Proposal: Introduce file:// prefix for explicit file loading in multipart data

[h6ah4i]

Hi, I noticed that the current implementation of multipart/form-data attempts to read a file if the specified form value is a string.

https://github.com/k1LoW/runn/blob/10bfec2fc03d0bd49d9c0bda14f08fffcdbca39e/http.go#L256:L271

This implementation caused some errors for me, and I believe the behavior can be improved by introducing a file:// prefix.

1. runn does not raise an error if the specified file does not exist or if the provided path string is incorrect.
2. absolute file paths are not accepted.

Introducing a file:// prefix could help address these issues and make the behavior more explicit and reliable.

[k1LoW]

@h6ah4i Thank you for your proposal!

Indeed, it is better to introduce file:// prefix to check files strictly.

However, I would like to keep the current behavior without prefix at the side.

This is partly for backward compatibility, but also because I want to match the behavior of other path resolution.

So, how about making it so that files are only checked strictly when a file:// prefix is added?

Then we can introduce file:// prefix in other path resolution implementations in the future.

[h6ah4i]

@k1LoW Preserving backward compatibility is an important concern as well. I agree with the direction you're taking! 👍

[k1LoW]

Released as v0.122.0 👍