Flask-Compress

1.24 · active · verified Thu Apr 09

Flask-Compress is a Flask extension that allows you to easily compress your Flask application's responses using various algorithms like gzip, deflate, brotli, or zstandard. It helps reduce bandwidth usage and improve page load times. The library is actively maintained, with the current version being 1.24, and it typically sees releases for bug fixes, performance improvements, and feature enhancements.

Warnings

gotcha Enabling streaming compression for static content served directly by Flask might not be ideal. Flask-Compress will compress static content chunk-by-chunk, which can be less efficient than having a web server (like Nginx) handle static file compression.
Fix: For static files, consider configuring your front-end web server (e.g., Nginx, Apache) to pre-compress or dynamically compress them, rather than relying on Flask-Compress.
gotcha ETag support is disabled by default for streaming responses because it typically requires buffering the entire response in memory to compute the ETag, which can negate the benefits of streaming. If you enable ETag support for streaming endpoints, be aware of the potential memory impact.
Fix: To enable ETag for streaming, set `COMPRESS_EVALUATE_CONDITIONAL_REQUEST` to `True` and optionally `COMPRESS_STREAMING_ENDPOINT_CONDITIONAL` for specific endpoints. Evaluate memory usage carefully.
gotcha While compression improves network efficiency, it increases CPU usage on the server. For applications with very high traffic or limited CPU resources, this trade-off should be carefully considered and monitored.
Fix: Monitor server CPU usage after enabling compression. Adjust `COMPRESS_LEVEL` (for gzip/deflate) or `COMPRESS_BROTLI_QUALITY` to find an optimal balance between compression ratio and CPU load. If CPU becomes a bottleneck, offload compression to a reverse proxy or CDN.

Install

pip install flask-compress Install latest stable version

Imports

Compress
```
from flask_compress import Compress
```

Quickstart

This quickstart demonstrates how to initialize Flask-Compress with your Flask application. Once initialized, Flask-Compress automatically compresses responses for specified MIME types, such as HTML or JSON, without further configuration. The `/large-data` endpoint serves a large JSON payload which will be compressed.

from flask import Flask, request, jsonify
from flask_compress import Compress
import os

app = Flask(__name__)
Compress(app)

@app.route('/')
def hello_world():
    return 'Hello, Compressed World!'

@app.route('/large-data')
def large_data():
    # Simulate a large JSON response
    data = {'items': [{'id': i, 'name': f'Item {i}', 'description': 'This is a long description for item'} for i in range(1000)]}
    return jsonify(data)

if __name__ == '__main__':
    app.run(debug=True)

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