Initialize the client with the fake host for Lite server

[whitphx]

Description

Lite apps hosted on HF Spaces show the following error during the initialization while the app will be successfully launched finally.

This PR fixes it.

[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
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🦄	Changes	detected!	Details

---

Install Gradio from this PR

pip install https://gradio-pypi-previews.s3.amazonaws.com/80d91dc036fafed80a45bf2abcea965b3de3f707/gradio-4.40.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@80d91dc036fafed80a45bf2abcea965b3de3f707#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-npm-previews.s3.amazonaws.com/80d91dc036fafed80a45bf2abcea965b3de3f707/gradio-client-1.4.0.tgz

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/app	minor
@gradio/wasm	minor
gradio	minor

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With the following changelog entry.

Initialize the client with the fake host for Lite server

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[whitphx]

This host is passed to the client object through the code below

gradio/js/app/src/Index.svelte

Lines 276 to 287 in 9b42ba8

	api_url =
	BUILD_MODE === "dev" || gradio_dev_mode === "dev"
	? `http://localhost:${
	typeof server_port === "number" ? server_port : 7860
	}`
	: host || space || src || location.origin;
	app = await Client.connect(api_url, {
	status_callback: handle_status,
	with_null_state: true,
	events: ["data", "log", "status", "render"]
	});

and the client makes an HTTP call if the URL matches HF Spaces' host here, which causes the error:

gradio/client/js/src/client.ts

Lines 235 to 238 in 9b42ba8

	const { http_protocol, host, space_id } = await process_endpoint(
	this.app_reference,
	this.options.hf_token
	);

So we explicitly set the different value to host, which is also considered as a special host name representing the Lite's server.

[whitphx]

@pngwn Should we use src rather than host? #3065

[pngwn]

That is a breaking change, so it will need to happen in 5.0.

[whitphx]

@pngwn Thanks but do you mean we need to wait for this to be merged until 5.0, or just using host not src is ok and we can merge this?

[whitphx]

Should be merged after #9102?

[pngwn]

Looks great. Thanks @whitphx!