(Delphi ActiveX) Send JSON REST Request, Get JSON Response

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).

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
success: Integer;
gAuth: TChilkatAuthGoogle;
rest: TChilkatRest;
bAutoReconnect: Integer;
jsonReqBody: TChilkatJsonObject;
pObjVersioning: IChilkatJsonObject;
jsonResponseStr: WideString;

begin
// 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 := TChilkatAuthGoogle.Create(Self);
// 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 := TChilkatRest.Create(Self);

// Connect using TLS.
bAutoReconnect := 1;
success := rest.Connect('www.googleapis.com',443,1,bAutoReconnect);

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

// 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 := TChilkatJsonObject.Create(Self);
success := jsonReqBody.AddStringAt(-1,'name','chilkat-bucket-c');
success := jsonReqBody.AddStringAt(-1,'kind','storage#bucket');
success := jsonReqBody.AddStringAt(-1,'location','US');
success := jsonReqBody.AddObjectAt(-1,'versioning');

pObjVersioning := jsonReqBody.ObjectOf('versioning');
success := pObjVersioning.AddBoolAt(-1,'enabled',1);

// Show the HTTP request body we'll be sending.
Memo1.Lines.Add(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 <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// Show the JSON response.  (See below for a sample JSON response.)
Memo1.Lines.Add('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="
// }
// 
end;