From f058da6fe9cfb4bf8f89ef8416a528906f404650 Mon Sep 17 00:00:00 2001
From: Philippe Coval <rzr@users.sf.net>
Date: Mon, 2 Mar 2020 10:30:09 +0100
Subject: [PATCH] build: Add caching feature for offline use

Note that fonts will remain online,
so caching at browser level or proxy might help.

Origin: https://github.com/rzr/rzr-presentations
Change-Id: I59ba3e177511fd63b59baccfd97604587766bdb6
Signed-off-by: Philippe Coval <rzr@users.sf.net>
---
 Makefile | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/Makefile b/Makefile
index 63681de..d2465df 100644
--- a/Makefile
+++ b/Makefile
@@ -18,6 +18,8 @@ reveal_zip_url?=https://github.com/hakimel/reveal.js/archive/master.zip
 reveal_dir?=./reveal.js
 sudo?=sudo
 deploy_branch?=gh-pages
+cache_dir?=./cache/url
+make?=make -f ${CURDIR}/Makefile
 
 
 help:
@@ -27,6 +29,7 @@ help:
 	@echo "#  make all # Build html"
 	@echo "#  make start # View HTML in Web browser"
 	@echo "#  make download # Download deps"
+	@echo "#  make offline # Cache inlined resources and generate cached pages"
 	@echo "#  make upload # to build and publish"
 	@echo "#  make setup/debian setup download start # ..."
 	@echo "# Config:"	
@@ -131,3 +134,70 @@ upload:
 	echo "# About to push to origin in 5 secs ?"
 	sleep 5 ; git push -f origin HEAD:gh-pages
 	git checkout master
+
+%.lst: %.org Makefile
+	echo "" > "$@"
+	-grep -o -e 'https\?://[^]"]*' -- "$<" \
+ | grep -E ".**\.(gif|png|svg|jpg|jpeg|webm|mp4)"\
+ | sort -u >> "$@.tmp"
+	mv "$@.tmp" "$@"
+
+
+%/curl:	
+	@mkdir -p http https
+	@ln -fs http http:
+	@ln -fs https https:
+	ls "${@D}" > /dev/null 2>&1 \
+ || curl --create-dirs -o "./${@D}" -- "${@D}"
+	find . -iname "*#*" | while read file; do \
+    basename=$$(basename -- "$${file}"); \
+    dirname=$$(dirname -- "$${file}"); \
+    dstname=$$(echo "$${basename}" | sed -e 's|#.|%23.|g'); \
+    ln -fs "$${basename}" "$${dirname}/$${dstname}"; \
+    dstname=$$(echo "$${basename}" | sed -e 's|#.||g'); \
+    ln -fs "$${basename}" "$${dirname}/$${dstname}"; \
+  done
+
+
+.PHONY: cache
+cache: ${target}.lst Makefile
+	@mkdir -p "${<D}/${cache_dir}"
+	cd "${<D}/${cache_dir}" && \
+  cat "${CURDIR}/$<" | while read url ; do \
+    ${make} $${url}/curl || exit $$? ; \
+  done
+
+
+${target}._cache.org: ${target}.lst ${target}.org cache reveal.js
+	sed -e 's|^#+REVEAL_ROOT:.*|#+REVEAL_ROOT: ${CURDIR}/reveal.js|g' \
+  < ${target}.org > $@.tmp
+	sort -u $< | while read url; do \
+    sed -e "s|$${url}|${cache_dir}/$${url}|g" \
+      -e "s|${cache_dir}/http://|${cache_dir}/http/|g" \
+      -e "s|${cache_dir}/https://|${cache_dir}/https/|g" \
+      -i "${@}.tmp" ; \
+  done
+	mv "${@}.tmp" "$@"
+
+html-cache: ${target}.org ${target}._cache.org
+	make html target="${target}._cache"
+	sed -e "s|#./|/./|g" -i "${target}._cache.html"
+
+offline: all/cache all/html-cache
+	sync
+
+offline/start: offline
+	${MAKE} ${@F} target="${target}._cache"
+
+commit/offline:
+	-git branch -D ${@F}/master
+	git checkout -b ${@F}/master
+	${MAKE} download
+	-git add -f .
+	-git commit -am 'deploy: Cache downloaded files'
+	${MAKE} cache
+	-git add -f .
+	-git commit -am 'deploy: Cache downloaded files, see lst file for sources'
+	${MAKE} ${@F}
+	-git add -f .
+	-git commit -am 'deploy: Render cached files'