fix: update api_server_backend.py to adapt latest gradio

[kv-chiu]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily receiving feedbacks. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

I tried to run the demo, but ran into two bugs

1. concurrency_count

2. no update method

Modification

1. remove concurrency_count
2. fix Textbox.update to Textbox.postprocess(self, value: str)

ref:

1. gradio update log
   Breaking Changes in Gradio 4.0 gradio-app/gradio#6339
2. gradio Blocks docs
   https://www.gradio.app/docs/gradio/blocks#blocks-queue
3. gradio Textbox docs
   https://www.gradio.app/docs/gradio/textbox

BC-breaking (Optional)

Does the modification introduce changes that break the backward-compatibility of the downstream repositories?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
3. If the modification has a dependency on downstream projects of a newer version, this PR should be tested with all supported versions of downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[AllentDan]

Currently, lmdeploy gradio demos use gradio<4.0.0. I notice the change is BC breaking, does it mean gradio<4.0.0 can not run the demo because of fix Textbox.update to Textbox.postprocess(self, value: str)

[kv-chiu]

Currently, lmdeploy gradio demos use gradio<4.0.0. I notice the change is BC breaking, does it mean gradio<4.0.0 can not run the demo because of fix Textbox.update to Textbox.postprocess(self, value: str)

have fixed it:

[AllentDan]

Hi, @kv-chiu I tested the PR with gradio 4.29.0, and got the following error when clicking Reset button.

lmdeploy/serve/gradio/api_server_backend.py", line 80, in reset_restful_func
    gr.Textbox.update(value=''),
AttributeError: type object 'Textbox' has no attribute 'update'

[AllentDan]

there are linting errors, which can fixed by running the following commands:

pip install pre-commit
cd the/root/path/of/lmdeploy
pre-commit install .
pre-commit run --all-files

[lvhan028]

@irexyc may review if VLM demo works

[kv-chiu]

@AllentDan

fixed (using gradio==4.29.0, If you encounter the error 'No module named "gradio_client",' simply reinstall Gradio to resolve the issue.)

QQ202456-173610.mp4