A persistent cache for python requests
requests-cache is a persistent HTTP cache that provides an easy way to get better performance with the python requests library.
Complete project documentation can be found at requests-cache.readthedocs.io.
- 🍰 Ease of use: Keep using the
requestslibrary you're already familiar with. Add caching with a drop-in replacement for
requests.Session, or install globally to add transparent caching to all
- 🚀 Performance: Get sub-millisecond response times for cached responses. When they expire, you still save time with conditional requests.
- 💾 Persistence: Works with several storage backends including SQLite, Redis, MongoDB, and DynamoDB; or save responses as plain JSON files, YAML, and more
- 🕗 Expiration: Use Cache-Control and other standard HTTP headers, define your own expiration schedule, keep your cache clutter-free with backends that natively support TTL, or any combination of strategies
- ⚙️ Customization: Works out of the box with zero config, but with a robust set of features for configuring and extending the library to suit your needs
- 🧩 Compatibility: Can be combined with other popular libraries based on requests
First, install with pip:
pip install requests-cache
To illustrate, we'll call an endpoint that adds a delay of 1 second, simulating a slow or rate-limited website.
This takes 1 minute:
import requests session = requests.Session() for i in range(60): session.get('https://httpbin.org/delay/1')
This takes 1 second:
import requests_cache session = requests_cache.CachedSession('demo_cache') for i in range(60): session.get('https://httpbin.org/delay/1')
With caching, the response will be fetched once, saved to
demo_cache.sqlite, and subsequent
requests will return the cached response near-instantly.
If you don't want to manage a session object, or just want to quickly test it out in your application without modifying any code, requests-cache can also be installed globally, and all requests will be transparently cached:
import requests import requests_cache requests_cache.install_cache('demo_cache') requests.get('https://httpbin.org/delay/1')
Headers and Expiration
By default, requests-cache will keep cached responses indefinitely. In most cases, you will want to use one of the two following strategies to balance cache freshness and performance:
Define exactly how long to keep responses:
expire_after parameter to set a fixed expiration time for all responses:
from requests_cache import CachedSession from datetime import timedelta # Keep responses for 360 seconds session = CachedSession('demo_cache', expire_after=360) # Or use timedelta objects to specify other units of time session = CachedSession('demo_cache', expire_after=timedelta(hours=1))
See Expiration for more features and settings.
Use Cache-Control headers:
cache_control parameter to enable automatic expiration based on
Cache-Control and other
standard HTTP headers sent by the server:
from requests_cache import CachedSession session = CachedSession('demo_cache', cache_control=True)
See Cache Headers for more details.
The default settings work well for most use cases, but there are plenty of ways to customize caching behavior when needed. Here is a quick example of some of the options available:
from datetime import timedelta from requests_cache import CachedSession session = CachedSession( 'demo_cache', use_cache_dir=True, # Save files in the default user cache dir cache_control=True, # Use Cache-Control response headers for expiration, if available expire_after=timedelta(days=1), # Otherwise expire responses after one day allowable_codes=[200, 400], # Cache 400 responses as a solemn reminder of your failures allowable_methods=['GET', 'POST'], # Cache whatever HTTP methods you want ignored_parameters=['api_key'], # Don't match this request param, and redact if from the cache match_headers=['Accept-Language'], # Cache a different response per language stale_if_error=True, # In case of request errors, use stale cache data if possible )
To find out more about what you can do with requests-cache, see:
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