Pascal (Lazarus/Delphi)

Send JSON REST Request, Get JSON Response

See more REST Examples

Demonstrates sending a RESTful JSON request, and receiving a JSON response. This example will create a bucket in Google Cloud Storage (which involves sending and receiving JSON). Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.AuthGoogle,
  Chilkat.JsonObject,
  Chilkat.Rest;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  gAuth: TAuthGoogle;
  rest: TRest;
  bAutoReconnect: Boolean;
  jsonReqBody: TJsonObject;
  objVersioning: TJsonObject;
  jsonResponseStr: string;

begin
  success := False;

  //  This example will create a bucket in Google Cloud Storage.

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

  gAuth := TAuthGoogle.Create;
  //  Obtain an access token as shown in one of the following examples:
  //  See Get Access Token using a Service Account JSON Key
  //  See Get Access Token using a P12 File

  rest := TRest.Create;

  //  Connect using TLS.
  bAutoReconnect := True;
  success := rest.Connect('www.googleapis.com',443,True,bAutoReconnect);

  //  Provide the authentication credentials (i.e. the access key)
  success := rest.SetAuthGoogle(gAuth);

  //  Build the JSON request body for creating a bucket.
  //  The only required property is the "name", but we'll add more
  //  to make a better example..
  jsonReqBody := TJsonObject.Create;
  jsonReqBody.AppendString('name','chilkat-bucket-c');
  jsonReqBody.AppendString('kind','storage#bucket');
  jsonReqBody.AppendString('location','US');

  objVersioning := TJsonObject.Create;
  jsonReqBody.AppendObject2('versioning',objVersioning);
  objVersioning.AppendBool('enabled',True);

  //  Show the HTTP request body we'll be sending.
  WriteLn(jsonReqBody.Emit());

  //  Add the required query parameter.
  //  See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
  success := rest.AddQueryParam('project','chilkattest-1050');

  //  Add the Content-Type HTTP request header.
  success := rest.AddHeader('Content-Type','application/json; charset=UTF-8');

  jsonResponseStr := rest.FullRequestString('POST','/storage/v1/b',jsonReqBody.Emit());
  if (rest.LastMethodSuccess = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  Show the JSON response.  (See below for a sample JSON response.)
  WriteLn('Json Response: ' + jsonResponseStr);

  //  {
  //   "kind": "storage#bucket",
  //   "id": "chilkat-bucket-c",
  //   "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-bucket-c",
  //   "projectNumber": "999992999999",
  //   "name": "chilkat-bucket-c",
  //   "timeCreated": "2016-04-29T21:08:10.451Z",
  //   "updated": "2016-04-29T21:08:10.451Z",
  //   "metageneration": "1",
  //   "owner": {
  //    "entity": "project-owners-999992999999"
  //   },
  //   "location": "US",
  //   "versioning": {
  //    "enabled": true
  //   },
  //   "storageClass": "STANDARD",
  //   "etag": "CAE="
  //  }
  //  


  gAuth.Free;
  rest.Free;
  jsonReqBody.Free;
  objVersioning.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.