### Use cases:

* Make uploading and linking files from an empty status (FEATURE <mention class="mention" data-id="43576" data-type="work_package" data-text="#43576">#43576</mention>).
* Create a link between a work package and an existing file in Nextcloud (FEATURE Begin of the insertion<mention class="mention" data-id="43657" data-type="work_package" data-text="#43657">#43657</mention>).
* Chose a file from Nextcloud via a _file picker (FEATURE <mention class="mention" data-id="43654" data-type="work_package" data-text="#43654">#43654</mention>)_
* Create a _file link_ between the work package and the fileEnd of the insertion Begin of the deletion #TBC).End of the deletion
* Upload a file from within a work package in OpenProject (FEATURE Begin of the insertion<mention class="mention" data-id="43656" data-type="work_package" data-text="#43656">#43656</mention>).End of the insertion Begin of the deletion #TBC).End of the deletion
* Chose a location in Nextcloud via a _location Begin of the insertionpicker (FEATURE_ <mention class="mention" data-id="43655" data-type="work_package" data-text="#43655">#43655</mention>_)_End of the insertion Begin of the deletion picker_End of the deletion
* Save the file in Nextcloud
* Create a _file link_ between the work package Begin of the insertionand the fileEnd of the insertion
* Delete _file links_ from a work package Begin of the insertionwithoutEnd of the insertion Begin of the deletion (withoutEnd of the deletion deleting Begin of the insertionthe filesEnd of the insertion Begin of the deletion itEnd of the deletion in Begin of the insertionNextcloud (related to feature #TDC).End of the insertion Begin of the deletion Nextcloud).End of the deletion
* Allow users to drag and drop files in both attachments and Nextcloud (FEATURE <mention class="mention" data-id="43577" data-type="work_package" data-text="#43577">#43577</mention>).
* Make the previous use cases available through work package copy and creation (FEATURE <mention class="mention" data-id="43578" data-type="work_package" data-text="#43578">#43578</mention> and <mention class="mention" data-id="41524" data-type="work_package" data-text="#41524">#41524</mention>).

### Generic visuals

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/36987/content"><img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/36988/content"><img class="op-uc-image op-uc-image_inline" Begin of the insertionsrc="/api/v3/attachments/36989/content"><img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/37083/content">End of the insertion Begin of the deletion src="/api/v3/attachments/36989/content">End of the deletion

Begin of the insertion###

End of the insertion ### Implementation chunks:

* File picker for selecting link targets (files and directories). Queries Nextcloud with the user&#39;s access token (probably via WebDAV). Tunneled through OpenProject backend.
* Location picker for upload targets (a target is always a directory). Queries Nextcloud with the user&#39;s access token (probably via WebDAV). Tunneled through OpenProject backend.
* If possible, direct upload of files to Nextcloud without tunneling through OpenProject server. This requires some sort of one-time upload tokens, which can get exposed to the OpenProject frontend. Fallback could be tunneling all uploaded files through OpenProject.
* Remove file links from OpenProject when files get deleted in Nextcloud (either some sort of callback triggered by Nextcloud or through polling when user opens the _Files_ tab).

### Implementation decisions:

* The file name we present in OpenProject is the name of the file that the file&#39;s owner sees. Apparently in Nextcloud a file can have multiple names and paths every time a file gets shared. To have a &quot;canonical&quot; name for all OpenProject users we will always show the file name that the file&#39;s owner sees.
* OpenProject updates the &quot;cached&quot; file name in OpenProject when a user open the _Files_ tab.

### Out of scope:

* Syncing of access rights to the files in Nextcloud according to the roles and privileges of members in a OpenProject project. That will get partly tackled later with shared project folders (<mention class="mention" data-id="41400" data-type="work_package" data-text="#41400">#41400</mention>)
* Linking between a OpenProject project (instead of work packages) and files in Nextcloud. That is feasible and intended to built in a later stage. The outlook could be a possible replacement for the current &quot;Documents&quot; module.