cainmagi/dash-file-cache

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dash_file_cache		dash_file_cache
display		display
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examples		examples
src		src
tests		tests
version		version
.babelrc		.babelrc
.editorconfig		.editorconfig
.eslintignore		.eslintignore
.eslintrc		.eslintrc
.flake8		.flake8
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.prettierrc		.prettierrc
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CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
CONTRIBUTING.md		CONTRIBUTING.md
Changelog.md		Changelog.md
Dockerfile		Dockerfile
Dockerfile.dockerignore		Dockerfile.dockerignore
LICENSE		LICENSE
MANIFEST.in		MANIFEST.in
README.md		README.md
SECURITY.md		SECURITY.md
_dispatch.py		_dispatch.py
_validate_init.py		_validate_init.py
classifiers.txt		classifiers.txt
conftest.py		conftest.py
dash-file-cache.code-workspace		dash-file-cache.code-workspace
package.json		package.json
py-description.txt		py-description.txt
pyproject.toml		pyproject.toml
requirements-dev.txt		requirements-dev.txt
requirements.txt		requirements.txt
review_checklist.md		review_checklist.md
setup.py		setup.py
tsconfig.json		tsconfig.json
webpack.config.js		webpack.config.js
webpack.serve.config.js		webpack.serve.config.js
yarn.config.cjs		yarn.config.cjs
yarn.lock		yarn.lock

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Dash File Cache

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GitHub release (latest SemVer) GitHub all releases GitHub PyPI - Downloads

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Dash File Cache is a Dash extension library.

Utilities for providing convenient methods to serve cached data in Plotly-Dash or Flask.

The data cache enables the following features:

Load a server-side file dynamically and send the file to users (the frontend).
Support in-memory files (like io.BytesIO()) or on-disk files (specified by a path).
Support different kinds of cache (single-thread, multi-processing, or file-based).
Customized components helping the dashboard trigger download events from the server side.

1. Install

Intall the latest released version of this package by using the PyPI source:

python -m pip install dash-file-cache

If users want to install the developer's version, they need to ensure that the following packages are installed.

Then use the following commands to install it.

git clone --depth 1 --single-branch https://github.com/cainmagi/dash-file-cache
cd dash-file-cache
python -m pip install -r requirements.txt -r requirements-dev.txt
yarn install
yarn dlx @yarnpkg/sdks vscode
yarn build
python -m pip install .[dev]

For VSCode users, please install the recommended extensions specified in the project workspace file.

2. Usage

The following codes show a minimal example of this package

from typing import Optional
import io
import dash
from dash import html
from dash import Input, Output
from dash_file_cache import ServiceData, CachePlain
app = dash.Dash("demo")
service = ServiceData(CachePlain(1))
service.serve(app)
app.layout = html.Div(
 (
 html.Div(
 html.P(
 (
 html.Span("Get Image:", style={"paddingRight": "0.5rem"}),
 html.Button(id="btn", children="Image"),
 )
 )
 ),
 html.Div((html.P("Cache address:"), html.P(id="addr"))),
 html.Div((html.P("Cached Image:"), html.Img(id="cache"))),
 ),
)
@app.callback(
 Output("addr", "children"),
 Input("btn", "n_clicks"),
 prevent_initial_call=True,
)
def click_get_image(
 n_clicks: Optional[int],
):
 if not n_clicks:
 return dash.no_update
 addr = service.register(
 io.StringIO(
 R'<svg height="100" width="100" xmlns="http://www.w3.org/2000/svg">'
 R'<circle r="45" cx="50" cy="50" fill="red" /></svg>'
 ),
 content_type="image/svg+xml",
 mime_type="image/svg+xml",
 one_time_service=True,
 )
 return addr
@app.callback(
 Output("cache", "src"),
 Input("addr", "children"),
 prevent_initial_call=True,
)
def update_cache(addr):
 if not addr:
 return dash.no_update
 return addr
if __name__ == "__main__":
 app.run(host="127.0.0.1", port="8080", debug=True)