkat.
CkAi_putProvider(ai,'google');

// Use your provider's API key.
CkAi_putApiKey(ai,'MY_API_KEY');

// Choose a model.
CkAi_putModel(ai,'gemini-2.5-flash');

// Indicate streaming mode is to be used.
CkAi_putStreaming(ai,True);

// Create a new conversation to be maintained locally in memory.
// If the conversation is the first to be created, it is also automatically selected.
systemMsg := 'You are a creative storyteller';
developerMsg := '';
conversationName := 'test_conversation';
CkAi_NewConvo(ai,conversationName,systemMsg,developerMsg);

// Add a text input.
CkAi_InputAddText(ai,'Write a detailed story about a turtle who decides to run a bakery.  Describe the setting, the kinds of pastries, how the turtle feels, and include at least three paragraphs.');

// Ask the AI for text output.
success := CkAi_Ask(ai,'text');
if (success = False) then
  begin
    Memo1.Lines.Add(CkAi__lastErrorText(ai));
    Exit;
  end;

sbEventName := CkStringBuilder_Create();
sbDelta := CkStringBuilder_Create();
sbFullResponse := CkStringBuilder_Create();
finished := False;
abortFlag := False;
maxWaitMs := 5000;

while not finished do
  begin

    result := CkAi_PollAi(ai,abortFlag);
    if (result = 1) then
      begin
        // We have output waiting.  It should be instantly available.  The maxWaitMs is just-in-case.
        success := CkAi_NextAiEvent(ai,maxWaitMs,sbEventName,sbDelta);
        if (success = False) then
          begin
            Memo1.Lines.Add(CkAi__lastErrorText(ai));
            Exit;
          end;

        // Some AI providers send many "empty" events.  Just ignore them.
        if (not CkStringBuilder_ContentsEqual(sbEventName,'empty',True)) then
          begin

            // The delta contains the new output.  This could be emitted to a display or the terminal
            // as real-time output.
            if (CkStringBuilder_ContentsEqual(sbEventName,'delta',True)) then
              begin
                // This example will emit each delta to its own line.
                Memo1.Lines.Add(CkStringBuilder__getAsString(sbDelta));

                // Accumulate the delta's so we can show the full response later.
                CkStringBuilder_AppendSb(sbFullResponse,sbDelta);
              end
            else
              begin
                // A streaming AI response is always terminated by a single "null_terminator" event.
                finished := CkStringBuilder_ContentsEqual(sbEventName,'null_terminator',True);
              end;
          end;
      end
    else
      begin
        if (result = 0) then
          begin
            // Nothing is immediately available. Sleep for 1/10 of a second before polling again.
            CkAi_SleepMs(ai,100);
          end
        else
          begin
            // Something failed..
            Memo1.Lines.Add(CkAi__lastErrorText(ai));
            finished := True;
          end;
      end;
  end;

// -------------------------------------------------------------
// The response is in markdown format.
// Also see Markdown to HTML Conversion Examples.
// -------------------------------------------------------------

// Show the accumulated (full) response.
Memo1.Lines.Add('----');
Memo1.Lines.Add(CkStringBuilder__getAsString(sbFullResponse));
Memo1.Lines.Add('----');

// ----------------------------------------------------------------------------------------------------------
// For the 2nd request in this conversation, ask for a shorter version of the story.
CkAi_InputAddText(ai,'Rewrite the story, but this time make it shorter, about one third as long.');
success := CkAi_Ask(ai,'text');
if (success = False) then
  begin
    Memo1.Lines.Add(CkAi__lastErrorText(ai));
    Exit;
  end;

CkStringBuilder_Clear(sbFullResponse);
finished := False;

while not finished do
  begin

    result := CkAi_PollAi(ai,abortFlag);
    if (result = 1) then
      begin
        // We have output waiting.  It should be instantly available.  The maxWaitMs is just-in-case.
        success := CkAi_NextAiEvent(ai,maxWaitMs,sbEventName,sbDelta);
        if (success = False) then
          begin
            Memo1.Lines.Add(CkAi__lastErrorText(ai));
            Exit;
          end;

        // Some AI providers send many "empty" events.  Just ignore them.
        if (not CkStringBuilder_ContentsEqual(sbEventName,'empty',True)) then
          begin

            // The delta contains the new output.  This could be emitted to a display or the terminal
            // as real-time output.
            if (CkStringBuilder_ContentsEqual(sbEventName,'delta',True)) then
              begin
                // This example will emit each delta to its own line.
                Memo1.Lines.Add(CkStringBuilder__getAsString(sbDelta));

                // Accumulate the delta's so we can show the full response later.
                CkStringBuilder_AppendSb(sbFullResponse,sbDelta);
              end
            else
              begin
                // A streaming AI response is always terminated by a single "null_terminator" event.
                finished := CkStringBuilder_ContentsEqual(sbEventName,'null_terminator',True);
              end;
          end;
      end
    else
      begin
        if (result = 0) then
          begin
            // Nothing is immediately available. Sleep for 1/10 of a second before polling again.
            CkAi_SleepMs(ai,100);
          end
        else
          begin
            // Something failed..
            Memo1.Lines.Add(CkAi__lastErrorText(ai));
            finished := True;
          end;
      end;
  end;

Memo1.Lines.Add('----');
Memo1.Lines.Add(CkStringBuilder__getAsString(sbFullResponse));

CkAi_Dispose(ai);
CkStringBuilder_Dispose(sbEventName);
CkStringBuilder_Dispose(sbDelta);
CkStringBuilder_Dispose(sbFullResponse);

end;