Periodically fetching webcam images (JPEG) with wget and cron

download_image.sh

#!/bin/sh

# === BEGIN CONFIGURATION ===
# Capture source

url="https://www.wien.gv.at/webcam-inselcam/inselcam.jpeg"

# Capture destination and timestamp format

currentdate=`date +"%Y%m%d-%H%M%S"`
fpath="/usr/home/tsp/downimg/"
fname="donauinselwien-${currentdate}.jpg"
expectedtype="image/jpeg"
verbose=0

# Tool configuration (if not in path)

binwget="/usr/local/bin/wget"

# === END CONFIGURATION ===

# Download script follows.
# First check wget is available

if [ ! -x "${binwget}" ]; then
        echo "Error: wget is not executable or nonexistent at ${binwget}"
        return 250
fi

# Download file (quitely)

${binwget} -q -O ${fpath}${fname} ${url}

# Check result is what we want ... first validate return code
# then check filetype

if [ $? -ne 0 ]; then
        # Error. Delete file in case wget has written anything ...
        rm ${fpath}${fname}
        return 1
else
        # Check filetype
        ftype=`file --mime-type -b "${fpath}${fname}"`
        if [ "$ftype" == "${expectedtype}" ]; then
                if [ ${verbose} -ne 0 ]; then
                        echo "SUCCESS: Fetched ${url} into ${fpath}${fname} (type ${ftype})"
                fi
                return 0
        else
                # Wrong type. Delete the file.
                echo "Invalid filetype ${ftype} (expected ${expectedtype})"
                rm ${fpath}${fname}
                return 2
        fi
fi