Unable to delete an attachment with special characters in the file name

[IvanTheBearable]

Category

• Bug

Describe the bug

Attempting to delete a SharePoint list attachment with special characters in the file name produces an exception.

Steps to reproduce

Given:

• spListItem = a PnP.Core.Model.SharePoint.ListItem
• The list item has an attachment with a name like FW You're all booked to fly XXX on 27 Feb 2020, reference XXXX.eml (note the ' in "You're")

await spListItem.EnsurePropertiesAsync(p => p.AttachmentFiles);
IAttachment[] oldAttachmentsArray = spListItem.AttachmentFiles.AsRequested().ToArray();
for (int i=oldAttachmentsArray.Count()-1; i>=0; i--)
{
    try
    {
        await oldAttachmentsArray[i].DeleteAsync();
    } catch (Exception ex)
    {
        LogException(ex, "Failed to delete existing attachment '{AttachmentName}'.", new object[1] { oldAttachmentsArray[i].FileName });
    }
}

The DeleteAsync above produces a "SharePoint Rest service exception" with an error code of "Microsoft.SharePoint.Client.InvalidClientQueryException" and the message "The expression "web/lists/getbyid(guid'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx')/items(244)/attachmentfiles/getbyfilename('FW You're all booked to fly XXX on 27 Feb 2020, reference XXXX.eml')" is not valid."

Expected behavior

The attachment should be deleted without an exception.

Environment details (development & target environment)

• SDK version: [PnP.Core 1.6.0]
• OS: [Windows 10]
• SDK used in: [Azure Function App]
• Framework: [.NET Core v3.1]
• Browser(s): [N/A]
• Tooling: [Visual Studio 2022]
• Additional details: The more context you can provide, the easier it is (and therefore quicker) to help.

Additional context

I did some searching of the repo in hopes of spotting an easy fix, or at least saving someone a bit of time. I'm guessing the problem starts in src/sdk/PnP.Core/Model/SharePoint/Core/Internal/Attachment.cs:

[SharePointType("SP.Attachment", Uri = "_api/web/lists/getbyid(guid'{List.Id}')/items({Parent.Id})/attachmentfiles/getbyfilename('{Id}')", LinqGet = "_api/web/lists/getbyid(guid'{List.Id}')/items({Parent.Id})/attachmentfiles")]
    internal sealed class Attachment : BaseDataModel<IAttachment>, IAttachment

There needs to be some mechanism to encode that {Id}. AttachmentCollection.FileUpload (which works) encodes the file name like this:

var encodedServerFileName = WebUtility.UrlEncode(newFile.FileName.Replace("'", "''")).Replace("+", "%20");
string fileCreateRequest = $"_api/web/lists/getbyid(guid'{{List.Id}}')/items({{Parent.Id}})/attachmentfiles/addusingpath(decodedUrl='{encodedServerFileName}')";

[jansenbe]

Thanks for using PnP Core SDK and reporting this issue @IvanTheBearable . We'll have a look and try to fix this asap.

[jansenbe]

@IvanTheBearable : a fix has been made (see a77c05b for the details) including test case. The fix will appear in the next nightly build (1.6.31 or higher). Will close this issue now, but don't hesitate to reopen if for some reason the fix is not working for you.