(Delphi ActiveX) HttpPostJson2Async Example

Demonstrates use of the HttpPostJson2Async method.

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: TChilkatHttp;
success: Integer;
jsonBody: WideString;
task: IChilkatTask;
resp: TChilkatHttpResponse;
statusCode: Integer;
json: TChilkatJsonObject;

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

// See PostJson2 Example for the synchronous equivalent of this example.

http := TChilkatHttp.Create(Self);

// Sends a POST equivalent to the following CURL command:

// curl -X POST https://sandbox.plaid.com/institutions/get \
//   -H 'content-type: application/json' \
//   -d '{
//     "client_id": String,
//     "secret":String,
//     "count": Number,
//     "offset": Number
//   }'

// Suppress some default headers that would automatically added..
http.AcceptCharset := '';
http.UserAgent := '';
http.AcceptLanguage := '';
http.AllowGzip := 0;

jsonBody := '{"client_id": "PLAID_CLIENT_ID", "secret":"PLAID_SECRET", "count": 10, "offset": 0}';
task := http.PostJson2Async('https://sandbox.plaid.com/institutions/get','application/json',jsonBody);
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

// Start the background task.
success := task.Run();
if (not success) then
  begin
    Memo1.Lines.Add(task.LastErrorText);

    Exit;
  end;

// The application is now free to do anything else
// while the HTTP POST is in progress

// For this example, we'll simply sleep and periodically
// check to see if the HTTP POST is finished.  
while task.Finished <> 1 do
  begin
    // Sleep 100 ms.
    task.SleepMs(100);
  end;

// When we get here, the task is either finished successfully or not, or was canceled/aborted.

// If the task was "canceled", it was canceled prior to actually starting.  This could
// happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
// background thread pool scheduler.  

// If the task was "aborted", it indicates that it was canceled while running in a background thread.  
// The ResultErrorText will likely indicate that the task was aborted.

// If the task "completed", then it ran to completion, but the actual success/failure of the method
// is determined by getting the result of the underlying method call.
// A task status of 7 indicates completion.
if (task.StatusInt <> 7) then
  begin
    Memo1.Lines.Add('Task did not complete.');
    Memo1.Lines.Add('task status: ' + task.Status);

    Exit;
  end;

// When called synchronously, the PostJson2 method returns an HTTP response object,
// unless the method failed and there was no response to be had.
// Check to see if PostJson2 method failed (and thus there is no response object).
if (task.TaskSuccess = 0) then
  begin
    Memo1.Lines.Add('The underlying task failed, and there is no HTTP response object.');
    Memo1.Lines.Add('The LastErrorText for the underlying method call is:');
    Memo1.Lines.Add(task.ResultErrorText);

    Exit;
  end;

// To get the HTTP response object, create a new instance and load it with the result from the task.
resp := TChilkatHttpResponse.Create(Self);
resp.LoadTaskResult(task);

statusCode := resp.StatusCode;
Memo1.Lines.Add('Response status code = ' + IntToStr(statusCode));

// Examine the JSON response..
json := TChilkatJsonObject.Create(Self);
json.Load(resp.BodyStr);
json.EmitCompact := 0;
Memo1.Lines.Add('JSON Response Body:');
Memo1.Lines.Add(json.Emit());
end;