Using Plug.Upload in your changesets

Hello Everyone,

I am working on a small Phoenix/Ecto project. One of the features of this application is going to be that people can upload images. Right now I am using arc (and arc_ecto) to make the uploading procedure easier.

However, I want to store the dimensions and other metadata of the image that has been saved in the database as well, to make it nicer to display it in a gallery later.
I know there are multiple packages on Hex.pm that allow you to do this, such as fastimage, but these libraries work with a pathname to the file.

  • Exactly how can I make a library that takes a pathname consume a %Plug.Upload{} struct? I believe it contains a :path field, but I have been unable to build a %Plug.Upload{} manually to try it out. There is documentation of Plug.Upload, but it is rather short and uninformative (does the :path field include or exclude the actual filename itself, or only its folder? How do you make a %Plug.Upload{} struct manually?).
  • Related to this: How can you test file-uploading code? I am interested in doing both a feature-test, testing only if when you have a file if the dimensions are read and added to the changeset properly, and a full-stack test where a file is selected from the browser and it is then attempted to be uploaded.

Any help is greatly appreciated!