(filesystem)=

Filesystem

This backend stores responses in files on the local filesystem, with one file per response.

Use Cases

This backend is useful if you would like to use your cached response data outside of requests-cache, for example:

• Manually viewing cached responses without the need for extra tools (e.g., with a simple text editor)
• Using cached responses as sample data for automated tests
• Reading cached responses directly from another application or library, without depending on requests-cache

Usage Example

Initialize with a {py:class}.FileCache instance:

>>> from requests_cache import CachedSession, FileCache
>>> session = CachedSession(backend=FileCache())

Or by alias:

>>> session = CachedSession(backend='filesystem')

File Formats

By default, responses are saved as JSON files. If you prefer a deiffernt format, you can use of the other available {ref}serializers or provide your own. For example, to save responses as YAML files (requires pyyaml):

>>> session = CachedSession('~/http_cache', backend='filesystem', serializer='yaml')
>>> session.get('https://httpbin.org/get')
>>> print(list(session.cache.paths()))
> ['/home/user/http_cache/4dc151d95200ec.yaml']

Cache Files

• See {ref}files for general info on specifying cache paths
• The path for a given response will be in the format <cache_name>/<cache_key>
• Redirects are stored in a separate SQLite database, located at <cache_name>/redirects.sqlite
• Use {py:meth}.FileCache.paths to get a list of all cached response paths

Performance and Limitations

• Write performance will vary based on the serializer used, in the range of roughly 1-3ms per write.
• This backend stores response files in a single directory, and does not currently implement fan-out. This means that on most filesystems, storing a very large number of responses will result in reduced performance.
• This backend currently uses a simple threading lock rather than a file lock system, so it is not an ideal choice for highly parallel applications.