Uploading File to Google Drive from External HTML without Authorization

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Google Apps Script / upload

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This is a sample script for uploading a file to Google Drive from the external HTML without the authorization. In this case, the client side can be used at the outside of Google. And as the server side, the Web Apps created by Google Apps Script is used.

Usage

Please do the following flow.

1. Create new project of Google Apps Script.

Sample script of Web Apps is a Google Apps Script. So please create a project of Google Apps Script.

If you want to directly create it, please access to https://script.new/. In this case, if you are not logged in Google, the log in screen is opened. So please log in to Google. By this, the script editor of Google Apps Script is opened.

2. Prepare script.

Please copy and paste the following script (Google Apps Script) to the script editor. This script is for the Web Apps.

Server side: Google Apps Script

Please set the folder ID that you want to put the file.

function doPost(e) {
  const folderId = "###"; // Folder ID which is used for putting the file.

  const blob = Utilities.newBlob(
    JSON.parse(e.postData.contents),
    e.parameter.mimeType,
    e.parameter.filename
  );
  const file = DriveApp.getFolderById(folderId || "root").createFile(blob);
  const responseObj = {
    filename: file.getName(),
    fileId: file.getId(),
    fileUrl: file.getUrl(),
  };
  return ContentService.createTextOutput(
    JSON.stringify(responseObj)
  ).setMimeType(ContentService.MimeType.JSON);
}
  • When you modified the script of Web Apps, please redeploy the Web Apps as new version. By this, the latest script is reflected to Web Apps. Please be careful this.

3. Deploy Web Apps.

  1. On the script editor, Open a dialog box by “Publish” -> “Deploy as web app”.
  2. Select “Me” for “Execute the app as:”.
    • By this, the script is run as the owner.
  3. Select “Anyone, even anonymous” for “Who has access to the app:”.
  4. Click “Deploy” button as new “Project version”.
  5. Automatically open a dialog box of “Authorization required”.
    1. Click “Review Permissions”.
    2. Select own account.
    3. Click “Advanced” at “This app isn’t verified”.
    4. Click “Go to ### project name ###(unsafe)”
    5. Click “Allow” button.
  6. Click “OK”.
  7. Copy the URL of Web Apps. It’s like https://script.google.com/macros/s/###/exec.
    • When you modified the Google Apps Script, please redeploy as new version. By this, the modified script is reflected to Web Apps. Please be careful this.

4. Upload a file from client side to server side.

Client side: HTML & Javascript

Please set the URL of your Web Apps to the following script.

<form id="form">
  <input name="file" id="uploadfile" type="file" />
  <input id="submit" type="submit" />
</form>

<script>
  const form = document.getElementById("form");
  form.addEventListener("submit", (e) => {
    e.preventDefault();
    const file = form.file.files[0];
    const fr = new FileReader();
    fr.readAsArrayBuffer(file);
    fr.onload = (f) => {
      const url = "https://script.google.com/macros/s/###/exec"; // Please set the URL of Web Apps.

      const qs = new URLSearchParams({
        filename: file.name,
        mimeType: file.type,
      });
      fetch(`${url}?${qs}`, {
        method: "POST",
        body: JSON.stringify([...new Int8Array(f.target.result)]),
      })
        .then((res) => res.json())
        .then(console.log)
        .catch(console.log);
    };
  });
</script>
  • At the client side, when you selected a file from your local PC and push the button, the file is uploaded to your Google Drive by retrieving the data at the Web Apps (server side).

Limitation

In this case, the maximum file size is 50 MB. Because in the current stage, the maximum blob size is 50 MB at Google Apps Script.

References

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