`SqliteCacheRequestsDocumentLoader`¶

Prerequisite

This functionality requires an extra dependency, requests-cache. Install PyLD with:

pip install 'PyLD[requests-cache]'

Remote document loader with persistent SQLite HTTP caching.

Parameters:

Name	Type	Description	Default
`secure`	`bool`	require all requests to use HTTPS (default: False).	`False`
`sqlite_file_path`	`Path \| None`	absolute path to the `.sqlite` cache file; when omitted, defaults to the platform user cache directory under `pyld/`.	`None`

When sqlite_file_path is omitted, the cache defaults to the platform user cache directory:

OS	Default path
Linux	`~/.cache/pyld/http_cache.sqlite`
macOS	`~/Library/Caches/pyld/http_cache.sqlite`
Windows	`%LOCALAPPDATA%\pyld\http_cache.sqlite`

SqliteCacheRequestsDocumentLoader retrieves remote JSON-LD documents and keeps them in a persistent SQLite cache. It is useful for applications that repeatedly load the same remote contexts across process runs.

HTTP cache headers (Cache-Control, Expires, validators) are honored, so publishers can control how cached context documents are reused.

JSON-LD Best Practices recommends:

Best Practice 14: Cache JSON-LD Contexts

Services providing a JSON-LD Context SHOULD set HTTP cache-control headers to allow liberal caching of such contexts, and clients SHOULD attempt to use a locally cached version of these documents.

§ 8.1 Cache JSON-LD Contexts

Example sqlite_cache_basic.py

import json
from pathlib import Path

from pyld import SqliteCacheRequestsDocumentLoader, jsonld

doc = {
    "@context": {"name": "http://schema.org/name"},
    "name": "Earth",
}

loader = SqliteCacheRequestsDocumentLoader(
    sqlite_file_path=Path("/tmp/pyld_example_http_cache.sqlite"),
)

# At the first execution, this will perform a network request to https://schema.org,
# but subsequent executions of the same code will not, using a cached response.
result = jsonld.expand(doc, options={"documentLoader": loader})

print(json.dumps(result, indent=2))

Output

[
  {
    "http://schema.org/name": [
      {
        "@value": "Earth"
      }
    ]
  }
]

Decisions

This page is influenced by the decision to use requests-cache for persistent HTTP caching in synchronous Python code.

SqliteCacheRequestsDocumentLoader¶

`SqliteCacheRequestsDocumentLoader`¶