Delphi DLL

Google Calendar Search Events (List Events with Optional Query Parameters)

See more Google Calendar Examples

Demonstrates how to specify optional query parameters for listing events. This example uses the "q" parameter to free-text search for events, and uses the "timeMin" parameter to specify a lower bound for an event's end time. Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Http, StringBuilder, HttpRequest, JsonObject, CkDateTime;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
jsonToken: HCkJsonObject;
http: HCkHttp;
sbUrl: HCkStringBuilder;
req: HCkHttpRequest;
dt: HCkDateTime;
sbResponse: HCkStringBuilder;
json: HCkJsonObject;
numEvents: Integer;
i: Integer;

begin
success := False;

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

// This example uses a previously obtained access token having permission for the 
// Google Calendar scope.

// In this example, Get Google Calendar OAuth2 Access Token, the access
// token was saved to a JSON file.  This example fetches the access token from the file..
jsonToken := CkJsonObject_Create();
success := CkJsonObject_LoadFile(jsonToken,'qa_data/tokens/googleCalendar.json');
if (CkJsonObject_HasMember(jsonToken,'access_token') = False) then
  begin
    Memo1.Lines.Add('No access token found.');
    Exit;
  end;
http := CkHttp_Create();
CkHttp_putAuthToken(http,CkJsonObject__stringOf(jsonToken,'access_token'));

// We'll want to build a URL with the query params..
sbUrl := CkStringBuilder_Create();
CkStringBuilder_Append(sbUrl,'https://www.googleapis.com/calendar/v3/calendars/{$calendarId}/events?');

// Use the HTTP request object as a helper for creating the URL encoded query param list..
req := CkHttpRequest_Create();

// Find events with the word "pizza".
CkHttpRequest_AddParam(req,'q','pizza');

// Get events for the current date/time or later.
dt := CkDateTime_Create();
CkDateTime_SetFromCurrentSystemTime(dt);
CkHttpRequest_AddParam(req,'timeMin',CkDateTime__getAsTimestamp(dt,False));

// Add these query params to the URL:
CkStringBuilder_Append(sbUrl,CkHttpRequest__getUrlEncodedParams(req));

// Examine the URL..
Memo1.Lines.Add('URL: ' + CkStringBuilder__getAsString(sbUrl));

// The URL looks like this:
// https://www.googleapis.com/calendar/v3/calendars/{$calendarId}/events?q=pizza&timeMin=2017-08-11T13%3A35%3A28Z

// Let's get events in the primary calendar.  A calendar ID could have be used instead of "primary".
CkHttp_SetUrlVar(http,'calendarId','primary');
sbResponse := CkStringBuilder_Create();
success := CkHttp_QuickGetSb(http,CkStringBuilder__getAsString(sbUrl),sbResponse);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

if (CkHttp_getLastStatus(http) <> 200) then
  begin
    // Note: If a 401 unauthorized response is received, it likely means that the OAuth2 access token needs
    // to be refreshed or re-fetched.
    Memo1.Lines.Add('Error response status: ' + IntToStr(CkHttp_getLastStatus(http)));
    Memo1.Lines.Add(CkStringBuilder__getAsString(sbResponse));
    Exit;
  end;

Memo1.Lines.Add(CkStringBuilder__getAsString(sbResponse));

// A sample JSON response:
// (Code for parsing the Google Calendar events is shown below.)

// {
//  "kind": "calendar#events",
//  "etag": "\"p32cafkumkb7ta0g\"",
//  "summary": "support@chilkatcloud.com",
//  "updated": "2017-08-11T13:19:48.143Z",
//  "timeZone": "America/Chicago",
//  "accessRole": "owner",
//  "defaultReminders": [
//   {
//    "method": "popup",
//    "minutes": 10
//   }
//  ],
//  "nextSyncToken": "CJin09aiz9UCEJin09aiz9UCGAU=",
//  "items": [
//   {
//    "kind": "calendar#event",
//    "etag": "\"3004915160212000\"",
//    "id": "02pv1cpdp7vm11htnfi3ii7iie",
//    "status": "confirmed",
//    "htmlLink": "https://www.google.com/calendar/event?eid=MDJwdjFjcGRwN3ZtMTFodG5maTNpaTdpaWUgc3VwcG9ydEBjaGlsa2F0Y2xvdWQuY29t",
//    "created": "2017-08-11T13:19:40.000Z",
//    "updated": "2017-08-11T13:19:40.106Z",
//    "summary": "Eat Lou Malnati's Pizza",
//    "creator": {
//     "email": "support@chilkatcloud.com",
//     "self": true
//    },
//    "organizer": {
//     "email": "support@chilkatcloud.com",
//     "self": true
//    },
//    "start": {
//     "dateTime": "2017-08-12T12:00:00-05:00"
//    },
//    "end": {
//     "dateTime": "2017-08-12T13:00:00-05:00"
//    },
//    "iCalUID": "02pv1cpdp7vm11htnfi3ii7iie@google.com",
//    "sequence": 0,
//    "hangoutLink": "https://plus.google.com/hangouts/_/chilkatcloud.com/support?hceid=c3VwcG9ydEBjaGlsa2F0Y2xvdWQuY29t.02pv1cpdp7vm11htnfi3ii7iie",
//    "reminders": {
//     "useDefault": true
//    }
//   }
//  ]
// }
// 
// 

json := CkJsonObject_Create();
CkJsonObject_LoadSb(json,sbResponse);

numEvents := CkJsonObject_SizeOfArray(json,'items');
i := 0;
while i < numEvents do
  begin
    CkJsonObject_putI(json,i);
    Memo1.Lines.Add(CkJsonObject__stringOf(json,'items[i].summary'));
    Memo1.Lines.Add(CkJsonObject__stringOf(json,'items[i].start.dateTime'));
    Memo1.Lines.Add(CkJsonObject__stringOf(json,'items[i].end.dateTime'));
    Memo1.Lines.Add('--');
    i := i + 1;
  end;

// Sample output:

// Eat Lou Malnati's Pizza
// 2017-08-12T12:00:00-05:00
// 2017-08-12T13:00:00-05:00
// --

CkJsonObject_Dispose(jsonToken);
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbUrl);
CkHttpRequest_Dispose(req);
CkDateTime_Dispose(dt);
CkStringBuilder_Dispose(sbResponse);
CkJsonObject_Dispose(json);

end;