website/content/blog/blogroll-from-subscriptions.md

date	draft	math	medium_enabled	medium_post_id	tags	title
2022-12-18 13:05:49-05:00	false	false	true	913b5fa85507	Blogging	Blogroll From Subscriptions

While I was browsing around personal websites, I found a fun little piece of code from Jake Bauer's links page.

grep "xmlUrl" static/subscriptions.opml |\
sed 's/.*text=\"\(.*\)\" xmlUrl=\"\(https\?:\/\/[^\/]*\/\)\(.*\)\" .*/<li><a href=\"\2\">\1<\/a> (<a href=\"\2\3\">feed<\/a>)<\/li>/g'

This takes the subscriptions exported from yarr and generates a HTML list which you can then include in a blogroll page.

Running this script on my export from Feedbin yielded some extra metadata being shown in the HTML. For example: Joke Bauer type="rss" (Feed). So let's edit the code snippet above so that it works for my subscription export.

From my subscriptions.xml here's an example entry:

<outline text="Jake Bauer" title="Jake Bauer" type="rss" xmlUrl="https://www.paritybit.ca/feed.xml" htmlUrl="https://www.paritybit.ca/"/>

It looks like I need to extract the title, xmlUrl, and htmlUrl attributes in that specific order. I'll use the same technique from a previous post on capturing quoated strings.

grep "xmlUrl" subscriptions.xml |\
sed 's/.*title=\"\([^\"]*\)\".*xmlUrl=\"\([^\"]*\)\".*htmlUrl=\"\([^\"]*\)\".*/<li><a href=\"\3\">\1<\/a> (<a href=\"\2\">feed<\/a>)<\/li>/g'

We can then clean this up into a create_blogroll script saved within ~/.local/bin.

#!/bin/sh

set -o errexit
set -o nounset

show_usage() {
    echo "Usage: create_blogroll [subscriptions.xml]"
    exit 1
}

# Check argument count
if [ "$#" -ne 1 ]; then
    show_usage
fi

QUOTED_STR="\"\([^\"]*\)\""
XML_EXPR=".*title=$QUOTED_STR.*xmlUrl=$QUOTED_STR.*htmlUrl=$QUOTED_STR.*"
HTML_EXPR="<li><a href=\"\3\">\1<\/a> (<a href=\"\2\">feed<\/a>)<\/li>"
REPLACE_EXPR="s/$XML_EXPR/$HTML_EXPR/g"

grep "xmlUrl" "$1" | sed "$REPLACE_EXPR"