Google Script - How to use unzip - google-apps-script

Question

I am downloading a .zip from a website. It contains one .txt file. I would like to access the data in the txt and write it to a spreadsheet. I'm open to either accessing it directly and not extracting the zip OR extracting the zip, saving the txt to a Google Drive Folder, and accessing it once it is saved.
When I use Utilities.unzip(), I can never get it to unzip the file and usually end up with an "Invalid argument" error. In the code below, the last section before else contains the unzip command. It successfully saves the file to the correct Google Folder but then I can't extract it.
function myFunction() {
// define where to gather data from
var url = '<insert url here>';
var filename = "ReportUploadTesting05.zip";
var response = UrlFetchApp.fetch(url, {
// muteHttpExceptions: true,
// validateHttpsCertificates: false,
followRedirects: true // Default is true anyway.
});
// get spreadsheet for follow up info
var Sp = SpreadsheetApp.getActiveSpreadsheet();
if (response.getResponseCode() === 200) {
// get folder details of spreadsheet for saving future files
var folderURL = getParentFolder(Sp);
var folderID = getIdFromUrl(folderURL);
var folder = DriveApp.getFolderById(folderID);
// save zip file
var blob = response.getBlob();
var file = folder.createFile(blob);
file.setName(filename);
file.setDescription("Downloaded from " + url);
var fileID = file.getId();
Logger.log(fileID);
Logger.log(blob)
// extract zip (not working)
file.setContent('application/zip')
var fileUnzippedBlob = Utilities.unzip(file); // invalid argument error occurs here
var filename = 'unzipped file'
var fileUnzipped = folder.createFile(fileUnzippedBlob)
fileUnzipped.setName(filename)
}
else {
Logger.log(response.getResponseCode());
}
}
I've followed the instructions on the Utilities page. I can get their exact example to work. I've tried creating a .zip on my computer, uploading it to Google Drive and attempted to open it unsuccessfully. Obviously there are some subtleties of using the unzip that I'm missing.
Could you help me understand this?

Answer 1

I was running into the same "Invalid arguments" error in my testing, so instead of using:
file.setContent('application/zip')
I used:
file.setContentTypeFromExtension();
And, that solved the problem for me. Also, as #tukusejssirs mentioned, a zip file can contain multiple files, so unzip() returns an array of blobs (as documented here). That means you either need to loop through the files, or if you know you only have one, explicitly reference it's position in the array, like this:
var fileUnzipped = folder.createFile(fileUnzippedBlob[0])
Here's my entire script, which covers both of these issues:
/**
* Fetches a zip file from a URL, unzips it, then uploads a new file to the user's Drive.
*/
function uploadFile() {
var url = '<url goes here>';
var zip = UrlFetchApp.fetch('url').getBlob();
zip.setContentTypeFromExtension();
var unzippedFile = Utilities.unzip(zip);
var filename = unzippedFile[0].getName();
var contentType = unzippedFile[0].getContentType();
var csv = unzippedFile[0];
var file = {
title: filename,
mimeType: contentType
};
file = Drive.Files.insert(file, csv);
Logger.log('ID: %s, File size (bytes): %s', file.id, file.fileSize);
var fileId = file.id;
// Move the file to a specific folder within Drive (Link: https://drive.google.com/drive/folders/<folderId>)
var folderId = '<folderId>';
var folder = DriveApp.getFolderById(folderId);
var driveFile = DriveApp.getFileById(fileId);
folder.addFile(driveFile);
}

Answer 2

I think the answer to your question may be found here. Is there a size limit to a blob for Utilities.unzip(blob) in Google Apps Script?
If the download is over 100 mb the full file cannot be downloaded. Due to that it will not be in the proper zip format. Throwing the cannot unzip file error.

Answer 3

I believe that the creation of the blob from a file (in this case the .zip file) requires the .next(); otherwise it did not work for me.
Also note that the .zip file might contain more than one file, therefore I included a for cycle.
Anyway, my working/tested solution/script is the following:
function unzip(folderName, fileZipName){
// Variables
// var folderName = "folder_name";
// var fileZipName = "file_name.zip";
var folderId = getFolderId(folderName);
var folder = DriveApp.getFolderById(folderId);
var fileZip = folder.getFilesByName(fileZipName);
var fileExtractedBlob, fileZipBlob, i;
// Decompression
fileZipBlob = fileZip.next().getBlob();
fileZipBlob.setContentType("application/zip");
fileExtractedBlob = Utilities.unzip(fileZipBlob);
for (i=0; i < fileExtractedBlob.length; i++){
folder.createFile(fileExtractedBlob[i]);
}
}