Add script to download latest Galileo almanac from EUSPA website

src/utils/scripts/download-galileo-almanac.sh

@@ -0,0 +1,126 @@
+#!/bin/sh
+# GNSS-SDR shell script that tries to download the latest Galileo Almanac file
+# published by the European GNSS Service Centre.
+#
+# Usage: ./download-galileo-almanac.sh
+#
+# SPDX-FileCopyrightText: 2022 Carles Fernandez-Prades <cfernandez(at)cttc.es>
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+if ! [ -x "$(command -v wget)" ]; then
+    echo "Please install wget before using this script."
+    exit 1
+fi
+
+help()
+{
+    echo "This script tries to download the most recent Galileo Almanac XML file"
+    echo "published by the European GNSS Service Centre."
+    echo "More info at https://www.gsc-europa.eu/product-almanacs"
+    echo "If today there is no published file, the script will look up to one week ago."
+    echo ""
+    echo "Usage:"
+    echo "./download-galileo-almanac.sh [OPTION]"
+    echo "  Options:"
+    echo "  -h, --help        Prints this message"
+    echo "  -r, --rename      Gets latest Galileo Almanac XML file and saves it as gal_almanac.xml"
+    echo "  -d, --date [date] Retrieves file for a specific date, with format YYYY-MM-DD"
+    echo "  -rd [date]        Retrieves file for a specific date, with format YYYY-MM-DD"
+    echo "                    and saves it as gal_almanac.xml"
+    echo ""
+    echo "  Examples:"
+    echo "  ./download-galileo-almanac.sh                # Gets latest Galileo Almanac XML file"
+    echo "  ./download-galileo-almanac.sh -r             # Gets latest Galileo Almanac XML file, stores it as gal_almanac.xml"
+    echo "  ./download-galileo-almanac.sh -d 2022-03-15  # Gets Galileo Almanac XML file for that day"
+    echo "  ./download-galileo-almanac.sh -rd 2022-03-15 # Gets Galileo Almanac XML file for that day, stores it as gal_almanac.xml"
+}
+
+if (([ "$1" = "-h" ]) || ([ "$1" = "--help" ])) ; then
+    help
+    exit 0
+fi
+
+RENAME=""
+if (([ "$1" = "-r" ]) || ([ "$1" = "--rename" ])) ; then
+    RENAME=" -O gal_almanac.xml "
+fi
+
+BASE_URL="https://www.gsc-europa.eu/sites/default/files/sites/all/files/"
+YEAR=$(date '+%Y')
+SPACING="-"
+MONTH=$(date '+%m')
+DAY=$(date '+%d')
+
+TERMINATION1="_0.xml"
+TERMINATION2=".xml"
+
+COUNTER=1
+MAX_COUNTER=7
+
+if (([ "$1" = "-d" ]) || ([ "$1" = "--date" ])) ; then
+    if wget "$BASE_URL$2$TERMINATION2" >/dev/null 2>&1 ; then
+        echo "Downloaded latest Galileo almanac from $BASE_URL$2$TERMINATION2"
+        exit 0
+    else
+        echo "Couldn't find an XML file for that date."
+        exit 1
+    fi
+elif [ "$1" = "-rd" ] ; then
+    if wget -O gal_almanac.xml "$BASE_URL$2$TERMINATION2" >/dev/null 2>&1 ; then
+        echo "Downloaded latest Galileo almanac from $BASE_URL$2$TERMINATION2"
+        exit 0
+    else
+        echo "Couldn't find an XML file for that date."
+        rm gal_almanac.xml
+        exit 1
+    fi
+else
+    echo "According to system time, today is $(date '+%Y-%m-%d'). Searching for the latest Galileo almanac ..."
+fi
+
+lowercase()
+{
+    echo "$1" | sed "y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/"
+}
+
+OS=`lowercase \`uname\``
+
+date_before()
+{
+    if [ "$OS" = "darwin" ]; then
+        YEAR=$(date -v -"$COUNTER"d '+%Y')
+        MONTH=$(date -v -"$COUNTER"d '+%m')
+        DAY=$(date -v -"$COUNTER"d '+%d')
+    else
+        YEAR=$(date -d "$COUNTER day ago" '+%Y')
+        MONTH=$(date -d "$COUNTER day ago" '+%m')
+        DAY=$(date -d "$COUNTER day ago" '+%d')
+    fi
+    COUNTER=$(($COUNTER+1))
+}
+
+
+try_download()
+{
+    while [ $COUNTER -le $MAX_COUNTER ]
+    do
+        url="$BASE_URL$YEAR$SPACING$MONTH$SPACING$DAY$TERMINATION2"
+        if wget $RENAME $url >/dev/null 2>&1 ; then
+        	echo "Downloaded latest Galileo almanac from $url"
+            exit 0
+        else
+            date_before
+            try_download
+        fi
+    done
+}
+
+
+url="$BASE_URL$YEAR$SPACING$MONTH$SPACING$DAY$TERMINATION1"
+if wget $RENAME $url >/dev/null 2>&1 ; then
+	echo "Downloaded latest Galileo almanac from $url"
+else
+    try_download
+    echo "Couldn't find a recent Galileo almanac."
+    exit 1
+fi