unable to access folder just created Google Drive - google-apps-script

Question

I created a script that generates a folder in Google Drive and gets the folder ID of that folder.
Upon trying to access that folder in a unique function I get the error:
no item with the given ID could be found, or you do not have permission to access it on Folder
Please see my script below (called independently from html):
var childFolderIdA;
function doGet() {
return HtmlService.createHtmlOutputFromFile('multifile').setTitle('test – multi upload').setSandboxMode(HtmlService.SandboxMode.IFRAME);
}
function test(parent,child){
createSharedSubFolder(parent,child);
}
function createSharedSubFolder(parent,child) { // folder names as string parameters
var folders = DriveApp.getFolders();
var exist = false
while (folders.hasNext()) {
var folder = folders.next();
if(folder.getName()==parent){exist = true ; var folderId = folder.getId(); break};// find the existing parent folder
}
if(exist){ //parent folder exists
var child = DriveApp.getFolderById(folderId).createFolder(child).setSharing(DriveApp.Access.ANYONE, DriveApp.Permission.EDIT);
var childFolderId = child.getId();
childFolderIdA = childFolderId;
}else{
var childFolder = DriveApp.createFolder(parent).createFolder(child); //create parent and child folders
childFolder.setSharing(DriveApp.Access.ANYONE, DriveApp.Permission.EDIT);
}
}
function saveFile(data,name,folderName) {
var contentType = data.substring(5,data.indexOf(';'));
var file = Utilities.newBlob(Utilities.base64Decode(data.substr(data.indexOf('base64,')+7)), contentType, name); //does the uploading of the files
DriveApp.getFolderById(childFolderIdA).createFile(file);
}

Answer 1

You can't depend on global variables to save state between calls. Each time you call a script a new script instance is spawned. Each one will maintain its own state.
For example:
google.script.run.createSharedSubFolder(...) --> Script Instance 1..var childFolderIdA=folderId;
google.script.run.saveFile(...) --> Script Instance 2..var childFolderIdA=null;
You can save the the folderId to the users property store:
PropertiesService.getUserProperties().setProperty("childFolderId", childFolderId);
You can retrieve the folder Id:
var folderId = PropertiesService.getUserProperties().getProperty("childFolderId");
Your code with this change:
function doGet() {
return HtmlService.createHtmlOutputFromFile('multifile').setTitle('test – multi upload').setSandboxMode(HtmlService.SandboxMode.IFRAME);
}
function test(parent,child){
createSharedSubFolder(parent,child);
}
function createSharedSubFolder(parent,child) { // folder names as string parameters
var folders = DriveApp.getFolders();
var exist = false
while (folders.hasNext()) {
var folder = folders.next();
if(folder.getName()==parent){exist = true ; var folderId = folder.getId(); break};// find the existing parent folder
}
if(exist){ //parent folder exists
var child = DriveApp.getFolderById(folderId).createFolder(child).setSharing(DriveApp.Access.ANYONE, DriveApp.Permission.EDIT);
var childFolderId = child.getId();
PropertiesService.getUserProperties().setProperty("childFolderId", childFolderId);
}else{
var childFolder = DriveApp.createFolder(parent).createFolder(child); //create parent and child folders
childFolder.setSharing(DriveApp.Access.ANYONE, DriveApp.Permission.EDIT);
}
}
function saveFile(data,name,folderName) {
var contentType = data.substring(5,data.indexOf(';'));
var file = Utilities.newBlob(Utilities.base64Decode(data.substr(data.indexOf('base64,')+7)), contentType, name); //does the uploading of the files
var childFolderId = PropertiesService.getUserProperties().getProperty("childFolderId");
DriveApp.getFolderById(childFolderId).createFile(file);
}