Fixes URL resolution on Windows

[abidlabs]

Previously, we would run utils.abspath() on a path before we knew whether it was a URL or a string path. On Windows, this would lead to an error if the path provided was a URL. This fixes that and makes the code a little clearer to read.

Test code (run this on a Windows machine):

import gradio as gr
 
with gr.Blocks() as demo:
    gr.Gallery(["https://images.unsplash.com/photo-1507003211169-0a1dd7228f2d?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=387&q=80"])

demo.launch()

[gradio-pr-bot]

All the demos for this PR have been deployed at https://huggingface.co/spaces/gradio-pr-deploys/pr-3108-all-demos

[freddyaboulton]

@abidlabs Is that test code supposed to fail on Windows with the latest gradio version? The gallery shows up correctly for me on windows.

This is what I did. Lemme know if I messed something up cause I'm not used to windows development.

Install gradio from Pypi in a virtualenv on Windows

Run the test case

Gallery shows up for me 🤔

The proposed change looks good to me though and the deployed demos are working fine - just want to make sure I'm testing properly

[abidlabs]

Very strange, it isn't working for me on Windows @freddyaboulton. Can you try this simpler repro:

from pathlib import Path

url = "https://images.unsplash.com/photo-1507003211169-0a1dd7228f2d?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=387&q=80"

Path(url).resolve()

[freddyaboulton]

Yea calling .resolve() on a url returns a faulty path on windows but also ubuntu!

Windows

Ubuntu

It's strange it's broken for you since I just looked at the file route code again and we call validate_url on path not abspath so it should correctly detect it's a url no?

        @app.head("/file={path:path}", dependencies=[Depends(login_check)])
        @app.get("/file={path:path}", dependencies=[Depends(login_check)])
        async def file(path: str, request: fastapi.Request):
            abs_path = str(utils.abspath(path))
            blocks = app.get_blocks()
            if utils.validate_url(path):
                return RedirectResponse(url=path, status_code=status.HTTP_302_FOUND)

I wonder if something else is at play 🤔

[abidlabs]

Ahh it looks like it's a Python 3.9 vs. 3.10 thing, specifically on Windows 🤯

When I run the same code I asked you to run on Python 3.9, I get this error raised:

Apparently, pathlib fixed it at some point in Python 3.10: python/cpython@4696f12

[abidlabs]

You're right, we do call validate_url, but the problem is that we call it after we call utils.abspath(path).

This PR changes the order so that we only call abspath after we've confirmed that it is not a URL. Let me know if that makes sense

[freddyaboulton]

Thanks for the fix + debugging with me @abidlabs !

[abidlabs]

Thank you @freddyaboulton!