Adds a gr.DownloadButton component

[abidlabs]

After #7528, I wanted to go through the process of creating a new component with the new approach of working with the files, i.e. setting the URLs in the backend using serve_static_file() to mimic the work that a custom component developer would have to do.

I decided to add the long-requested gr.DownloadButton component (fixes: #5426)

[gradio-pr-bot]

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/3a94fad9a48b48e38312c9aba9b46018079d392e/gradio-4.19.2-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@3a94fad9a48b48e38312c9aba9b46018079d392e#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/app	minor
@gradio/downloadbutton	minor
@gradio/uploadbutton	minor
gradio	minor

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With the following changelog entry.

Adds a gr.DownloadButton component

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[abidlabs]

Will probably need to be rebased once #7528 is in

[dawoodkhan82]

Missing param for icon

[abidlabs]

Added here as well as in gr.UploadButton. Fixed the param description in gr.Button

[dawoodkhan82]

from pathlib import Path
import gradio as gr

def upload_file(filepath):
    name = Path(filepath).name
    return [gr.UploadButton(visible=False), gr.DownloadButton(label=f"Download {name}", value=filepath, visible=True, icon="gradio-logo.png")]

def download_file():
    return [gr.UploadButton(visible=True), gr.DownloadButton(visible=False)]

with gr.Blocks() as demo:
    gr.Markdown("First upload a file and and then you'll be able download it (but only once!)")
    with gr.Row():
        u = gr.UploadButton("Upload a file", file_count="single")
        d = gr.DownloadButton("Download a file", visible=False, icon="gradio-logo.png")

    u.upload(upload_file, u, [u, d])
    d.click(download_file, None, [u, d])


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

Tested with this code. And seems like updating the icon for the DownloadButton doesn't work. Gives error: AttributeError: 'DownloadButton' object has no attribute 'proxy_url'.

[abidlabs]

Sooo I'm looking into this issue @dawoodkhan82 but it actually looks like a separate bug that resulted from #7528

You'll see the same error if you replace gr.DownloadButton with gr.UploadButton, e.g. in this short example:

import gradio as gr

with gr.Blocks() as demo:
    u = gr.UploadButton()
    d = gr.DownloadButton()
    
    demo.load(lambda : gr.UploadButton(icon="cheetah.jpg"), None, u)
#     demo.load(lambda : gr.DownloadButton(icon="cheetah.jpg"), None, d)
    
demo.launch()

I'm working on it, but it might be tricky and I think can potentially be a separate PR for better visibility. How does the rest of this PR look?

[abidlabs]

Nvm the fix was easier than I thought -- I've merged it into this PR. Your example works for me now @dawoodkhan82

[dawoodkhan82]

LGTM, tested updating the icon as well. Thanks for including that fix @abidlabs

[abidlabs]

Thanks @dawoodkhan82 for testing thoroughly!