File uploaded resources of type application/zip not working

[sebplorenz]

1. Create a new ressource
2. when creating the resource on the "Representation" page upload a zip file and set file type to application/zip
3. Finish creating the resource
4. Download resource from another connector
   -> Opening the downloaded zip file fails. It is not recognized as a zip file

[omarsilva1]

I have tested the functionality to upload zip files with a python script that puts the file in the DSC. It worked fine.
I believe this is a problem in the DSC-UI @SebastianOpriel, probably the encoding on file upload.

[omarsilva1]

There might be a problem with how the DSC encodes the binary files. I have compared the binaries of an original zip file and the artifact data from the DSC and they are different.

[omarsilva1]

Persisting a ZIP file with the DSC UI produces a corrupt ZIP file. The file that is returned on request is bigger than the original file, which means they can't be possibly equal. I believe 1) some zip file headers are maybe persisted as well instead of only the file or 2) the file is persisted in a different encoding.
This leads to the ZIP file being corrupt when dowloading it.

I've been experimenting with different results and managed to write a method where the content length doesnt change on output, but didnt reach a solution where the zip file is not corrupt.

There is also the possibility that the frontend is encoding the files before sending it to the DSC.

A possible consideration could be to create a separate endpoint for zip file handling. Part of the problem is that the DSC handles all input files the same (all use the same REST endpoint). It might make it easier to handle ZIP files differently than normal files. Storing the whole file content in one database entry also doesnt seem to be the best practice. I'll keep looking for alternatives.

[tmberthold]

It could be due to the UI, there the method readAsBinaryString() is used [1], which doesn't seem to work with binary data [2], the same happens in my tests for example also with a PNG file.

[1] https://github.com/International-Data-Spaces-Association/DataspaceConnectorUI/blob/a723eb0109283a219f5b273d25c30a1ee7cf4793/src/pages/dataoffering/resources/addresource/representation/ResourceRepresentationPage.js#L129
[2] https://stackoverflow.com/a/17512132