Hi Alll--
I have a Linux project that builds against URL dependencies. Make itself does
not recognize URL resources and the ':' in the URL naming scheme is
problematic. I was able to sidestep these constraints with the following idiom
using timestamp files and lexical substitution. The lexical operations
transforms the URL scheme to a local file path
It seems to work -- at least when you have a reasonably modern HTTP server such
as Apache or nginx
I was wondering if anyone else had experience with a similar scheme.
# Define tracking files for URL sources. These are empty files with a
modification date
# set to the Last-Modified attribute of the source. Tracking files reside in
a ".<scheme>"
# directory with a pattern matching the resource and path.
#
# The use of ":" for scheme and port separator conflicts with Makefile syntax.
This can
# be accomodated with $(substr <scheme>:,.<scheme>,<url>). Port specification
is not
# currently supported.
#
# Dependencies: curl, wget, touch
# Requires: HTTP headers contain "Last-Modified:" field.
.http/%:
#...establish timestamp of the source
mkdir -p $$(dirname $@)
tstamp="$$(curl -sI $(subst .http,http:,$@) 2>/dev/null | sed -n
's/Last-Modified: //p')" && \
touch -d "$${tstamp}" $@
URL_SOURCES: http://some-url ....
URL_TRACKING : $(subst http:,.http, $(URL_SOURCES))
# Pattern for single file retrieval
$(DESTPATH)/% : $(subst http:,.http, http://some-url ...)/%
mkdir -p $(dir $@)
curl $(subst .http,http:,$^) > $@
# Pattern for directory tree retrieval using wget.
# Note: The --cut-dirs parameter is dependent on the source path
$(DEST_DIR) : $(subst http:,.http, http://some-url)/
mkdir -p $(dir $@)
wget -r -np -nH --cut-dirs=n -P $(dir $@) $(subst .http,http:,$^)
