Google Drive: GFile, Export as Text

// (c) 2019, Questetra, Inc. (the MIT License)

//// == OAuth2 Setting example ==
// Authorization Endpoint URL:
//  "https://accounts.google.com/o/oauth2/auth?access_type=offline&approval_prompt=force"
// Token Endpoint URL:
//  "https://accounts.google.com/o/oauth2/token"
// Scope:
//  "https://www.googleapis.com/auth/drive.readonly"
// Client ID:
//  ( from https://console.developers.google.com/ )
// Consumer Secret:
//  ( from https://console.developers.google.com/ )
//  *Redirect URLs: "https://s.questetra.net/oauth2callback"

// Google Sheets, not supported (As of 2019)
// Google スプレッドシート はサポートされていません（2019年現在）


//////// START "main()" ////////
main();
function main(){ 

//// == Config Retrieving / 工程コンフィグの参照 ==
const oauth2  = configs.get( "conf_OAuth2"  ) + "";
const fileId  = configs.get( "conf_FileId") + "";
const dataIdC = configs.get( "conf_DataIdC" ) + "";
const dataIdD = configs.get( "conf_DataIdD" ) + "";
engine.log( " AutomatedTask Config: File ID: " + fileId );
if( fileId === "" ){
  throw new Error( "\n AutomatedTask ConfigError:" + 
                   " String {B} (File ID) is required \n" );
}


//// == Data Retrieving / ワークフローデータの参照 ==
// (nothing)


//// == Calculating / 演算 ==
/// obtain OAuth2 Access Token
const token   = httpClient.getOAuth2Token( oauth2 );

/// get File Name (Metadata)
let apiRequest = httpClient.begin(); // HttpRequestWrapper
apiRequest = apiRequest.bearer( token );
apiRequest = apiRequest.queryParam( "supportsAllDrives", "true" );
// This parameter will only be effective until June 1, 2020.
// see https://developers.google.com/drive/api/v3/reference/files/get
const apiUri = "https://www.googleapis.com/drive/v3/files/" + fileId;
engine.log( " AutomatedTask Trying: GET " + apiUri );
const response = apiRequest.get( apiUri );
const responseCode = response.getStatusCode() + "";
engine.log( " AutomatedTask ApiResponse: Status " + responseCode );
if( responseCode !== "200"){
  throw new Error( "\n AutomatedTask UnexpectedResponseError: " +
         responseCode + "\n" + response.getResponseAsString() + "\n" );
}
const responseStr = response.getResponseAsString() + "";
const responseObj = JSON.parse( responseStr );
engine.log( " AutomatedTask ApiResponse: File Name: " + responseObj.name );
engine.log( " AutomatedTask ApiResponse: File MIME Type: " + responseObj.mimeType );

/// get Text
let apiRequest2 = httpClient.begin(); // HttpRequestWrapper
apiRequest2 = apiRequest2.bearer( token );
apiRequest2 = apiRequest2.queryParam( "mimeType", "text/plain" );
// https://developers.google.com/drive/api/v3/ref-export-formats
const apiUri2 = "https://www.googleapis.com/drive/v3/files/" + 
                 fileId + "/export";
engine.log( " AutomatedTask Trying: GET " + apiUri2 );
const response2 = apiRequest2.get( apiUri2 );
const responseCode2 = response2.getStatusCode() + "";
engine.log( " AutomatedTask ApiResponse: Status " + responseCode2 );
if( responseCode2 !== "200"){
  throw new Error( "\n AutomatedTask UnexpectedResponseError: " +
         responseCode2 + "\n" + response2.getResponseAsString() + "\n" );
}
let strText = response2.getResponseAsString() + "";
engine.log( " AutomatedTask ApiResponse: Text Info exported" );


//// == Data Updating / ワークフローデータへの代入 ==
engine.setDataByNumber( dataIdC, strText );
if( dataIdD !== "" ){
  engine.setDataByNumber( dataIdD, responseObj.name );
}


} //////// END "main()" ////////