Google script to list (on a Google Sheet) all files shared in your google drive, including all viewers, editors, and sharing permissions. Credit goes to @woodwardtw (https://gist.github.com/woodwardtw/22a199ecca73ff15a0eb) as this is an improvement on his code which only assesses a single folder and one level of sub-folders down.

whatFilesHaveIShared.gs

function listFolders(folder) {
     var sheet = SpreadsheetApp.getActiveSheet();
     sheet.appendRow(["Name", "Sharing Access", "Sharing Permission", "Get Editors", "Get Viewers", "Date", "Size", "URL", "Download", "Description", "Type"]); //writes the headers
     
     //var folder = DriveApp.getFolderById("INSERT_YOUR_FILE_ID");//that long chunk of random numbers/letters in the URL when you navigate to the folder
     //getLooseFiles(folder, sheet);
     //getSubFolders(folder, sheet);
  
     //instead of getting folder by ID rather get all folders and cycle through each. Note this will miss loose files in parent directory.
     var folder = DriveApp.getFolders()
     while (folder.hasNext()) {
         var name = folder.next();
         getLooseFiles(name, sheet);
         getSubFolders(name, sheet);
      };

 }

function getLooseFiles(folder, sheet) {
     var files = folder.getFiles();//initial loop on loose files w/in the folder
     var cnt = 0;
     var file;

     while (files.hasNext()) {
         var file = files.next();
         var listEditors = file.getEditors(); //gets the editor email(s), doesn't show your own as it's assumed
         var editors = [];
         for (var cnt = 0; cnt < listEditors.length; cnt++) {
             editors.push(listEditors[cnt].getEmail());
             Logger.log(editors);
         };
         var listViewers = file.getViewers(); //gets the viewer email(s)
         var viewers = [];
         for (var cnt = 0; cnt < listViewers.length; cnt++) {
             viewers.push(listViewers[cnt].getEmail());
             Logger.log(viewers);
         }
         cnt++;  //data chunk pushes all the file info to the ss

         data = [
             file.getName(),
             file.getSharingAccess(),
             file.getSharingPermission(),
             editors.toString(),
             viewers.toString(),
             file.getDateCreated(),
             file.getSize(),
             file.getUrl(),
             "https://docs.google.com/uc?export=download&confirm=no_antivirus&id=" + file.getId(),
             file.getDescription(),
             file.getMimeType(),
         ];

       if(data[1] != "PRIVATE") {
         sheet.appendRow(data);
       }

     };

}

function getSubFolders(folder, sheet) {
var subfolders = folder.getFolders(); //same thing as above but for all the subfolders in the folder

     while (subfolders.hasNext()) {
         Logger.log(folder);
         var name = subfolders.next();
         getLooseFiles(name, sheet);
         getSubFolders(name, sheet);
     };
}

Code throws "Exception: The file or folder has invalid access settings." on the sharing permissions instructions. Discovering files with particular sharing permissions is the point of the code. How can the code anticipate, capture, and continue?

Hey,

Thanks a lot for this, it helped me a lot.

I've made some improvments, so it's harder to timeout when there are lots of files involved.
(it took me about 3min for 500 files instead of timing out at 6mn).

I just cached all the files in a list and flushed them all at once into the spreadsheet instead of calling the API for each files.

you can check that out here : https://github.com/moya-a/G-Drive-SharedFiles-Checker

Cheers :)