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product-pricelimiter.sh use getopts (breaking change)
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- Major refactor that use getopts instead of positional arguments.
  This is required to make both MaxPrice & N optional.
- Print all error regarding invalid or missing arguments at once.
- Better wording for potential prices (float numbers) in selector.
- More complete explanation for the HTML element (-s Selector).
- If bc is installed, add 2 decimals to all prices.
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@oh2fih
oh2fih committed Aug 8, 2024
1 parent 0b79900 commit 3f7612b
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2 changes: 1 addition & 1 deletion README.md
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Expand Up @@ -18,7 +18,7 @@ Miscellaneous scripts for different purposes. Mostly unrelated to each other.
| Infosec<br>Automation | [`make-mac-prefixes.py`](bin/make-mac-prefixes.py)<br>Python 3 | Processes registered MAC address prefixes from [IEEE MA-L Assignments (CSV)](https://standards.ieee.org/products-programs/regauth/) (stdin) to Nmap's [`nmap-mac-prefixes`](https://github.com/nmap/nmap/blob/master/nmap-mac-prefixes) (stdout) with a few additional unregistered OUIs.<br>`curl https://standards-oui.ieee.org/oui/oui.csv \| make-mac-prefixes.py > nmap-mac-prefixes` |
| WordPress | [`test-cache-enabler.py`](bin/test-cache-enabler.py)<br>Python 3 | Tests whether the Cache Enabler by KeyCDN (WordPress) is working properly on the URLs given as arguments.<br>`test-cache-enabler.py https://example.com [...]` |
| Web | [`detect-modified-html-element.sh`](bin/detect-modified-html-element.sh)<br>Shell (bash) | Checks HTML element changes on a web page since last run. Configured via environment variables.<br>Recommended to be executed as a SystemD [service](systemd/detect-modified-html-element.service.example). |
| Web | [`product-pricelimiter.sh`](bin/product-pricelimiter.sh)<br>Shell (bash) | Compare product price on a web page with a given maximum price. Use, e.g., developer tools on your browser to find the HTML element containing the price.<br>`product-pricelimiter.sh ProductURL Element [MaxPrice] [N]` |
| Web | [`product-pricelimiter.sh`](bin/product-pricelimiter.sh)<br>Shell (bash) | Compare product price on a web page with a given maximum price. Use, e.g., developer tools on your browser to find the HTML element containing the price.<br>`product-pricelimiter.sh -u ProductURL -s Selector [-m MaxPrice] [-n N]` |
| Web | <del>`koronarokotusaika.sh`</del><br>Shell (bash) | This script has been removed as koronarokotusaika.fi (bookcovidvaccine.fi) has been shut down on April 28, 2023. |
| Web | <del>`xxl-product-pricelimiter.sh`</del><br>Shell (bash) | This script has been replaced by the generalized [`product-pricelimiter.sh`](bin/product-pricelimiter.sh) as the HTML structure of XXL.fi has changed. |

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123 changes: 75 additions & 48 deletions bin/product-pricelimiter.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,14 @@ read -r -d '' USAGE << EOM
# ------------------------------------------------------------------------------
# Compare product price on a web page with a given maximum price.
#
# Usage: product-pricelimiter.sh ProductURL Element [MaxPrice] [N]
# Usage: product-pricelimiter.sh -u ProductURL -s Selector [-m MaxPrice] [-n N]
#
# ProductURL web page URL to fetch the current price from
# Element the HTML element containing the price (#id or .class)
# MaxPrice maximum price used for comparison; float number
# N in case there are multiple floats in the element, choose Nth
# -u ProductURL web page URL to fetch the current price from
# -s Selector the HTML element containing the price; search the price from
# elements or attributes that match a (CSS) selector (e.g.
# h3, #id, .class or combinations like "#id div.class")
# -m MaxPrice maximum price used for comparison; float number
# -n N in case there are multiple floats in the element, choose Nth
#
# Exit codes:
#
Expand All @@ -28,41 +30,62 @@ EOM
UA="Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
UA+="(KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36"

# Test the inputs...

if [ "$#" -lt 2 ]; then
echo -e "\033[0;33m${USAGE}\033[0m" >&2
exit 1
fi

producturl="$1"
selector="$2"

if [ "$#" -ge 3 ]; then
if [[ "$3" =~ ^[+-]?[0-9]+[\.,]?[0-9]*$ ]] 2>/dev/null; then
maxprice=$(printf "%s" "$3" | sed 's/,/./g')
else
echo -e "\033[0;31mMax price should be a (float) number!\033[0m" >&2
exit 1
fi
# Validate arguments

n=1
INVALID=0

while getopts ":hu:s:m:n:" opt; do
case ${opt} in
h)
# Allow -h for help; invalid or missing arguments prints the usage anyway.
;;
u)
producturl="$OPTARG"
regex='http(s)?://[-A-Za-z0-9\+&@#/%?=~_|!:,.;]*[-A-Za-z0-9\+&@#/%=~_|]'
if ! [[ $producturl =~ $regex ]]; then
echo -e "\033[0;31mThe argument for -u was not a valid URL!\033[0m" >&2
echo -e "\033[0;31m(Expecting regex: ${regex} )\033[0m" >&2
((INVALID=INVALID+1))
fi
;;
s)
selector="$OPTARG"
;;
m)
if [[ "$OPTARG" =~ ^[+-]?[0-9]+[\.,]?[0-9]*$ ]] 2>/dev/null; then
maxprice=$(printf "%s" "$OPTARG" | sed 's/,/./g')
else
echo -e "\033[0;31mMaxPrice (-m) should be a (float) number!\033[0m" >&2
((INVALID=INVALID+1))
fi
;;
n)
if [[ "$OPTARG" =~ ^[0-9]+$ ]] ; then
n="$OPTARG"
else
echo -e "\033[0;31mN (-n) should be an integer!\033[0m" >&2
((INVALID=INVALID+1))
fi
;;
\?)
echo -e "\033[0;31mInvalid option: -${OPTARG}\033[0m" >&2
((INVALID=INVALID+1))
;;
:)
echo -e "\033[0;31mOption -${OPTARG} requires an argument\033[0m" >&2
((INVALID=INVALID+1))
;;
esac
done

if [ -z "$producturl" ] || [ -z "$selector" ]; then
echo -e "\033[0;31mMissing mandatory options (-u or -s)!\033[0m" >&2
((INVALID=INVALID+1))
fi

if [ "$#" -ge 4 ]; then
if [[ "$4" =~ ^[0-9]+$ ]] ; then
n="$4"
else
echo -e "\033[0;31mN should be an integer!\033[0m" >&2
exit 1
fi
else
n=1
fi

# Validate the URL

regex='(https?)://[-A-Za-z0-9\+&@#/%?=~_|!:,.;]*[-A-Za-z0-9\+&@#/%=~_|]'
if ! [[ $producturl =~ $regex ]]; then
echo -e "\033[0;31mThe first argument was not a valid URL!\033[0m" >&2
if [ "$INVALID" -gt 0 ]; then
echo -e "\033[0;33m${USAGE}\033[0m" >&2
exit 1
fi

Expand Down Expand Up @@ -114,10 +137,12 @@ prices=$(
| sed 's/,/./g' \
)
if [ "$prices" == "" ]; then
echo -e "\033[0;31mPrices not found from \"${selector}\"!\033[0m" >&2
echo -ne "\033[0;31mPotential prices (float numbers) " >&2
echo -e "not found in '${selector}'!\033[0m" >&2
exit 1
else
echo -e "\033[0;32mPrices (float numbers) in \"${selector}\":\033[0m" >&2
echo -ne "\033[0;32mPotential prices (float numbers) " >&2
echo -e "in '${selector}':\033[0m" >&2
export GREP_COLORS='ms=00;32'
echo "$prices" | cat -n | grep --color=always -e "^" -e "\s${n}\s.*" >&2
fi
Expand All @@ -130,14 +155,16 @@ if (( n > count )); then
fi

price=$(echo "$prices" | head -n "$n" | tail -n 1)
echo -e "\033[0;32mThe price (#${n} in \"${selector}\") is now ${price}\033[0m"
if command -v bc &> /dev/null; then
price=$(echo "scale=2; ${price}/1" | bc | sed 's/^\./0./')
fi
echo -e "\033[0;32mThe price (#${n} in '${selector}') is now ${price}\033[0m"

# Compare (Nth or first) price with the limit.
# If installed, use bc for more accurate comparison.

if [ "$#" -ge 3 ]; then
if [ -n "$maxprice" ]; then
if command -v bc &> /dev/null; then
price=$(echo "scale=2; ${price}/1" | bc | sed 's/^\./0./')
maxprice=$(echo "scale=2; ${maxprice}/1" | bc | sed 's/^\./0./')
diff=$(
echo "scale=2; (${maxprice} - ${price})/1" \
Expand All @@ -146,11 +173,11 @@ if [ "$#" -ge 3 ]; then
| sed 's/^\./0./'
)
if (( $(echo "${maxprice} < ${price}" | bc -l) )); then
isLower=0
isLowerOrEqual=0
echo -ne "\033[0;33mMaximum price ${maxprice}; "
echo -e "the price is ${diff} higher\033[0m"
else
isLower=1
isLowerOrEqual=1
echo -ne "\033[0;32mMaximum price ${maxprice}; "
echo -e "the price is ${diff} lower\033[0m"
fi
Expand All @@ -159,13 +186,13 @@ if [ "$#" -ge 3 ]; then
echo -e "comparison; using a fallback solution!\033[0m" >&2
lower=$(printf "%s\n%s" "$price" "$maxprice" | sort -g | head -1)
if [ "$lower" = "$price" ]; then
isLower=1
isLowerOrEqual=1
else
isLower=0
isLowerOrEqual=0
fi
fi

if [ "$maxprice" == "$price" ] || [ "$isLower" = 1 ]; then
if [ "$maxprice" == "$price" ] || [ "$isLowerOrEqual" = 1 ]; then
echo -e "\033[0;32mGood to buy!\033[0m"
exit 0
else
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