Getting a file as a blob from Google Drive

Getting a file as a blob from Google Drive can be accomplished using the Google Drive API provided by the DriveApp service. Here’s a step-by-step guide on how to retrieve a file by its ID and get it as a blob, which you can then use for various operations such as copying, modifying, or sending it via email.

Step-by-Step Guide to Get a File as a Blob

1. Identify the File ID

First, you need the unique ID of the file on Google Drive. This can usually be found in the file’s URL.

2. Retrieve the File and Convert to Blob

Here’s a simple function that demonstrates how to get a file as a blob:

function getFileAsBlob() {
  const fileId = 'YOUR_FILE_ID';  // Replace this with the actual file ID
  try {
    const file = DriveApp.getFileById(fileId);
    const blob = file.getBlob();
    Logger.log("File retrieved and converted to blob successfully.");
    return blob;
  } catch (error) {
    Logger.log("Error retrieving file: " + error.toString());
    return null;
  }
}

Explanation of the Code

• getFileById: This method retrieves a file object from Google Drive using the provided file ID.
• getBlob: Converts the file into a blob, which is a data type that represents binary data in an immutable, raw format. You can use blobs to manipulate file data in memory, send it as email attachments, etc.

Example Uses of the Blob

Once you have the blob, you can use it in several ways:

Send as an Email Attachment

Here’s how you can send this blob as an attachment in an email using Google Apps Script:

function sendEmailWithAttachment(blob) {
  const recipient = "example@example.com";  // Set the recipient email address
  const subject = "Here's your file";
  const body = "Attached is the file you requested.";
  
  const options = {
    attachments: [blob],
    name: 'Automated Email Sender'
  };

  MailApp.sendEmail(recipient, subject, body, options);
  Logger.log("Email sent with attachment.");
}

Save a Copy in Google Drive

To save a copy of the blob as a new file in Google Drive:

function saveBlobToDrive(blob) {
  const folder = DriveApp.getFolderById('YOUR_FOLDER_ID'); // Replace with your folder ID
  const newFile = folder.createFile(blob);
  Logger.log("New file created with ID: " + newFile.getId());
}

Running the Functions

To utilize these functions, replace placeholders such as 'YOUR_FILE_ID' and 'YOUR_FOLDER_ID' with actual IDs from your Google Drive. Also, ensure you have appropriate permissions set to access files and send emails.