gistfile1.sh

#!/usr/bin/env sh

INSTALL_DIR=`pwd`/maxmind

log() {
    printf "\033[90m...\033[0m $@\n"
}

abort() {
    printf "\033[31mError: $@\033[0m\n" && exit 1
}

HOST="http://geolite.maxmind.com/download/geoip/database"

# MaxMind files
GEOIP_COUNTRY_DAT="GeoIP.dat"
GEOIP_COUNTRY="${HOST}/GeoLiteCountry/${GEOIP_COUNTRY_DAT}.gz"
GEOIP_CITY_DAT="GeoLiteCity.dat"
GEOIP_CITY="${HOST}/${GEOIP_CITY_DAT}.gz"

HTTP_HEAD=
which wget > /dev/null && HTTP_HEAD="wget -S --spider"
which curl > /dev/null && HTTP_HEAD="curl -Is"

test -z "$HTTP_HEAD" && abort "curl or wget required"

HTTP_GET=
which wget > /dev/null && HTTP_GET="wget -q -O-"
which curl > /dev/null && HTTP_GET="curl -s"

test -d $INSTALL_DIR || mkdir -p $INSTALL_DIR

download() {
    log "downloading $2.gz"
    $HTTP_GET $1 | gzip -d - > $INSTALL_DIR/$2
}

# If the file needs downloaded, return 0
# Else, return 1
check_last_modified() {
    # If the file doesn't exist at all, return 0
    test -f $INSTALL_DIR/$2 || return 0

    # Grab the HTTP headers
    local headers="$( $HTTP_HEAD $1 2> /dev/null )"

    # Strip out the Last-Modified header
    local last_modified="$( \
          echo "$headers" \
        | grep -i 'last-modified' \
        | sed 's/[Ll]ast-[Mm]odified://g' )"

    # Convert string format to epoch time
    last_modified=`date -d "$last_modified" +%s`

    # Modified time of existing file
    local mtime=`stat -c %Y $INSTALL_DIR/$2`

    # If the file on the remote server is newer, return 0
    test $last_modified -gt $mtime && return 0

    # We must have the latest file, return 1
    return 1
}

check_last_modified $GEOIP_COUNTRY $GEOIP_COUNTRY_DAT \
    && download $GEOIP_COUNTRY $GEOIP_COUNTRY_DAT

check_last_modified $GEOIP_CITY $GEOIP_CITY_DAT \
    && download $GEOIP_CITY $GEOIP_CITY_DAT