Hey everyone!
It seems this has been open for a while, and as per George's last statement
I'm assuming a pull request is still welcome? If so I've been working on
this the past few days 📅
(As a small side note, there does already seem to be a PR open but I
provided my thoughts on that here.
<https://github.com/rails/rails/pull/34842#issuecomment-465752227> I
believe Igor responded in support as well)
I had a question about the `:presence` validator.
*The Issue*
I assume we want validates :avatar, presence: true to validate that a ::Blob
is actually attached. However activestorage attachments don't work like
standard model fields: all changes to attachments and blobs are processed
*after* the record itself is saved (for good reason).
This unfortunately means any validations for :presence run at a time when
the attachment changes (stored in @attachment_changes) have not yet been
applied.
*Potential Workaround + Another Issue*
One workaround would be to have the validator look at what changes are
queued up to be applied and decide if an attachment *is expected *to be
present or blank after the record is saved.
This would work well, but the :detach, :purge, and :purge_later throw a
wrench in this logic. They *immediately* delete the attachments (or at
least queue them up for deletion) before setting the attachment to nil. So
when the record is finally validated later it might fail :presence
validations but it's too late because the association ::Attachment/::Blob
records are already destroyed.
All this makes what should be a "simple" presence check much more complex
because of the nature of how attachments are stored. Unless I'm missing an
obvious solution, which I might be!
My personal thought: If we want attachments to feel like true model fields
then the validation should be performed first and the deletion should be
blocked/avoided if the validation fails. (And of course, users can always
bypass validations as needed).
Would love to hear your thoughts. In the mean time, I'm happy to implement
the size and content type validations.
As always, thanks for everyone's time here. As an avid Rails user,
everyone's contribution is much appreciated.
On Tuesday, November 27, 2018 at 3:51:01 PM UTC-5, ifom...@gmail.com wrote:
>
> Hi George,
>
> thanks for your positive feedback! I'll see how far I can get :)
>
> Best regards,
> Ivan
>
> On Tuesday, November 27, 2018 at 4:21:28 PM UTC+1, George Claghorn wrote:
>>
>> Validations are planned for Rails 6. Here’s a rough sketch of the API I
>> have in mind:
>>
>> validates_attached :logo, presence: true, byte_size: { less_than:
>> 10.megabytes, message: "must be smaller than 10 MB" }, content_type:
>> /\Aimage\//
>>
>> I intended to implement this myself, and laid the groundwork for it in
>> the commit Rob mentioned, but Igor Kasyanchuk asked if he could fold
>> active_storage_validations into Active Storage proper:
>> https://github.com/rails/rails/issues/33741. Since September, I’ve been
>> giving him time to open a PR.
>>
>> Please feel free to investigate yourself. Rails 6 is slated for early
>> next year, so if nobody else opens a PR before then, I’ll come back to
>> validations after the holidays.
>>
>> On Mon, Nov 26, 2018 at 4:13 PM <ifom...@gmail.com> wrote:
>>
>>> Hmmm...
>>>
>>> Hi Rob,
>>>
>>> thanks for your reply!
>>>
>>> I see how one can validate presence of a blob from this change, but I'm
>>> not sure what could be the syntax for validating content type, filename, or
>>> file size after this change. Could you please elaborate on that? The commit
>>> you referred to provides neither documentation nor tests for these cases.
>>>
>>> Best regards,
>>> Ivan
>>>
>>> On Monday, November 26, 2018 at 9:53:12 PM UTC+1, Rob Zolkos wrote:
>>>>
>>>> Rails 6 will have validations for AS
>>>> https://github.com/rails/rails/commit/e8682c5bf051517b0b265e446aa1a7eccfd47bf7#diff-c76fb6202b7f95a08fe12f40c4999ac9R11
>>>>
>>>> On Mon, Nov 26, 2018 at 3:36 PM <ifom...@gmail.com> wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> I think this is one of the essential features that are missing in
>>>>> Active Storage. Thus I'm pretty sure it's gonna be implemented pretty
>>>>> soon
>>>>> one way or another, and I wonder what is the maintainers' plan for it, if
>>>>> there is any.
>>>>>
>>>>> I know about active_storage_validations gem, but its functionality is
>>>>> quite limited and the gem itself is pretty self-inconsistent and raw
>>>>> (though it's the best publicly available gem I could find, kudos to the
>>>>> maintainers!)
>>>>>
>>>>> One approach I'm thinking of would be to adapt paperclip's validators
>>>>> for Active Storage (thanks to MIT license), and I think I could do it,
>>>>> but
>>>>> I'm not sure if it's gonna be accepted. One doesn't have to invent the
>>>>> wheel, but I'd like to hear an expert opinion.
>>>>>
>>>>> Thank you,
>>>>>
>>>>> Ivan
>>>>>
>>>>> --
>>>>> You received this message because you are subscribed to the Google
>>>>> Groups "Ruby on Rails: Core" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>>> an email to rubyonrails-co...@googlegroups.com.
>>>>> To post to this group, send email to rubyonra...@googlegroups.com.
>>>>> Visit this group at https://groups.google.com/group/rubyonrails-core.
>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>
>>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "Ruby on Rails: Core" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to rubyonrails-co...@googlegroups.com.
>>> To post to this group, send email to rubyonra...@googlegroups.com.
>>> Visit this group at https://groups.google.com/group/rubyonrails-core.
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
--
You received this message because you are subscribed to the Google Groups "Ruby
on Rails: Core" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rubyonrails-core+unsubscr...@googlegroups.com.
To post to this group, send email to rubyonrails-core@googlegroups.com.
Visit this group at https://groups.google.com/group/rubyonrails-core.
For more options, visit https://groups.google.com/d/optout.
