How to recursively read all items using graph api for drive ?

Question

Hello,

I have requirement to read all the files metadata from the drive using graph api.

The composition of drive includes thousands of folder in multi-level hierarchy. I have implemented a BFS approach which reads each folder and all files from the provided top folder, and store the new folder names for subsequent reads for files.

But when I saw this video demo on pagination, it was mentioned that 'expand=children' can able to do the same without additional handling of navigating sub-folders. I tried using the API, the response does not contain nextLink on children even if child folder has more files. Is this functionality working as expected or did I miss something here?

Video demo: https://learn.microsoft.com/en-us/graph/paging

API I tried from video: https://graph.microsoft.com/v1.0/me/drives?$expand=root($expand=children)

My drive has folders in multiple levels:

root/folder1/folder2...../folderN

Current Approach (which is working):

This approach, I have to build the endpoint based on folder discovered, which seems bit complex than what is found from video demo. Any thoughts would be appreciated? Thanks!

https://graph.microsoft.com/v1.0/me/drive/root:/folderName/......:/children

Answer 1

Hi Naresh Goty, Thanks for reaching out. You can use the following code to recursively read all the items in a drive using graph api.

private async Task<List<DriveItem>> GetAllFilesFromOneDriveSubFolderAsync(GraphServiceClient graphClient, DriveItem oneDriveSubFolder)
{
    var subDriveItems = new List<DriveItem>();
    var subDriveItemFiles = new List<DriveItem>();

    //Fetching out all the files and sub folders inside the subfolder
    IDriveItemChildrenCollectionPage items = await graphClient.Drives[oneDriveSubFolder.ParentReference.DriveId]
                                                                .Items[oneDriveSubFolder.Id].Children
                                                                .Request()
                                                                .GetAsync();
    subDriveItems.AddRange(items.CurrentPage);

    //Checking if there are more than one pages, if so fetch out from all the subsequent pages
    var next = items.NextPageRequest;
    while (next != null)
    {
        items = await next.GetAsync();
        subDriveItems.AddRange(items.CurrentPage);
        next = items.NextPageRequest;
    }

    //In case there is still sub folder then repeating the process to fetch out files
    foreach (DriveItem driveItem in subDriveItems)
    {
        if (driveItem.Folder != null)
        {
            subDriveItemFiles.AddRange(await GetAllFilesFromOneDriveSubFolderAsync(graphClient, driveItem));
        }
        else if (driveItem.File != null)
        {
            subDriveItemFiles.Add(driveItem);
        }
   }
    return subDriveItemFiles;
}


        public async Task<List<DriveItem>> GetUsersOneDriveRootFilesAsync(GraphServiceClient graphClient, string userId, string driveId)
        {
            var driveItems = new List<DriveItem>();
            var driveItemFiles = new List<DriveItem>();

            //Fetching out all the files and sub folders inside the root folder of users one drive
            var items = await graphClient.Drives[driveId]
                                            .Root.ItemWithPath("/Templates")
                                            .Children
                                            .Request()
                                            .WithMaxRetry(3, 3)
                                            .GetAsync();

            driveItems.AddRange(items.CurrentPage);

            //Checking if there are more than one pages, if so fetch out from all the subsequent pages
            var next = items.NextPageRequest;
            while (next != null)
            {
                items = await next.GetAsync();
                driveItems.AddRange(items.CurrentPage);
                next = items.NextPageRequest;
            }

            // In case there is still sub folder then fetching out the files from the folder.
            foreach (DriveItem driveItem in driveItems)
            {
                if (driveItem.Folder != null)
                {
                    driveItemFiles.AddRange(await GetAllFilesFromOneDriveSubFolderAsync(graphClient, driveItem));
                }
                else if (driveItem.File != null)
                {
                    driveItemFiles.Add(driveItem);
                }
            }
            return driveItemFiles;
        }

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Answer 2

Unfortunatly this code is out of date, this is not working for me