From 5123ffb5014de4e2634bb713f897fc682bd94f2c Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Mon, 13 Apr 2020 06:50:56 +1200
Subject: [PATCH] Add implementation notes for response caching.

---
 ISSUES/cache-responses.md  | 19 +++++++++++++++++++
 ISSUES/cache-responses.md~ |  0
 2 files changed, 19 insertions(+)
 delete mode 100644 ISSUES/cache-responses.md~

diff --git a/ISSUES/cache-responses.md b/ISSUES/cache-responses.md
index aa5155f..4033371 100644
--- a/ISSUES/cache-responses.md
+++ b/ISSUES/cache-responses.md
@@ -3,3 +3,22 @@ HTTP responses should be cached locally according to their cache-control headers
 Especially once Rhapsode starts supporting hyperlinks.
 
 This could be developed as an independant project and integrated in!
+
+## Caching headers
+* `CacheControl`, legacy `Pragma: no-cache`
+* `Expires`, may also be set via `CacheControl` or `Last-Modified`
+* `Etag` - echo back in `If-None-Match`
+* `Last-Modified` - echo back in `If-Modified-Since`
+* `Vary` - indicates which headers to compare for equality before using a cache.
+
+Use cached data for 304 responses.
+
+## Implementation
+I'd store an index file, with cached bodies stored seperately.
+
+There'd be four parts to implementing the cache:
+1. Annotating the request.
+2. Loading cached data for 304 responses.
+3. Storing cache responses.
+
+GNOME's implementation: https://github.com/GNOME/libsoup/blob/mainline/libsoup/soup-cache.c
diff --git a/ISSUES/cache-responses.md~ b/ISSUES/cache-responses.md~
deleted file mode 100644
index e69de29..0000000
-- 
2.30.2