Improve File Explorer performance

[aliabid94]

Previously we would load the entire directory structure at the root directory and send that to the frontend when the fileexplorer component loaded. This could be prohibitively expensive for higher level directories to crawl through all the nested subdirectories, taking on the order of minutes to load. Now the API call only returns the content of a single level, and when opening a folder, we load the content of that folder. See gif below, showing network requests as well.

Also fixed root_dir update issue.
Fixes: #7149

Demo code to repro fix (change root_dir values ofc):

import gradio as gr

with gr.Blocks() as app:
    file_explorer = gr.FileExplorer(
        value=["/Users/aliabid/Desktop/gradio/demo/hello_blocks/run.py", "/Users/aliabid/Desktop/gradio/demo/change_vs_input/run.py"],
        root_dir="/Users/aliabid/Desktop/gradio/demo/", 
        file_count="multiple",
        height=200
    )
    select_btn = gr.Button("Select")
    selected_file = gr.Textbox(label="Selected")

    select_btn.click(lambda x:x, inputs=file_explorer, outputs=selected_file)

    change_root_btn = gr.Button("Change Root")
    change_root_btn.click(lambda: gr.FileExplorer(root_dir="/Users/aliabid/Desktop/gradio/"), outputs=file_explorer)


if __name__ == "__main__":
    app.launch()

[gradio-pr-bot]

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/712a7fd4f92f71521d324e0eb6fd0db8824638b8/gradio-4.18.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@712a7fd4f92f71521d324e0eb6fd0db8824638b8#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/fileexplorer	patch
gradio	patch

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With the following changelog entry.

Improve File Explorer performance

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[abidlabs]

Nice! There are some bugs related to the FileExplorer maybe it would make sense to include fixes in this PR:

• Updating the root parameter in the fileexplorer component does not change the front-end display of the file directory. #7149
• The interactive parameter in gr.FileExplorer has no effect. It should either be correctly documented or the feature should be added #6627

(Edit: it looks like @freddyaboulton has already addressed the first one.)

[aliabid94]

ready for review

[abidlabs]

Great PR @aliabid94! Everything looks good to me, just left a few nits on the code above. I also added the windows-tests label to test the logic on windows paths.

On the UI side, I preferred having the checkboxes next to everything, even if they weren't clickable. Now, you have this empty space, which looks odd imo:

[abidlabs]

Can we properly document interactive parameter below and fix #6627?

[pngwn]

Yeah I liked the disabled checkboxes, they make the alignment tidier and hint more clearly that selecting the entire folder is explicitly not allowed on this app.

[aliabid94]

I think it's hard to tell the checkboxes are disabled when all of them are disabled, e.g.

but don't feel strongly, will revert

[shimizust]

Thanks so much for the fix @aliabid94 ! I was just running into this issue