Make sure the hash key changes after cropping an image. #142
+103
−58
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Problem:
Even though an image gets changed via cropping it does maintain the same url. Which leads cache/proxy and browsers to potentially not download the new version of the cropped image.
Example:
After uploading a new image the url to the thumb scale is http://nohost/plone/testimage/@@images/image-128-fba13e5e2040bf30b80360aeaf2bb42f.png
After cropping the url is still http://nohost/plone/testimage/@@images/image-128-fba13e5e2040bf30b80360aeaf2bb42f.png
Explenation:
One part of the hash key in the default storage (IImageScaleStorage) is the _p_mtime (modification time if an object got changed during a transaction). This is basically the only parameter that we can change, without rewriting the storage, image factory and utilities.
Solution:
Mark the ImageBlobField as changed if a scale gets cropped.
This way we force the storage to generate a new has key for (all) the scales.