A file derivate is the derivate version of a file that is attached to some content document, serving a special purpose.
For example: If an image of size 1600x1200 pixels is attached to some content document then OpenWGA automatically creates scaled down "thumbnail" versions of this image and stores them as a file derivates which are connected to this image. An OpenWGA design which displays this image but has only space to display images of up to 800 pixels width can choose to display a derivate of appropriate size instead of the original file attachment to save bandwidth and download time.
This addresses a common problem in content management where authors frequently upload images that are way too large to use one the web. Mostly they also do not have the necessary know how to recognize the problem or to fix it by manually downscaling those images. File derivates are a way to automatically create "web-friendly" versions of these large files that also get automatically used.
However, the usages of file derivates are not limited to thumbnails for images. They can store any binary data that is related to some attached file and which is used somewhere in web content management. Some examples:
- An image showing the first page of a PDF file
- Versions of a video file in other video codecs
- An icon describing the data type of any attachment
Table of contents:
- How derivates are created
- Querying file derivates
- Predefining derivate queries for ranges
- File derivates and online scaling
- File derivates and "Client Hints"
- Derivate creation in a cluster