README

Grepfeed

Filters out rss/atom feeds. Returns articles matching a pattern. The output is another valid xml feed.

What's included

a cli util grepfeed.js;
a standalone http server that shares the same engine w/ the cli util.
a web client that uses the included server as an intermediary and acts as a gui version of the cli util.

Requirements

node >= 14.17.6
GNU make

Setup

cli/server

  $ npm i grepfeed

or manually after cloning the repo:

$ NODE_ENV=production npm i

web client, that isn't included in the npm pkg
```
$ npm i
$ make
```

How it works

lib/feed.js contains all the code that parses & transforms xml feeds. Its core is Grep class--a Transform stream:

readable_stream.pipe(<our filter>).pipe(writable_stream)

cli

cli/grepfeed extends Grep to override several methods where it's convenient to write the output in any format one wants. 3 interfaces are included: text-only (the default), json, xml. The latter produces a valid rss 2.0 feed. E.g.

$ curl http://example.com/rss | cli/grepfeed.js apple -d=2016 -x

parses the input feed, selects only articles written in 2016 or newer that match the regexp pattern /apple/. -x means xml output.

Usage: grepfeed.js [opt] [PATTERN] < xml

  -e      print only articles w/ enclosures
  -n NUM  number of articles to print
  -x      xml output
  -j      json output
  -m      print only meta
  -V      program version

Filter by:

  -d      [-]date[,date]
  -c      categories

Or/and search for a regexp PATTERN in each rss article & print the
matching ones. The internal order of the search: title, summary,
description, author.

  -v      invert match

server

Acts as a proxy: downloads a requested feed & returns the filtered xml. Query params match cli/grepfeed.js command line interface. To start a server, run

$ server/index.js .

(To select a diff port, use PORT env var.)

This following example yields the same xml as in the cli/grepfeed.js case, only does it through http:

$ curl '127.0.0.1:3000/api/?_=apple&d=2016&url=http%3A%2F%2Fexample.com%2Frss'

Notice d means -d in the cli/grepfeed.js example, -x doesn't make sense here, _ means the 1st command line arg, apple in this case. The server doesn't invoke cli/grepfeed.js program; they both use minimist to parse command options, thus the perceived similarity in the behaviour.

web client

A web client is a simple React app (chrome/ff only) that internally talks to the above server. If you have built the web client, pass to the server the dir w/ the compiled client files:

$ server/index.js _out

& open http://127.0.0.1:3000 in a browser.

License

MIT.

Have fun!

Usage no npm install needed!