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Persistent cache for requests library

Project description

Requests-Cache

Build Coverage Documentation PyPI PyPI - Python Versions PyPI - Format Code Shelter

Summary

requests-cache is a transparent, persistent HTTP cache for the python requests library. It's a convenient tool to use with web scraping, consuming REST APIs, slow or rate-limited sites, or any other scenario in which you're making lots of requests that are expensive and/or likely to be sent more than once.

See full project documentation at: https://requests-cache.readthedocs.io

Features

Quickstart

First, install with pip:

pip install requests-cache

Next, use requests_cache.CachedSession to send and cache requests. To quickly demonstrate how to use it:

This takes ~1 minute:

import requests

session = requests.Session()
for i in range(60):
    session.get('http://httpbin.org/delay/1')

This takes ~1 second:

import requests_cache

session = requests_cache.CachedSession('demo_cache')
for i in range(60):
    session.get('http://httpbin.org/delay/1')

The URL in this example adds a delay of 1 second, simulating a slow or rate-limited website. 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, requests-cache can also be installed globally:

requests_cache.install_cache('demo_cache')
requests.get('http://httpbin.org/delay/1')

Next Steps

To find out more about what you can do with requests-cache, see:

History

0.6.0 (2021-04-09)

See all included issues and PRs

Thanks to Code Shelter and contributors for making this release possible!

Serialization

Note: Due to the following changes, responses cached with previous versions of requests-cache will be invalid. These old responses will be treated as expired, and will be refreshed the next time they are requested. They can also be manually converted or removed, if needed (see notes below).

  • Add example script to convert an existing cache from previous serialization format to new one
  • When running remove_expired_responses(), also remove responses that are invalid due to updated serialization format
  • Add CachedResponse class to wrap cached requests.Response objects, which makes additional cache information available to client code
  • Add CachedHTTPResponse class to wrap urllib3.response.HTTPResponse objects, available via CachedResponse.raw
    • Re-construct the raw response on demand to avoid storing extra data in the cache
    • Improve emulation of raw request behavior used for iteration, streaming requests, etc.
  • Add BaseCache.urls property to get all URLs persisted in the cache
  • Add optional support for itsdangerous for more secure serialization

Cache Expiration

  • Cached responses are now stored with an absolute expiration time, so CachedSession.expire_after no longer applies retroactively. To revalidate previously cached items with a new expiration time, see below:
  • Add support for overriding original expiration (i.e., revalidating) in CachedSession.remove_expired_responses()
  • Add support for setting expiration for individual requests
  • Add support for setting expiration based on URL glob patterns
  • Add support for setting expiration as a datetime
  • Add support for explicitly disabling expiration with -1 (Since None may be ambiguous in some cases)

Backends

  • SQLite: Allow passing user paths (~/path-to-cache) to database file with db_path param
  • SQLite: Add timeout parameter
  • Make default table names consistent across backends ('http_cache')

Bugfixes

  • Fix caching requests with data specified in json parameter
  • Fix caching requests with verify parameter
  • Fix duplicate cached responses due to some unhandled variations in URL format
    • To support this, the url-normalize library has been added to dependencies
  • Fix usage of backend-specific params when used in place of cache_name
  • Fix potential TypeError with DbPickleDict initialization
  • Fix usage of CachedSession.cache_disabled if used within another contextmanager
  • Fix non-thread-safe iteration in BaseCache
  • Fix get_cache(), clear(), and remove_expired_responses() so they will do nothing if requests-cache is not installed
  • Update usage of deprecated MongoClient save() method

General

Docs & Tests

  • Add type annotations to main functions/methods in public API, and include in documentation on readthedocs
  • Add Contributing Guide, Security info, and more examples & detailed usage info in User Guide and Advanced Usage sections.
  • Increase test coverage and rewrite most tests using pytest
  • Add containerized backends for both local and CI integration testing

0.5.2 (2019-08-14)

  • Fix DeprecationWarning from collections #140

0.5.1 (2019-08-13)

  • Remove Python 2.6 Testing from travis #133
  • Fix DeprecationWarning from collections #131
  • vacuum the sqlite database after clearing a table #134
  • Fix handling of unpickle errors #128

0.5.0 (2019-04-18)

Project is now added to Code Shelter

  • Add gridfs support, thanks to @chengguangnan
  • Add dynamodb support, thanks to @ar90n
  • Add response filter #104, thanks to @christopher-dG
  • Fix bulk_commit #78
  • Fix remove_expired_responses missed in init.py #93
  • Fix deprecation warnings #122, thanks to mbarkhau

0.4.13 (2016-12-23)

  • Support PyMongo3, thanks to @craigls #72
  • Fix streaming releate issue #68

0.4.12 (2016-03-19)

  • Fix ability to pass backend instance in install_cache #61

0.4.11 (2016-03-07)

  • ignore_parameters feature, thanks to @themiurgo and @YetAnotherNerd (#52, #55)
  • More informative message for missing backend dependencies, thanks to @Garrett-R (#60)

0.4.10 (2015-04-28)

  • Better transactional handling in sqlite #50, thanks to @rgant
  • Compatibility with streaming in requests >= 2.6.x

0.4.9 (2015-01-17)

  • expire_after now also accepts timedelta, thanks to @femtotrader
  • Added Ability to include headers to cache key (include_get_headers option)
  • Added string representation for CachedSession

0.4.8 (2014-12-13)

  • Fix bug in reading cached streaming response

0.4.7 (2014-12-06)

  • Fix compatibility with Requests > 2.4.1 (json arg, response history)

0.4.6 (2014-10-13)

  • Monkey patch now uses class instead lambda (compatibility with rauth)
  • Normalize (sort) parameters passed as builtin dict

0.4.5 (2014-08-22)

  • Requests==2.3.0 compatibility, thanks to @gwillem

0.4.4 (2013-10-31)

  • Check for backend availability in install_cache(), not at the first request
  • Default storage fallbacks to memory if sqlite is not available

0.4.3 (2013-09-12)

  • Fix response.from_cache not set in hooks

0.4.2 (2013-08-25)

  • Fix UnpickleableError for gzip responses

0.4.1 (2013-08-19)

  • requests_cache.enabled() context manager
  • Compatibility with Requests 1.2.3 cookies handling

0.4.0 (2013-04-25)

  • Redis backend. Thanks to @michaelbeaumont
  • Fix for changes in Requests 1.2.0 hooks dispatching

0.3.0 (2013-02-24)

  • Support for Requests 1.x.x
  • CachedSession
  • Many backward incompatible changes

0.2.1 (2013-01-13)

  • Fix broken PyPi package

0.2.0 (2013-01-12)

  • Last backward compatible version for Requests 0.14.2

0.1.3 (2012-05-04)

  • Thread safety for default sqlite backend
  • Take into account the POST parameters when cache is configured with 'POST' in allowable_methods

0.1.2 (2012-05-02)

  • Reduce number of sqlite database write operations
  • fast_save option for sqlite backend

0.1.1 (2012-04-11)

  • Fix: restore responses from response.history
  • Internal refactoring (MemoryCache -> BaseCache, reduce_response and restore_response moved to BaseCache)
  • connection option for MongoCache

0.1.0 (2012-04-10)

  • initial PyPI release

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