text/gemini; lang=en
# rss-mash
I haven’t been programming for a while but I spent a few minutes putting together a li’l rss-mash utility that takes RSS URLs on the command line and prints a combined XML file of all those items to the standard output.
I made it with zshbrev. Here is the code:
```Code
(define (sxml-url (= ->string url))
(call-with-input-request url #f html->sxml))
(define (rss-mash . (= (c map sxml-url) feeds))
(serialize-sxml
`(*TOP* (*PI* xml "version=\"1.0\" encoding=\"utf-8\"")
(rss (@ (version "2.0") (xmlns:dc "http://purl.org/dc/elements/1.1/"))
(channel
(title ,(string-intersperse
(map (o cadar (sxpath "//channel/title")) feeds)
" + "))
(description
"A mashup of feeds")
,@(sort
(apply
lset-union
(bi-each equal? (sxpath "guid"))
(map (sxpath "//item") feeds))
(bi-each > (o (c date '+%s '--date) cadar (sxpath "pubdate")))))))))
```
I already had sxml-url, which has been pretty useful both at the command line, where it prints an SXML representation of any web page, and in other zshbrev apps, like rss-mash which is the new part.
It’s also hopefully a pretty clear demo of how zshbrev turns command line arguments into function arguments, and function output into stdout in a pretty dwimmy way (it should work regardless of whether your function prints something or returns a value, like a tree or string).
This currently only works with RSS, not Atom. It’s just a li’l hack quickly thrown together.
## Installation and usage
First:
```Code
apt install chicken
chicken-install brev zshbrev
```
< Paste the code from earlier in this post (the two define calls) into ~/.zshbrev/functions, then:
```Code
zshbrev
~/.zshbrev/bin/rss-mash https://the-first/url.xml https://a-second/url.xml
```
You can add ~/.zshbrev/bin/ to your path if you wanna.
=> /zshbrev zshbrev
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