Add MultipleFileField to handle and clean multiple files

[will-moore]

Fixes #464

This adds the update suggested at the last link below to conform to the security release below:

#410
https://www.djangoproject.com/weblog/2023/may/03/security-releases/
django/django@eed53d0

To test:

• Build should be green (using latest Django 3.2.19)
• Multiple file upload should still be working
• When uploading multiple files to file annotations, ALL files should be validated (e.g. to prevent empty files to be uploaded) instead of only the last file being validated.

[sbesson]

See #466 which exposes another underlying issue related to the validation of the files uploaded via the FilesAnnotationForm (and allows to create a scenario to test this PR).
While testing the two PRs together, it should be noted that this PR requires Django 3.2.19 as the API for auto-setting multiple: true when allow_multiple_selected is set to True was introduced in django/django@eed53d0. In other terms, with this PR and Django 3.2.18, the multiple selection is disabled. Django should be set to 3.2.19 as the minimum version via setup.py

[will-moore]

Excluding to allow testing of #466 ahead of this...

EDIT: remove flag

[will-moore]

Testing on merge-ci:

• upload 1 or more non-empty files works -> Creates FileAnnoations
• upload multiple Files which includes an empty file first, last or middle (if 3) fails silently - (form is invalid).

[sbesson]

Having looked at how the code is organized, all custom widget/fields are declared omeroweb.webclient.custom_forms and imported here to construct the webclient forms.

[sbesson]

Might be worth adding a comment and/or a reference to the documentation explaining why we are subclassing these Django classes.

[dominikl]

Functional test looks good 👍 If there's one empty file included in a multi file upload then none of the files get uploaded/attached, not even the non-empty ones. Is that expected?

[sbesson]

@dominikl that's the expectation as per the new field class. If any of the files fails validation, then the entire multi-file upload is cancelled.

The other place that uses a FileField is the photo upload in My account and this shows an informative message if an empty file is uploaded

@will-moore is there a way to propagate the error message to the user in the files annotation UI?

[will-moore]

@dominikl - yes the whole form is considered invalid if any file is invalid.
We don't have any handling of invalid forms here (same as other annotations). Could add that, but probably not essential in this PR?

[dominikl]

👍 I don't think either that it has to go into this PR, better get it out as soon as possible.

[jburel]

omeroweb/webclient/custom_forms.py:385:89: E501 line too long (94 > 88 characters)

[sbesson]

The last commit follows the new recommendation from Django documentation with a new custom class and restores compatibility with Django 3.2.19.

The last commit will need to be retested functionally but from a code review perspective, no objection to moving forward with the current suggestion.

[knabar]

Code looks good to me

[will-moore]

Running https://merge-ci.openmicroscopy.org/jenkins/job/OMERO-python-superbuild-push/1446/ to include latest changes...
Built with https://merge-ci.openmicroscopy.org/jenkins/job/OMERO-python-superbuild-build/1402/
and deployed with https://merge-ci.openmicroscopy.org/jenkins/job/OMERO-web/1659/

[pwalczysko]

Tested on merge-ci, user-3. From jenkins, this PR is included on https://merge-ci.openmicroscopy.org/jenkins/job/OMERO-python-superbuild-push/1447/console

Merged PRs:
  - PR 425 will-moore 'Add hook for mapr or other app to extend webclient main page'
  - PR 456 kkoz 'Allow Tiled Image Histograms'
  - PR 462 will-moore 'OME.formatDate handles null input'
  - PR 465 will-moore 'Add MultipleFileField to handle and clean multiple files'
  - PR 467 knabar 'Add change log for 5.20.0'
  - PR 469 will-moore 'Temp setGroupForSession to edit current group'

The test:

1. Create an empty file using touch on the cli and try to attach it in the Attachments harmonica of webclient.
2. Try to attach the empty file also with other, non-empty files
3. Try to upload the empty file as a photo in user settings of web UI

The tests went as expected, the file upload was rejected in all cases where the empty file was selected, either with non-empty files or alone.
The upload of photos and files (non-empty ones) still works.

LGTM