Microsoft 365 Outlook: Post Attachment to Calendar Event

// Post Outlook Calendar Event Attachment via Microsoft Graph API v1.0 (ver. 202209)
// (c) 2023, Questetra, Inc. (the MIT License)

//// == 工程コンフィグの参照 / Config Retrieving ==
const oauth2  = configs.get( "conf_OAuth2" ) + "";

const eventId = configs.get( "conf_eventId" ) + "";
const files   = engine.findDataByNumber( configs.get( "conf_attachment" ) );

const dataId_attachmentId = configs.get( "conf_attachmentId" );
const dataId_log          = configs.get( "conf_log" );

//// == 演算 / Calculating ==
if( eventId == "" ){
  throw `Event ID none.`;
}

if( !files ){
  throw `File none.`;
}
const file = files.get(0);

//ファイルサイズ確認
// API仕様的には3MBまで、ファイルだけでなくペイロード全体での制限、余裕をみて2.9MBまでとする
// https://learn.microsoft.com/ja-jp/graph/api/event-post-attachments?view=graph-rest-1.0&tabs=javascript
if (file.getLength() > 3040871) {
  throw `File size over.`;
}

let fileData = "";
fileRepository.readFile(file, 3145728, function(bytes) {
  fileData = base64.encodeToString(bytes);
});

let requestObj = {};
  requestObj['@odata.type'] = '#microsoft.graph.fileAttachment';
  requestObj.name = file.getName();
  requestObj.contentBytes = fileData;

//engine.log("json:" + JSON.stringify( requestObj ));

let accessLog = "";
let uri = "https://graph.microsoft.com/v1.0/me/events/" + eventId + "/attachments";
let response = httpClient.begin()
  .authSetting( oauth2 )
  .body( JSON.stringify( requestObj ), "application/json" )
  .post( uri );
accessLog += "---POST request--- " + response.getStatusCode() + "\n";
accessLog += response.getResponseAsString() + "\n";


//// == ワークフローデータへの代入 / Data Updating ==
const status = response.getStatusCode();

if( status >= 300 ){
  engine.log(accessLog);
  throw `Failed in POST request. status: ${status}`;
} else {
  const jsonObj = JSON.parse( response.getResponseAsString() );
  const attachmentId = jsonObj.id + "";

  if( dataId_attachmentId !== "" ){
    engine.setDataByNumber( dataId_attachmentId, attachmentId );
  }
}

if( dataId_log !== "" ){
  engine.setDataByNumber( dataId_log, accessLog );
}