Some tasks don't have to run on every tenant. The task to calculate the
TSV is only done for records which were present before we added the TSV
column, and that isn't going to happen in any tenants because we added
the TSV column before adding the tenants table. Similarly, the migration
needed for existing polls isn't necessary because there weren't any
tenants before we allowed to set the starting/ending time to polls.
We aren't adding any tests for these tasks because tests for rake tasks
are slow and tests creating tenants are also slow, making the
combination of the two even slower, particularly if we add tests for
every single task we're changing. We're adding tests for the
`.run_on_each` method instead.
This fixes a few issues we've had for years.
First, when attaching an image and then sending a form with validation
errors, the image preview would not be rendered when the form was
displayed once again. Now it's rendered as expected.
Second, when attaching an image, removing it, and attaching a new
one, browsers were displaying the image preview of the first one. That's
because Paperclip generated the same URL from both files (as they both
had the same hash data and prefix). Browsers usually cache images and
render the cached image when getting the same URL.
Since now we're storing each image in a different Blob, the images have
different URLs and so the preview of the second one is correctly
displayed.
Finally, when users downloaded a document, they were getting files with
a very long hexadecimal hash as filename. Now they get the original
filename.
Our previous system to delete cached attachments didn't work for
documents because the `custom_hash_data` is different for files created
from a file and files created from cached attachments.
When creating a document attachment, the name of the file is taken into
account to calculate the hash. Let's say the original file name is
"logo.pdf", and the generated hash is "123456". The cached attachment
will be "123456.pdf", so the generated hash using the cached attachment
will be something different, like "28af3". So the file that will be
removed will be "28af3.pdf", and not "123456.pdf", which will still be
present.
Furthermore, there are times where users choose a file and then they
close the browser or go to a different page. In those cases, we weren't
deleting the cached attachments either.
So we're adding a rake task to delete these files once a day. This way
we can simplify the logic we were using to destroy cached attachments.
Note there's related a bug in documents: when editing a record (for
example, a proposal), if the title of the document changes, its hash
changes, and so it will be impossible to generate a link to that
document. Changing the way this hash is generated is not an option
because it would break links to existing files. We'll try to fix it when
moving to Active Storage.
