Gallery doesn't download Nextcloud image thumbnails

[direc85]

REPRODUCIBILITY: always
BUILD ID = OS VERSION: 5.0.0.72
HARDWARE: any
DID IT WORK CORRECTLY ON THE PREVIOUS PUBLIC RELEASE: no

DESCRIPTION:
Thumbnails are not downloaded when a Nextcloud album is opened in Gallery. They're available only after the image is opened, which downloads the full-size image.

PRECONDITIONS:
Nextcloud account with photos added to phone.

STEPS TO REPRODUCE:
Open Gallery, go to Nextcloud album

EXPECTED RESULT:
Thumbnails for new images are fetched

ACTUAL RESULT:
Thumbnails are not loaded until the picture is opened

ADDITIONAL INFORMATION:
A simple way to reproduce this is taking a photo and sharing it to Nextcloud.

[poetaster]

Not sure if this was noted:

There is the possibility to request the existing preview.

GET: https://cloud.yourserver.org/core/preview?fileId=11750924&x=250&y=250

Send username and password in the header for authentication.
If there is no preview image, a status 404 is returned.

retrieved from https://help.nextcloud.com/t/retrieving-preview-thumbnail-wtih-webdav/95243/10 (via @nephros)

[nephros]

Also:

Thumbnail downloading is not supported at the moment. This is not an error,

from:

https://github.com/sailfishos/sailfish-account-nextcloud/blob/85ef4d351129bf84aad793855f4c3ba66778d148/common/synccacheimages.cpp#L245

[nephros]

And: would this be the correct approach to retrieve them?

sailfishos/sailfish-account-nextcloud@main...nephros:sailfish-account-nextcloud:set-tb-dev

(nevermind the git commit history, just view the diff ;) )

[poetaster]

Certainly looks like the suggested URL, BUT for the a=0 ... what's that? Also, I'm not sure where the auth header is set in this context? something like:

    request.setRawHeader("Authorization", "Bearer " + m_token.toUtf8());

EDIT: presumably, the Auth header is sent before this?

[Karry]

Hi @nephros . When I saw your patch, I wanted to wrote you that you should solve request timeouts, queue of the downloading to avoid server overload... But then I dig deeper and found that it is solved in ImageDownloader already... I compile your branch and install packages on my phone and... It fails to fetch thumbnails with the error:

[W] unknown:94 - file:///usr/lib64/qt5/qml/com/jolla/gallery/nextcloud/NextcloudPhotoListPage.qml:94:13: 
QML NextcloudImageDownloader: 
NextcloudImageDownloader failed to load image:Image download error: Protocol "" is unknown

Anyway, it looks promising. Should I dig deeper to the error, or you know where is the problem?

Few points for further improvements (it seems to me that it is not handled):

• download folder preview (random image from the folder? or there is some Nexcloud specific api?)
• retries on network failure
• listen on network status, when device switched from offline state to online, retry thumbnail fetching

[nephros]

@Karry if you have the time to debug that would be great. It's been a while since I wrote this! :)

About the other thumbnails, yes they can be done once the principal method works well, and likely in the same general way.