Lite: Set the home dir path per appId at each runtime

[whitphx]

Description

Fix the bug introduced in the SharedWorker mode (#6099).

#6099 introduced app-level home dirs (/home/pyodide/<appId>) so each app running on a SharedWorker has separated home dir on the file system.
However, the current directory is not set properly in the Python environment, so file access methods such as open() with relative paths which are assumed to be resolved based on the app-level home dir can fail.
This PR fixes it, by calling os.chdir() and setting `os.environ["HOME"].

[gradio-pr-bot]

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/b9e76582b7b0168ec4be9b17a6fc629204a1c13b/gradio-4.8.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@b9e76582b7b0168ec4be9b17a6fc629204a1c13b#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/wasm	minor
gradio	minor

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With the following changelog entry.

Lite: Set the home dir path per appId at each runtime

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[whitphx]

Here is an example:

app.py

import gradio as gr

def fn():
    with open("text.txt") as f:
        return f.read()


demo = gr.Interface(fn=fn, inputs=None, outputs="text")

demo.launch()

text.txt

Lorem ipsum

• text.txt is mounted to FS specified as a relative path, text.txt. It is assumed to be mounted at <app-home-dir>/text.txt.
• open() tries to read the file with a relative path. It is assumed to read the file from <app-home-dir>/text.txt. Before Lite: SharedWorker mode #6099, it actually worked.
• However, after Lite: SharedWorker mode #6099, this started to fail. This PR fixes it.

[whitphx]

I found this branch is not working because it is originally for v3, but the main is now v4 and it's been merged to this branch, then this branch fails to build.
To test this PR, plz rebase to lite-v4 or wait until it's merged.

[aliabd]

Thanks for clarifying @whitphx, tested and lgtm!

[whitphx]

Thanks!

[pngwn]

@whitphx What is the status of this PR? Is it waiting on the lite v4 branch?

If it isn't currently ready + working can we close it and reopen later?

[whitphx]

@pngwn Will merge it soon