curl-exit-code-to-string

#!/bin/bash

# Convert curl return code to human friendly text.
# See 'man curl' for more info.

DIE() {
    echo "Error: $1" >&2
    exit 1
}

Generate() {
    local tmp=$(mktemp)
    local data=""

    # Get exit codes and strings from the curl man page.
    data="$(MANWIDTH=$width man curl | sed -n '/^EXIT CODES$/,/^AUTHORS \/ CONTRIBUTORS$/'p | grep "^ [ ]*[0-9][0-9]* [ ]*")"
    data="$(echo "$data" | sed "s|\"|'|g")"
    data="$(echo "$data" | sed 's|^\([ ]*[0-9]*\)[ ]*\(.*\)|\1) echo "\2" ;;|')"

    echo "==> Creating $converter" >&2
    cat <<EOF > "$converter"
#!/bin/bash
_generated_func_() {
    local curlRetCode="\$1"
    local msg
    case "\$curlRetCode" in
$(echo "$data")
       0) echo "OK" ;;
       *) echo "[Error] The manual page of 'curl' does not recognize error code '\$curlRetCode'."
          return 1
          ;;
    esac
}
_generated_func_ "\$1"
EOF
    [ -r "$converter" ] || DIE "Creating '$converter' failed."
    chmod +x "$converter"
}

usage_f() {
    local msg="$1"

    cat <<EOF
Convert the curl exit code to a descriptive string.

Usage: $progname { curl-exit-code | option }
Options:
  -c, --create    Generate up to date curl string list.
  -r, --remove    Remove the current curl string list.
  -h, --help      This help.

Example:
  $progname 6
EOF

    case "$msg" in
        "")     exit 0 ;;     # exit normally
        "stay") ;;            # do not exit
        *)                    # exit with a message
            printf "\nError: %s\n" "$msg" >&2
            exit 1
            ;;
    esac
}

CurlReturnCodeToString() {
    local progname=curl-exit-code-to-string
    local width=300   # man page error strings can be long, currently code 9 line needs over 200 characters ...

    [ -n "$1" ] || usage_f "parameter missing"

    local curlRetCode=""
    local cdir="$HOME/.config/$progname"
    local converter="$cdir/curl-code-to-string-converter"
    local timenow_sec=$(date +%s)
    local timefile_sec=0
    local generate_interval_seconds=$((3600*24*7))   # weekly automatic generation of the curl error code list


    mkdir -p "$cdir"

    [ -r "$converter" ] && timefile_sec=$(stat -c %Y "$converter")

    while [ -n "$1" ] ; do
        case "$1" in
            --create | -c)  Generate ; return ;;
            --remove | -r)  echo "==> Removing $converter" >&2 ; rm -f "$converter" ; return ;;
            --converter)    echo "$converter" ; return 0 ;;
            --width)        echo "$width" ; return 0 ;;
            --help | -h)    usage_f ;;
            -*)             DIE "unsupported option '$1'" ;;
            *)              curlRetCode="$1" ;;
        esac
        shift
    done

    # ((timenow_sec += generate_interval_seconds))  # testing generation!

    [ $timenow_sec -gt $((timefile_sec + generate_interval_seconds)) ] && Generate
    [ -x "$converter" ] || DIE "curl code to text converter '$converter' not found or not executable."

    "$converter" "$curlRetCode"
}

CurlReturnCodeToString "$@"