ListItemAttachments - Inconsistent file handling

[rikkerorbak]

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Category

[ ] Enhancement

[x?] Bug

[x] Question

Version

Please specify what version of the library you are using: [ 3.15.0 ]

Expected / Desired Behavior / Question

I am experiencing inconsistent uploading and deletion of files. Often, perhaps only when creating a new list item, a few files will often not be uploaded. Checking the dev tools, the addFile-method fails with a 404 or 409.
I don't know if my code is the issue (this is my first webpart, and I am generally not a terribly experienced developer), but I can't figure out what the issue is. Things seem to work fine on an existing item.
Another observation is that when attaching files to an existing list item, I see the loading animation running, but I don't see that when attaching to a new list item; not sure if that says anything.

Regarding deletion, I sometimes experience that a file, often the last after having added a few, does not get deleted but instead remains in the container.

Thank you so much! I've spent days troubleshooting this and really hope I can get help figuring it out!

/Rikke

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[Tanddant]

I did a bit of digging on this one - it seems to be related to a concurrency issue.

I can't find any docs confirming it, but several others confirm it:

• https://sharepoint.stackexchange.com/questions/254588/multiple-attachment-upload-causing-409-conflict-error-spfx-pnp
• Multiple attachment upload causing 409 conflict error. pnpjs#428
• https://anomepani.github.io/posts/upload-multiple-attachments-in-sharepoint-list-using-rest-api-on-sharepoint-online/

When uploading attachments Microsoft doesn't like us uploading multiple files at the same time

Quick code the validate:

import { sp, IAttachmentAddResult } from "@pnp/sp/presets/all";

(async () => {

  const file = sp.web.lists.getByTitle("Generic list").items.getById(3).attachmentFiles;
  const promises: Promise<IAttachmentAddResult>[] = [];
  for (let x = 1; x <= 100; x++) {
    promises.push(file.add(`${x}.txt`, "This is an attachemnt"));
  }

  const parsed: IAttachmentAddResult[] = await Promise.all(promises);

  for (let p of parsed) {
    console.log(p)
  }


})().catch(console.log)

Bingo!

I guess the solution would be to change this

to something along the lines of

public async uploadAttachments(itemId: number): Promise<void> {
  if (this.state.filesToUpload) {
    for (const file of this.state.filesToUpload) {
      await this._spservice.addAttachment(
        this.props.listId,
        itemId,
        file.name,
        file,
        this.props.webUrl);
    }
  }
  return new Promise<void>((resolve, reject) => {
    this.setState({
      filesToUpload: [],
      itemId: itemId
    }, () => this.loadAttachments().then(resolve));
  });
}

@joelfmrodrigues will you look this over and I'll be happy to submit a PR resolving the issue - it will slow down the experience, but will resolve the issue when adding multiple files