PROXY="--proxy http://localhost:8080/"
d=${1%/*}
[ -z "$FEEDER_SKIP_DOWNLOAD" ] || {
    echo temporarily skipping feed download >&2
    sha512 < $d/feed
    exit
}
read url < $d/url
[ -s $d/etag ] && etag_compare="--etag-compare $d/etag" || etag_compare=""
[ -z "$FEEDER_CURL_VERBOSE" ] && silent="--silent" || silent="--verbose"
curl --fail \
    --user-agent "go.stargrave.org-feeder/0.1.0" \
    --compressed \
    --location --max-redirs 2 \
    --dump-header $d/hdr \
    --output $d/out \
    --remote-time \
    --time-cond $d/out \
    --etag-save $d/etag \
    $PROXY \
    $silent \
    $etag_compare \
    "$url" >&2
if [ -s $d/out ] ; then
    cp -a $d/out $d/feed
    truncate -s 0 $d/out
    touch -r $d/feed $d/out
fi
sha512 < $d/feed