(Delphi ActiveX) BatchModify - Add a Label to each Message in Search Results

Searchs GMail for messages meeting a criteria and adds a label to each message found.

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;
http: TChilkatHttp;
userId: WideString;
query: WideString;
url: WideString;
sb: TChilkatStringBuilder;
json: TChilkatJsonObject;
json2: TChilkatJsonObject;
i: Integer;
numMessages: Integer;
id: WideString;
labelId: WideString;
resp: IChilkatHttpResponse;

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

http := TChilkatHttp.Create(Self);
http.AuthToken := 'GMAIL-ACCESS-TOKEN';

userId := 'me';
http.SetUrlVar('userId',userId);

query := 'subject:questions';
http.SetUrlVar('query',query);

url := 'https://www.googleapis.com/gmail/v1/users/{$userId}/messages?q={$query}';

sb := TChilkatStringBuilder.Create(Self);
success := http.QuickGetSb(url,sb.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

json := TChilkatJsonObject.Create(Self);
json.LoadSb(sb.ControlInterface);
json.EmitCompact := 0;
Memo1.Lines.Add(json.Emit());

if (http.LastStatus <> 200) then
  begin
    Memo1.Lines.Add('Failed.');
    Exit;
  end;

// If successful, the received JSON looks like this:
// {
//   "messages": [
//     {
//       "id": "166f583051d36144",
//       "threadId": "166f583051d36144"
//     },
//     {
//       "id": "166f5815e1f36144",
//       "threadId": "166f5815e1f36144"
//     },
// 	...
//     {
//       "id": "166f580639e36144",
//       "threadId": "166f580639e36144"
//     },
//     {
//       "id": "15dbc2e28ec789c6",
//       "threadId": "15dbc2e28ec789c6"
//     }
//   ],
//   "nextPageToken": "13434766102274844688",
//   "resultSizeEstimate": 103
// }
// 

// Next, we'll be sending an HTTP POST to add the label "questions" to each message in the
// search results.  The JSON to be sent for the batchModify is this:

// 	{
// 	  "ids": [
// 	    string
// 	  ],
// 	  "addLabelIds": [
// 	    string
// 	  ],
// 	  "removeLabelIds": [
// 	    string
// 	  ]
// 	}

// We'll omit "removeLabelIds" because we're not removing any labels.
// We are parsing the JSON search results, and at the same time building the batchModify JSON.

json2 := TChilkatJsonObject.Create(Self);

i := 0;
numMessages := json.SizeOfArray('messages');
while (i < numMessages) do
  begin
    json.I := i;
    id := json.StringOf('messages[i].id');
    json2.I := i;
    json2.UpdateString('ids[i]',id);
    i := i + 1;
  end;

// We need the id of the label (not the name).
// I know the name of the label is "questions", but I need to know the id.
// See this example: Get Label Id by Name
// The id of my label named "questions" is "Label_43"
labelId := 'Label_43';
json2.UpdateString('addLabelIds[0]',labelId);
json2.UpdateNewArray('removeLabelIds');

json2.EmitCompact := 0;
Memo1.Lines.Add(json2.Emit());

// Send the batchModify
url := 'https://www.googleapis.com/gmail/v1/users/{$userId}/messages/batchModify';
resp := http.PostJson3(url,'application/json',json2.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('status = ' + IntToStr(resp.StatusCode));

// A 204 response status indicate success.
if (resp.StatusCode <> 204) then
  begin
    Memo1.Lines.Add(resp.BodyStr);
    Memo1.Lines.Add('Failed.');

    Exit;
  end;

// The 204 response has an empty response body..

Memo1.Lines.Add('BatchModify success!');
end;