Add example script to convert an existing cache from previous serialization format to new one

1 files changed, 44 insertions, 0 deletions

diff --git a/examples/convert_cache.py b/examples/convert_cache.py
new file mode 100644
index 0000000..ce4f18f
--- /dev/null
+++ b/examples/convert_cache.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+"""Example of converting data cached in older versions of requests-cache (<=0.5.2)
+into the current format
+"""
+from requests import Response
+from requests_cache import CachedResponse, CachedSession
+import requests_cache.backends.base
+
+
+class _Store:
+    pass
+
+
+# Add placeholder object used by pickle to deserialize old responses
+requests_cache.backends.base._Store = _Store
+requests_cache.backends.base._RawStore = _Store
+
+
+def convert_old_response(cached_response, timestamp):
+    temp_response = Response()
+    for field in Response.__attrs__:
+        setattr(temp_response, field, getattr(cached_response, field, None))
+
+    new_response = CachedResponse(temp_response)
+    new_response.created_at = timestamp
+    return new_response
+
+
+def convert_cache(*args, **kwargs):
+    session = CachedSession(*args, **kwargs)
+    print(f'Checking {len(session.cache.responses)} cached responses')
+
+    with session.cache.responses.bulk_commit():
+        for key, response in session.cache.responses.items():
+            if isinstance(response, tuple):
+                print(f'Converting response {key}')
+                session.cache.responses[key] = convert_old_response(*response)
+
+    print('Conversion complete')
+
+
+# Example: convert a cache named 'demo_cache.sqlite' in the current directory
+if __name__ == '__main__':
+    convert_cache('demo_cache', backend='sqlite')