Cloud.File.Storage.Manager.SharePoint 1.4.0

Cloud File Storage Manager

Provides complete implementation to handle easily cloud file storage operations like get informations about files, reading, downloadURL generation, file update, file move and delete. Primarily for SharePoint right now.

Configuration

Let's add a section to the appsettings.json

"SharePointStorageSettings": {
    // The SharePoint site URL (e.g., https://tenant.sharepoint.com/sites/sitename)
    "SiteUrl": "",
    "DocumentLibraryName": "",
    "TenantId": "",
    "ClientId": "",
    "ClientSecret": "",
    // Optional: The folder name where the files will be stored, like: "MainFolder/WorkFolder/Test"
    "WorkFolderPath": ""
}

In the application, configure this settings part

services.AddSingleton<ICloudFileStorageManager, SharePointCloudFileStorageManager>(services => new SharePointCloudFileStorageManager(new SharePointCloudFileStorageManagerOptions()
{
    SiteUrl = config.GetSection("SharePointStorageSettings").GetValue<string>("SiteUrl"),
    DocumentLibraryName = config.GetSection("SharePointStorageSettings").GetValue<string>("DocumentLibraryName"),
    TenantId = config.GetSection("SharePointStorageSettings").GetValue<string>("TenantId"),
    ClientId = config.GetSection("SharePointStorageSettings").GetValue<string>("ClientId"),
    ClientSecret = config.GetSection("SharePointStorageSettings").GetValue<string>("ClientSecret"),
    WorkFolderPath = config.GetSection("SharePointStorageSettings").GetValue<string>("WorkFolderPath")
}));

Azure App Registration configuration

Create an Azure AD app registration:

1. Go to Azure Portal > App registrations
2. Create a new registration
3. Add API permissions: Sites.ReadWrite.All - Microsoft Graph (Manage / API permissions section)
4. Create a client secret

Then, you have all the necessary values to connect your app to SharePoint and perform actions there.

Behaviour

Work folder

When WorkFolderPath is set, every path is relative to that folder of the document library. A path that already starts with the work folder segments (compared case-insensitively) is made relative to it, so MainFolder/WorkFolder/Test/report.csv and report.csv address the same file when WorkFolderPath is MainFolder/WorkFolder/Test. Any other path is used as-is below the work folder. Without WorkFolderPath the paths are relative to the root of the document library.

Paths

Both / and \ separate segments. A segment is rejected with an ArgumentException when it is empty or whitespace, consists only of dots and spaces, contains a control character or a colon (:), or does so after percent-decoding. A segment whose percent-decoded form contains / or \ is rejected as well. The colon is reserved by the Microsoft Graph path syntax.

Root protection

The work folder itself (or the library root when no work folder is set) and the RootDirectoryPath root cannot be deleted, moved, renamed or overwritten. These calls throw an InvalidOperationException, also when the path only consists of the work folder prefix.

Uploads

• Files below 20 MB are uploaded in a single request, larger files with a Graph upload session in 3.2 MB chunks.
• Non-seekable streams are first buffered to a temporary file, which is deleted when the upload finishes or fails.
• Missing parent folders are created on upload and move. When a folder cannot be created, the InvalidOperationException keeps the original error as its inner exception.

Listing and file information

GetDirectoryContents follows the Graph paging links and returns every file and folder once. Folders are reported with Exists = true and IsDirectory = true.

Reading

ReadFile downloads the file into a temporary file that is deleted when the returned stream is disposed. When the download fails, the temporary file is removed right away.

Download links

GetDownloadUrl returns the pre-authenticated download link Microsoft Graph provides for the file (@microsoft.graph.downloadUrl). Graph keeps the link valid for about an hour; the validity argument is ignored. Anyone holding the link can download the file without signing in.

Not supported

Watch is not supported and throws a PlatformNotSupportedException.