alifeee · November 21, 2024 00:22
diff --git a/randomrss.cgi b/randomrss.cgi
 #!/bin/bash
 # https://gist.github.com/alifeee/da157fcb92605d4fcdf3932aabcf56fe
 # a CGI script to get a random RSS feed from an OPML file
 # must have installed xmlstarlet
 # $ sudo apt install xmlstarlet

 echo "Content-type: text/html"
 echo ""

 cat <<HTML
 <!DOCTYPE html>
 <html>
 <head>
 <style>
 .err {
  color: red;
 }
 body {
  font-family: monospace;
 }
 .feed {
  font-size: 1rem;
 }
 pre {
  padding: 0.25rem;
  background: lightgray;
 }
 </style>
 </head>
 <body>
 <header>
 <h1>random feed picker</h1>
 <p>by <a href="https://alifeee.co.uk/">alifeee</a>, <a href="https://gist.github.com/alifeee/da157fcb92605d4fcdf3932aabcf56fe">source</a></p>
 </header>
 <main>
 <h2>upload an OPML file</h2>
 <p>most (all!?) feed readers offer an "export" feature which will give you an OPML file containing links to all your feeds.</p>
 <form enctype="multipart/form-data" method="post">
  <input type="file" id="opmlfile" name="opml file">
  <br>
  <br>
  <button type="submit">get random feed!</button>
 </form>
 </body>
 </html>
 HTML

 # wait for POST request
 if [[ "${REQUEST_METHOD}" != "POST" ]]; then
  exit 0
 fi

 # else we deal with the post request

 echo '<h2>random picker results</h2>'
 # get in_file from multipart/form-data
 in_file=$(cat /dev/stdin)
 length=$(echo "${in_file}" | wc -l)
 # remove top 3 and bottom 2 lines, form-data makes files look like this
 opml=$(echo "${in_file}" | awk 'NR>4 && NR<'"$(( $length - 1 ))"'')

 repl_html='s/&/\&amp;/g; s/</\&lt;/g; s/>/\&gt;/g; s/"/\&quot;/g; s/'"'"'/\&#39;/g'

 echo '<p>...got OPML file...</p>'
 echo "<details><summary>...show file...</summary>"
 echo '<pre>'
 echo "${opml}" | sed "${repl_html}"
 echo '</pre>'
 echo "</details>"

 # select many different things for the many formats of RSS feeds
 # to find new ones, use `xmlstarlet el -a file.xml` to list XPATHs
 declare -a XPATHS
 # atom
 # rss
 XPATHS=( \
  "//entry/link/@href" \
  "//item/link" \
 )
 IFS="|"; XPATH="${XPATHS[*]}"

 { echo "${opml}" | xmlstarlet val - > /dev/null; } || { echo "<p class=err>opml feed was invalid :(</p>"; exit 1; }

 feed_urls=$(echo "${opml}" | xmlstarlet sel -t -v '//@xmlUrl')

 echo "<p>...found" $(echo "${feed_urls}" | wc -l) "urls...</p>"
 echo "<details><summary>...show feed urls...</summary>"
 echo '<pre>'
 echo "${feed_urls}" | sed "${repl_html}"
 echo '</pre>'
 echo "</details>"

 random_url=$(echo "${feed_urls}" | sort --random-sort | head -n1)

 # for testing
 #random_url="https://sometimes.digital/feed.xml"

 echo "<p>your random feed is <a href='${random_url}'>${random_url}</a>!</p>"

 # -L to follow redirects
 feed_xml=$(curl -s -L "${random_url}")

 echo '<p>...got feed file...</p>'
 echo "<details><summary>...show file...</summary>"
 echo '<pre>'
 echo "${feed_xml}" | sed "${repl_html}"
 echo '</pre>'
 echo "</details>"

 if [ -z "${feed_xml}" ]; then
  echo "<p class=err>feed was empty :(</p>"
  exit 1
 fi
 # validate XML
 { echo "${feed_xml}" | xmlstarlet val - > /dev/null; } || { echo "<p class=err>feed was invalid :(</p>"; exit 1; }

 feed_items=$(\
  echo "${feed_xml}" | sed -E 's/ xmlns[^"=]*="[^"]*"//g' \
    | xmlstarlet sel -t -v "${XPATH}" \
    | sort | uniq
 )

 echo "<p>...in the feed I find" $(echo "${feed_items}" | wc -l) "items...</p>"
 echo "<details><summary>...show item urls...</summary>"
 echo '<ul>'
 echo "${feed_items}" | sed "${repl_html}" | awk '{printf "<li><a href=\"%s\">%s</a></li>", $0, $0}'
 echo '</ul>'
 echo "</details>"

 echo "<p>your random item is...</p>"
 random=$(echo "${feed_items}" | sort --random-sort | head -n1)
 echo "<p class=feed><a href=${random}>${random}</a></p>"

 cat <<HTML
 <p>to get another feed, refresh the page! (hopefully you will be asked to resubmit the form)</p>
 <p>or return to <a href="./randomrss.cgi">form</a></p>
 </main>
 </body>
 </html>
 HTML
	#!/bin/bash
	# https://gist.github.com/alifeee/da157fcb92605d4fcdf3932aabcf56fe
	# a CGI script to get a random RSS feed from an OPML file
	# must have installed xmlstarlet
	# $ sudo apt install xmlstarlet

	echo "Content-type: text/html"
	echo ""

	cat <<HTML
	<!DOCTYPE html>
	<html>
	<head>
	<style>
	.err {
	color: red;
	}
	body {
	font-family: monospace;
	}
	.feed {
	font-size: 1rem;
	}
	pre {
	padding: 0.25rem;
	background: lightgray;
	}
	</style>
	</head>
	<body>
	<header>
	<h1>random feed picker</h1>
	<p>by <a href="https://alifeee.co.uk/">alifeee</a>, <a href="https://gist.github.com/alifeee/da157fcb92605d4fcdf3932aabcf56fe">source</a></p>
	</header>
	<main>
	<h2>upload an OPML file</h2>
	<p>most (all!?) feed readers offer an "export" feature which will give you an OPML file containing links to all your feeds.</p>
	<form enctype="multipart/form-data" method="post">
	<input type="file" id="opmlfile" name="opml file">
	<br>
	<br>
	<button type="submit">get random feed!</button>
	</form>
	</body>
	</html>
	HTML

	# wait for POST request
	if [[ "${REQUEST_METHOD}" != "POST" ]]; then
	exit 0
	fi

	# else we deal with the post request

	echo '<h2>random picker results</h2>'
	# get in_file from multipart/form-data
	in_file=$(cat /dev/stdin)
	length=$(echo "${in_file}" \| wc -l)
	# remove top 3 and bottom 2 lines, form-data makes files look like this
	opml=$(echo "${in_file}" \| awk 'NR>4 && NR<'"$(( $length - 1 ))"'')

	repl_html='s/&/\&/g; s/</\</g; s/>/\>/g; s/"/\"/g; s/'"'"'/\'/g'

	echo '<p>...got OPML file...</p>'
	echo "<details><summary>...show file...</summary>"
	echo '<pre>'
	echo "${opml}" \| sed "${repl_html}"
	echo '</pre>'
	echo "</details>"

	# select many different things for the many formats of RSS feeds
	# to find new ones, use `xmlstarlet el -a file.xml` to list XPATHs
	declare -a XPATHS
	# atom
	# rss
	XPATHS=( \
	"//entry/link/@href" \
	"//item/link" \
	)
	IFS="\|"; XPATH="${XPATHS[*]}"

	{ echo "${opml}" \| xmlstarlet val - > /dev/null; } \|\| { echo "<p class=err>opml feed was invalid :(</p>"; exit 1; }

	feed_urls=$(echo "${opml}" \| xmlstarlet sel -t -v '//@xmlUrl')

	echo "<p>...found" $(echo "${feed_urls}" \| wc -l) "urls...</p>"
	echo "<details><summary>...show feed urls...</summary>"
	echo '<pre>'
	echo "${feed_urls}" \| sed "${repl_html}"
	echo '</pre>'
	echo "</details>"

	random_url=$(echo "${feed_urls}" \| sort --random-sort \| head -n1)

	# for testing
	#random_url="https://sometimes.digital/feed.xml"

	echo "<p>your random feed is <a href='${random_url}'>${random_url}</a>!</p>"

	# -L to follow redirects
	feed_xml=$(curl -s -L "${random_url}")

	echo '<p>...got feed file...</p>'
	echo "<details><summary>...show file...</summary>"
	echo '<pre>'
	echo "${feed_xml}" \| sed "${repl_html}"
	echo '</pre>'
	echo "</details>"

	if [ -z "${feed_xml}" ]; then
	echo "<p class=err>feed was empty :(</p>"
	exit 1
	fi
	# validate XML
	{ echo "${feed_xml}" \| xmlstarlet val - > /dev/null; } \|\| { echo "<p class=err>feed was invalid :(</p>"; exit 1; }

	feed_items=$(\
	echo "${feed_xml}" \| sed -E 's/ xmlns[^"=]="[^"]"//g' \
	\| xmlstarlet sel -t -v "${XPATH}" \
	\| sort \| uniq
	)

	echo "<p>...in the feed I find" $(echo "${feed_items}" \| wc -l) "items...</p>"
	echo "<details><summary>...show item urls...</summary>"
	echo '<ul>'
	echo "${feed_items}" \| sed "${repl_html}" \| awk '{printf "<li><a href=\"%s\">%s</a></li>", $0, $0}'
	echo '</ul>'
	echo "</details>"

	echo "<p>your random item is...</p>"
	random=$(echo "${feed_items}" \| sort --random-sort \| head -n1)
	echo "<p class=feed><a href=${random}>${random}</a></p>"

	cat <<HTML
	<p>to get another feed, refresh the page! (hopefully you will be asked to resubmit the form)</p>
	<p>or return to <a href="./randomrss.cgi">form</a></p>
	</main>
	</body>
	</html>
	HTML