Allow importing snapshot from URL + Progress bar (#762)

[snaumov]

Summary of changes
Changes introduced in this pull request:

• Ability to import the snapshot from the remote url
• Download progress indicator

Reference issue to close (if applicable)

Closes #762

Other information and links

[austinabell]

Happy to make a pass after to clean up some of these things, but the one thing that absolutely needs to change is writing to a temporary file just to read and delete it

[austinabell]

btw, conformance test vectors are failing because you committed a previous commit of the repo to this PR

[austinabell]

LGTM great changes, thanks for making those adjustments! One thing about this is that it doesn't add the progress bar to loading a local car file (and those imports can take a long time) but this can be easily added after this PR comes in

[snaumov]

@austinabell right. I thought about this too at some point :) I can rename make_http_reader to make_reader back, and make it accept &str and check if the incoming str is a Url or local path, and depending on that either return FetchProgress that reads from url or from local file. Thoughts?

[austinabell]

@austinabell right. I thought about this too at some point :) I can rename make_http_reader to make_reader back, and make it accept &str and check if the incoming str is a Url or local path, and depending on that either return FetchProgress that reads from url or from local file. Thoughts?

Or you can just wrap the file reader in that progress bar (capacity you can get from the file metadata). Either way should work, it's up to you. My intuition would be that the generics of the solution you suggest would be a little tricky to workaround, but it would be a slightly cleaner solution indeed

[snaumov]

@austinabell right. I thought about this too at some point :) I can rename make_http_reader to make_reader back, and make it accept &str and check if the incoming str is a Url or local path, and depending on that either return FetchProgress that reads from url or from local file. Thoughts?

Or you can just wrap the file reader in that progress bar (capacity you can get from the file metadata). Either way should work, it's up to you. My intuition would be that the generics of the solution you suggest would be a little tricky to workaround, but it would be a slightly cleaner solution indeed

Updated MR, using TryFrom now instead for both File and Url.

[ec2]

Looks great! Thanks as always for the contribution!!!!!!!

[austinabell]

oo very nice, thanks!