functions.sh

#!/bin/bash

# Authenticates credentials against Central and returns the cookie jar file name. USERNAME and
# PASSWORD must be set before calling this function.
#   USERNAME="foo"
#   PASSWORD="bar"
#   COOKIE_JAR=$(startSession)
startSession() {
    # Authentication to XNAT and store cookies in cookie jar file
    local COOKIE_JAR=.cookies-$(date +%Y%M%d%s).txt
    curl -k -s -u ${USERNAME}:${PASSWORD} --cookie-jar ${COOKIE_JAR} "https://central.xnat.org/data/JSESSION" > /dev/null
    echo ${COOKIE_JAR}
}

# Downloads a resource from a URL and stores the results to the specified path. The first parameter
# should be the destination path and the second parameter should be the URL.
download() {
    local OUTPUT=${1}
    local URL=${2}
    curl -H 'Expect:' --keepalive-time 2 -k --cookie ${COOKIE_JAR} -o ${OUTPUT} ${URL}
}

# Downloads a resource from a URL and stores the results to the specified path. The first parameter
# should be the destination path and the second parameter should be the URL. This function tries to
# resume a previously started but interrupted download.
continueDownload() {
    local OUTPUT=${1}
    local URL=${2}
    curl -H 'Expect:' --keepalive-time 2 -k --continue - --cookie ${COOKIE_JAR} -o ${OUTPUT} ${URL}
}

# Gets a resource from a URL.
get() {
    local URL=${1}
    curl -H 'Expect:' --keepalive-time 2 -k --cookie ${COOKIE_JAR} ${URL}
}

# Ends the user session.
endSession() {
    # Delete the JSESSION token - "log out"
    curl -i -k --cookie ${COOKIE_JAR} -X DELETE "https://central.xnat.org/data/JSESSION"
    rm -f ${COOKIE_JAR}
}

bailOnWget() {
    echo "There are session management issues using wget. It's probably best not to do this."
    exit -1
}