Does Uploading an Identical Image Result in Duplicate Assets?

9 replies
Last updated: Jun 10, 2020
Is it correct that if I upload the exact same image, I won't get duplicate assets? For every upload I do of the same image, it returns a result with the exact same
_id
and
url
, and
count(*[_type == "sanity.imageAsset"])
doesn't change.This is the behavior I want, but I would assume it uploaded a new asset for each attempt, and didn't do a compare or something. So just want to confirm this behavior before I rely upon it.
🙂
Apr 8, 2020, 11:08 AM
Yes, it’s correct and you can expect it to be consistent, reliable behaviour. Just confirmed with
user A
:
If we already have an image with the same hash it’s not stored and we’ll return the asset id of the existing one
Apr 8, 2020, 11:36 AM
Thanks
user M
! Thats very cool! 🙂
Apr 8, 2020, 11:42 AM
user M
How does this know it is the same image? Does it look for the
originalFilename
?
Jun 3, 2020, 4:05 PM
It uses a cryptographic hash function (SHA-1) to calculate a hash value on upload - if hash values are the same, the image is considered identical and not stored but instead linked from the existing one.
Jun 3, 2020, 4:35 PM
user M
So does it still replace the image file with the current one being uploaded, or does it just ignore the request altogether and keep using the "old" file if it matches an existing asset?
Jun 3, 2020, 6:12 PM
It will keep using the existing (old) file, as it’s identical, so no need to replace 🙂
Jun 3, 2020, 6:17 PM
Gotcha. So does that mean there's no way to replace the file for an existing asset? It has to be deleted and then another one created?
Jun 3, 2020, 6:23 PM
And if that's the case, can a custom ID for the asset be specified on upload so that it can match the old asset that was deleted to keep references on documents intact?
Jun 3, 2020, 6:27 PM
user M
Was still wondering if you had an answer here. Is there no way to make an existing asset ID use a new uploaded file?
Jun 10, 2020, 4:14 PM

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