Get file buffer using Google Drive API and async/await - node.js

Question

I'm trying to get the buffer of some drive pdf files so I can parse it and use the data.
I've managed to get the file names and id using async/await and a "drive.files.list" wrapped with promise. Now I need to use the file ids to get the buffer and then read it.
The function I need should return a promise that I can wait (using await) to be fulfilled to get a buffer. (My parser works fine when I get pdf buffer from website responses)
function getBuffer(drive, file) {
return new Promise((resolve, reject) => {
/////Google Auth
var jwToken = new google.auth.JWT(
key.client_email,
null,
key.private_key, ["https://www.googleapis.com/auth/drive"],
null
);
jwToken.authorize((authErr) => {
if (authErr) {
return reject([false, "Auth Error: " + authErr]);
}
});
drive.files.get({
auth: jwToken,
fileId: file.id,
alt: 'media',
supportsAllDrives: true
}, function (err, res) {
if (err) {
return reject('The API returned an error: ' + err);
};
console.log(res);
const buffer = res;
resolve(buffer);
});
});
}
And I use it this way:
var buffer = await getBuffer(drive,files[i]);
The output I get in "console.log(res)" is something like this:
...
��M�7�|�ı�[��Ξ�A����EBS]��P��r�����j�3�|�I.��i�+ϢKU���U�:[�═�,^߻t덲�v��=}'*8���ѻ��#ғ�s��No��-��q8E9�/f� �(�`�j'3
"╚�-��� ������[jp&��╚k��M��vy� In�:a�զ�OlN��u����6�n���q�/Y�i4�?&%��q�,��p╚.ZV&n�Ɨ��2G������X����Y
D],�ggb�&�N���G����NS�Lח\U�^R|_f<��f*�|��]�{�3�-P�~�CS��t��>g�Y��#�#7Wjۋ╗=�5�����#ջ���5]>}&v�╝═�wg��eV�^>�#�{��Ѿ��ޤ��>O�� z�?{8Ij�0╗B�.�Cjm�4������║��m�,╗�������O���fS��ӂcE��g�3(�G��}d^O������7����|�
H�N��;
{��x�bȠ�׮�i]=���~��=��ٟ<��C��
wi��'a�-��p═M�6o��ϴ��ve��+��'
...
And when I try to use the parser (pdf2json) I get this error:
"An error occurred while parsing the PDF: stream must have data"
Thanks in advance :D

Answer 1

You want to download a file from Google Drive.
You want to convert the downloaded data to the buffer.
You have already been able to download files from Google Drive using googleapis with Node.js.
If my understanding is correct, how about this modification? In this modification, the file is downloaded as the stream type and the data is converted to the buffer.
Modified script:
From:
drive.files.get({
auth: jwToken,
fileId: file.id,
alt: 'media',
supportsAllDrives: true
}, function (err, res) {
if (err) {
return reject('The API returned an error: ' + err);
};
console.log(res);
const buffer = res;
resolve(buffer);
});
To:
drive.files.get(
{
auth: jwToken,
fileId: file.id,
alt: "media",
supportsAllDrives: true
},
{ responseType: "stream" },
function(err, { data }) {
if (err) {
return reject("The API returned an error: " + err);
}
let buf = [];
data.on("data", function(e) {
buf.push(e);
});
data.on("end", function() {
const buffer = Buffer.concat(buf);
console.log(buffer);
// fs.writeFile("filename", buffer, err => console.log(err)); // For testing
resolve(buffer);
});
}
);
Note:
As a test case, I could confirm that when buffer is saved to a file using fs.writeFile("filename", buffer, err => console.log(err));, the downloaded file can be created.
Reference:
google-api-nodejs-client
If I misunderstood your question and this was not the direction you want, I apologize.