Bash for resolving OpenSearch template URLS for INSPIRE Atom services

resolve-opensearch-atom.sh

#!/usr/bin/env bash
set -euo pipefail
PROGRAM_NAME="$0"

function get-query-params() {
    file="$1"
    params=$(
        xmlstarlet sel -T \
            -N os="http://a9.com/-/spec/opensearch/1.1/" \
            -t -m "//os:OpenSearchDescription/os:Query/@*" \
            -n -v "concat(name(),',', .)" "$file" # concat(substring-before(name(), ":"), "_", substring-after(name(), ":"))
    )
    echo -n "$params" | tr ":" "_" | jq --slurp --raw-input 'split("\n") | .[1:] | map(split(",")) | map({(.[0]) : .[1]}) | add'
}

function get-xpath-att() {
    file="$1"
    xpath="$2"
    att="$3"
    xmlstarlet sel -T \
        -N os="http://a9.com/-/spec/opensearch/1.1/" \
        -t -m "$xpath" \
        -n -v "$att" "$file"
}

function get-params-url() {
    local url="$1"
    local params=""
    for param in $(grep -oP "\{.*?\}" <<<"$url"); do
        param="$(echo -n ${param:1:-2})" # slice string from 1 till -2
        params="${params}${param},"
    done
    echo -n "${params::-1}"
}

function usage() {
    echo "DESCRIPTION: resolve template query links opensearch description documents"
    echo "USAGE: ${PROGRAM_NAME} <opensearch description url/file> <url-type, values: get-ds, desc-ds, results>"
    exit 1
}

if [[ $# -ne 2 ]]; then
    usage
fi

FILE="$1"
MODE="$2"

if [[ $FILE == https://* ]] || [[ $FILE == http://* ]]; then
    NEW_FILE="/tmp/$(uuidgen).xml"
    curl -s "$FILE" -o "$NEW_FILE"
    FILE="$NEW_FILE"
fi

QUERY_PARAMS=$(get-query-params "$FILE")
if [[ $MODE == "get-ds" ]]; then
    URL=$(get-xpath-att "$FILE" "//os:OpenSearchDescription/os:Url[@rel='results'][last()]" "@template")
elif [[ $MODE == "desc-ds" ]]; then
    URL=$(get-xpath-att "$FILE" "//os:OpenSearchDescription/os:Url[@rel='describedby' and @type='application/atom+xml']" "@template")
elif [[ $MODE == "results" ]]; then
    URL=$(get-xpath-att "$FILE" "//os:OpenSearchDescription/os:Url[@rel='results' and @type='application/atom+xml']" "@template")
else
    echo "ERROR: unsupported url-type ${MODE}"
    echo "       supported url-types are get-ds, desc-ds"
    exit 1
fi
URL_PARAM_KEYS="$(get-params-url "$URL")"

for URL_PARAM_KEY in ${URL_PARAM_KEYS//,/$IFS}; do
    URL_PARAM_KEY_ESCP=$(tr ":" "_" <<<"$URL_PARAM_KEY")
    URL_PARAM_VAL=$(jq -r ".${URL_PARAM_KEY_ESCP}" <<<$QUERY_PARAMS | tr "_" ":")
    if [[ $URL_PARAM_VAL == "null" ]]; then
        echo "ERROR: unable to find value for query param: $URL_PARAM_KEY"
        exit 1
    fi
    URL=$(sed "s|{${URL_PARAM_KEY}?}|${URL_PARAM_VAL}|g" <<<"$URL")
done
echo "$URL"